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If I create a new project in Visual Studio 2010 SP1 and select "WPF Application" and tries to build the generated application, I get the error

The name 'InitializeComponent' does not exist in the current context.

I got a similar error this morning when I tried to build my current project. Yesterday, I had no problem compiling and running it.

I created a new project and got the error whenever I compiled the project. I have just sent the project to a colleague, and he has just compiled without any errors.

What is wrong?

This user "error" looks like easy to solve, just a simple x:Class proper definition. Until there all is ok, developer should pay more attention, but what if is not this error but a ghost error with the same error message? I read A LOT of different voodoo workarounds from 2012. It would help from VS a much clear error message and OF COURSE a bugfix for the ghost errors with the same message. Developers are since 2012 changing the build config from files, projects, copy-pasting the project, deleting files from App folder, restarting VS, etc. Bravo MS... a 4 years bug and still getting older! juagicre Mar 23, 2016 at 12:02 For any future readers of this question: This problem seems to have a lot of possible sources. In my case the first few answers did not help, but one of the answers further down was correct. MOnsDaR Jul 23, 2016 at 10:06 While this can be caused by many things (Namespace renamed \ Page type - MSBuild), i have eventually found the solution for what was causing it on the project I inherited. In the .csproj files, i had to change the "ToolsVersion" from 4 to 15 (VS 2017). MrMikeJJ Dec 14, 2018 at 11:54 Wow, this is still happening in Visual Studio 2022. I'm seeing it in a file that I can verify has NOT changed. I added an answer that worked for me today. Paul McCarthy Sep 1, 2022 at 12:03

I've encountered this a couple times and keep forgetting what causes it. I ran into this when I renamed the namespace on my code behind file but not in my XAML.

So check if you've done the same.

The namespace and class names need to match since they are both part of a partial class

namespace ZZZ
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow
         //...
<!-- XAML -->
<Window x:Class="ZZZ.MainWindow">
                Thank you Sean.  I came here to post this answer here but you already beat me to it.  This is exactly what had happened and it solved my problem.  Your comment should be higher up the charts because it would have saved me 15 minutes.
– Magnum
                Feb 15, 2012 at 2:34
                This is the answer. Not sure why it hasn't been chosen, but this is it and I ran into this coding some Xamarin.Forms.
– Marcus Shockley
                Oct 16, 2014 at 13:12
                For me (in Xamarain.Forms) using a "Quick Start" project downloaded from Azure, it was the white space / indent between xmlns:x="schemas.microsoft.com/winfx/2009/xaml" and x:Class that was the problem. I deleted this and retyped it and it worked!
– James
                May 21, 2016 at 22:00
                This still happens in Visual Studio 2019 v16.3 in WPF .NET CORE 3.0 if you got custom controls (xaml + cs) defined in an external library.
– rvnlord
                Oct 2, 2019 at 14:46

For those who have no errors in Debug mode, but do have the specified error in Release mode (and yet the project runs fine), here is something simple to try:

  • Open the XAML file corresponding to the offending xaml.cs file.
  • Make an edit--any edit, like add a space somewhere
  • Save the file and close it
  • This method worked for me in VS 2015, and according to other users, also 2017 and 2019

    Crazily enough, this worked for me with VS2015. And it fixed all of the errors in all the XAML files. This is a really WTF moment. – William Denman Jan 18, 2016 at 19:27 Dang, I just got burned by this one again. Fortunately I found the same answer that I already up-voted and commented on. I really should but this as a post-it note on my monitor. – William Denman May 25, 2016 at 16:49 Holy frig!! This actually works. I have VS2019 and encountered this. Seriously Microsoft?? Why does Jetbrains Rider not have these issues? Super unprofessional. – Philip Vaughn Aug 27, 2019 at 13:56 This works. In Visual Studio Code, have to restart OmniSharp as well in order to force the re-build. – night_owl May 18, 2021 at 15:51 I went to the less drastic approach: I searched for the corresponding g.i.cs file, renamed it and re-compiled. That file got regenerated and everything worked fine. In case this would not have been the case, I would have been able to rename it back as before, which you can't if you delete it :-) – Dominique Mar 15, 2022 at 13:58

    There's a very specific reason for this, and it's in the project settings. This usually happens whenever you try to add a WPF control/window to a .NET 2.0 class library or project. The reason for this error is that the project does not know it's building a WPF control or window and therefore tries to build it as a C# 2.0 project.

    The solution involves editing the .csproj file. Right click on the project causing the problem and select “Unload Project”. Right click the unloaded project and select “Edit .csproj”. The .csproj file will open and you can see the XML. look for the following line:

    <Import Project=…..
    

    It's near the end of the file, and the only line that you have is probably

    <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
    

    This tells Visual Studio to build the project as a .NET 2.0 project. What we want to do is to tell Visual Studio that this is actually a WPF project, so we have to add the following line:

    <Import Project="$(MSBuildBinPath)\Microsoft.WinFX.targets" />
    

    This line will tell Visual Studio to build the project as a WPF project. Now your .csproj file bottom should look like this:

    <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
    <Import Project="$(MSBuildBinPath)\Microsoft.WinFX.targets" />
    

    Save the .csproj file, right click it in Solution Explorer and select “Reload Project” compile and that's it, you're all done!

    I tried this before I wrote this question and it doesn't help. I think it's a bit weird that I can't compile new project but my colleague can... – user876402 Aug 3, 2011 at 11:27 I tried it too and it didn't help. Adding the new import resulted in a new warning (see below) but the original error is still there."C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\Microsoft.WinFX.targets" cannot be imported again. It was already imported at "C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\Microsoft.NETFramework.targets (76,3)". This is most likely a build authoring error. This subsequent import will be ignored. " – user316117 Aug 3, 2012 at 14:09 Worked for me! The only difference (maybe due to VS 2019) was that MSBuildToolsPath was used instead of MsBuildBinPath for the reference to Microsoft.CSharp.targets. But the code I needed to insert was just as specified in the answer. Wonderful! – mike Aug 9, 2022 at 9:36

    this happened with me when I accidentaly deleted the class reference from the xaml definition:

    I've replaced the

    <Window x:Class="myapp.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    

    first line with this:

    <RibbonWindow 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    

    I know this isn't the answer to the original question (because thats project builds on another machine), but the error message was the same, so maybe I'll help someone with this situation.

    this wasn't exactly my problem but it helped me localize it. I had the namespace without the class name afterwards – Rivenfall May 26, 2015 at 14:32 This helped me find my issue, in my case I was missing the x:Class line, adding this in fixed it for me – apc Mar 21, 2017 at 11:53

    None of the above answers worked for me. I tried them all except the duplicate ones. However for some weird reason this worked in my cross-platform project in Visual Studio 2015:

  • Right-click the project that is causing the problem in the Solution Explorer. In the pop-up menu choose: Add --> Class
  • Select cross-platform --> Forms Xaml Page. Keep the pretty Page1.cs standard name and click Add.
  • Notice how the previous InitializeComponent()-problem just disappeared for some reason.
  • Delete the newly created Page1.cs and continue programming as if Visual Studio was working just fine.
  • This one worked for me. I had made a copy & paste and rename of a usercontrol I had, when the InitializeComponent() started failing. – Rafael Ventura Jul 14, 2017 at 10:51 How on earth did you stumble across this fix? I tried everything else and this worked. Using VS 2017, so problem is current. – blearyeye Jan 18, 2018 at 17:21

    You might get this error when you import a class from another project, or change the path of the xaml file, or the namespace of either the xaml or behind .cs file.

    One: It might have a namespace that is not the same as what you have in you new project

    namespace TrainerB.MVC.Forms
         public partial class AboutDeveloper : ContentPage
              public AboutDeveloper()
                   InitializeComponent();
    

    As you can see the name space in the imported file begins with the old project name: "TrainerB", but your new project might have a different name, so just change it to the correct new project name, in both the .xaml file and the behind .cs file.

    change the properties of the .xaml file to:

    Build Action: Embedded Resource

    Custom Tool: MSBuild:UpdateDesignTimeXaml

    Omg! really thank you for that solution. I tested every solution found there and nothing work. The trick was in the properties of the xaml file. +1 – IgniteCoders Jan 18, 2017 at 5:22

    Check the Designer file.

    I had this same issue. In my case, the cause was that the namespace for FileName.Designer.cs did not match the (correct) namespace used in FileName.cs.

    Changing the namespace of FileName.Designer.cs to match that of FileName.cs solved the problem immediately.

    I had also problems with namespaces then adding new items to project. Problem was that I used spaces in project's name then I created it. – Randel Dec 20, 2020 at 1:03

    I've had this (although it was very much my fault and was caused after I copied and pasted some code in); it can occur when the namespace doesn't match between the XAML and code behind

    <UserControl x:Class="DockPanel.TreeView" />
    

    and the code behind is

    namespace NotDockPanel
    

    I encountered this while renaming a usercontrol. The way I fixed it was to comment out InitializeComponent, verify that all the names were correct (xaml and code behind), build the project, uncomment InitializeComponent, then build again. It sounds like there may be a couple causes/solutions for this issue, but this way did it for me.

    I didn't rename anything? However this solution worked for me. The *.g.cs and *.g.i.cs were missing in the obj folder, commenting it out and building the project generated the missing files. Not sure how it got into this state. – finlaybob Mar 1, 2017 at 11:46

    I agree with the answer above that the namespaces have to match. However, I had a problem like this where the namespaces matched.

    To fix, I simply changed the namespace in the XAML to an INCORRECT one, saved, then changed it back to the CORRECT one. Voila!

    I would have added this as a comment to the correct answer, but I don't have the rep to do so :( – heights1976 Apr 15, 2016 at 17:09 Thanks for this! Worked for me after going crazy trying all sorts of things. My solution did build originally with no errors, then after PC was asleep for a while tried again and was getting the error. Maybe something to do with sleep mode? – JeremyB Jul 30, 2016 at 7:25 I had the same issue and solution. I believe it had something to do with IntelliSense. Changing the namespace in the xaml probably triggered an update of the relevant parts in the IntelliSense db. This is only a guess though. – FishySwede Aug 8, 2018 at 8:16 I found that this did the job for me, in a multi-targeting project, with target frameworks net47;net5.0-windows. – fuglede Apr 10, 2022 at 17:41 This worked for me in a multi-targeting WPF user control library targeting net48, net5.0-windows, and net6.0-windows. The only context to have this problem net6.0-windows, and changing Sdk to Microsoft.NET.Sdk.WindowsDesktop fixed it. I then changed it back to Microsoft.NET.Sdk, and the problem remained fixed. I am so over the instability of every modern version of Visual Studio. Each new version seems to bring new features and new instabilities, with only a small portion of the old problems fixed. – Daniel Aug 31, 2022 at 14:30

    If you are using Xamarin Forms and you move a XAML file the "build action" of the file is changed. Xamarin Forms requires "build action = Embedded Resource".

    Apply "build action" in Visual Studio:

    Select the XAML file -> Properties -> Build Action = Embedded Resource

    If the error appears in all Xaml.cs files, then it has to be changed in every Xaml.cs files. Thank you for your comment, after 2 days this solved it. (: – Jaime Santos Nov 1, 2021 at 15:05
  • Right click on folder in project to create new UserControl. This creates a class and xaml file that derives from user control in the namespace of the folder.

  • Then you decide to change the namespace of the class because you're really just using folders for organization of code. The x:Class attribute will not get automatically updated so it will be searching for a class that doesn't exist. Could probably use a better error message like "x:Class type could not be found in namesace bla.blaa.blaaa."

  • If the Namespaces are correct then also there is a same error,

    Just close your application and open it again.

    This may solve your problem

    Some times, XDesProc.exe (Microsoft Visual Studio XAML UI Designer) will Stop the Visual Studio to work properly, and will not load the xaml file properly. So Restarting the Visual Studio solved my problem. (You can also go the Processes in the Task Manager, and stop only that process without Restarting Visual Studio). – Syed Siraj Wajeed Feb 15, 2017 at 7:29 I discovered this in VS2017. I had changed everything else and the namespaces were correct everywhere but the InitializeComponent() calls had the error, and the partial keywords in the xaml.cs files had a warning, something like "partial class has only one file". I happened to close and reopen the solution and discovered both these issues resolved themselves. – Steve Crane Jun 9, 2017 at 7:32

    This happened to me because a Nuget package uninstaller blew away all the attributes on the <Application> element in App.xaml. This included the x:Class attribute, which specifies the application class name. So the partial class containing the InitializeComponent() method was never generated.

    I fixed the problem by reverting App.xaml to the source-controlled copy.

    I got the same error due to a missing x:Class attribute, but it had nothing to do with Nuget. It just disappeared somehow, probably some visual studio magic. – Ismail Degani Feb 21, 2013 at 22:19 Exact specifics are not exact considering the question was not clear on how the exception manifested. However the underlying symptom is identical therefore I don't see anything wrong with my answer. My intention was to add to the conversation as no answer/comment helped in my case. I was merely attempting to add to the knowledge base for the often times nondescript compile errors. – Rock Mar 18, 2016 at 19:08 Thanks! It solved my problem! It seems that the given option (Startup object) was reset automatically when I moved the MainWindow.xaml from root to View directory. – AlexMelw Jul 17, 2017 at 10:56

    I know this was answered due to a different cause, but this is a highly hit posting and I had ran into the same issue with a class library. In this case, it turned out to be both a change in my namespace (answered in this post here) and that the compiler could not rebuild the Window.g.i.cs which defines the InitializeComponent() method. It couldn't because the class library was missing the ProjectTypeGuid value for WPF projects in the csproj file. Instructions for this are here and here. I thought I would share in case someone else has run into the same issue. Just changing the namespace isn't enough in this case.

    I had commented out the resources in the App.xaml file

    <Application x:Class="MyApp.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
      <Application.Resources>
        <!--<ResourceDictionary>
          <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary
                Source="/PresentationFramework.Aero, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, ProcessorArchitecture=MSIL;component/themes/aero.normalcolor.xaml" />
          </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>-->
      </Application.Resources>
    </Application>
    

    Commenting thiis back in to fixed the build error.

    <Application x:Class="MyApp.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
      <Application.Resources>
        <ResourceDictionary>
          <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary
                Source="/PresentationFramework.Aero, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, ProcessorArchitecture=MSIL;component/themes/aero.normalcolor.xaml" />
          </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
      </Application.Resources>
    </Application>
    

    Digging a bit deeper I found that the app.g.cs file in {Project}\obj\debug only contained the following when I left the resource commented in.

    /// <summary>
    /// InitializeComponent
    /// </summary>
    [System.Diagnostics.DebuggerNonUserCodeAttribute()]
    public void InitializeComponent() {
        if (_contentLoaded) {
            return;
        _contentLoaded = true;
        System.Uri resourceLocater = new System.Uri("/MyApp;component/app.xaml", System.UriKind.Relative);
        #line 1 "..\..\..\App.xaml"
        System.Windows.Application.LoadComponent(this, resourceLocater);
        #line default
        #line hidden
    

    For those who find this on the internet. Check the Windows.csproj file if the compilation is there. There should be 2 entries

    <Page Include="YourFile.xaml">
      <SubType>Designer</SubType>
      <Generator>MSBuild:Compile</Generator>
    </Page>
    <Compile Include="YourFile.xaml.cs">
      <DependentUpon>YourFile.xaml</DependentUpon>
    </Compile>
                    In my csproj I was missing the <DependentUpon>YourFile.xaml</DependentUpon> for some reason and this is what fixed it for me!
    – Isaac Baker
                    Apr 22, 2019 at 20:55
    

    After some action the namespace of the .cs file and the one in .xaml file may be different (in xaml look for the x:Class="namespace.yourType").

    Fix them to be the same.

    This issue happened for me when creating a "WPF Application Project" then changing its build target to "Class Library" to be used as an external tool by another program.

    I changed all my .xaml files for my windows so their build action were set to "Page". What I did not realize was that that the project also contained "App.xaml" and "App.xaml.cs".

    "App.xaml" needs to be set to "Page" as well, or deleted altogether (along with "App.xaml.cs"). I did the former, then the latter as I realized the files were useless.

    Worked for me. Except I left App.xaml as Application definition. Working in WinUI3 Preview 5/Reunion 0.5. – On The Net Again Mar 18, 2021 at 13:00

    Since this seems to be the go-to thread for the problem regarding missing 'InitializeComponent', I'll include my answer here.

    I too was having this issue and I've tried everything I found here and in all other Forums that Google could find, however none resolved the issue for me. After two hours of trying everything, I finally figured out what was wrong with my setup.

    In our project, we are using Metro components from MahApps. The view that was giving me trouble was a view inheriting from MetroWindow, like this:

    <Controls:MetroWindow x:Class="ProjectNamespace.MyView"
                          xmlns:Controls="http://metro.mahapps.com/winfx/xaml/controls"
    

    Now, I have defined my static resources as

    <Controls:MetroWindow.Resources>
        <prop:Resources x:Key="LocalizedStrings"/>
    </Controls:MetroWindow.Resources>
    

    That's how I've defined Resources in UserControls in all my other views, so that's what I assumed will work.

    That was, however, not the case with Controls:MetroWindow! There I absolutely needed the resource definition as follows:

    <Controls:MetroWindow.Resources>
        <ResourceDictionary>
            <prop:Resources x:Key="LocalizedStrings"/>
        </ResourceDictionary>
    </Controls:MetroWindow.Resources>
    

    So my issue, in summary, was a missing <ResourceDictionary> tag. I really don't know why this produced the 'InitializeComponent' error and it weirdly didn't even produce it on every machine of mine, but that's how I fixed it. Hope this helps (the remaining 0.001% of people encountering this issue).

    I just encountered this problem, and it turned out to be that my project is stored in my user folder, which is stored on the network, and we had a momentary network outage. I did a build; it complained that my files had been modified outside the editor (they hadn't; the file locks just got borked), and it built fine, removing the error regarding the InitializeComponent() method.

    BTW, in case you're wondering, developing something from a network drive is bad practice. It becomes particularly problematic when you're trying to leverage .NET's managed code; in my experience, it freaks out every time you build. I forgot to put this little throw-away project in the proper folder, and ended up paying the price.

    So I realize this is an older question, but we were having a similar issue. We were able to build a project using VS2012, but not using msbuild from the command line. I went into the .proj file and noticed it didn't have a record for "ProjectTypeGuids" under the default "PropertyGroup" section, so I added this:

    <ProjectTypeGuids>{60dc8134-eba5-43b8-bcc9-bb4bc16c2548};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
    

    which is the project GUID for WPF. I then deleted and re-added the UserControl and it started working. I'm not sure if I had to do that last step, but it works for me now.