Search Results

Search found 25440 results on 1018 pages for 'agent based modeling'.

Page 889/1018 | < Previous Page | 885 886 887 888 889 890 891 892 893 894 895 896  | Next Page >

  • WPF ObservableCollection in xaml

    - by Cloverness
    Hi, I have created an ObservableCollection in the code behind of a user control. It is created when the window loads: private void UserControl_Loaded(object sender, RoutedEventArgs e) { Entities db = new Entities(); ObservableCollection<Image> _imageCollection = new ObservableCollection<Image>(); IEnumerable<library> libraryQuery = from c in db.ElectricalLibraries select c; foreach (ElectricalLibrary c in libraryQuery) { Image finalImage = new Image(); finalImage.Width = 80; BitmapImage logo = new BitmapImage(); logo.BeginInit(); logo.UriSource = new Uri(c.url); logo.EndInit(); finalImage.Source = logo; _imageCollection.Add(finalImage); } } I need to get the ObservableCollection of images which are created based on the url saved in a database. But I need a ListView or other ItemsControl to bind to it in XAML file like this: But I can't figure it out how to pass the ObservableCollection to the ItemsSource of that control. I tried to create a class and then create an instance of a class in xaml file but it did not work. Should I create a static resource somehow Any help will be greatly appreciated.

    Read the article

  • GridView ObjectDataSource LINQ Paging and Sorting using multiple table query.

    - by user367426
    I am trying to create a pageing and sorting object data source that before execution returns all results, then sorts on these results before filtering and then using the take and skip methods with the aim of retrieving just a subset of results from the database (saving on database traffic). this is based on the following article: http://www.singingeels.com/Blogs/Nullable/2008/03/26/Dynamic_LINQ_OrderBy_using_String_Names.aspx Now I have managed to get this working even creating lambda expressions to reflect the sort expression returned from the grid even finding out the data type to sort for DateTime and Decimal. public static string GetReturnType<TInput>(string value) { var param = Expression.Parameter(typeof(TInput), "o"); Expression a = Expression.Property(param, "DisplayPriceType"); Expression b = Expression.Property(a, "Name"); Expression converted = Expression.Convert(Expression.Property(param, value), typeof(object)); Expression<Func<TInput, object>> mySortExpression = Expression.Lambda<Func<TInput, object>>(converted, param); UnaryExpression member = (UnaryExpression)mySortExpression.Body; return member.Operand.Type.FullName; } Now the problem I have is that many of the Queries return joined tables and I would like to sort on fields from the other tables. So when executing a query you can create a function that will assign the properties from other tables to properties created in the partial class. public static Account InitAccount(Account account) { account.CurrencyName = account.Currency.Name; account.PriceTypeName = account.DisplayPriceType.Name; return account; } So my question is, is there a way to assign the value from the joined table to the property of the current table partial class? i have tried using. from a in dc.Accounts where a.CompanyID == companyID && a.Archived == null select new { PriceTypeName = a.DisplayPriceType.Name}) but this seems to mess up my SortExpression. Any help on this would be much appreciated, I do understand that this is complex stuff.

    Read the article

  • Nested and complicated select statement

    - by Selase
    What i want to do here is simple...display an ivestigators ID and him corresponding name... That can be easily done from the users table by selecting based on the user type. However i want to select only some type of investigators. The analogy here is investigators are assigned to an exhibit for them to investigate. One investigator can be assigned to a maximum of 3 cases only. Now during the assigning of investigators, i want to write a select statement that would retrieve only investigatorID's that have been assigned to less than or equal to 2 cases. I have included exhibit and users table that shows sample data below. Now i sort of have an idea that i will have to first of all pick out all the investigators by their ID from the users list and then filter them through the exhibit table by dropping those assigned to 3 cases and leaving just those with two cases. then afterwards i use this IDs to select the Investigators name. the big questions is how do i write the statement??

    Read the article

  • Most watched videos this week

    - by Jan Hancic
    I have a youtube like web-page where users upload&watch videos. I would like to add a "most watched videos this week" list of videos to my page. But this list should not contain just the videos that ware uploaded in the previous week, but all videos. I'm currently recording views in a column, so I have no information on when a video was watched. So now I'm searching for a solution to how to record this data. The first is the most obvious (and the correct one, as far as I know): have a separate table in which you insert a new line every time you want to record a new view (storing the ID of the video and the timestamp). I'm worried that I would quickly get huge amounts of data in this table, and queries using this table would be extremely slow (we get about 3 million views a month). The second solution isn't as flexible but is more easy on the database. I would add 7 columns to the "videos" table (one for each day of the week): views_monday, views_tuesday , views_wednesday, ... And increment the value in the correct column based on the day it is. And I would reset the current day's column to 0 at midnight. I could then easily get the most watched videos of the week by summing this 7 columns. What do you think, should I bother with the first solution or will the second one suffice for my case? If you have a better solution please share! Oh, I'm using MySQL.

    Read the article

  • In SQL Server what is most efficient way to compare records to other records for duplicates with in

    - by Glenn
    We have an SQL Server that gets daily imports of data files from clients. This data is interrelated and we are always scrubbing it and having to look for suspect duplicate records between these files. Finding and tagging suspect records can get pretty complicated. We use logic that requires some field values to be the same, allows some field values to differ, and allows a range to be specified for how different certain field values can be. The only way we've found to do it is by using a cursor based process, and it places a heavy burden on the database. So I wanted to ask if there's a more efficient way to do this. I've heard it said that there's almost always a more efficient way to replace cursors with clever JOINS. But I have to admit I'm having a lot of trouble with this one. For a concrete example suppose we have 1 table, an "orders" table, with the following 6 fields. order_id, customer_id product_id, quantity, sale_date, price We want to look through the records to find suspect duplicates on the following example criteria. These get increasingly harder. 1. Records that have the same product_id, sale_date, and quantity but different customer_id's should be marked as suspect duplicates for review. 2. Records that have the same customer_id, product_id, quantity and have sale_dates within five days of each other should be marked as suspect duplicates for review 3. Records that have the same customer_id, product_id, but different quantities within 20 units, and sales dates within five days of each other should be considered suspect. Is it possible to satisfy each one of these criteria with a single SQL Query that uses JOINS? Is this the most efficient way to do this?

    Read the article

  • Bizzare results when running two Visual Studio Express C++ 2008 solutions

    - by Jamie Keeling
    This is a follow on from my previous question although this is about something else. I've been having a problem where for some reason my message that I pass from one process to another only displays the first letter, in this case "M". My application based on a MSDN sample so to make sure I hadn't missed something I create a seperate solution, added the MSDN sample (Without any changes for my needs) and unsuprisingly it works fine. Now for the weird bit, when I run the MSDN sample running (As in debugging) and have my own application running, the text prints out fine without any problems. The second I run my on it's own without the original MSDN sample being open it fails to work and only shows an "M". I've looked in the debugger and don't seem to notice anything suspicious (It's a slightly dated picture, I've fixed the data type inconsistency). Can anyone provide a solution as to this? I've never encountered anything like this before. To look at my source code it's easier to just look at the link I posted at the top of the question, there's no point in me posting it twice. Thank you for any help.

    Read the article

  • Help with AJAX, Using PHP and hiding elements.

    - by ryan
    Hey, This is my first time with AJAX, so I'm a bit confused and need your help. I have four div id's and want to toggle hide/show between them based on result from database. Sounds simple, eh! But it is hard to implement for me. HELP!. This is my code - <div id="1">HEya</div> <div id="2">What's up?</div> <input type="submit" id='approve' name="action" value="Approve" onclick="a()" class="approve" /> <input type="submit" id='reject' value="Reject" name="action" onclick="r()" class="reject"/> <script language="javascript" type="text/javascript"> //if cookie exists, at the beginning the form should be hidden if (<?php $responseanswer['response']=='approve'; ?> ){ document.getElementById('1').style.display = 'none'; document.getElementById('2').style.display = 'inline'; } //if user clicks reject, hide one element dislay another else if (<?php $responseanswer['response']=='reject'; ?>){ //if cookie exists document.getElementById('2').style.display = 'none'; document.getElementById('1').style.display = 'block'; } else { function a() { var a = document.getElementById('2'); document.getElementById('1').style.display= 'block'; } //on reject creating a new cookie function r() { var a = document.getElementById('reject'); document.getElementById('1').style.display = 'none'; document.getElementById('2').style.display= 'block'; } } </script> Eveything is fine, but the div is not hiding.

    Read the article

  • Algorithm to pick values from set to match target value?

    - by CSharperWithJava
    I have a fixed array of constant integer values about 300 items long (Set A). The goal of the algorithm is to pick two numbers (X and Y) from this array that fit several criteria based on input R. Formal requirement: Pick values X and Y from set A such that the expression X*Y/(X+Y) is as close as possible to R. That's all there is to it. I need a simple algorithm that will do that. Additional info: The Set A can be ordered or stored in any way, it will be hard coded eventually. Also, with a little bit of math, it can be shown that the best Y for a given X is the closest value in Set A to the expression X*R/(X-R). Also, X and Y will always be greater than R From this, I get a simple iterative algorithm that works ok: int minX = 100000000; int minY = 100000000; foreach X in A if(X<=R) continue; else Y=X*R/(X-R) Y=FindNearestIn(A, Y);//do search to find closest useable Y value in A if( X*Y/(X+Y) < minX*minY/(minX+minY) ) then minX = X; minY = Y; end end end I'm looking for a slightly more elegant approach than this brute force method. Suggestions?

    Read the article

  • Convert a image to a monochrome byte array

    - by Scott Chamberlain
    I am writing a library to interface C# with the EPL2 printer language. One feature I would like to try to implement is printing images, the specification doc says p1 = Width of graphic Width of graphic in bytes. Eight (8) dots = one (1) byte of data. p2 = Length of graphic Length of graphic in dots (or print lines) Data = Raw binary data without graphic file formatting. Data must be in bytes. Multiply the width in bytes (p1) by the number of print lines (p2) for the total amount of graphic data. The printer automatically calculates the exact size of the data block based upon this formula. I plan on my source image being a 1 bit per pixel bmp file, already scaled to size. I just don't know how to get it from that format in to a byte[] for me to send off to the printer. I tried ImageConverter.ConvertTo(Object, Type) it succeeds but the array it outputs is not the correct size and the documentation is very lacking on how the output is formatted. My current test code. Bitmap i = (Bitmap)Bitmap.FromFile("test.bmp"); ImageConverter ic = new ImageConverter(); byte[] b = (byte[])ic.ConvertTo(i, typeof(byte[])); Any help is greatly appreciated even if it is in a totally different direction.

    Read the article

  • ListView - Index and Position Behavior upon restart()

    - by tunneling
    I am using a ListView with an ArrayAdapter that holds objects. When I select an item, I am capturing the position and index of the selected item. If I scroll down prior to selection, the position and index represent the location of the item in the list. Selecting that items takes me to another activity. When I use the back button to return to the list, it seems that the ListView get's a new position and index for the visible items. As a result, I can't figure out how to reference the selected item during the restart() of the ListView Activity. I have tried to caputure position and index, but as I've said, they change upon returning to the Activity. Is my understanding of the ListView "redraw" correct? Does it renumber my items based on what's visible? -When in the life cycle is getView() called? Is there a way to force an update to the ListView so that my caputured index still points to the same object? Thanks, Jason

    Read the article

  • Adding date to multiple fields via datepicker

    - by Andy
    i have a form in drupal with jquery based date module. there are multiple fields with date picker enabled. i want to set the value of all of them (they all have class .date-popup-init) to the value of the first field (#edit-field, the 'from' date) when that field is set. my code so far: <script type="text/javascript"> var DatePicked = function() { var firstdate = $("#edit-field"); var updater = firstdate.datepicker("getDate"); $(".date-popup-init").each(function(){ $(this).datepicker("setDate", updater); }); } $(function() { $("#edit-field").datepicker({ onSelect: DatePicked }); }); </script> this seems to randomly work; it sets the date of some fields to the value of #edit-field, seemingly different fields each time. also, the form adds more datepicker-enabled fields via ajax. is there any way to ensure that all these new fields, when they load, pick up the value of #edit-field as well? disclaimer: last night was my first attempt at javascript of any kind. i have a basic idea now. the above was cobbled through countless google examples.

    Read the article

  • Query Parameter Value Is Null When Enum Item 0 is Cast with Int32

    - by Timothy
    When I use the first item in a zero-based Enum cast to Int32 as a query parameter, the parameter value is null. I've worked around it by simply setting the first item to a value of 1, but I was wondering though what's really going on here? This one has me scratching my head. Why is the parameter value regarded as null, instead of 0? Enum LogEventType : int { SignIn, SignInFailure, SignOut, ... } private static DataTable QueryEventLogSession(DateTime start, DateTime stop) { DataTable entries = new DataTable(); using (FbConnection conn = new FbConnection(DSN)) { using (FbDataAdapter adapter = new FbDataAdapter( "SELECT event_type, event_timestamp, event_details FROM event_log " + "WHERE event_timestamp BETWEEN @start AND @stop " + "AND event_type IN (@signIn, @signInFailure, @signOut) " + "ORDER BY event_timestamp ASC", conn)) { adapter.SelectCommand.Parameters.AddRange(new Object[] { new FbParameter("@start", start), new FbParameter("@stop", stop), new FbParameter("@signIn", (Int32)LogEventType.SignIn), new FbParameter("@signInFailure", (Int32)LogEventType.SignInFailure), new FbParameter("@signOut", (Int32)LogEventType.SignOut)}); Trace.WriteLine(adapter.SelectCommand.CommandText); foreach (FbParameter p in adapter.SelectCommand.Parameters) { Trace.WriteLine(p.Value.ToString()); } adapter.Fill(entries); } } return entries; }

    Read the article

  • Determining Best Table Structure for MySQL Performance

    - by Joe Majewski
    I'm working on a browser-based RPG for one of my websites, and right now I'm trying to determine the best way to organize my SQL tables for performance and maintenance. Here's my question: Does the number of columns in an SQL table affect the speed in which it can be queried? I am not a newbie when it comes to PHP or MySQL. I used to develop things with the common goal of getting them to work, but I've recently advanced to the stage where a functional program is not good enough unless it's fast and reliable. Anyways, right now I have a members table that has around 15 columns. It contains information such as the player's username, password, email, logins, page views, etcetera. It doesn't contain any information on the player's progress in the game, however. If I added columns for things such as army size, gold, turns, and whatnot, then it could easily rise to around 40 or 50 total columns. Oh, and my database structure IS normalized. Will a table with 50 columns that gets constantly queried be a bad idea? Should I split it into two tables; one for the user's general information and one for the user's game statistics? I know I could check the query time myself, but I haven't actually created the tables yet and I think I'd be better off with some professional advice on this important decision for my game. Thank you for your time! :)

    Read the article

  • Why does a Silverlight application show a blank browser screen when created from exported template?

    - by Edward Tanguay
    I created a silverlight app (without website) named TestApp, with one TextBox: <UserControl x:Class="TestApp.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480"> <Grid x:Name="LayoutRoot"> <TextBlock Text="this is a test"/> </Grid> </UserControl> I press F5 and see "this is a test" in my browser (firefox). I select File | Export Template | name it TestAppTemplate and save it. I create a new silverlight app based on the above template. The MainPage.xaml has the exact same XAML as above. I press F5 and see a blank screen in my browser. I look at the HTML source of both of these and they are identical. Everything I have compared in both projects is identical. What do I have to do so that a Silverlight application which is created from my exported template does not show a blank screen? (creating a WPF application from an exported template like this works fine)

    Read the article

  • logic before dispatcher + controller?

    - by Spoonface
    I believe for a typical MVC web application the router / dispatcher routine is used to decide which controller is loaded based primarily on the area requested in the url by the user. However, in addition to checking the url query string, I also like to use the dispatcher to check whether the user is currently logged in or not to decide which controller is loaded. For example if they are logged in and request the login page, the dispatcher would load their account instead. But is this a fairly non-standard design? Would it violate MVC in any way? I only ask as the examples I've read through this weekend have had no major calculations performed before the dispatcher routine, and commonly check whether the user is logged in or not per controller, and then redirect where necessary. But to me it seems odd to redirect a logged in user from the login area to account area if you could just load the account controller in the first place? I hope I've explained my consternation well enough, but could anyone offer some details on how they handle logged in users, and similar session data?

    Read the article

  • Sending data back to Controller Spring-MVC

    - by Umesh Awasthi
    I am not sure if this is a complex problem but as a starting person this seems a bit complex to me. I have an object based on which i need to show some values on the UI and let user select some of them, i need to send data back to another controller when user click on the submit button.Here is the structure of my data object public class PrsData{ private Map<String, List<PrsCDData>> prsCDData; } public class PrsCDData{ private Map<String, Collection<ConfiguredDesignData>> configuredDesignData; } public ConfiguredDesignData{ // simple fields } I have set the object in model before showing the view like model.addAttribute("prsData", productData.getPrData()); In the form i have following settings <form:form method="post" commandName="prsData" action="${addProductToCartAction}" > <form:hidden path="prsCDData['${prsCDDataMap.key}'] [${status.index}].configuredDesignData['${configuredDesignDataMap.key}'] [${configuredDesignDataStatus.index}].code"/> <form:hidden path="prsCDData['${prsCDDataMap.key}'] [${status.index}].configuredDesignData['${configuredDesignDataMap.key}'] [${configuredDesignDataStatus.index}].description"/> </form:form> This is what i have at AddProductToCartController public String addToCart(@RequestParam("productCodePost") final String code, @ModelAttribute("prsData") final PrsData prsData, final Model model, @RequestParam(value = "qty", required = false, defaultValue = "1") final long qty) On submitting the form i am getting following exception org.springframework.beans.NullValueInNestedPathException: Invalid property 'prsCDData[Forced][0]' of bean class [com.product.data.PrsData]: Cannot access indexed value of property referenced in indexed property path 'prsCDData[Forced][0]': returned null It seems like its trying to access the values on this controller while i am trying to send value to that controller and trying to create same object with selected values Can any one tell me where i am doing wrong and what i need to take care of

    Read the article

  • C#: Non-constructed generics as properties (eg. List<T>)

    - by Dav
    The Problem It's something I came across a while back and was able to work around it somehow. But now it came back, feeding on my curiosity - and I'd love to have a definite answer. Basically, I have a generic dgv BaseGridView<T> : DataGridView where T : class. Constructed types based on the BaseGridView (such as InvoiceGridView : BaseGridView<Invoice>) are later used in the application to display different business objects using the shared functionality provided by BaseGridView (like virtual mode, buttons, etc.). It now became necessary to create a user control that references those constructed types to control some of the shared functionality (eg. filtering) from BaseGridView. I was therefore hoping to create a public property on the user control that would enable me to attach it to any BaseGridView in Designer/code: public BaseGridView<T> MyGridView { get; set; }. The trouble is, it doesn't work :-) When compiled, I get the following message: The type or namespace name 'T' could not be found (are you missing a using directive or an assembly reference?) Solutions? I realise I could extract the shared functionality to an interface, mark BaseGridView as implementing that interface, and then refer to the created interface in my uesr control. But I'm curious if there exists some arcane C# command/syntax that would help me achieve what I want - without polluting my solution with an interface I don't really need :-)

    Read the article

  • Should we retire the term "Context"?

    - by MrGumbe
    I'm not sure if there is a more abused term in the world of programming than "Context." A word that has a very clear meaning in the English language has somehow morphed into a hot mess in software development, where the definition where the connotation can be completely different based on what library you happen to be developing in. Tomcat uses the word context to mean the configuration of a web application. Java applets, on the other hand, use an AppletContext to define attributes of the browser and HTML tag that launched it, but the BeanContext is defined as a container. ASP.NET uses the HttpContext object as a grab bag of state - containing information about the current request / response, session, user, server, and application objects. Context Oriented Programming defines the term as "Any information which is computationally accessible may form part of the context upon which behavioral variations depend," which I translate as "anything in the world." The innards of the Windows OS uses the CONTEXT structure to define properties about the hardware environment. The .NET installation classes, however, use the InstallContext property to represent the command line arguments entered to the installation class. The above doesn't even touch how all of us non-framework developers have used the term. I've seen plenty of developers fall into the subconscious trap of "I can't think of anything else to call this class, so I'll name it 'WidgetContext.'" Do you all agree that before naming our class a "Context," we may want to first consider some more descriptive terms? "Environment", "Configuraton", and "ExecutionState" come readily to mind.

    Read the article

  • jquery delay a link from being followed

    - by Dan Sinker
    I have a short css-based animation that I want to play out before a link is followed (a card that swooped in on page load swoops out after click). Currently, however, the page called loads too quickly. I want to be able to briefly delay the href from being followed. Here's what I've got: $(document).ready(function() { $("#card").css("top","0px"); $(".clickit").click(function() { $("#card").css("top","-500"); }); }); The first line swoops the card in on page load. After that is the click call that modifies the CSS, but like I said there needs to be some kind of delay in there because the page loads immediately, instead of after the animation. The CSS that is modified looks like this: #card { width: 400px; height: 500px; position: relative; top: -500px; -webkit-transition:all .5s; } (yes, I know this is webkit-only right now) This is a problem very similar to this question from 2008, but I know jQuery has been updated significantly since then, so I wanted to see if there was a more modern solution. Thank you!

    Read the article

  • Passing a outside variable into a <asp:sqldatasource> tag. ASP.NET 2.0

    - by MadMAxJr
    I'm designing some VB based ASP.NET 2.0, and I am trying to make more use of the various ASP tags that visual studio provides, rather than hand writing everything in the code-behind. I want to pass in an outside variable from the Session to identify who the user is for the query. <asp:sqldatasource id="DataStores" runat="server" connectionstring="<%$ ConnectionStrings:MY_CONNECTION %>" providername="<%$ ConnectionStrings:MY_CONNECTION.ProviderName %>" selectcommand="SELECT THING1, THING2 FROM DATA_TABLE WHERE (THING2 IN (SELECT THING2 FROM RELATED_DATA_TABLE WHERE (USERNAME = @user)))" onselecting="Data_Stores_Selecting"> <SelectParameters> <asp:parameter name="user" defaultvalue ="" /> </SelectParameters> </asp:sqldatasource> And on my code behind I have: Protected Sub Data_Stores_Selecting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.SqlDataSourceSelectingEventArgs) Handles Data_Stores.Selecting e.Command.Parameters("user").Value = Session("userid") End Sub Oracle squaks at me with ORA-01036, illegal variable name. Am I declaring the variable wrong in the query? I thought external variables share the same name with a @ prefixed. from what I understand, this should be placing the value I want into the query when it executes the select. EDIT: Okay, thanks for the advice so far, first error was corrected, I need to use : and not @ for the variable declaration in the query. Now it generates an ORA-01745 invalid host/bind variable name. EDIT AGAIN: Okay, looks like user was a reserved word. It works now! Thanks for other points of view on this one. I hadn't thought of that approach.

    Read the article

  • Retrieving a unique result set with Core Data

    - by randombits
    I have a core data based app that manages a bunch of entities. I'm looking to be able to do the following. I have an entity "SomeEntity" with the attributes: name, type, rank, foo1, foo2. Now, SomeEntity has several rows if when we're speaking strictly in SQL terms. What I'm trying to accomplish is to retrieve only available types, even though each instance can have duplicate types. I also need them returned in order according to rank. So in SQL, what I'm looking for is the following: SELECT DISTINCT(type) ORDER BY rank ASC Here is the code I have so far that's breaking: NSError *error = NULL; NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; [fetchRequest setReturnsDistinctResults:YES]; [fetchRequest setPropertiesToFetch:[NSArray arrayWithObjects:@"type", @"rank", nil]]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"SomeEntity" inManagedObjectContext:managedObjectContext]; [fetchRequest setEntity:entity]; // sort by rank NSSortDescriptor *rankDescriptor = [[NSSortDescriptor alloc] initWithKey:@"rank" ascending:YES]; NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:rankDescriptor,nil]; [fetchRequest setSortDescriptors:sortDescriptors]; [sortDescriptors release]; [rankDescriptor release]; NSArray *fetchResults = [managedObjectContext executeFetchRequest:fetchRequest error:&error]; [fetchRequest release]; return fetchResults; Right now that is crashing with the following: Invalid keypath section passed to setPropertiesToFetch:

    Read the article

  • Set service dependencies after install

    - by Dennis
    I have an application that runs as a Windows service. It stores various things settings in a database that are looked up when the service starts. I built the service to support various types of databases (SQL Server, Oracle, MySQL, etc). Often times end users choose to configure the software to use SQL Server (they can simply modify a config file with the connection string and restart the service). The problem is that when their machine boots up, often times SQL Server is started after my service so my service errors out on start up because it can't connect to the database. I know that I can specify dependencies for my service to help guide the Windows service manager to start the appropriate services before mine. However, I don't know what services to depend upon at install time (when my service is registered) since the user can change databases later on. So my question is: is there a way for the user to manually indicate the service dependencies based on the database that they are using? If not, what is the proper design approach that I should be taking? I've thought about trying to do something like wait 30 seconds after my service starts up before connecting to the database but this seems really flaky for various reasons. I've also considered trying to "lazily" connect to the database; the problem is that I need a connection immediately upon start up since the database contains various pieces of vital info that my service needs when it first starts. Any ideas?

    Read the article

  • Merging similar dictionaries in a list together

    - by WonderSteve
    New to python here. I've been pulling my hair for hours and still can't figure this out. I have a list of dictionaries: [ {'FX0XST001.MID5': '195', 'Name': 'Firmicutes', 'Taxonomy ID': '1239', 'Type': 'phylum'} {'FX0XST001.MID13': '4929', 'Name': 'Firmicutes', 'Taxonomy ID': '1239','Type': 'phylum'}, {'FX0XST001.MID6': '826', 'Name': 'Firmicutes', 'Taxonomy ID': '1239', 'Type': 'phylum'}, . . . . {'FX0XST001.MID6': '125', 'Name': 'Acidobacteria', 'Taxonomy ID': '57723', 'Type': 'phylum'} {'FX0XST001.MID25': '70', 'Name': 'Acidobacteria', 'Taxonomy ID': '57723', 'Type': 'phylum'} {'FX0XST001.MID40': '40', 'Name': 'Acidobacteria', 'Taxonomy ID': '57723', 'Type': 'phylum'} ] I want to merge the dictionaries in the list based on their Type, Name, and Taxonomy ID [ {'FX0XST001.MID5': '195', 'FX0XST001.MID13': '4929', 'FX0XST001.MID6': '826', 'Name': 'Firmicutes', 'Taxonomy ID': '1239', 'Type': 'phylum'} . . . . {'FX0XST001.MID6': '125', 'FX0XST001.MID25': '70', 'FX0XST001.MID40': '40', 'Name': 'Acidobacteria', 'Taxonomy ID': '57723', 'Type': 'phylum'}] I have the data structure setup like this because I need to write the data to CSV using csv.DictWriter later. Would anyone kindly point me to the right direction?

    Read the article

  • What are salesforce.com and Apex like as an application development platform?

    - by mhollers
    I have recently discovered that salesforce.com is much more than an online CRM after coming across a Morrison's Case Study in which they develop a works management application. I've been trying it out with a view to recreating our own Works Management system on the platform. My background is in Microsoft and .Net, and the obvious 1st choice would be asp.net. However, there's only really myself with .net experience and my manager with a more legacy Synergy programming background, and I am self taught and am looking at evaluating other RAD options (eg Ironspeed). the nature of the business is in the main 2-5 concurrent construction type contracts that run for 3-5 yrs each, each requiring 15-50 system users. Traditionally we have used our character based Works Mangement system for everything and tweaked it for each contract. The Salesforce licensing model on the face of it suits this sort of flexibilty, but I'm worried about the development flexibilty/learning curve and all the issues that surround lock-in. There doesn't seem to be much neutral sober analysis of the platform on the web that isn't salesforce's own material/blogs Has anyone any experience of developing an application on salesforce as compared to the more 'traditional' .Net route?

    Read the article

  • Should a programmer have mastery over C++

    - by Yogendra
    I was wondering if it is necessary for programmers to have expertise on at least 1 programming language? Programming languages like C#, java, VB.Net etc change every year or two. Should a programmer have mastery over C++, which is a stable language and rarely undergoes changes? I am a C# developer and using it for about 7 years now, I still don't have mastery on it. EDIT I think my question is being misunderstood. I am not against changes or evolution. I love the new features and abstraction provided by languages such as C#, VB, Java. And I keep waiting for new features if it makes a programmers life easy. But this fact also make this languages very difficult to master. They are continuously evolving. Languages like C++ have slow evolution cycle. So given this scenario, Is it helpful to be master of C++? This is what my original question meant. Note:- Based on the answers by friends below, I have understood that languages and framework are tools for expressing the concepts. Also it might be a good idea to express the concepts in different programming languages.

    Read the article

< Previous Page | 885 886 887 888 889 890 891 892 893 894 895 896  | Next Page >