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  • Progressively stream the output of an ASP.NET page - or render a page outside of an HTTP request

    - by Evgeny
    I have an ASP.NET 2.0 page with many repeating blocks, including a third-party server-side control (so it's not just plain HTML). Each is quite expensive to generate, in terms of both CPU and RAM. I'm currently using a standard Repeater control for this. There are two problems with this simple approach: The entire page must be rendered before any of it is returned to the client, so the user must wait a long time before they see any data. (I write progress messages using Response.Write, so there is feedback, but no actual results.) The ASP.NET worker process must hold everything in memory at the same time. There is no inherent needs for this: once one block is processed it won't be changed, so it could be returned to the client and the memory could be freed. I would like to somehow return these blocks to the client one at a time, as each is generated. I'm thinking of extracting the stuff inside the Repeater into a separate page and getting it repeatedly using AJAX, but there are some complications involved in that and I wonder if there is some simper approach. Ideally I'd like to keep it as one page (from the client's point of view), but return it incrementally. Another way would be to do something similar, but on the server: still create a separate page, but have the server access it and then Response.Write() the HTML it gets to the response stream for the real client request. Is there a way to avoid an HTTP request here, though? Is there some ASP.NET method that would render a UserControl or a Page outside of an HTTP request and simply return the HTML to me as a string? I'm open to other ideas on how to do this as well.

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  • asp.net dropdown iniside datagrid

    - by harold-sota
    I'm inserting a dropdwon list in datagrid on row editing. When i run the project the datasource is not rekognized. The asp.net part is there: <asp:TemplateField HeaderText="Lookup 1"> <EditItemTemplate> <asp:DropDownList ID="Loocup1DropDownList" Width="100%" runat="server" DataSource ="<%GetValueForDropDownCombinationContent()%>" DataValueField="LOOKUP_ID" DataTextField="lookup_name" > </asp:DropDownList> </EditItemTemplate> <ItemTemplate> <asp:Label ID="LOOKUP1_NAME" runat="server" Text='<%# Bind("LOOKUP1_NAME") %>'></asp:Label> </ItemTemplate> This is the vb.net function: Protected Function GetValueForDropDownCombinationContent() As DataSet Dim dsProductLookups As New DataSet dsProductLookups = DocumentManager.Data.DataRepository.Provider.ExecuteDataSet("sp_GetCombinationsLookups", productCombo.SelectedValue) Return dsProductLookups End Function any ideas???

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  • Control button Post Back when click it in ASP.NET with VB.NET

    - by Lefteris Gkinis
    In my Default.aspx web page i use the following code in order to save some Attributes to an xml file <asp:Button ID="Button1" Text="Save Attributes" CssClass="Button01" runat="server" OnClientClick="SaveAttributesButton_Click(); return, false;" > </asp:Button> when i Click on the button that starts to make postback all the code right from the page load I have already use the HTML Button but this need a java script which is run when the page load And sub without my command Please is there anybody which can assist me on this issue?

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  • How to adjust asp.net URL routing based on domain/host?

    - by DrewF
    What's the best way to adjust the path destination for a routing table created in the global.asax Application_Start event based on the domain/sub domain/host? The following worked in IIS6, but with IIS7 the request object is decoupled from the Application_Start event and therefore does not work anymore: Dim strHost As String = Context.Request.Url.Host Dim strDir As String = "" If strHost.Contains("domain1.com") Then strDir = "area1/" Else strDir = "area2/" End If routes.MapPageRoute("Search", "Search", "~/" & strDir & "search.aspx")

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  • .NET make a copy of an embedded file resource to the local drive

    - by Matt H.
    Hi, i'm new to the realm to working with Files in .NET I'm creating a WPF application in VB.NET with the 3.5 Framework. (If you provide an example in C#, that's perfectly fine.) In my project I have a Template for an MS Access database. My desired behavior is that when the users clicks File--New, they can create a new copy of this template, give it a filename, and save it to their local directory. The database already has the tables and some starting data needed to interface with my application (a user-friendly data editor) I'm thinking the approach is to include this "template.accdb" file as a resource in the project, and write it to a file somehow at runtime? Any guidance will be very, very appreciated. Thanks!

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  • Strange behaviour on postback in ASP.NET

    - by C-King
    I'm working on a website with a login form. To log in, a postback is used to an OnClick handler in the codebehind. Somehow, the value returned from the Text-property of the username and password textboxes is ten times the value I entered, separated by commas. I checked my entire code for double ID's (which seems to be the most common problem causing this behaviour), but I found each ID defined only once. In the ASPX file I have this: <asp:Label ID="lblFeedback" ForeColor="Red" Font-Bold="true" runat="server" Visible="false" /><br /> <asp:Panel ID="pnlLogin" runat="server"> <table style="border-style: none;"> <tr> <td> <asp:Label ID="lblUsername" AssociatedControlID="txtUsername" runat="server" /> </td> <td> <asp:TextBox ID="txtUsername" runat="server" /><br /> </td> </tr> <tr> <td> <asp:Label ID="lblPassword" AssociatedControlID="txtPassword" runat="server" /> </td> <td> <asp:TextBox ID="txtPassword" runat="server" TextMode="password" /><br /> </td> </tr> <tr> <td> </td> <td> <asp:Button ID="btnLogin" OnClick="btnLogin_Click" runat="server" /> </td> </tr> </table> </asp:Panel> The OnClick handler in the Codebehind: protected void btnLogin_Click(object sender, EventArgs e) { string username = Util.Escape(txtUsername.Text); string password = Util.Escape(txtPassword.Text); WebsiteUser user = WebsiteUser.Create(username, password); if (user != null) { //Set some session variables and redirect to user profile } else { lblFeedback.Text = Localizer.Translate("INVALID_LOGIN"); lblFeedback.ForeColor = Color.Red; lblFeedback.Visible = true; pnlLogin.Visible = true; } } The website is running on ASP.NET 2.0 on ISS 5.1 (Win XP Pro)

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  • Which is the "best" data access framework/approach for C# and .NET?

    - by Frans
    (EDIT: I made it a community wiki as it is more suited to a collaborative format.) There are a plethora of ways to access SQL Server and other databases from .NET. All have their pros and cons and it will never be a simple question of which is "best" - the answer will always be "it depends". However, I am looking for a comparison at a high level of the different approaches and frameworks in the context of different levels of systems. For example, I would imagine that for a quick-and-dirty Web 2.0 application the answer would be very different from an in-house Enterprise-level CRUD application. I am aware that there are numerous questions on Stack Overflow dealing with subsets of this question, but I think it would be useful to try to build a summary comparison. I will endeavour to update the question with corrections and clarifications as we go. So far, this is my understanding at a high level - but I am sure it is wrong... I am primarily focusing on the Microsoft approaches to keep this focused. ADO.NET Entity Framework Database agnostic Good because it allows swapping backends in and out Bad because it can hit performance and database vendors are not too happy about it Seems to be MS's preferred route for the future Complicated to learn (though, see 267357) It is accessed through LINQ to Entities so provides ORM, thus allowing abstraction in your code LINQ to SQL Uncertain future (see Is LINQ to SQL truly dead?) Easy to learn (?) Only works with MS SQL Server See also Pros and cons of LINQ "Standard" ADO.NET No ORM No abstraction so you are back to "roll your own" and play with dynamically generated SQL Direct access, allows potentially better performance This ties in to the age-old debate of whether to focus on objects or relational data, to which the answer of course is "it depends on where the bulk of the work is" and since that is an unanswerable question hopefully we don't have to go in to that too much. IMHO, if your application is primarily manipulating large amounts of data, it does not make sense to abstract it too much into objects in the front-end code, you are better off using stored procedures and dynamic SQL to do as much of the work as possible on the back-end. Whereas, if you primarily have user interaction which causes database interaction at the level of tens or hundreds of rows then ORM makes complete sense. So, I guess my argument for good old-fashioned ADO.NET would be in the case where you manipulate and modify large datasets, in which case you will benefit from the direct access to the backend. Another case, of course, is where you have to access a legacy database that is already guarded by stored procedures. ASP.NET Data Source Controls Are these something altogether different or just a layer over standard ADO.NET? - Would you really use these if you had a DAL or if you implemented LINQ or Entities? NHibernate Seems to be a very powerful and powerful ORM? Open source Some other relevant links; NHibernate or LINQ to SQL Entity Framework vs LINQ to SQL

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  • MVC3 View For Loop values initialization

    - by Ryan
    So I have a for loop in my View that is supposed to render out the input boxes. Now inside these input boxes I want to put lables that disappear when you click on them. This is all simple. Now it's probably because my brain was wired for php first, and it has been difficult to get it to think in lambdas and object orientation, but I can't figure out how to do this: @{ for (int i = 0; i < 3; i++) { <div class="editor-label grid_2">User</div> Model.Users[i].UserFirstName = "First Name"; Model.Users[i].UserLastName = "Last Name"; Model.Users[i].UserEmailAddress = "Email Address"; <div class="grid_10"> @Html.TextBoxFor(m => Model.Users[i].UserFirstName, new { @class = "user-input" }) @Html.TextBoxFor(m => Model.Users[i].UserLastName, new { @class = "user-input" }) @Html.TextBoxFor(m => Model.Users[i].UserEmailAddress, new { @class = "user-input-long" }) @Html.CheckBoxFor(m => Model.Users[i].IsUserAdmin) <span>&nbsp;admin?</span> </div> <div class="clear"> </div> } } And initialize the values for the users. And you're probably thinking "Of course that won't work. You're going to get a Null Reference Exception", and you would be correct. I might need to initialize them somewhere else and I don't realize it but I'm just not sure. I've tried the [DefaultValue("First Name")] route and that doesn't work. I'm probably thinking about this wrong, but my brain is already shot from trying to figure out how to wire up these events to the controller, so any help would be appreciated!

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  • Pass existing model into AJAX PartialViewResult

    - by Joe
    I’m using AJAX to asynchronously update a partial view and need to pass the existing model into the partial view. Controller Action public ActionResult Edit(int id) { var vM = new MyViewModel(); // vM is viewModel return View(vM); } Edit View @using (Html.BeginForm()) { @Html.ValidationSummary(true) ... <span id = "Ship"> @Html.Partial("AJAX_Views/_Ship")</span> _Ship Partial View @model MyProject.ViewModels.MyViewModel <table class="detailtable" style="min-width:398px"> <tr> <th style="padding-left:132px" colspan="2"> <span class="editor-label">Shipping&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Address</span> <span class="editor-label" style="padding-left:55px"> @Ajax.ActionLink("Delete", "SHIPDEL", new AjaxOptions { UpdateTargetId = "Ship", InsertionMode = InsertionMode.Replace, HttpMethod = "Get" })</span> <tr><th style="min-width:152px"><span class="editor-label">Street:</span></th> @Html.HiddenFor(m => m.CmpAdrsSh.Id) @Html.HiddenFor(m => m.CmpAdrsSh.CompPersonId) @Html.HiddenFor(m => m.CmpAdrsSh.IsShip) <td><span class="editor-field">@Html.EditorFor(m => m.CmpAdrsSh.Street) @Html.ValidationMessageFor(m => m.CmpAdrsSh.Street) </span></td></tr> <tr><th><span class="editor-label">City:</span></th> <td><span class="editor-field">@Html.EditorFor(m => m.CmpAdrsSh.City) @Html.ValidationMessageFor(m => m.CmpAdrsSh.City) </span></td></tr> <tr><th><span class="editor-label">State:</span></th> <td><span class="editor-field">@Html.DropDownList("CmpAdrsSh.State", (IEnumerable<SelectListItem>)ViewBag._State) @Html.ValidationMessageFor(m => m.CmpAdrsSh.State) </span></td></tr> <tr><th><span class="editor-label">Zip:</span></th> <td><span class="editor-field">@Html.EditorFor(m => m.CmpAdrsSh.Zip) @Html.ValidationMessageFor(m => m.CmpAdrsSh.Zip) </span></td></tr> _ShipDel Partial View @model MyProject.ViewModels.MyViewModel <table class="detailtable" style="min-width:398px"> <tr> <th style="padding-left:132px" colspan="2"> <span class="editor-label">Shipping&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Address</span> <span class="editor-label" style="padding-left:10px; color:red">Marked for Deletion.</span></th></tr> <tr><td>To not Delete Select Cancel below!</td></tr> @Html.HiddenFor(m => m.CmpAdrsSh.Street) @Html.HiddenFor(m => m.CmpAdrsSh.City) @Html.HiddenFor(m => m.CmpAdrsSh.State) @Html.HiddenFor(m => m.CmpAdrsSh.Zip) Controller PartialViewResult Action public PartialViewResult SHIPDEL() { return PartialView("AJAX_Views/_ShipDel"); } I tried adding this.ModelState to the Action but then the view will not render. I'm guessing I somehow have to pass the model to the SHIPDEL Action first. I couldn't find an @Ajax.ActionLink overload that would allow this. public PartialViewResult SHIPDEL() { return PartialView("AJAX_Views/_ShipDel", this.ModelState); } In the _ShipDel Partial View I need to expose the CmpAdrsSh properties so the model validates in the POST Action. The model is empty at this point. How do I pass the existing vM model into the _ShipDel partial view? Thank you,

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  • .NET - Verify and Install .NET Framework 3.5 before running application

    - by Tufo
    PLEASE READ THE FULL QUESTION BEFORE POST YOUR ANSWER Hello guys! I'm currently developing a "Extremelly customized Installer Application" in C# for installing a old classic ASP application. It'll be used during the 2.0 version is developed (ASP.NET MVC with C#). As its so different from the efault install packages, I've made it as normal windows application, not as setup application (a setup application don't let us customize so much as I need). And here is the problem: As its a windows application, I must "Release" it and send the compiled .EXE with the .DLLs, I must not "Publish" because if i do so, the published .EXE will "install the installer" and not my application. I need a way to verify and install the .NET Framework 3.5 like a bootstrap package prerequisite used in publishing option, but remember that I'm not publishing, I'm doing a "Release" build. Thanks for any help!

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  • asp.net Wizard control strange issue

    - by epitka
    Update: There was actually a hidden panel with validator in the user control that was causing page not to be valid on the first postback. Consider this issue resolved. This is first time I am using this control and it is behaving rather strange. I have to click on the "Next" button twice for it to move to the next step. I tried explicitly setting active index, using MoveTo etc. Nothing works. Here is the markup for the control. Anybody has any ideas why? <asp:Wizard ID="UserWizard" runat="server" ActiveStepIndex="0" StartNextButtonImageUrl = "~/App_Themes/Default/images/buttons/continue.gif" StartNextButtonType="Image" StepNextButtonType="Image" StepNextButtonImageUrl="~/App_Themes/Default/images/buttons/continue.gif" FinishPreviousButtonImageUrl="~/App_Themes/Default/images/buttons/back.gif" FinishPreviousButtonType="Image" FinishCompleteButtonImageUrl="~/App_Themes/Default/images/buttons/save.gif" FinishCompleteButtonType="Image" CancelButtonType="Image" CancelButtonImageUrl="~/App_Themes/Default/images/buttons/back.gif" DisplaySideBar="false" > <WizardSteps> <asp:WizardStep Title="User Profile" ID="UserProfile" runat="server"> <uhc:ctlUserProfileEdit ID="ctlUserProfileEdit" runat="server"> </uhc:ctlUserProfileEdit> <br clear="all" /> <div> <asp:ImageButton ID="cmdResetPassword" runat="server" ImageUrl="~/App_Themes/Default/images/buttons/resetpassword.gif" /> </div> <div> <asp:UpdatePanel ID="upSchools" runat="server" ChildrenAsTriggers="true"> <ContentTemplate> <uhc:ctlSchoolLocationSelector ID="ctlSchoolLocationSelector" runat="server" /> </ContentTemplate> </asp:UpdatePanel> </div> </asp:WizardStep> <asp:WizardStep Title="Roles" ID="Roles" runat="server"> <uhc:ctlPermissionInternal ID="ctlPermissionInternal1" runat="server"></uhc:ctlPermissionInternal> <uhc:ctlPermissionExternal ID="ctlPermissionExternal1" runat="server"></uhc:ctlPermissionExternal> </asp:WizardStep> </WizardSteps> </asp:Wizard>

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  • Spring Framework 3.0.5 MVC Issue

    - by user578923
    I know that this may be absolutely dumb but for the life of me I cannot figure out why I'm getting these errors in my Spring Project, it is basically from the MVC tutorial with a few modifications. This is the error I get when running my tomcat server. `Caused by: java.lang.NoClassDefFoundError: org/springframework/web/servlet/mvc/SimpleFormController at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:634) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:277) at java.net.URLClassLoader.access$000(URLClassLoader.java:73) at java.net.URLClassLoader$1.run(URLClassLoader.java:212) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:205) at java.lang.ClassLoader.loadClass(ClassLoader.java:321) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294) at java.lang.ClassLoader.loadClass(ClassLoader.java:266) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1581) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1511) at org.springframework.util.ClassUtils.forName(ClassUtils.java:257) at org.springframework.beans.factory.support.AbstractBeanDefinition.resolveBeanClass(AbstractBeanDefinition.java:408) at org.springframework.beans.factory.support.AbstractBeanFactory.doResolveBeanClass(AbstractBeanFactory.java:1271) at org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1242) ... 54 more Caused by: java.lang.ClassNotFoundException: org.springframework.web.servlet.mvc.SimpleFormController at java.net.URLClassLoader$1.run(URLClassLoader.java:217) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:205) at java.lang.ClassLoader.loadClass(ClassLoader.java:321) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294) at java.lang.ClassLoader.loadClass(ClassLoader.java:266) ... 71 more` I just cannot figure out the issue with my classpath...I would appreciate any help. Here are all the jars in my classpath. I know that the class is inside the web-servlet jar but it's not seeing it. Is there a conflict? aopalliance.jar aspectjweaver.jar commons-codec.jar commons-dbcp.jar commons-logging.jar commons-pool.jar jstl.jar org.springframework.aop-3.0.5.RELEASE.jar org.springframework.asm-3.0.5.RELEASE.jar org.springframework.aspects-3.0.5.RELEASE.jar org.springframework.beans-3.0.5.RELEASE.jar org.springframework.context.support-3.0.5.RELEASE.jar org.springframework.context-3.0.5.RELEASE.jar org.springframework.core-3.0.5.RELEASE.jar org.springframework.expression-3.0.5.RELEASE.jar org.springframework.instrument.tomcat-3.0.5.RELEASE.jar org.springframework.instrument-3.0.5.RELEASE.jar org.springframework.jdbc-3.0.5.RELEASE.jar org.springframework.jms-3.0.5.RELEASE.jar org.springframework.orm-3.0.5.RELEASE.jar org.springframework.oxm-3.0.5.RELEASE.jar org.springframework.test-3.0.5.RELEASE.jar org.springframework.transaction-3.0.5.RELEASE.jar org.springframework.web.portlet-3.0.5.RELEASE.jar org.springframework.web.servlet-3.0.5.RELEASE.jar org.springframework.web.struts-3.0.5.RELEASE.jar org.springframework.web-3.0.5.RELEASE.jar postgresql-9.0-801.jdbc3.jar servlet-api.jar spring-security-config-3.0.5.RELEASE.jar spring-security-core-3.0.5.RELEASE.jar spring-security-web-3.0.5.RELEASE.jar standard.jar

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  • asp.net textbox with java script problem

    - by Eyla
    I'm trying to check if asp.net textbox is empty or not using java script. my code working ok but if I enter only numbers will conder it empty so I have either enter letters and numbers or only letters. Please advice. here is my code <script type="text/javascript"> function check(){ var txt = document.getElementById('<%=txt.ClientID%>').value; //(isNaN(cmbStateHome) == false if (isNaN(txt) == false) { alert("Please enter some thing."); } else {alert("ok");} } } </script> <asp:TextBox ID="txt" runat="server"></asp:TextBox> <asp:TextBox ID="txtZipCodeHome" runat="server" Style="top: 361px; left: 88px; position: absolute; <asp:LinkButton ID="LinkButton1" runat="server" OnClientClick="check()">LinkButton</asp:LinkButton>

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  • How to change the text of the multiple asp:label using for loop in C# ASP.NET

    - by Minelava
    I want to change the asp label multiple times. Here is the asp.net code <asp:Label ID="lbl_Text1" runat="server" Text=""> <asp:Label ID="lbl_Text2" runat="server" Text=""> <asp:Label ID="lbl_Text3" runat="server" Text=""> <asp:Label ID="lbl_Text4" runat="server" Text=""> Instead of using this: C# Code lbl_Text1.Text = "hello"; lbl_Text2.Text = "hello"; lbl_Text3.Text = "hello"; lbl_Text4.Text = "hello"; I tried to use for loop for (int i = 1; i <= 4; i++) { lbl_Text[i].Text = "hello"; } And I get this error..... cannot apply indexing with [] to an expression of type 'system.web.ui.webcontrols.label' Is there anyone can help me on that?

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  • JQuery within a partial view not being called

    - by XN16
    I have a view that has some jQuery to load a partial view (via a button click) into a div in the view. This works without a problem. However within the partial view I have a very similar bit of jQuery that will load another partial view into a div in the first partial view, but this isn't working, it almost seems like the jQuery in the first partial view isn't being loaded. I have tried searching for solutions, but I haven't managed to find an answer. I have also re-created the jQuery function in a @Ajax.ActionLink which works fine, however I am trying to avoid the Microsoft helpers as I am trying to learn jQuery. Here is the first partial view which contains the jQuery that doesn't seem to work, it also contains the @Ajax.ActionLink that does work: @model MyProject.ViewModels.AddressIndexViewModel <script> $(".viewContacts").click(function () { $.ajax({ url: '@Url.Action("CustomerAddressContacts", "Customer")', type: 'POST', data: { addressID: $(this).attr('data-addressid') }, cache: false, success: function (result) { $("#customerAddressContactsPartial-" + $(this).attr('data-addressid')) .html(result); }, error: function () { alert("error"); } }); return false; }); </script> <table class="customers" style="width: 100%"> <tr> <th style="width: 25%"> Name </th> <th style="width: 25%"> Actions </th> </tr> </table> @foreach (Address item in Model.Addresses) { <table style="width: 100%; border-top: none"> <tr id="[email protected]"> <td style="width: 25%; border-top: none"> @Html.DisplayFor(modelItem => item.Name) </td> <td style="width: 25%; border-top: none"> <a href="#" class="viewContacts standardbutton" data-addressid="@item.AddressID">ContactsJQ</a> @Ajax.ActionLink("Contacts", "CustomerAddressContacts", "Customer", new { addressID = item.AddressID }, new AjaxOptions { UpdateTargetId = "customerAddressContactsPartial-" + @item.AddressID, HttpMethod = "POST" }, new { @class = "standardbutton"}) </td> </tr> </table> <div id="[email protected]"></div> } If someone could explain what I am doing wrong here and how to fix it then I would be very grateful. Thanks very much.

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  • Programação paralela no .NET Framework 4 – Parte II

    - by anobre
    Olá pessoal, tudo bem? Este post é uma continuação da série iniciada neste outro post, sobre programação paralela. Meu objetivo hoje é apresentar o PLINQ, algo que poderá ser utilizado imediatamente nos projetos de vocês. Parallel LINQ (PLINQ) PLINQ nada mais é que uma implementação de programação paralela ao nosso famoso LINQ, através de métodos de extensão. O LINQ foi lançado com a versão 3.0 na plataforma .NET, apresentando uma maneira muito mais fácil e segura de manipular coleções IEnumerable ou IEnumerable<T>. O que veremos hoje é a “alteração” do LINQ to Objects, que é direcionado a coleções de objetos em memória. A principal diferença entre o LINQ to Objects “normal” e o paralelo é que na segunda opção o processamento é realizado tentando utilizar todos os recursos disponíveis para tal, obtendo uma melhora significante de performance. CUIDADO: Nem todas as operações ficam mais rápidas utilizando recursos de paralelismo. Não deixe de ler a seção “Performance” abaixo. ParallelEnumerable Tudo que a gente precisa para este post está organizado na classe ParallelEnumerable. Esta classe contém os métodos que iremos utilizar neste post, e muito mais: AsParallel AsSequential AsOrdered AsUnordered WithCancellation WithDegreeOfParallelism WithMergeOptions WithExecutionMode ForAll … O exemplo mais básico de como executar um código PLINQ é utilizando o métodos AsParallel, como o exemplo: var source = Enumerable.Range(1, 10000); var evenNums = from num in source.AsParallel() where Compute(num) > 0 select num; Algo tão interessante quanto esta facilidade é que o PLINQ não executa sempre de forma paralela. Dependendo da situação e da análise de alguns itens no cenário de execução, talvez seja mais adequado executar o código de forma sequencial – e nativamente o próprio PLINQ faz esta escolha.  É possível forçar a execução para sempre utilizar o paralelismo, caso seja necessário. Utilize o método WithExecutionMode no seu código PLINQ. Um teste muito simples onde podemos visualizar a diferença é demonstrado abaixo: static void Main(string[] args) { IEnumerable<int> numbers = Enumerable.Range(1, 1000); IEnumerable<int> results = from n in numbers.AsParallel() where IsDivisibleByFive(n) select n; Stopwatch sw = Stopwatch.StartNew(); IList<int> resultsList = results.ToList(); Console.WriteLine("{0} itens", resultsList.Count()); sw.Stop(); Console.WriteLine("Tempo de execução: {0} ms", sw.ElapsedMilliseconds); Console.WriteLine("Fim..."); Console.ReadKey(true); } static bool IsDivisibleByFive(int i) { Thread.SpinWait(2000000); return i % 5 == 0; }   Basta remover o AsParallel da instrução LINQ que você terá uma noção prática da diferença de performance. 1. Instrução utilizando AsParallel   2. Instrução sem utilizar paralelismo Performance Apesar de todos os benefícios, não podemos utilizar PLINQ sem conhecer todos os seus detalhes. Lembre-se de fazer as perguntas básicas: Eu tenho trabalho suficiente que justifique utilizar paralelismo? Mesmo com o overhead do PLINQ, vamos ter algum benefício? Por este motivo, visite este link e conheça todos os aspectos, antes de utilizar os recursos disponíveis. Conclusão Utilizar recursos de paralelismo é ótimo, aumenta a performance, utiliza o investimento realizado em hardware – tudo isso sem custo de produtividade. Porém, não podemos usufruir de qualquer tipo de tecnologia sem conhece-la a fundo antes. Portanto, faça bom uso, mas não esqueça de manter o conhecimento a frente da empolgação. Abraços.

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