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  • Adding a hyperlink in a client report definition file (RDLC)

    - by rajbk
    This post shows you how to add a hyperlink to your RDLC report. In a previous post, I showed you how to create an RDLC report. We have been given the requirement to the report we created earlier, the Northwind Product report, to add a column that will contain hyperlinks which are unique per row.  The URLs will be RESTful with the ProductID at the end. Clicking on the URL will take them to a website like so: http://localhost/products/3  where 3 is the primary key of the product row clicked on. To start off, open the RDLC and add a new column to the product table.   Add text to the header (Details) and row (Product Website). Right click on the row (not header) and select “TextBox properties” Select Action – Go to URL. You could hard code a URL here but what we need is a URL that changes based on the ProductID.   Click on the expression button (fx) The expression builder gives you access to several functions and constants including the fields in your dataset. See this reference for more details: Common Expressions for ReportViewer Reports. Add the following expression: = "http://localhost/products/" & Fields!ProductID.Value Click OK to exit the Expression Builder. The report will not render because hyperlinks are disabled by default in the ReportViewer control. To enable it, add the following in your page load event (where rvProducts is the ID of your ReportViewerControl): protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { rvProducts.LocalReport.EnableHyperlinks = true; } } We want our links to open in a new window so set the HyperLinkTarget property of the ReportViewer control to “_blank”   We are done adding hyperlinks to our report. Clicking on the links for each product pops open a new windows. The URL has the ProductID added at the end. Enjoy!

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  • ASP.NET MVC Paging/Sorting/Filtering using the MVCContrib Grid and Pager

    - by rajbk
    This post walks you through creating a UI for paging, sorting and filtering a list of data items. It makes use of the excellent MVCContrib Grid and Pager Html UI helpers. A sample project is attached at the bottom. Our UI will eventually look like this. The application will make use of the Northwind database. The top portion of the page has a filter area region. The filter region is enclosed in a form tag. The select lists are wired up with jQuery to auto post back the form. The page has a pager region at the top and bottom of the product list. The product list has a link to display more details about a given product. The column headings are clickable for sorting and an icon shows the sort direction. Strongly Typed View Models The views are written to expect strongly typed objects. We suffix these strongly typed objects with ViewModel since they are designed specifically for passing data down to the view.  The following listing shows the ProductViewModel. This class will be used to hold information about a Product. We use attributes to specify if the property should be hidden and what its heading in the table should be. This metadata will be used by the MvcContrib Grid to render the table. Some of the properties are hidden from the UI ([ScaffoldColumn(false)) but are needed because we will be using those for filtering when writing our LINQ query. public ActionResult Index( string productName, int? supplierID, int? categoryID, GridSortOptions gridSortOptions, int? page) {   var productList = productRepository.GetProductsProjected();   // Set default sort column if (string.IsNullOrWhiteSpace(gridSortOptions.Column)) { gridSortOptions.Column = "ProductID"; }   // Filter on SupplierID if (supplierID.HasValue) { productList = productList.Where(a => a.SupplierID == supplierID); }   // Filter on CategoryID if (categoryID.HasValue) { productList = productList.Where(a => a.CategoryID == categoryID); }   // Filter on ProductName if (!string.IsNullOrWhiteSpace(productName)) { productList = productList.Where(a => a.ProductName.Contains(productName)); }   // Create all filter data and set current values if any // These values will be used to set the state of the select list and textbox // by sending it back to the view. var productFilterViewModel = new ProductFilterViewModel(); productFilterViewModel.SelectedCategoryID = categoryID ?? -1; productFilterViewModel.SelectedSupplierID = supplierID ?? -1; productFilterViewModel.Fill();   // Order and page the product list var productPagedList = productList .OrderBy(gridSortOptions.Column, gridSortOptions.Direction) .AsPagination(page ?? 1, 10);     var productListContainer = new ProductListContainerViewModel { ProductPagedList = productPagedList, ProductFilterViewModel = productFilterViewModel, GridSortOptions = gridSortOptions };   return View(productListContainer); } The following diagram shows the rest of the key ViewModels in our design. We have a container class called ProductListContainerViewModel which has nested classes. The ProductPagedList is of type IPagination<ProductViewModel>. The MvcContrib expects the IPagination<T> interface to determine the page number and page size of the collection we are working with. You convert any IEnumerable<T> into an IPagination<T> by calling the AsPagination extension method in the MvcContrib library. It also creates a paged set of type ProductViewModel. The ProductFilterViewModel class will hold information about the different select lists and the ProductName being searched on. It will also hold state of any previously selected item in the lists and the previous search criteria (you will recall that this type of state information was stored in Viewstate when working with WebForms). With MVC there is no state storage and so all state has to be fetched and passed back to the view. The GridSortOptions is a type defined in the MvcContrib library and is used by the Grid to determine the current column being sorted on and the current sort direction. The following shows the view and partial views used to render our UI. The Index view expects a type ProductListContainerViewModel which we described earlier. <%Html.RenderPartial("SearchFilters", Model.ProductFilterViewModel); %> <% Html.RenderPartial("Pager", Model.ProductPagedList); %> <% Html.RenderPartial("SearchResults", Model); %> <% Html.RenderPartial("Pager", Model.ProductPagedList); %> The View contains a partial view “SearchFilters” and passes it the ProductViewFilterContainer. The SearchFilter uses this Model to render all the search lists and textbox. The partial view “Pager” uses the ProductPageList which implements the interface IPagination. The “Pager” view contains the MvcContrib Pager helper used to render the paging information. This view is repeated twice since we want the pager UI to be available at the top and bottom of the product list. The Pager partial view is located in the Shared directory so that it can be reused across Views. The partial view “SearchResults” uses the ProductListContainer model. This partial view contains the MvcContrib Grid which needs both the ProdctPagedList and GridSortOptions to render itself. The Controller Action An example of a request like this: /Products?productName=test&supplierId=29&categoryId=4. The application receives this GET request and maps it to the Index method of the ProductController. Within the action we create an IQueryable<ProductViewModel> by calling the GetProductsProjected() method. /// <summary> /// This method takes in a filter list, paging/sort options and applies /// them to an IQueryable of type ProductViewModel /// </summary> /// <returns> /// The return object is a container that holds the sorted/paged list, /// state for the fiters and state about the current sorted column /// </returns> public ActionResult Index( string productName, int? supplierID, int? categoryID, GridSortOptions gridSortOptions, int? page) {   var productList = productRepository.GetProductsProjected();   // Set default sort column if (string.IsNullOrWhiteSpace(gridSortOptions.Column)) { gridSortOptions.Column = "ProductID"; }   // Filter on SupplierID if (supplierID.HasValue) { productList.Where(a => a.SupplierID == supplierID); }   // Filter on CategoryID if (categoryID.HasValue) { productList = productList.Where(a => a.CategoryID == categoryID); }   // Filter on ProductName if (!string.IsNullOrWhiteSpace(productName)) { productList = productList.Where(a => a.ProductName.Contains(productName)); }   // Create all filter data and set current values if any // These values will be used to set the state of the select list and textbox // by sending it back to the view. var productFilterViewModel = new ProductFilterViewModel(); productFilterViewModel.SelectedCategoryID = categoryID ?? -1; productFilterViewModel.SelectedSupplierID = supplierID ?? -1; productFilterViewModel.Fill();   // Order and page the product list var productPagedList = productList .OrderBy(gridSortOptions.Column, gridSortOptions.Direction) .AsPagination(page ?? 1, 10);     var productListContainer = new ProductListContainerViewModel { ProductPagedList = productPagedList, ProductFilterViewModel = productFilterViewModel, GridSortOptions = gridSortOptions };   return View(productListContainer); } The supplier, category and productname filters are applied to this IQueryable if any are present in the request. The ProductPagedList class is created by applying a sort order and calling the AsPagination method. Finally the ProductListContainerViewModel class is created and returned to the view. You have seen how to use strongly typed views with the MvcContrib Grid and Pager to render a clean lightweight UI with strongly typed views. You also saw how to use partial views to get data from the strongly typed model passed to it from the parent view. The code also shows you how to use jQuery to auto post back. The sample is attached below. Don’t forget to change your connection string to point to the server containing the Northwind database. NorthwindSales_MvcContrib.zip My name is Kobayashi. I work for Keyser Soze.

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  • ASP.NET MVC Paging/Sorting/Filtering a list using ModelMetadata

    - by rajbk
    This post looks at how to control paging, sorting and filtering when displaying a list of data by specifying attributes in your Model using the ASP.NET MVC framework and the excellent MVCContrib library. It also shows how to hide/show columns and control the formatting of data using attributes.  This uses the Northwind database. A sample project is attached at the end of this post. Let’s start by looking at a class called ProductViewModel. The properties in the class are decorated with attributes. The OrderBy attribute tells the system that the Model can be sorted using that property. The SearchFilter attribute tells the system that filtering is allowed on that property. Filtering type is set by the  FilterType enum which currently supports Equals and Contains. The ScaffoldColumn property specifies if a column is hidden or not The DisplayFormat specifies how the data is formatted. public class ProductViewModel { [OrderBy(IsDefault = true)] [ScaffoldColumn(false)] public int? ProductID { get; set; }   [SearchFilter(FilterType.Contains)] [OrderBy] [DisplayName("Product Name")] public string ProductName { get; set; }   [OrderBy] [DisplayName("Unit Price")] [DisplayFormat(DataFormatString = "{0:c}")] public System.Nullable<decimal> UnitPrice { get; set; }   [DisplayName("Category Name")] public string CategoryName { get; set; }   [SearchFilter] [ScaffoldColumn(false)] public int? CategoryID { get; set; }   [SearchFilter] [ScaffoldColumn(false)] public int? SupplierID { get; set; }   [OrderBy] public bool Discontinued { get; set; } } Before we explore the code further, lets look at the UI.  The UI has a section for filtering the data. The column headers with links are sortable. Paging is also supported with the help of a pager row. The pager is rendered using the MVCContrib Pager component. The data is displayed using a customized version of the MVCContrib Grid component. The customization was done in order for the Grid to be aware of the attributes mentioned above. Now, let’s look at what happens when we perform actions on this page. The diagram below shows the process: The form on the page has its method set to “GET” therefore we see all the parameters in the query string. The query string is shown in blue above. This query gets routed to an action called Index with parameters of type ProductViewModel and PageSortOptions. The parameters in the query string get mapped to the input parameters using model binding. The ProductView object created has the information needed to filter data while the PageAndSorting object is used for paging and sorting the data. The last block in the figure above shows how the filtered and paged list is created. We receive a product list from our product repository (which is of type IQueryable) and first filter it by calliing the AsFiltered extension method passing in the productFilters object and then call the AsPagination extension method passing in the pageSort object. The AsFiltered extension method looks at the type of the filter instance passed in. It skips properties in the instance that do not have the SearchFilter attribute. For properties that have the SearchFilter attribute, it adds filter expression trees to filter against the IQueryable data. The AsPagination extension method looks at the type of the IQueryable and ensures that the column being sorted on has the OrderBy attribute. If it does not find one, it looks for the default sort field [OrderBy(IsDefault = true)]. It is required that at least one attribute in your model has the [OrderBy(IsDefault = true)]. This because a person could be performing paging without specifying an order by column. As you may recall the LINQ Skip method now requires that you call an OrderBy method before it. Therefore we need a default order by column to perform paging. The extension method adds a order expressoin tree to the IQueryable and calls the MVCContrib AsPagination extension method to page the data. Implementation Notes Auto Postback The search filter region auto performs a get request anytime the dropdown selection is changed. This is implemented using the following jQuery snippet $(document).ready(function () { $("#productSearch").change(function () { this.submit(); }); }); Strongly Typed View The code used in the Action method is shown below: public ActionResult Index(ProductViewModel productFilters, PageSortOptions pageSortOptions) { var productPagedList = productRepository.GetProductsProjected().AsFiltered(productFilters).AsPagination(pageSortOptions);   var productViewFilterContainer = new ProductViewFilterContainer(); productViewFilterContainer.Fill(productFilters.CategoryID, productFilters.SupplierID, productFilters.ProductName);   var gridSortOptions = new GridSortOptions { Column = pageSortOptions.Column, Direction = pageSortOptions.Direction };   var productListContainer = new ProductListContainerModel { ProductPagedList = productPagedList, ProductViewFilterContainer = productViewFilterContainer, GridSortOptions = gridSortOptions };   return View(productListContainer); } As you see above, the object that is returned to the view is of type ProductListContainerModel. This contains all the information need for the view to render the Search filter section (including dropdowns),  the Html.Pager (MVCContrib) and the Html.Grid (from MVCContrib). It also stores the state of the search filters so that they can recreate themselves when the page reloads (Viewstate, I miss you! :0)  The class diagram for the container class is shown below.   Custom MVCContrib Grid The MVCContrib grid default behavior was overridden so that it would auto generate the columns and format the columns based on the metadata and also make it aware of our custom attributes (see MetaDataGridModel in the sample code). The Grid ensures that the ShowForDisplay on the column is set to true This can also be set by the ScaffoldColumn attribute ref: http://bradwilson.typepad.com/blog/2009/10/aspnet-mvc-2-templates-part-2-modelmetadata.html) Column headers are set using the DisplayName attribute Column sorting is set using the OrderBy attribute. The data is formatted using the DisplayFormat attribute. Generic Extension methods for Sorting and Filtering The extension method AsFiltered takes in an IQueryable<T> and uses expression trees to query against the IQueryable data. The query is constructed using the Model metadata and the properties of the T filter (productFilters in our case). Properties in the Model that do not have the SearchFilter attribute are skipped when creating the filter expression tree.  It returns an IQueryable<T>. The extension method AsPagination takes in an IQuerable<T> and first ensures that the column being sorted on has the OrderBy attribute. If not, we look for the default OrderBy column ([OrderBy(IsDefault = true)]). We then build an expression tree to sort on this column. We finally hand off the call to the MVCContrib AsPagination which returns an IPagination<T>. This type as you can see in the class diagram above is passed to the view and used by the MVCContrib Grid and Pager components. Custom Provider To get the system to recognize our custom attributes, we create our MetadataProvider as mentioned in this article (http://bradwilson.typepad.com/blog/2010/01/why-you-dont-need-modelmetadataattributes.html) protected override ModelMetadata CreateMetadata(IEnumerable<Attribute> attributes, Type containerType, Func<object> modelAccessor, Type modelType, string propertyName) { ModelMetadata metadata = base.CreateMetadata(attributes, containerType, modelAccessor, modelType, propertyName);   SearchFilterAttribute searchFilterAttribute = attributes.OfType<SearchFilterAttribute>().FirstOrDefault(); if (searchFilterAttribute != null) { metadata.AdditionalValues.Add(Globals.SearchFilterAttributeKey, searchFilterAttribute); }   OrderByAttribute orderByAttribute = attributes.OfType<OrderByAttribute>().FirstOrDefault(); if (orderByAttribute != null) { metadata.AdditionalValues.Add(Globals.OrderByAttributeKey, orderByAttribute); }   return metadata; } We register our MetadataProvider in Global.asax.cs. protected void Application_Start() { AreaRegistration.RegisterAllAreas();   RegisterRoutes(RouteTable.Routes);   ModelMetadataProviders.Current = new MvcFlan.QueryModelMetaDataProvider(); } Bugs, Comments and Suggestions are welcome! You can download the sample code below. This code is purely experimental. Use at your own risk. Download Sample Code (VS 2010 RTM) MVCNorthwindSales.zip

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  • Running ASP.NET Webforms and ASP.NET MVC side by side

    - by rajbk
    One of the nice things about ASP.NET MVC and its older brother ASP.NET WebForms is that they are both built on top of the ASP.NET runtime environment. The advantage of this is that, you can still run them side by side even though MVC and WebForms are different frameworks. Another point to note is that with the release of the ASP.NET routing in .NET 3.5 SP1, we are able to create SEO friendly URLs that do not map to specific files on disk. The routing is part of the core runtime environment and therefore can be used by both WebForms and MVC. To run both frameworks side by side, we could easily create a separate folder in your MVC project for all our WebForm files and be good to go. What this post shows you instead, is how to have an MVC application with WebForm pages  that both use a common master page and common routing for SEO friendly URLs.  A sample project that shows WebForms and MVC running side by side is attached at the bottom of this post. So why would we want to run WebForms and MVC in the same project?  WebForms come with a lot of nice server controls that provide a lot of functionality. One example is the ReportViewer control. Using this control and client report definition files (RDLC), we can create rich interactive reports (with charting controls). I show you how to use the ReportViewer control in a WebForm project here :  Creating an ASP.NET report using Visual Studio 2010. We can create even more advanced reports by using SQL reporting services that can also be rendered by the ReportViewer control. Now, consider the sample MVC application I blogged about called ASP.NET MVC Paging/Sorting/Filtering using the MVCContrib Grid and Pager. Assume you were given the requirement to add a UI to the MVC application where users could interact with a report and be given the option to export the report to Excel, PDF or Word. How do you go about doing it?   This is a perfect scenario to use the ReportViewer control and RDLCs. As you saw in the post on creating the ASP.NET report, the ReportViewer control is a Web Control and is designed to be run in a WebForm project with dependencies on, amongst others, a ScriptManager control and the beloved Viewstate.  Since MVC and WebForm both run under the same runtime, the easiest thing to is to add the WebForm application files (index.aspx, rdlc, related class files) into our MVC project. You can copy the files over from the WebForm project into the MVC project. Create a new folder in our MVC application called CommonReports. Add the index.aspx and rdlc file from the Webform project   Right click on the Index.aspx file and convert it to a web application. This will add the index.aspx.designer.cs file (this step is not required if you are manually adding a WebForm aspx file into the MVC project).    Verify that all the type names for the ObjectDataSources in code behind to point to the correct ProductRepository and fix any compiler errors. Right click on Index.aspx and select “View in browser”. You should see a screen like the one below:   There are two issues with our page. It does not use our site master page and the URL is not SEO friendly. Common Master Page The easiest way to use master pages with both MVC and WebForm pages is to have a common master page that each inherits from as shown below. The reason for this is most WebForm controls require them to be inside a Form control and require ControlState or ViewState. ViewMasterPages used in MVC, on the other hand, are designed to be used with content pages that derive from ViewPage with Viewstate turned off. By having a separate master page for MVC and WebForm that inherit from the Root master page,, we can set properties that are specific to each. For example, in the Webform master, we can turn on ViewState, add a form tag etc. Another point worth noting is that if you set a WebForm page to use a MVC site master page, you may run into errors like the following: A ViewMasterPage can be used only with content pages that derive from ViewPage or ViewPage<TViewItem> or Control 'MainContent_MyButton' of type 'Button' must be placed inside a form tag with runat=server. Since the ViewMasterPage inherits from MasterPage as seen below, we make our Root.master inherit from MasterPage, MVC.master inherit from ViewMasterPage and Webform.master inherits from MasterPage. We define the attributes on the master pages like so: Root.master <%@ Master Inherits="System.Web.UI.MasterPage"  … %> MVC.master <%@ Master MasterPageFile="~/Views/Shared/Root.Master" Inherits="System.Web.Mvc.ViewMasterPage" … %> WebForm.master <%@ Master MasterPageFile="~/Views/Shared/Root.Master" Inherits="NorthwindSales.Views.Shared.Webform" %> Code behind: public partial class Webform : System.Web.UI.MasterPage {} We make changes to our reports aspx file to use the Webform.master. See the source of the master pages in the sample project for a better understanding of how they are connected. SEO friendly links We want to create SEO friendly links that point to our report. A request to /Reports/Products should render the report located in ~/CommonReports/Products.aspx. Simillarly to support future reports, a request to /Reports/Sales should render a report in ~/CommonReports/Sales.aspx. Lets start by renaming our index.aspx file to Products.aspx to be consistent with our routing criteria above. As mentioned earlier, since routing is part of the core runtime environment, we ca easily create a custom route for our reports by adding an entry in Global.asax. public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}");   //Custom route for reports routes.MapPageRoute( "ReportRoute", // Route name "Reports/{reportname}", // URL "~/CommonReports/{reportname}.aspx" // File );     routes.MapRoute( "Default", // Route name "{controller}/{action}/{id}", // URL with parameters new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults ); } With our custom route in place, a request to Reports/Employees will render the page at ~/CommonReports/Employees.aspx. We make this custom route the first entry since the routing system walks the table from top to bottom, and the first route to match wins. Note that it is highly recommended that you write unit tests for your routes to ensure that the mappings you defined are correct. Common Menu Structure The master page in our original MVC project had a menu structure like so: <ul id="menu"> <li> <%=Html.ActionLink("Home", "Index", "Home") %></li> <li> <%=Html.ActionLink("Products", "Index", "Products") %></li> <li> <%=Html.ActionLink("Help", "Help", "Home") %></li> </ul> We want this menu structure to be common to all pages/views and hence should reside in Root.master. Unfortunately the Html.ActionLink helpers will not work since Root.master inherits from MasterPage which does not have the helper methods available. The quickest way to resolve this issue is to use RouteUrl expressions. Using  RouteUrl expressions, we can programmatically generate URLs that are based on route definitions. By specifying parameter values and a route name if required, we get back a URL string that corresponds to a matching route. We move our menu structure to Root.master and change it to use RouteUrl expressions: <ul id="menu"> <li> <asp:HyperLink ID="hypHome" runat="server" NavigateUrl="<%$RouteUrl:routename=default,controller=home,action=index%>">Home</asp:HyperLink></li> <li> <asp:HyperLink ID="hypProducts" runat="server" NavigateUrl="<%$RouteUrl:routename=default,controller=products,action=index%>">Products</asp:HyperLink></li> <li> <asp:HyperLink ID="hypReport" runat="server" NavigateUrl="<%$RouteUrl:routename=ReportRoute,reportname=products%>">Product Report</asp:HyperLink></li> <li> <asp:HyperLink ID="hypHelp" runat="server" NavigateUrl="<%$RouteUrl:routename=default,controller=home,action=help%>">Help</asp:HyperLink></li> </ul> We are done adding the common navigation to our application. The application now uses a common theme, routing and navigation structure. Conclusion We have seen how to do the following through this post Add a WebForm page from a WebForm project to an existing ASP.NET MVC application Use a common master page for both WebForm and MVC pages Use routing for SEO friendly links Use a common menu structure for both WebForm and MVC. The sample project is attached below. Version: VS 2010 RTM Remember to change your connection string to point to your Northwind database NorthwindSalesMVCWebform.zip

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  • ActionResult types in MVC2

    - by rajbk
    In ASP.NET MVC, incoming browser requests gets mapped to a controller action method. The action method returns a type of ActionResult in response to the browser request. A basic example is shown below: public class HomeController : Controller { public ActionResult Index() { return View(); } } Here we have an action method called Index that returns an ActionResult. Inside the method we call the View() method on the base Controller. The View() method, as you will see shortly, is a method that returns a ViewResult. The ActionResult class is the base class for different controller results. The following diagram shows the types derived from the ActionResult type. ASP.NET has a description of these methods ContentResult – Represents a text result. EmptyResult – Represents no result. FileContentResult – Represents a downloadable file (with the binary content). FilePathResult – Represents a downloadable file (with a path). FileStreamResult – Represents a downloadable file (with a file stream). JavaScriptResult – Represents a JavaScript script. JsonResult – Represents a JavaScript Object Notation result that can be used in an AJAX application. PartialViewResult – Represents HTML and markup rendered by a partial view. RedirectResult – Represents a redirection to a new URL. RedirectToRouteResult – Represents a result that performs a redirection by using the specified route values dictionary. ViewResult – Represents HTML and markup rendered by a view. To return the types shown above, you call methods that are available in the Controller base class. A list of these methods are shown below.   Methods without an ActionResult return type The MVC framework will translate action methods that do not return an ActionResult into one. Consider the HomeController below which has methods that do not return any ActionResult types. The methods defined return an int, object and void respectfully. public class HomeController : Controller { public int Add(int x, int y) { return x + y; }   public Employee GetEmployee() { return new Employee(); }   public void DoNothing() { } } When a request comes in, the Controller class hands internally uses a ControllerActionInvoker class which inspects the action parameters and invokes the correct action method. The CreateActionResult method in the ControllerActionInvoker class is used to return an ActionResult. This method is shown below. If the result of the action method is null, an EmptyResult instance is returned. If the result is not of type ActionResult, the result is converted to a string and returned as a ContentResult. protected virtual ActionResult CreateActionResult(ControllerContext controllerContext, ActionDescriptor actionDescriptor, object actionReturnValue) { if (actionReturnValue == null) { return new EmptyResult(); }   ActionResult actionResult = (actionReturnValue as ActionResult) ?? new ContentResult { Content = Convert.ToString(actionReturnValue, CultureInfo.InvariantCulture) }; return actionResult; }   In the HomeController class above, the DoNothing method will return an instance of the EmptyResult() Renders an empty webpage the GetEmployee() method will return a ContentResult which contains a string that represents the current object Renders the text “MyNameSpace.Controllers.Employee” without quotes. the Add method for a request of /home/add?x=3&y=5 returns a ContentResult Renders the text “8” without quotes. Unit Testing The nice thing about the ActionResult types is in unit testing the controller. We can, without starting a web server, create an instance of the Controller, call the methods and verify that the type returned is the expected ActionResult type. We can then inspect the returned type properties and confirm that it contains the expected values. Enjoy! Sulley: Hey, Mike, this might sound crazy but I don't think that kid's dangerous. Mike: Really? Well, in that case, let's keep it. I always wanted a pet that could kill me.

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  • CascadingDropDown jQuery Plugin for ASP.NET MVC

    - by rajbk
    CascadingDropDown is a jQuery plugin that can be used by a select list to get automatic population using AJAX. A sample ASP.NET MVC project is attached at the bottom of this post.   Usage The code below shows two select lists : <select id="customerID" name="customerID"> <option value="ALFKI">Maria Anders</option> <option value="ANATR">Ana Trujillo</option> <option value="ANTON">Antonio Moreno</option> </select>   <select id="orderID" name="orderID"> </select> When a customer is selected in the first select list, the second list will auto populate itself with the following code: $("#orderID").CascadingDropDown("#customerID", '/Sales/AsyncOrders'); Internally, an AJAX post is made to ‘/Sales/AsyncOrders’ with the post body containing  customerID=[selectedCustomerID]. This executes the action AsyncOrders on the SalesController with signature AsyncOrders(string customerID).  The AsyncOrders method returns JSON which is then used to populate the select list. The JSON format expected is shown below : [{ "Text": "John", "Value": "10326" }, { "Text": "Jane", "Value": "10801" }] Details $(targetID).CascadingDropDown(sourceID, url, settings) targetID The ID of the select list that will auto populate.  sourceID The ID of the select list, which, on change, causes the targetID to auto populate. url The url to post to Options promptText Text for the first item in the select list Default : -- Select -- loadingText Optional text to display in the select list while it is being loaded. Default : Loading.. errorText Optional text to display if an error occurs while populating the list Default: Error loading data. postData Data you want posted to the url in place of the default Example : { postData : { customerID : $(‘#custID’), orderID : $(‘#orderID’) }} will cause customerID=ALFKI&orderID=2343 to be sent as the POST body. Default: A text string obtained by calling serialize on the sourceID onLoading (event) Raised before the list is populated. onLoaded (event) Raised after the list is populated, The code below shows how to “animate” the  select list after load. Example using custom options: $("#orderID").CascadingDropDown("#customerID", '/Sales/AsyncOrders', { promptText: '-- Pick an Order--', onLoading: function () { $(this).css("background-color", "#ff3"); }, onLoaded: function () { $(this).animate({ backgroundColor: '#ffffff' }, 300); } }); To return JSON from our action method, we use the Json ActionResult passing in an IEnumerable<SelectListItem>. public ActionResult AsyncOrders(string customerID) { var orders = repository.GetOrders(customerID).ToList().Select(a => new SelectListItem() { Text = a.OrderDate.HasValue ? a.OrderDate.Value.ToString("MM/dd/yyyy") : "[ No Date ]", Value = a.OrderID.ToString(), }); return Json(orders); } Sample Project using VS 2010 RTM NorthwindCascading.zip

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  • Autopostback select lists in ASP.NET MVC using jQuery

    - by rajbk
    This tiny snippet of code show you how to have your select lists autopostback its containing form when the selected value changes. When the DOM is fully loaded, we get all select nodes that have an attribute of “data-autopostback” with a value of “true”. We wire up the “change” JavaScript event to all these select nodes. This event is fired as soon as the user changes their selection with the mouse.  When the event is fired, we find the closest form tag for the select node that raised the event and submit the form. $(document).ready(function () { $("select:[data-autopostback=true]").change(function () { $(this).closest("form").submit(); }); }); A select tag with autopostback enabled will look like this <select id="selCategory" name="Category" data-autopostback="true"> <option value='1'>Electronics</option> <option value='2'>Books</option> </select> The reason I am using “data-" suffix in the attribute is to be HTML5 Compliant. A custom data attribute is an attribute in no namespace whose name starts with the string "data-", has at least one character after the hyphen, is XML-compatible, and contains no characters in the range U+0041 to U+005A (LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z). The snippet can be used with any HTML page.

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  • A basic T4 template for generating Model Metadata in ASP.NET MVC2

    - by rajbk
    I have been learning about T4 templates recently by looking at the awesome ADO.NET POCO entity generator. By using the POCO entity generator template as a base, I created a T4 template which generates metadata classes for a given Entity Data Model. This speeds coding by reducing the amount of typing required when creating view specific model and its metadata. To use this template, Download the template provided at the bottom. Set two values in the template file. The first one should point to the EDM you wish to generate metadata for. The second is used to suffix the namespace and classes that get generated. string inputFile = @"Northwind.edmx"; string suffix = "AutoMetadata"; Add the template to your MVC 2 Visual Studio 2010 project. Once you add it, a number of classes will get added to your project based on the number of entities you have.    One of these classes is shown below. Note that the DisplayName, Required and StringLength attributes have been added by the t4 template. //------------------------------------------------------------------------------ // <auto-generated> // This code was generated from a template. // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // </auto-generated> //------------------------------------------------------------------------------   using System; using System.ComponentModel; using System.ComponentModel.DataAnnotations;   namespace NorthwindSales.ModelsAutoMetadata { public partial class CustomerAutoMetadata { [DisplayName("Customer ID")] [Required] [StringLength(5)] public string CustomerID { get; set; } [DisplayName("Company Name")] [Required] [StringLength(40)] public string CompanyName { get; set; } [DisplayName("Contact Name")] [StringLength(30)] public string ContactName { get; set; } [DisplayName("Contact Title")] [StringLength(30)] public string ContactTitle { get; set; } [DisplayName("Address")] [StringLength(60)] public string Address { get; set; } [DisplayName("City")] [StringLength(15)] public string City { get; set; } [DisplayName("Region")] [StringLength(15)] public string Region { get; set; } [DisplayName("Postal Code")] [StringLength(10)] public string PostalCode { get; set; } [DisplayName("Country")] [StringLength(15)] public string Country { get; set; } [DisplayName("Phone")] [StringLength(24)] public string Phone { get; set; } [DisplayName("Fax")] [StringLength(24)] public string Fax { get; set; } } } The gen’d class can be used from your project by creating a partial class with the entity name and setting the MetadataType attribute.namespace MyProject.Models{ [MetadataType(typeof(CustomerAutoMetadata))] public partial class Customer { }} You can also copy the code in the metadata class generated and create your own ViewModel class. Note that the template is super basic  and does not take into account complex properties. I have tested it with the Northwind database. This is a work in progress. Feel free to modify the template to suite your requirements. Standard disclaimer follows: Use At Your Own Risk, Works on my machine running VS 2010 RTM/ASP.NET MVC 2 AutoMetaData.zip Mr. Incredible: Of course I have a secret identity. I don't know a single superhero who doesn't. Who wants the pressure of being super all the time?

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  • Securing an ASP.NET MVC 2 Application

    - by rajbk
    This post attempts to look at some of the methods that can be used to secure an ASP.NET MVC 2 Application called Northwind Traders Human Resources.  The sample code for the project is attached at the bottom of this post. We are going to use a slightly modified Northwind database. The screen capture from SQL server management studio shows the change. I added a new column called Salary, inserted some random salaries for the employees and then turned off AllowNulls.   The reporting relationship for Northwind Employees is shown below.   The requirements for our application are as follows: Employees can see their LastName, FirstName, Title, Address and Salary Employees are allowed to edit only their Address information Employees can see the LastName, FirstName, Title, Address and Salary of their immediate reports Employees cannot see records of non immediate reports.  Employees are allowed to edit only the Salary and Title information of their immediate reports. Employees are not allowed to edit the Address of an immediate report Employees should be authenticated into the system. Employees by default get the “Employee” role. If a user has direct reports, they will also get assigned a “Manager” role. We use a very basic empId/pwd scheme of EmployeeID (1-9) and password test$1. You should never do this in an actual application. The application should protect from Cross Site Request Forgery (CSRF). For example, Michael could trick Steven, who is already logged on to the HR website, to load a page which contains a malicious request. where without Steven’s knowledge, a form on the site posts information back to the Northwind HR website using Steven’s credentials. Michael could use this technique to give himself a raise :-) UI Notes The layout of our app looks like so: When Nancy (EmpID 1) signs on, she sees the default page with her details and is allowed to edit her address. If Nancy attempts to view the record of employee Andrew who has an employeeID of 2 (Employees/Edit/2), she will get a “Not Authorized” error page. When Andrew (EmpID 2) signs on, he can edit the address field of his record and change the title and salary of employees that directly report to him. Implementation Notes All controllers inherit from a BaseController. The BaseController currently only has error handling code. When a user signs on, we check to see if they are in a Manager role. We then create a FormsAuthenticationTicket, encrypt it (including the roles that the employee belongs to) and add it to a cookie. private void SetAuthenticationCookie(int employeeID, List<string> roles) { HttpCookiesSection cookieSection = (HttpCookiesSection) ConfigurationManager.GetSection("system.web/httpCookies"); AuthenticationSection authenticationSection = (AuthenticationSection) ConfigurationManager.GetSection("system.web/authentication"); FormsAuthenticationTicket authTicket = new FormsAuthenticationTicket( 1, employeeID.ToString(), DateTime.Now, DateTime.Now.AddMinutes(authenticationSection.Forms.Timeout.TotalMinutes), false, string.Join("|", roles.ToArray())); String encryptedTicket = FormsAuthentication.Encrypt(authTicket); HttpCookie authCookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket); if (cookieSection.RequireSSL || authenticationSection.Forms.RequireSSL) { authCookie.Secure = true; } HttpContext.Current.Response.Cookies.Add(authCookie); } We read this cookie back in Global.asax and set the Context.User to be a new GenericPrincipal with the roles we assigned earlier. protected void Application_AuthenticateRequest(Object sender, EventArgs e){ if (Context.User != null) { string cookieName = FormsAuthentication.FormsCookieName; HttpCookie authCookie = Context.Request.Cookies[cookieName]; if (authCookie == null) return; FormsAuthenticationTicket authTicket = FormsAuthentication.Decrypt(authCookie.Value); string[] roles = authTicket.UserData.Split(new char[] { '|' }); FormsIdentity fi = (FormsIdentity)(Context.User.Identity); Context.User = new System.Security.Principal.GenericPrincipal(fi, roles); }} We ensure that a user has permissions to view a record by creating a custom attribute AuthorizeToViewID that inherits from ActionFilterAttribute. public class AuthorizeToViewIDAttribute : ActionFilterAttribute{ IEmployeeRepository employeeRepository = new EmployeeRepository(); public override void OnActionExecuting(ActionExecutingContext filterContext) { if (filterContext.ActionParameters.ContainsKey("id") && filterContext.ActionParameters["id"] != null) { if (employeeRepository.IsAuthorizedToView((int)filterContext.ActionParameters["id"])) { return; } } throw new UnauthorizedAccessException("The record does not exist or you do not have permission to access it"); }} We add the AuthorizeToView attribute to any Action method that requires authorization. [HttpPost][Authorize(Order = 1)]//To prevent CSRF[ValidateAntiForgeryToken(Salt = Globals.EditSalt, Order = 2)]//See AuthorizeToViewIDAttribute class[AuthorizeToViewID(Order = 3)] [ActionName("Edit")]public ActionResult Update(int id){ var employeeToEdit = employeeRepository.GetEmployee(id); if (employeeToEdit != null) { //Employees can edit only their address //A manager can edit the title and salary of their subordinate string[] whiteList = (employeeToEdit.IsSubordinate) ? new string[] { "Title", "Salary" } : new string[] { "Address" }; if (TryUpdateModel(employeeToEdit, whiteList)) { employeeRepository.Save(employeeToEdit); return RedirectToAction("Details", new { id = id }); } else { ModelState.AddModelError("", "Please correct the following errors."); } } return View(employeeToEdit);} The Authorize attribute is added to ensure that only authorized users can execute that Action. We use the TryUpdateModel with a white list to ensure that (a) an employee is able to edit only their Address and (b) that a manager is able to edit only the Title and Salary of a subordinate. This works in conjunction with the AuthorizeToViewIDAttribute. The ValidateAntiForgeryToken attribute is added (with a salt) to avoid CSRF. The Order on the attributes specify the order in which the attributes are executed. The Edit View uses the AntiForgeryToken helper to render the hidden token: ......<% using (Html.BeginForm()) {%><%=Html.AntiForgeryToken(NorthwindHR.Models.Globals.EditSalt)%><%= Html.ValidationSummary(true, "Please correct the errors and try again.") %><div class="editor-label"> <%= Html.LabelFor(model => model.LastName) %></div><div class="editor-field">...... The application uses View specific models for ease of model binding. public class EmployeeViewModel{ public int EmployeeID; [Required] [DisplayName("Last Name")] public string LastName { get; set; } [Required] [DisplayName("First Name")] public string FirstName { get; set; } [Required] [DisplayName("Title")] public string Title { get; set; } [Required] [DisplayName("Address")] public string Address { get; set; } [Required] [DisplayName("Salary")] [Range(500, double.MaxValue)] public decimal Salary { get; set; } public bool IsSubordinate { get; set; }} To help with displaying readonly/editable fields, we use a helper method. //Simple extension method to display a TextboxFor or DisplayFor based on the isEditable variablepublic static MvcHtmlString TextBoxOrLabelFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, bool isEditable){ if (isEditable) { return htmlHelper.TextBoxFor(expression); } else { return htmlHelper.DisplayFor(expression); }} The helper method is used in the view like so: <%=Html.TextBoxOrLabelFor(model => model.Title, Model.IsSubordinate)%> As mentioned in this post, there is a much easier way to update properties on an object. Download Demo Project VS 2008, ASP.NET MVC 2 RTM Remember to change the connectionString to point to your Northwind DB NorthwindHR.zip Feedback and bugs are always welcome :-)

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  • Creating an ASP.NET report using Visual Studio 2010 - Part 1

    - by rajbk
    This tutorial walks you through creating an report based on the Northwind sample database. You will add a client report definition file (RDLC), create a dataset for the RDLC, define queries using LINQ to Entities, design the report and add a ReportViewer web control to render the report in a ASP.NET web page. The report will have a chart control. Different results will be generated by changing filter criteria. At the end of the walkthrough, you should have a UI like the following.  From the UI below, a user is able to view the product list and can see a chart with the sum of Unit price for a given category. They can filter by Category and Supplier. The drop downs will auto post back when the selection is changed.  This demo uses Visual Studio 2010 RTM. This post is split into three parts. The last part has the sample code attached. Creating an ASP.NET report using Visual Studio 2010 - Part 2 Creating an ASP.NET report using Visual Studio 2010 - Part 3   Lets start by creating a new ASP.NET empty web application called “NorthwindReports” Creating the Data Access Layer (DAL) Add a web form called index.aspx to the root directory. You do this by right clicking on the NorthwindReports web project and selecting “Add item..” . Create a folder called “DAL”. We will store all our data access methods and any data transfer objects in here.   Right click on the DAL folder and add a ADO.NET Entity data model called Northwind. Select “Generate from database” and click Next. Create a connection to your database containing the Northwind sample database and click Next.   From the table list, select Categories, Products and Suppliers and click next. Our Entity data model gets created and looks like this:    Adding data transfer objects Right click on the DAL folder and add a ProductViewModel. Add the following code. This class contains properties we need to render our report. public class ProductViewModel { public int? ProductID { get; set; } public string ProductName { get; set; } public System.Nullable<decimal> UnitPrice { get; set; } public string CategoryName { get; set; } public int? CategoryID { get; set; } public int? SupplierID { get; set; } public bool Discontinued { get; set; } } Add a SupplierViewModel class. This will be used to render the supplier DropDownlist. public class SupplierViewModel { public string CompanyName { get; set; } public int SupplierID { get; set; } } Add a CategoryViewModel class. public class CategoryViewModel { public string CategoryName { get; set; } public int CategoryID { get; set; } } Create an IProductRepository interface. This will contain the signatures of all the methods we need when accessing the entity model.  This step is not needed but follows the repository pattern. interface IProductRepository { IQueryable<Product> GetProducts(); IQueryable<ProductViewModel> GetProductsProjected(int? supplierID, int? categoryID); IQueryable<SupplierViewModel> GetSuppliers(); IQueryable<CategoryViewModel> GetCategories(); } Create a ProductRepository class that implements the IProductReposity above. The methods available in this class are as follows: GetProducts – returns an IQueryable of all products. GetProductsProjected – returns an IQueryable of ProductViewModel. The method filters all the products based on SupplierId and CategoryId if any. It then projects the result into the ProductViewModel. GetSuppliers() – returns an IQueryable of all suppliers projected into a SupplierViewModel GetCategories() – returns an IQueryable of all categories projected into a CategoryViewModel  public class ProductRepository : IProductRepository { /// <summary> /// IQueryable of all Products /// </summary> /// <returns></returns> public IQueryable<Product> GetProducts() { var dataContext = new NorthwindEntities(); var products = from p in dataContext.Products select p; return products; }   /// <summary> /// IQueryable of Projects projected /// into the ProductViewModel class /// </summary> /// <returns></returns> public IQueryable<ProductViewModel> GetProductsProjected(int? supplierID, int? categoryID) { var projectedProducts = from p in GetProducts() select new ProductViewModel { ProductID = p.ProductID, ProductName = p.ProductName, UnitPrice = p.UnitPrice, CategoryName = p.Category.CategoryName, CategoryID = p.CategoryID, SupplierID = p.SupplierID, Discontinued = p.Discontinued }; // Filter on SupplierID if (supplierID.HasValue) { projectedProducts = projectedProducts.Where(a => a.SupplierID == supplierID); }   // Filter on CategoryID if (categoryID.HasValue) { projectedProducts = projectedProducts.Where(a => a.CategoryID == categoryID); }   return projectedProducts; }     public IQueryable<SupplierViewModel> GetSuppliers() { var dataContext = new NorthwindEntities(); var suppliers = from s in dataContext.Suppliers select new SupplierViewModel { SupplierID = s.SupplierID, CompanyName = s.CompanyName }; return suppliers; }   public IQueryable<CategoryViewModel> GetCategories() { var dataContext = new NorthwindEntities(); var categories = from c in dataContext.Categories select new CategoryViewModel { CategoryID = c.CategoryID, CategoryName = c.CategoryName }; return categories; } } Your solution explorer should look like the following. Build your project and make sure you don’t get any errors. In the next part, we will see how to create the client report definition file using the Report Wizard.   Creating an ASP.NET report using Visual Studio 2010 - Part 2

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  • How LINQ to Object statements work

    - by rajbk
    This post goes into detail as to now LINQ statements work when querying a collection of objects. This topic assumes you have an understanding of how generics, delegates, implicitly typed variables, lambda expressions, object/collection initializers, extension methods and the yield statement work. I would also recommend you read my previous two posts: Using Delegates in C# Part 1 Using Delegates in C# Part 2 We will start by writing some methods to filter a collection of data. Assume we have an Employee class like so: 1: public class Employee { 2: public int ID { get; set;} 3: public string FirstName { get; set;} 4: public string LastName {get; set;} 5: public string Country { get; set; } 6: } and a collection of employees like so: 1: var employees = new List<Employee> { 2: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 3: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 4: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 5: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" }, 6: }; Filtering We wish to  find all employees that have an even ID. We could start off by writing a method that takes in a list of employees and returns a filtered list of employees with an even ID. 1: static List<Employee> GetEmployeesWithEvenID(List<Employee> employees) { 2: var filteredEmployees = new List<Employee>(); 3: foreach (Employee emp in employees) { 4: if (emp.ID % 2 == 0) { 5: filteredEmployees.Add(emp); 6: } 7: } 8: return filteredEmployees; 9: } The method can be rewritten to return an IEnumerable<Employee> using the yield return keyword. 1: static IEnumerable<Employee> GetEmployeesWithEvenID(IEnumerable<Employee> employees) { 2: foreach (Employee emp in employees) { 3: if (emp.ID % 2 == 0) { 4: yield return emp; 5: } 6: } 7: } We put these together in a console application. 1: using System; 2: using System.Collections.Generic; 3: //No System.Linq 4:  5: public class Program 6: { 7: [STAThread] 8: static void Main(string[] args) 9: { 10: var employees = new List<Employee> { 11: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 12: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 13: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 14: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" }, 15: }; 16: var filteredEmployees = GetEmployeesWithEvenID(employees); 17:  18: foreach (Employee emp in filteredEmployees) { 19: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 20: emp.ID, emp.FirstName, emp.LastName, emp.Country); 21: } 22:  23: Console.ReadLine(); 24: } 25: 26: static IEnumerable<Employee> GetEmployeesWithEvenID(IEnumerable<Employee> employees) { 27: foreach (Employee emp in employees) { 28: if (emp.ID % 2 == 0) { 29: yield return emp; 30: } 31: } 32: } 33: } 34:  35: public class Employee { 36: public int ID { get; set;} 37: public string FirstName { get; set;} 38: public string LastName {get; set;} 39: public string Country { get; set; } 40: } Output: ID 2 First_Name Jim Last_Name Ashlock Country UK ID 4 First_Name Jill Last_Name Anderson Country AUS Our filtering method is too specific. Let us change it so that it is capable of doing different types of filtering and lets give our method the name Where ;-) We will add another parameter to our Where method. This additional parameter will be a delegate with the following declaration. public delegate bool Filter(Employee emp); The idea is that the delegate parameter in our Where method will point to a method that contains the logic to do our filtering thereby freeing our Where method from any dependency. The method is shown below: 1: static IEnumerable<Employee> Where(IEnumerable<Employee> employees, Filter filter) { 2: foreach (Employee emp in employees) { 3: if (filter(emp)) { 4: yield return emp; 5: } 6: } 7: } Making the change to our app, we create a new instance of the Filter delegate on line 14 with a target set to the method EmployeeHasEvenId. Running the code will produce the same output. 1: public delegate bool Filter(Employee emp); 2:  3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: var employees = new List<Employee> { 9: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 10: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 11: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 12: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 13: }; 14: var filterDelegate = new Filter(EmployeeHasEvenId); 15: var filteredEmployees = Where(employees, filterDelegate); 16:  17: foreach (Employee emp in filteredEmployees) { 18: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 19: emp.ID, emp.FirstName, emp.LastName, emp.Country); 20: } 21: Console.ReadLine(); 22: } 23: 24: static bool EmployeeHasEvenId(Employee emp) { 25: return emp.ID % 2 == 0; 26: } 27: 28: static IEnumerable<Employee> Where(IEnumerable<Employee> employees, Filter filter) { 29: foreach (Employee emp in employees) { 30: if (filter(emp)) { 31: yield return emp; 32: } 33: } 34: } 35: } 36:  37: public class Employee { 38: public int ID { get; set;} 39: public string FirstName { get; set;} 40: public string LastName {get; set;} 41: public string Country { get; set; } 42: } Lets use lambda expressions to inline the contents of the EmployeeHasEvenId method in place of the method. The next code snippet shows this change (see line 15).  For brevity, the Employee class declaration has been skipped. 1: public delegate bool Filter(Employee emp); 2:  3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: var employees = new List<Employee> { 9: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 10: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 11: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 12: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 13: }; 14: var filterDelegate = new Filter(EmployeeHasEvenId); 15: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 16:  17: foreach (Employee emp in filteredEmployees) { 18: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 19: emp.ID, emp.FirstName, emp.LastName, emp.Country); 20: } 21: Console.ReadLine(); 22: } 23: 24: static bool EmployeeHasEvenId(Employee emp) { 25: return emp.ID % 2 == 0; 26: } 27: 28: static IEnumerable<Employee> Where(IEnumerable<Employee> employees, Filter filter) { 29: foreach (Employee emp in employees) { 30: if (filter(emp)) { 31: yield return emp; 32: } 33: } 34: } 35: } 36:  The output displays the same two employees.  Our Where method is too restricted since it works with a collection of Employees only. Lets change it so that it works with any IEnumerable<T>. In addition, you may recall from my previous post,  that .NET 3.5 comes with a lot of predefined delegates including public delegate TResult Func<T, TResult>(T arg); We will get rid of our Filter delegate and use the one above instead. We apply these two changes to our code. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: var employees = new List<Employee> { 7: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 8: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 9: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 10: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 11: }; 12:  13: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 14:  15: foreach (Employee emp in filteredEmployees) { 16: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 17: emp.ID, emp.FirstName, emp.LastName, emp.Country); 18: } 19: Console.ReadLine(); 20: } 21: 22: static IEnumerable<T> Where<T>(IEnumerable<T> source, Func<T, bool> filter) { 23: foreach (var x in source) { 24: if (filter(x)) { 25: yield return x; 26: } 27: } 28: } 29: } We have successfully implemented a way to filter any IEnumerable<T> based on a  filter criteria. Projection Now lets enumerate on the items in the IEnumerable<Employee> we got from the Where method and copy them into a new IEnumerable<EmployeeFormatted>. The EmployeeFormatted class will only have a FullName and ID property. 1: public class EmployeeFormatted { 2: public int ID { get; set; } 3: public string FullName {get; set;} 4: } We could “project” our existing IEnumerable<Employee> into a new collection of IEnumerable<EmployeeFormatted> with the help of a new method. We will call this method Select ;-) 1: static IEnumerable<EmployeeFormatted> Select(IEnumerable<Employee> employees) { 2: foreach (var emp in employees) { 3: yield return new EmployeeFormatted { 4: ID = emp.ID, 5: FullName = emp.LastName + ", " + emp.FirstName 6: }; 7: } 8: } The changes are applied to our app. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: var employees = new List<Employee> { 7: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 8: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 9: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 10: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 11: }; 12:  13: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 14: var formattedEmployees = Select(filteredEmployees); 15:  16: foreach (EmployeeFormatted emp in formattedEmployees) { 17: Console.WriteLine("ID {0} Full_Name {1}", 18: emp.ID, emp.FullName); 19: } 20: Console.ReadLine(); 21: } 22:  23: static IEnumerable<T> Where<T>(IEnumerable<T> source, Func<T, bool> filter) { 24: foreach (var x in source) { 25: if (filter(x)) { 26: yield return x; 27: } 28: } 29: } 30: 31: static IEnumerable<EmployeeFormatted> Select(IEnumerable<Employee> employees) { 32: foreach (var emp in employees) { 33: yield return new EmployeeFormatted { 34: ID = emp.ID, 35: FullName = emp.LastName + ", " + emp.FirstName 36: }; 37: } 38: } 39: } 40:  41: public class Employee { 42: public int ID { get; set;} 43: public string FirstName { get; set;} 44: public string LastName {get; set;} 45: public string Country { get; set; } 46: } 47:  48: public class EmployeeFormatted { 49: public int ID { get; set; } 50: public string FullName {get; set;} 51: } Output: ID 2 Full_Name Ashlock, Jim ID 4 Full_Name Anderson, Jill We have successfully selected employees who have an even ID and then shaped our data with the help of the Select method so that the final result is an IEnumerable<EmployeeFormatted>.  Lets make our Select method more generic so that the user is given the freedom to shape what the output would look like. We can do this, like before, with lambda expressions. Our Select method is changed to accept a delegate as shown below. TSource will be the type of data that comes in and TResult will be the type the user chooses (shape of data) as returned from the selector delegate. 1:  2: static IEnumerable<TResult> Select<TSource, TResult>(IEnumerable<TSource> source, Func<TSource, TResult> selector) { 3: foreach (var x in source) { 4: yield return selector(x); 5: } 6: } We see the new changes to our app. On line 15, we use lambda expression to specify the shape of the data. In this case the shape will be of type EmployeeFormatted. 1:  2: public class Program 3: { 4: [STAThread] 5: static void Main(string[] args) 6: { 7: var employees = new List<Employee> { 8: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 9: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 10: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 11: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 12: }; 13:  14: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 15: var formattedEmployees = Select(filteredEmployees, (emp) => 16: new EmployeeFormatted { 17: ID = emp.ID, 18: FullName = emp.LastName + ", " + emp.FirstName 19: }); 20:  21: foreach (EmployeeFormatted emp in formattedEmployees) { 22: Console.WriteLine("ID {0} Full_Name {1}", 23: emp.ID, emp.FullName); 24: } 25: Console.ReadLine(); 26: } 27: 28: static IEnumerable<T> Where<T>(IEnumerable<T> source, Func<T, bool> filter) { 29: foreach (var x in source) { 30: if (filter(x)) { 31: yield return x; 32: } 33: } 34: } 35: 36: static IEnumerable<TResult> Select<TSource, TResult>(IEnumerable<TSource> source, Func<TSource, TResult> selector) { 37: foreach (var x in source) { 38: yield return selector(x); 39: } 40: } 41: } The code outputs the same result as before. On line 14 we filter our data and on line 15 we project our data. What if we wanted to be more expressive and concise? We could combine both line 14 and 15 into one line as shown below. Assuming you had to perform several operations like this on our collection, you would end up with some very unreadable code! 1: var formattedEmployees = Select(Where(employees, emp => emp.ID % 2 == 0), (emp) => 2: new EmployeeFormatted { 3: ID = emp.ID, 4: FullName = emp.LastName + ", " + emp.FirstName 5: }); A cleaner way to write this would be to give the appearance that the Select and Where methods were part of the IEnumerable<T>. This is exactly what extension methods give us. Extension methods have to be defined in a static class. Let us make the Select and Where extension methods on IEnumerable<T> 1: public static class MyExtensionMethods { 2: static IEnumerable<T> Where<T>(this IEnumerable<T> source, Func<T, bool> filter) { 3: foreach (var x in source) { 4: if (filter(x)) { 5: yield return x; 6: } 7: } 8: } 9: 10: static IEnumerable<TResult> Select<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) { 11: foreach (var x in source) { 12: yield return selector(x); 13: } 14: } 15: } The creation of the extension method makes the syntax much cleaner as shown below. We can write as many extension methods as we want and keep on chaining them using this technique. 1: var formattedEmployees = employees 2: .Where(emp => emp.ID % 2 == 0) 3: .Select (emp => new EmployeeFormatted { ID = emp.ID, FullName = emp.LastName + ", " + emp.FirstName }); Making these changes and running our code produces the same result. 1: using System; 2: using System.Collections.Generic; 3:  4: public class Program 5: { 6: [STAThread] 7: static void Main(string[] args) 8: { 9: var employees = new List<Employee> { 10: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 11: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 12: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 13: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 14: }; 15:  16: var formattedEmployees = employees 17: .Where(emp => emp.ID % 2 == 0) 18: .Select (emp => 19: new EmployeeFormatted { 20: ID = emp.ID, 21: FullName = emp.LastName + ", " + emp.FirstName 22: } 23: ); 24:  25: foreach (EmployeeFormatted emp in formattedEmployees) { 26: Console.WriteLine("ID {0} Full_Name {1}", 27: emp.ID, emp.FullName); 28: } 29: Console.ReadLine(); 30: } 31: } 32:  33: public static class MyExtensionMethods { 34: static IEnumerable<T> Where<T>(this IEnumerable<T> source, Func<T, bool> filter) { 35: foreach (var x in source) { 36: if (filter(x)) { 37: yield return x; 38: } 39: } 40: } 41: 42: static IEnumerable<TResult> Select<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) { 43: foreach (var x in source) { 44: yield return selector(x); 45: } 46: } 47: } 48:  49: public class Employee { 50: public int ID { get; set;} 51: public string FirstName { get; set;} 52: public string LastName {get; set;} 53: public string Country { get; set; } 54: } 55:  56: public class EmployeeFormatted { 57: public int ID { get; set; } 58: public string FullName {get; set;} 59: } Let’s change our code to return a collection of anonymous types and get rid of the EmployeeFormatted type. We see that the code produces the same output. 1: using System; 2: using System.Collections.Generic; 3:  4: public class Program 5: { 6: [STAThread] 7: static void Main(string[] args) 8: { 9: var employees = new List<Employee> { 10: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 11: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 12: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 13: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 14: }; 15:  16: var formattedEmployees = employees 17: .Where(emp => emp.ID % 2 == 0) 18: .Select (emp => 19: new { 20: ID = emp.ID, 21: FullName = emp.LastName + ", " + emp.FirstName 22: } 23: ); 24:  25: foreach (var emp in formattedEmployees) { 26: Console.WriteLine("ID {0} Full_Name {1}", 27: emp.ID, emp.FullName); 28: } 29: Console.ReadLine(); 30: } 31: } 32:  33: public static class MyExtensionMethods { 34: public static IEnumerable<T> Where<T>(this IEnumerable<T> source, Func<T, bool> filter) { 35: foreach (var x in source) { 36: if (filter(x)) { 37: yield return x; 38: } 39: } 40: } 41: 42: public static IEnumerable<TResult> Select<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) { 43: foreach (var x in source) { 44: yield return selector(x); 45: } 46: } 47: } 48:  49: public class Employee { 50: public int ID { get; set;} 51: public string FirstName { get; set;} 52: public string LastName {get; set;} 53: public string Country { get; set; } 54: } To be more expressive, C# allows us to write our extension method calls as a query expression. Line 16 can be rewritten a query expression like so: 1: var formattedEmployees = from emp in employees 2: where emp.ID % 2 == 0 3: select new { 4: ID = emp.ID, 5: FullName = emp.LastName + ", " + emp.FirstName 6: }; When the compiler encounters an expression like the above, it simply rewrites it as calls to our extension methods.  So far we have been using our extension methods. The System.Linq namespace contains several extension methods for objects that implement the IEnumerable<T>. You can see a listing of these methods in the Enumerable class in the System.Linq namespace. Let’s get rid of our extension methods (which I purposefully wrote to be of the same signature as the ones in the Enumerable class) and use the ones provided in the Enumerable class. Our final code is shown below: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; //Added 4:  5: public class Program 6: { 7: [STAThread] 8: static void Main(string[] args) 9: { 10: var employees = new List<Employee> { 11: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 12: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 13: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 14: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 15: }; 16:  17: var formattedEmployees = from emp in employees 18: where emp.ID % 2 == 0 19: select new { 20: ID = emp.ID, 21: FullName = emp.LastName + ", " + emp.FirstName 22: }; 23:  24: foreach (var emp in formattedEmployees) { 25: Console.WriteLine("ID {0} Full_Name {1}", 26: emp.ID, emp.FullName); 27: } 28: Console.ReadLine(); 29: } 30: } 31:  32: public class Employee { 33: public int ID { get; set;} 34: public string FirstName { get; set;} 35: public string LastName {get; set;} 36: public string Country { get; set; } 37: } 38:  39: public class EmployeeFormatted { 40: public int ID { get; set; } 41: public string FullName {get; set;} 42: } This post has shown you a basic overview of LINQ to Objects work by showning you how an expression is converted to a sequence of calls to extension methods when working directly with objects. It gets more interesting when working with LINQ to SQL where an expression tree is constructed – an in memory data representation of the expression. The C# compiler compiles these expressions into code that builds an expression tree at runtime. The provider can then traverse the expression tree and generate the appropriate SQL query. You can read more about expression trees in this MSDN article.

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  • Pre-filtering and shaping OData feeds using WCF Data Services and the Entity Framework - Part 1

    - by rajbk
    The Open Data Protocol, referred to as OData, is a new data-sharing standard that breaks down silos and fosters an interoperative ecosystem for data consumers (clients) and producers (services) that is far more powerful than currently possible. It enables more applications to make sense of a broader set of data, and helps every data service and client add value to the whole ecosystem. WCF Data Services (previously known as ADO.NET Data Services), then, was the first Microsoft technology to support the Open Data Protocol in Visual Studio 2008 SP1. It provides developers with client libraries for .NET, Silverlight, AJAX, PHP and Java. Microsoft now also supports OData in SQL Server 2008 R2, Windows Azure Storage, Excel 2010 (through PowerPivot), and SharePoint 2010. Many other other applications in the works. * This post walks you through how to create an OData feed, define a shape for the data and pre-filter the data using Visual Studio 2010, WCF Data Services and the Entity Framework. A sample project is attached at the bottom of Part 2 of this post. Pre-filtering and shaping OData feeds using WCF Data Services and the Entity Framework - Part 2 Create the Web Application File –› New –› Project, Select “ASP.NET Empty Web Application” Add the Entity Data Model Right click on the Web Application in the Solution Explorer and select “Add New Item..” Select “ADO.NET Entity Data Model” under "Data”. Name the Model “Northwind” and click “Add”.   In the “Choose Model Contents”, select “Generate Model From Database” and click “Next”   Define a connection to your database containing the Northwind database in the next screen. We are going to expose the Products table through our OData feed. Select “Products” in the “Choose your Database Object” screen.   Click “Finish”. We are done creating our Entity Data Model. Save the Northwind.edmx file created. Add the WCF Data Service Right click on the Web Application in the Solution Explorer and select “Add New Item..” Select “WCF Data Service” from the list and call the service “DataService” (creative, huh?). Click “Add”.   Enable Access to the Data Service Open the DataService.svc.cs class. The class is well commented and instructs us on the next steps. public class DataService : DataService< /* TODO: put your data source class name here */ > { // This method is called only once to initialize service-wide policies. public static void InitializeService(DataServiceConfiguration config) { // TODO: set rules to indicate which entity sets and service operations are visible, updatable, etc. // Examples: // config.SetEntitySetAccessRule("MyEntityset", EntitySetRights.AllRead); // config.SetServiceOperationAccessRule("MyServiceOperation", ServiceOperationRights.All); config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2; } } Replace the comment that starts with “/* TODO:” with “NorthwindEntities” (the entity container name of the Model we created earlier).  WCF Data Services is initially locked down by default, FTW! No data is exposed without you explicitly setting it. You have explicitly specify which Entity sets you wish to expose and what rights are allowed by using the SetEntitySetAccessRule. The SetServiceOperationAccessRule on the other hand sets rules for a specified operation. Let us define an access rule to expose the Products Entity we created earlier. We use the EnititySetRights.AllRead since we want to give read only access. Our modified code is shown below. public class DataService : DataService<NorthwindEntities> { public static void InitializeService(DataServiceConfiguration config) { config.SetEntitySetAccessRule("Products", EntitySetRights.AllRead); config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2; } } We are done setting up our ODataFeed! Compile your project. Right click on DataService.svc and select “View in Browser” to see the OData feed. To view the feed in IE, you must make sure that "Feed Reading View" is turned off. You set this under Tools -› Internet Options -› Content tab.   If you navigate to “Products”, you should see the Products feed. Note also that URIs are case sensitive. ie. Products work but products doesn’t.   Filtering our data OData has a set of system query operations you can use to perform common operations against data exposed by the model. For example, to see only Products in CategoryID 2, we can use the following request: /DataService.svc/Products?$filter=CategoryID eq 2 At the time of this writing, supported operations are $orderby, $top, $skip, $filter, $expand, $format†, $select, $inlinecount. Pre-filtering our data using Query Interceptors The Product feed currently returns all Products. We want to change that so that it contains only Products that have not been discontinued. WCF introduces the concept of interceptors which allows us to inject custom validation/policy logic into the request/response pipeline of a WCF data service. We will use a QueryInterceptor to pre-filter the data so that it returns only Products that are not discontinued. To create a QueryInterceptor, write a method that returns an Expression<Func<T, bool>> and mark it with the QueryInterceptor attribute as shown below. [QueryInterceptor("Products")] public Expression<Func<Product, bool>> OnReadProducts() { return o => o.Discontinued == false; } Viewing the feed after compilation will only show products that have not been discontinued. We also confirm this by looking at the WHERE clause in the SQL generated by the entity framework. SELECT [Extent1].[ProductID] AS [ProductID], ... ... [Extent1].[Discontinued] AS [Discontinued] FROM [dbo].[Products] AS [Extent1] WHERE 0 = [Extent1].[Discontinued] Other examples of Query/Change interceptors can be seen here including an example to filter data based on the identity of the authenticated user. We are done pre-filtering our data. In the next part of this post, we will see how to shape our data. Pre-filtering and shaping OData feeds using WCF Data Services and the Entity Framework - Part 2 Foot Notes * http://msdn.microsoft.com/en-us/data/aa937697.aspx † $format did not work for me. The way to get a Json response is to include the following in the  request header “Accept: application/json, text/javascript, */*” when making the request. This is easily done with most JavaScript libraries.

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  • Localization in ASP.NET MVC 2 using ModelMetadata

    - by rajbk
    This post uses an MVC 2 RTM application inside VS 2010 that is targeting the .NET Framework 4. .NET 4 DataAnnotations comes with a new Display attribute that has several properties including specifying the value that is used for display in the UI and a ResourceType. Unfortunately, this attribute is new and is not supported in MVC 2 RTM. The good news is it will be supported and is currently available in the MVC Futures release. The steps to get this working are shown below: Download the MVC futures library   Add a reference to the Microsoft.Web.MVC.AspNet4 dll.   Add a folder in your MVC project where you will store the resx files   Open the resx file and change “Access Modifier” to “Public”. This allows the resources to accessible from other assemblies. Internaly, it changes the “Custom Tool” used to generate the code behind from  ResXFileCodeGenerator to “PublicResXFileCodeGenerator”    Add your localized strings in the resx.   Register the new ModelMetadataProvider protected void Application_Start() { AreaRegistration.RegisterAllAreas();   RegisterRoutes(RouteTable.Routes);   //Add this ModelMetadataProviders.Current = new DataAnnotations4ModelMetadataProvider(); DataAnnotations4ModelValidatorProvider.RegisterProvider(); }   Use the Display attribute in your Model public class Employee { [Display(Name="ID")] public int ID { get; set; }   [Display(ResourceType = typeof(Common), Name="Name")] public string Name { get; set; } } Use the new HTML UI Helpers in your strongly typed view: <%: Html.EditorForModel() %> <%: Html.EditorFor(m => m) %> <%: Html.LabelFor(m => m.Name) %> ..and you are good to go. Adventure is out there!

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  • Creating an ASP.NET report using Visual Studio 2010 - Part 3

    - by rajbk
    We continue building our report in this three part series. Creating an ASP.NET report using Visual Studio 2010 - Part 1 Creating an ASP.NET report using Visual Studio 2010 - Part 2 Adding the ReportViewer control and filter drop downs. Open the source code for index.aspx and add a ScriptManager control. This control is required for the ReportViewer control. Add a DropDownList for the categories and suppliers. Add the ReportViewer control. The markup after these steps is shown below. <div> <asp:ScriptManager ID="smScriptManager" runat="server"> </asp:ScriptManager> <div id="searchFilter"> Filter by: Category : <asp:DropDownList ID="ddlCategories" runat="server" /> and Supplier : <asp:DropDownList ID="ddlSuppliers" runat="server" /> </div> <rsweb:ReportViewer ID="rvProducts" runat="server"> </rsweb:ReportViewer> </div> The design view for index.aspx is shown below. The dropdowns will display the categories and suppliers in the database. Changing the selection in the drop downs will cause the report to be filtered by the selections in the dropdowns. You will see how to do this in the next steps.   Attaching the RDLC to the ReportViewer control by clicking on the top right of the control, going to Report Viewer tasks and selecting Products.rdlc.   Resize the ReportViewer control by dragging at the bottom right corner. I set mine to 800px x 500px. You can also set this value in source view. Defining the data sources. We will now define the Data Source used to populate the report. Go back to the “ReportViewer Tasks” and select “Choose Data Sources” Select a “New data source..” Select “Object” and name your Data Source ID “odsProducts”   In the next screen, choose “ProductRepository” as your business object. Choose “GetProductsProjected” in the next screen.   The method requires a SupplierID and CategoryID. We will set these so that our data source gets the values from the drop down lists we defined earlier. Set the parameter source to be of type “Control” and set the ControlIDs to be ddlSuppliers and ddlCategories respectively. Your screen will look like this: We are now going to define the data source for our drop downs. Select the ddlCategory drop down and pick “Choose Data Source”. Pick “Object” and give it an id “odsCategories”   In the next screen, choose “ProductRepository” Select the GetCategories() method in the next screen.   Select “CategoryName” and “CategoryID” in the next screen. We are done defining the data source for the Category drop down. Perform the same steps for the Suppliers drop down.   Select each dropdown and set the AppendDataBoundItems to true and AutoPostback to true.     The AppendDataBoundItems is needed because we are going to insert an “All“ list item with a value of empty. Go to each drop down and add this list item markup as shown below> Finally, double click on each drop down in the designer and add the following code in the code behind. This along with the “Autopostback= true” attribute refreshes the report anytime a drop down is changed. protected void ddlCategories_SelectedIndexChanged(object sender, EventArgs e) { rvProducts.LocalReport.Refresh(); }   protected void ddlSuppliers_SelectedIndexChanged(object sender, EventArgs e) { rvProducts.LocalReport.Refresh(); } Compile your report and run the page. You should see the report rendered. Note that the tool bar in the ReportViewer control gives you a couple of options including the ability to export the data to Excel, PDF or word.   Conclusion Through this three part series, we did the following: Created a data layer for use by our RDLC. Created an RDLC using the report wizard and define a dataset for the report. Used the report design surface to design our report including adding a chart. Used the ReportViewer control to attach the RDLC. Connected our ReportWiewer to a data source and take parameter values from the drop downlists. Used AutoPostBack to refresh the reports when the dropdown selection was changed. RDLCs allow you to create interactive reports including drill downs and grouping. For even more advanced reports you can use Microsoft® SQL Server™ Reporting Services with RDLs. With RDLs, the report is rendered on the report server instead of the web server. Another nice thing about RDLs is that you can define a parameter list for the report and it gets rendered automatically for you. RDLCs and RDLs both have their advantages and its best to compare them and choose the right one for your requirements. Download VS2010 RTM Sample project NorthwindReports.zip   Alfred Borden: Are you watching closely?

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  • Code snippets for ASP.NET MVC2 in VS 2010

    - by rajbk
    VS 2010 comes with ready made snippets which helps you save time while coding. You insert a snippet by typing the name of the code snippet and hitting the Tab key twice. You can also use the following method if you wish to see a listing of snippets available. Press Ctrl + K, Ctrl + X Select ASP.NET MVC2 with the arrow keys and hit enter to see a list of snippets available.   The MVC related snippets you get out of the box (for C#) are listed below: HTML actionlink Markup snippet for an ASP.NET MVC action link helper <%= Html.ActionLink("linktext", "actionname") %>   beginformajaxcs Markup snippet for an ASP.NET MVC AJAX-enabled form helper in C# <% using (Ajax.BeginForm("actionname", new AjaxOptions {UpdateTargetId= "elementid" })) { %> <% } %>   beginformcs Markup snippet for an ASP.NET MVC form helper in C# <% using (Html.BeginForm()) { %> <% } %>   displayforcs Markup snippet for an ASP.NET MVC templated helper. <%= Html.DisplayFor(x => x.Property) %>   editorforcs Markup snippet for an ASP.NET MVC templated helper. <%= Html.EditorFor(x => x.Property) %>   foreachcs Markup snippet for an ASP.NET MVC foreach statement in C# <% foreach (var item in collection) { %> <% } %>   ifcs Markup snippet for a code-nugget if else statement in C# <% if (true) { %> <% } %>   ifelsecs Markup snippet for a code-nugget if else statement in C# <% if (true) { %> <% } else { %> <% } %>   renderpartialcs Markup snippet for an ASP.NET MVC partial view rendering in C# <% Html.RenderPartial("viewname"); %>   textboxmvc Markup snippet for an ASP.NET MVC textbox helper <%= Html.TextBox("name") %>   validationsummarymvc Markup snippet for an ASP.NET MVC validation summary helper <%= Html.ValidationSummary() %> CS mvcaction Code snippet for an action. public ActionResult Action() {     return View(); }   mvcpostaction Code snippet for an action via http post. [HttpPost] public ActionResult Action() {     return View(); }   Enjoy!

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  • ASP.NET Dynamic Data Deployment Error

    - by rajbk
    You have an ASP.NET 3.5 dynamic data website that works great on your local box. When you deploy it to your production machine and turn on debug, you get the YSD Server Error in '/MyPath/MyApp' Application. Parser Error Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately. Parser Error Message: Unknown server tag 'asp:DynamicDataManager'. Source Error: Line 5:  Line 6:  <asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server"> Line 7:      <asp:DynamicDataManager ID="DynamicDataManager1" runat="server" AutoLoadForeignKeys="true" /> Line 8:  Line 9:      <h2><%= table.DisplayName%></h2> Probable Causes The server does not have .NET 3.5 SP1, which includes ASP.NET Dynamic Data, installed. Download it here. The third tagPrefix shown below is missing from web.config <pages> <controls> <add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add tagPrefix="asp" namespace="System.Web.UI.WebControls" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add tagPrefix="asp" namespace="System.Web.DynamicData" assembly="System.Web.DynamicData, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </controls></pages>     Hope that helps!

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  • Joins in LINQ to SQL

    - by rajbk
    The following post shows how to write different types of joins in LINQ to SQL. I am using the Northwind database and LINQ to SQL for these examples. NorthwindDataContext dataContext = new NorthwindDataContext(); Inner Join var q1 = from c in dataContext.Customers join o in dataContext.Orders on c.CustomerID equals o.CustomerID select new { c.CustomerID, c.ContactName, o.OrderID, o.OrderDate }; SELECT [t0].[CustomerID], [t0].[ContactName], [t1].[OrderID], [t1].[OrderDate]FROM [dbo].[Customers] AS [t0]INNER JOIN [dbo].[Orders] AS [t1] ON [t0].[CustomerID] = [t1].[CustomerID] Left Join var q2 = from c in dataContext.Customers join o in dataContext.Orders on c.CustomerID equals o.CustomerID into g from a in g.DefaultIfEmpty() select new { c.CustomerID, c.ContactName, a.OrderID, a.OrderDate }; SELECT [t0].[CustomerID], [t0].[ContactName], [t1].[OrderID] AS [OrderID], [t1].[OrderDate] AS [OrderDate]FROM [dbo].[Customers] AS [t0]LEFT OUTER JOIN [dbo].[Orders] AS [t1] ON [t0].[CustomerID] = [t1].[CustomerID] Inner Join on multiple //We mark our anonymous type properties as a and b otherwise//we get the compiler error "Type inferencce failed in the call to 'Join’var q3 = from c in dataContext.Customers join o in dataContext.Orders on new { a = c.CustomerID, b = c.Country } equals new { a = o.CustomerID, b = "USA" } select new { c.CustomerID, c.ContactName, o.OrderID, o.OrderDate }; SELECT [t0].[CustomerID], [t0].[ContactName], [t1].[OrderID], [t1].[OrderDate]FROM [dbo].[Customers] AS [t0]INNER JOIN [dbo].[Orders] AS [t1] ON ([t0].[CustomerID] = [t1].[CustomerID]) AND ([t0].[Country] = @p0) Inner Join on multiple with ‘OR’ clause var q4 = from c in dataContext.Customers from o in dataContext.Orders.Where(a => a.CustomerID == c.CustomerID || c.Country == "USA") select new { c.CustomerID, c.ContactName, o.OrderID, o.OrderDate }; SELECT [t0].[CustomerID], [t0].[ContactName], [t1].[OrderID], [t1].[OrderDate]FROM [dbo].[Customers] AS [t0], [dbo].[Orders] AS [t1]WHERE ([t1].[CustomerID] = [t0].[CustomerID]) OR ([t0].[Country] = @p0) Left Join on multiple with ‘OR’ clause var q5 = from c in dataContext.Customers from o in dataContext.Orders.Where(a => a.CustomerID == c.CustomerID || c.Country == "USA").DefaultIfEmpty() select new { c.CustomerID, c.ContactName, o.OrderID, o.OrderDate }; SELECT [t0].[CustomerID], [t0].[ContactName], [t1].[OrderID] AS [OrderID], [t1].[OrderDate] AS [OrderDate]FROM [dbo].[Customers] AS [t0]LEFT OUTER JOIN [dbo].[Orders] AS [t1] ON ([t1].[CustomerID] = [t0].[CustomerID]) OR ([t0].[Country] = @p0)

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  • Using delegates in C# (Part 2)

    - by rajbk
    Part 1 of this post can be read here. We are now about to see the different syntaxes for invoking a delegate and some c# syntactic sugar which allows you to code faster. We have the following console application. 1: public delegate double Operation(double x, double y); 2:  3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: Operation op1 = new Operation(Division); 9: double result = op1.Invoke(10, 5); 10: 11: Console.WriteLine(result); 12: Console.ReadLine(); 13: } 14: 15: static double Division(double x, double y) { 16: return x / y; 17: } 18: } Line 1 defines a delegate type called Operation with input parameters (double x, double y) and a return type of double. On Line 8, we create an instance of this delegate and set the target to be a static method called Division (Line 15) On Line 9, we invoke the delegate (one entry in the invocation list). The program outputs 5 when run. The language provides shortcuts for creating a delegate and invoking it (see line 9 and 11). Line 9 is a syntactical shortcut for creating an instance of the Delegate. The C# compiler will infer on its own what the delegate type is and produces intermediate language that creates a new instance of that delegate. Line 11 uses a a syntactical shortcut for invoking the delegate by removing the Invoke method. The compiler sees the line and generates intermediate language which invokes the delegate. When this code is compiled, the generated IL will look exactly like the IL of the compiled code above. 1: public delegate double Operation(double x, double y); 2:  3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: //shortcut constructor syntax 9: Operation op1 = Division; 10: //shortcut invoke syntax 11: double result = op1(10, 2); 12: 13: Console.WriteLine(result); 14: Console.ReadLine(); 15: } 16: 17: static double Division(double x, double y) { 18: return x / y; 19: } 20: } C# 2.0 introduced Anonymous Methods. Anonymous methods avoid the need to create a separate method that contains the same signature as the delegate type. Instead you write the method body in-line. There is an interesting fact about Anonymous methods and closures which won’t be covered here. Use your favorite search engine ;-)We rewrite our code to use anonymous methods (see line 9): 1: public delegate double Operation(double x, double y); 2:  3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: //Anonymous method 9: Operation op1 = delegate(double x, double y) { 10: return x / y; 11: }; 12: double result = op1(10, 2); 13: 14: Console.WriteLine(result); 15: Console.ReadLine(); 16: } 17: 18: static double Division(double x, double y) { 19: return x / y; 20: } 21: } We could rewrite our delegate to be of a generic type like so (see line 2 and line 9). You will see why soon. 1: //Generic delegate 2: public delegate T Operation<T>(T x, T y); 3:  4: public class Program 5: { 6: [STAThread] 7: static void Main(string[] args) 8: { 9: Operation<double> op1 = delegate(double x, double y) { 10: return x / y; 11: }; 12: double result = op1(10, 2); 13: 14: Console.WriteLine(result); 15: Console.ReadLine(); 16: } 17: 18: static double Division(double x, double y) { 19: return x / y; 20: } 21: } The .NET 3.5 framework introduced a whole set of predefined delegates for us including public delegate TResult Func<T1, T2, TResult>(T1 arg1, T2 arg2); Our code can be modified to use this delegate instead of the one we declared. Our delegate declaration has been removed and line 7 has been changed to use the Func delegate type. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: //Func is a delegate defined in the .NET 3.5 framework 7: Func<double, double, double> op1 = delegate (double x, double y) { 8: return x / y; 9: }; 10: double result = op1(10, 2); 11: 12: Console.WriteLine(result); 13: Console.ReadLine(); 14: } 15: 16: static double Division(double x, double y) { 17: return x / y; 18: } 19: } .NET 3.5 also introduced lambda expressions. A lambda expression is an anonymous function that can contain expressions and statements, and can be used to create delegates or expression tree types. We change our code to use lambda expressions. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: //lambda expression 7: Func<double, double, double> op1 = (x, y) => x / y; 8: double result = op1(10, 2); 9: 10: Console.WriteLine(result); 11: Console.ReadLine(); 12: } 13: 14: static double Division(double x, double y) { 15: return x / y; 16: } 17: } C# 3.0 introduced the keyword var (implicitly typed local variable) where the type of the variable is inferred based on the type of the associated initializer expression. We can rewrite our code to use var as shown below (line 7).  The implicitly typed local variable op1 is inferred to be a delegate of type Func<double, double, double> at compile time. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: //implicitly typed local variable 7: var op1 = (x, y) => x / y; 8: double result = op1(10, 2); 9: 10: Console.WriteLine(result); 11: Console.ReadLine(); 12: } 13: 14: static double Division(double x, double y) { 15: return x / y; 16: } 17: } You have seen how we can write code in fewer lines by using a combination of the Func delegate type, implicitly typed local variables and lambda expressions.

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  • Pre-filtering and shaping OData feeds using WCF Data Services and the Entity Framework - Part 2

    - by rajbk
    In the previous post, you saw how to create an OData feed and pre-filter the data. In this post, we will see how to shape the data. A sample project is attached at the bottom of this post. Pre-filtering and shaping OData feeds using WCF Data Services and the Entity Framework - Part 1 Shaping the feed The Product feed we created earlier returns too much information about our products. Let’s change this so that only the following properties are returned – ProductID, ProductName, QuantityPerUnit, UnitPrice, UnitsInStock. We also want to return only Products that are not discontinued.  Splitting the Entity To shape our data according to the requirements above, we are going to split our Product Entity into two and expose one through the feed. The exposed entity will contain only the properties listed above. We will use the other Entity in our Query Interceptor to pre-filter the data so that discontinued products are not returned. Go to the design surface for the Entity Model and make a copy of the Product entity. A “Product1” Entity gets created.   Rename Product1 to ProductDetail. Right click on the Product entity and select “Add Association” Make a one to one association between Product and ProductDetails.   Keep only the properties we wish to expose on the Product entity and delete all other properties on it (see diagram below). You delete a property on an Entity by right clicking on the property and selecting “delete”. Keep the ProductID on the ProductDetail. Delete any other property on the ProductDetail entity that is already present in the Product entity. Your design surface should look like below:    Mapping Entity to Database Tables Right click on “ProductDetail” and go to “Table Mapping”   Add a mapping to the “Products” table in the Mapping Details.   After mapping ProductDetail, you should see the following.   Add a referential constraint. Lets add a referential constraint which is similar to a referential integrity constraint in SQL. Double click on the Association between the Entities and add the constraint with “Principal” set to “Product”. Let us review what we did so far. We made a copy of the Product entity and called it ProductDetail We created a one to one association between these entities Excluding the ProductID, we made sure properties were not duplicated between these entities  We added a ProductDetail entity to Products table mapping (Entity to Database). We added a referential constraint between the entities. Lets build our project. We get the following error: ”'NortwindODataFeed.Product' does not contain a definition for 'Discontinued' and no extension method 'Discontinued' accepting a first argument of type 'NortwindODataFeed.Product' could be found …" The reason for this error is because our Product Entity no longer has a “Discontinued” property. We “moved” it to the ProductDetail entity since we want our Product Entity to contain only properties that will be exposed by our feed. Since we have a one to one association between the entities, we can easily rewrite our Query Interceptor like so: [QueryInterceptor("Products")] public Expression<Func<Product, bool>> OnReadProducts() { return o => o.ProductDetail.Discontinued == false; } Similarly, all “hidden” properties of the Product table are available to us internally (through the ProductDetail Entity) for any additional logic we wish to implement. Compile the project and view the feed. We see that the feed returns only the properties that were part of the requirement.   To see the data in JSON format, you have to create a request with the following request header Accept: application/json, text/javascript, */* (easy to do in jQuery) The result should look like this: { "d" : { "results": [ { "__metadata": { "uri": "http://localhost.:2576/DataService.svc/Products(1)", "type": "NorthwindModel.Product" }, "ProductID": 1, "ProductName": "Chai", "QuantityPerUnit": "10 boxes x 20 bags", "UnitPrice": "18.0000", "UnitsInStock": 39 }, { "__metadata": { "uri": "http://localhost.:2576/DataService.svc/Products(2)", "type": "NorthwindModel.Product" }, "ProductID": 2, "ProductName": "Chang", "QuantityPerUnit": "24 - 12 oz bottles", "UnitPrice": "19.0000", "UnitsInStock": 17 }, { ... ... If anyone has the $format operation working, please post a comment. It was not working for me at the time of writing this.  We have successfully pre-filtered our data to expose only products that have not been discontinued and shaped our data so that only certain properties of the Entity are exposed. Note that there are several other ways you could implement this like creating a QueryView, Stored Procedure or DefiningQuery. You have seen how easy it is to create an OData feed, shape the data and pre-filter it by hardly writing any code of your own. For more details on OData, Google it with your favorite search engine :-) Also check out the one of the most passionate persons I have ever met, Pablo Castro – the Architect of Aristoria WCF Data Services. Watch his MIX 2010 presentation titled “OData: There's a Feed for That” here. Download Sample Project for VS 2010 RTM NortwindODataFeed.zip

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  • Creating an ASP.NET report using Visual Studio 2010 - Part 2

    - by rajbk
    We continue building our report in this three part series. Creating an ASP.NET report using Visual Studio 2010 - Part 1 Creating an ASP.NET report using Visual Studio 2010 - Part 3 Creating the Client Report Definition file (RDLC) Add a folder called “RDLC”. This will hold our RDLC report.   Right click on the RDLC folder, select “Add new item..” and add an “RDLC” name of “Products”. We will use the “Report Wizard” to walk us through the steps of creating the RDLC.   In the next dialog, give the dataset a name called “ProductDataSet”. Change the data source to “NorthwindReports.DAL” and select “ProductRepository(GetProductsProjected)”. The fields that are returned from the method are shown on the right. Click next.   Drag and drop the ProductName, CategoryName, UnitPrice and Discontinued into the Values container. Note that you can create much more complex grouping using this UI. Click Next.   Most of the selections on this screen are grayed out because we did not choose a grouping in the previous screen. Click next. Choose a style for your report. Click next. The report graphic design surface is now visible. Right click on the report and add a page header and page footer. With the report design surface active, drag and drop a TextBox from the tool box to the page header. Drag one more textbox to the page header. We will use the text boxes to add some header text as shown in the next figure. You can change the font size and other properties of the textboxes using the formatting tool bar (marked in red). You can also resize the columns by moving your cursor in between columns and dragging. Adding Expressions Add two more text boxes to the page footer. We will use these to add the time the report was generated and page numbers. Right click on the first textbox in the page footer and select “Expression”. Add the following expression for the print date (note the = sign at the left of the expression in the dialog below) "© Northwind Traders " & Format(Now(),"MM/dd/yyyy hh:mm tt") Right click on the second text box and add the following for the page count.   Globals.PageNumber & " of " & Globals.TotalPages Formatting the page footer is complete.   We are now going to format the “Unit Price” column so it displays the number in currency format.  Right click on the [UnitPrice] column (not header) and select “Text Box Properties..” Under “Number”, select “Currency”. Hit OK. Adding a chart With the design surface active, go to the toolbox and drag and drop a chart control. You will need to move the product list table down first to make space for the chart contorl. The document can also be resized by dragging on the corner or at the page header/footer separator. In the next dialog, pick the first chart type. This can be changed later if needed. Click OK. The chart gets added to the design surface.   Click on the blue bars in the chart (not legend). This will bring up drop locations for dropping the fields. Drag and drop the UnitPrice and CategoryName into the top (y axis) and bottom (x axis) as shown below. This will give us the total unit prices for a given category. That is the best I could come up with as far as what report to render, sorry :-) Delete the legend area to get more screen estate. Resize the chart to your liking. Change the header, x axis and y axis text by double clicking on those areas. We made it this far. Let’s impress the client by adding a gradient to the bar graph :-) Right click on the blue bar and select “Series properties”. Under “Fill”, add a color and secondary color and select the Gradient style. We are done designing our report. In the next section you will see how to add the report to the report viewer control, bind to the data and make it refresh when the filter criteria are changed.   Creating an ASP.NET report using Visual Studio 2010 - Part 3

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  • Adding an expression based image in a client report definition file (RDLC)

    - by rajbk
    In previous posts, I showed you how to create a report using Visual Studio 2010 and how to add a hyperlink to the report.  In this post, I show you how to add an expression based image to each row of the report. This similar to displaying a checkbox column for Boolean values.  A sample project is attached to the bottom of this post. To start off, download the project we created earlier from here.  The report we created had a “Discontinued” column of type Boolean. We are going to change it to display an “available” icon or “unavailable” icon based on the “Discontinued” row value.    Load the project and double click on Products.rdlc. With the report design surface active, you will see the “Report Data” tool window. Right click on the Images folder and select “Add Image..”   Add the available_icon.png and discontinued_icon.png images (the sample project at the end of this post has the icon png files)    You can see the images we added in the “Report Data” tool window.   Drag and drop the available_icon into the “Discontinued” column row (not the header) We get a dialog box which allows us to set the image properties. We will add an expression that specifies the image to display based the “Discontinued” value from the Product table. Click on the expression (fx) button.   Add the following expression : = IIf(Fields!Discontinued.Value = True, “discontinued_icon”, “available_icon”)   Save and exit all dialog boxes. In the report design surface, resize the column header and change the text from “Discontinued” to “In Production”.   (Optional) Right click on the image cell (not header) , go to “Image Properties..” and offset it by 5pt from the left. (Optional) Change the border color since it is not set by default for image columns. We are done adding our image column! Compile the application and run it. You will see that the “In Production” column has red ‘x’ icons for discontinued products. Download the VS 2010 sample project NorthwindReportsImage.zip Other Posts Adding a hyperlink in a client report definition file (RDLC) Rendering an RDLC directly to the Response stream in ASP.NET MVC ASP.NET MVC Paging/Sorting/Filtering using the MVCContrib Grid and Pager Localization in ASP.NET MVC 2 using ModelMetadata Setting up Visual Studio 2010 to step into Microsoft .NET Source Code Running ASP.NET Webforms and ASP.NET MVC side by side Pre-filtering and shaping OData feeds using WCF Data Services and the Entity Framework

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  • ASP.NET Asynchronous Pages and when to use them

    - by rajbk
    There have been several articles posted about using  asynchronous pages in ASP.NET but none of them go into detail as to when you should use them. I finally found a great post by Thomas Marquardt that explains the process in depth. He addresses a key misconception also: So, in your ASP.NET application, when should you perform work asynchronously instead of synchronously? Well, only 1 thread per CPU can execute at a time.  Did you catch that?  A lot of people seem to miss this point...only one thread executes at a time on a CPU. When you have more than this, you pay an expensive penalty--a context switch. However, if a thread is blocked waiting on work...then it makes sense to switch to another thread, one that can execute now.  It also makes sense to switch threads if you want work to be done in parallel as opposed to in series, but up until a certain point it actually makes much more sense to execute work in series, again, because of the expensive context switch. Pop quiz: If you have a thread that is doing a lot of computational work and using the CPU heavily, and this takes a while, should you switch to another thread? No! The current thread is efficiently using the CPU, so switching will only incur the cost of a context switch. Ok, well, what if you have a thread that makes an HTTP or SOAP request to another server and takes a long time, should you switch threads? Yes! You can perform the HTTP or SOAP request asynchronously, so that once the "send" has occurred, you can unwind the current thread and not use any threads until there is an I/O completion for the "receive". Between the "send" and the "receive", the remote server is busy, so locally you don't need to be blocking on a thread, but instead make use of the asynchronous APIs provided in .NET Framework so that you can unwind and be notified upon completion. Again, it only makes sense to switch threads if the benefit from doing so out weights the cost of the switch. Read more about it in these posts: Performing Asynchronous Work, or Tasks, in ASP.NET Applications http://blogs.msdn.com/tmarq/archive/2010/04/14/performing-asynchronous-work-or-tasks-in-asp-net-applications.aspx ASP.NET Thread Usage on IIS 7.0 and 6.0 http://blogs.msdn.com/tmarq/archive/2007/07/21/asp-net-thread-usage-on-iis-7-0-and-6-0.aspx   PS: I generally do not write posts that simply link to other posts but think it is warranted in this case.

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  • Running a Silverlight application in the Google App Engine platform

    - by rajbk
    This post shows you how to host a Silverlight application in the Google App Engine (GAE) platform. You deploy and host your Silverlight application on Google’s infrastructure by creating a configuration file and uploading it along with your application files. I tested this by uploading an old demo of mine - the four stroke engine silverlight demo. It is currently being served by the GAE over here: http://fourstrokeengine.appspot.com/ The steps to run your Silverlight application in GAE are as follows: Account Creation Create an account at http://appengine.google.com/. You are allocated a free quota at signup. Select “Create an Application”   Verify your account by SMS   Create your application by clicking on “Create an Application”   Pick an application identifier on the next screen. The identifier has to be unique. You will use this identifier when uploading your application. The application you create will by default be accessible at [applicationidentifier].appspot.com. You can also use custom domains if needed (refer to the docs).   Save your application. Download SDK  We will use the  Windows Launcher for Google App Engine tool to upload our apps (it is possible to do the same through command line). This is a GUI for creating, running and deploying applications. The launcher lets you test the app locally before deploying it to the GAE. This tool is available in the Google App Engine SDK. The GUI is written in Python and therefore needs an installation of Python to run. Download and install the Python Binaries from here: http://www.python.org/download/ Download and install the Google App Engine SDK from here: http://code.google.com/appengine/downloads.html Run the GAE Launcher. Select Create New Application.   On the next dialog, give your application a name (this must match the identifier we created earlier) For Parent Directory, point to the directory containing your Silverlight files. Change the port if you want to. The port is used by the GAE local web server. The server is started if you choose to run the application locally for testing purposes. Hit Save. Configure, Test and Upload As shown below, the files I am interested in uploading for my Silverlight demo app are The html page used to host the Silverlight control The xap file containing the compiled Silverlight application A favicon.ico file.   We now create a configuration file for our application called app.yaml. The app.yaml file specifies how URL paths correspond to request handlers and static files.  We edit the file by selecting our app in the GUI and clicking “Edit” The contents of file after editing is shown below (note that the contents of the file should be in plain text): application: fourstrokeengine version: 1 runtime: python api_version: 1 handlers: - url: /   static_files: Default.html   upload: Default.html - url: /favicon.ico   static_files: favicon.ico   upload: favicon.ico - url: /FourStrokeEngine.xap   static_files: FourStrokeEngine.xap   upload: FourStrokeEngine.xap   mime_type: application/x-silverlight-app - url: /.*   static_files: Default.html   upload: Default.html We have listed URL patterns for our files, specified them as static files and specified a mime type for our xap file. The wild card URL at the end will match all URLs that are not found to our default page (you would normally include a html file that displays a 404 message).  To understand more about app.yaml, refer to this page. Save the file. Run the application locally by selecting “Browse” in the GUI. A web server listening on the port you specified is started (8080 in my case). The app is loaded in your default web browser pointing to http://localhost:8080/. Make sure the application works as expected. We are now ready to deploy. Click the “Deploy” icon. You will be prompted for your username and password. Hit OK. The files will get uploaded and you should get a dialog telling you to “close the window”. We are done uploading our Silverlight application. Go to http://appengine.google.com/ and launch the application by clicking on the link in the “Current Version” column.   You should be taken to a URL which points to your application running in Google’s infrastructure : http://fourstrokeengine.appspot.com/. We are done deploying our application! Clicking on the link in the Application column will take you to the Admin console where you can see stats related to system usage.  To learn more about the Google Application Engine, go here: http://code.google.com/appengine/docs/whatisgoogleappengine.html

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  • Editing Project files, Resource Editors in VS 2010

    - by rajbk
    Editing Project Files Visual Studio 2010 gives you the ability to easily edit the project file associated with your project (.csproj or .vbproj). You might do this to change settings related to how the project is compiled since proj files are MSBuild files. One would normally close Visual Studio and edit the proj file using a text editor.  The better way is to first unload the project in Visual Studio by right clicking on the project in the solution explorer and selecting “Unload Project”   The project gets unloaded and is marked “unavailable” The project file can now be edited by right clicking on the unloaded project.    After editing the file, the project can be reloaded. Resource editors in VS 2010 Visual studio also comes with a number of resource editors (see list here). For example, you could open a file using the Binary editor like so. Go to File > Open > File.. Select a File and choose the “Open With..” option in the bottom right.   We are given the option to choose an editor.   Note that clicking on the “Add..” in the dialog above allows you to include your favorite editor.   Choosing the “Binary editor” above allows us to edit the file in hex format. In addition, we can also search for hex bytes or ASCII strings using the Find command.   The “Open With..” option is also available from within the solution explorer as shown below: Enjoy!   Mr. Incredible: No matter how many times you save the world, it always manages to get back in jeopardy again. Sometimes I just want it to stay saved! You know, for a little bit? I feel like the maid; I just cleaned up this mess! Can we keep it clean for... for ten minutes!

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  • Easy way to update models in your ASP.NET MVC business layer

    - by rajbk
    Brad Wilson just mentioned there is a static class ModelCopier that has a static method CopyModel(object from, object to) in the MVC Futures library. It uses reflection to match properties with the same name and compatible types. In short, instead of manually copying over properties as shown here: public void Save(EmployeeViewModel employeeViewModel){ var employee = (from emp in dataContext.Employees where emp.EmployeeID == employeeViewModel.EmployeeID select emp).SingleOrDefault(); if (employee != null) { employee.Address = employeeViewModel.Address; employee.Salary = employeeViewModel.Salary; employee.Title = employeeViewModel.Title; } dataContext.SubmitChanges();} you can use the method like so: public void Save(EmployeeViewModel employeeViewModel){ var employee = (from emp in dataContext.Employees where emp.EmployeeID == employeeViewModel.EmployeeID select emp).SingleOrDefault(); if (employee != null) { ModelCopier.CopyModel(employeeViewModel, employee); } dataContext.SubmitChanges();} Beautiful, isn’t it?

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