在创建新页面时,Xamarin.Forms-InitializeComponent 不存在

我正在使用 Visual Studio 来尝试 Xamarin: Http://developer.xamarin.com/guides/cross-platform/xamarin-forms/xaml-for-xamarin-forms/getting_started_with_xaml/

简而言之,我创建了一个 Xamarin。使用 PCL 表单解决方案,然后尝试向 PCL 项目添加 Forms XAML Page

创建的代码隐藏如下所示:

    public partial class Page1 : ContentPage
{
public Page1()
{
InitializeComponent();
}
}

这里的问题是 InitializeComponent();是红色的。 当我尝试建立我得到通知,The name 'InitializeComponent' does not exist in the current context

我一直在四处寻找解决方案,尽管其他人也遇到了同样的麻烦,但他们的解决方案对我没有用。下面是我试图使用的一个建议: Http://blog.falafel.com/xamarin-error-initializecomponent-does-not-exist-in-the-current-context/

如果你有解决这个问题的办法,请告诉我。谢谢!

更新:

我的 PCL (也是我想添加 XAML 页面的地方)包含:

应用程序:

    public class App : Application
{
public App()
{
// The root page of your application
MainPage = new ContentPage
{
Content = new StackLayout
{
VerticalOptions = LayoutOptions.Center,
Children = {
new Label {
XAlign = TextAlignment.Center,
Text = "Welcome to Xamarin Forms!"
}
}
}
};
}


protected override void OnStart()
{
// Handle when your app starts
}


protected override void OnSleep()
{
// Handle when your app sleeps
}


protected override void OnResume()
{
// Handle when your app resumes
}
}

还有我的 XAML 页面:

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="XamaTest.MyXamlPage">
<Label Text="{Binding MainText}" VerticalOptions="Center" HorizontalOptions="Center" />
</ContentPage>

暗号:

    public partial class MyXamlPage : ContentPage
{
public MyXamlPage()
{
InitializeComponent();
}
}
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Updating the Xamarin.Forms NuGet package should do the job

  • I had similar problem in Visual Studio 2013 update 4 environment and I tried all recommendations what I found on the web. Nothing solved my problem.
  • Then I tried workaround approach. I installed Visual Studio 2015 preview and create new blank app with xamarin forms project.
  • When I added new Xaml file everything was OK and issue with InitialComponent method disappeared.
  • I don t know where exactly is the reason of the problem but it seems to be issue around configuration settings.

A Clean and rebuild did the trick for me!

This problem appears when the projects of solution are referencing the version 1.4.0.0 of the dlls "Xamarin.Forms.Core", "Xamarin.Forms.Xaml" and "Xamarin.Forms.Platform" version 1.0.0.0.

To solve it I've had to downgrade to version 1.3.3.0 of the dlls but with this version Xamarin.Forms.Platform 1.0.0.0 don't exists.

Try adding a x:Name="..." on the xaml page... Nothing else worked for me - but after adding the x:Name attribute on some of the elements on the page the error dissapeared (most of the times - I still get it sometimes). I use the latest build (1.5.0.6447) of Xamarin.Forms...

XAML don't work on shared projects - it only works in portable projects...

UPDATE: This error doesn't usually appear in VS 2015, if it does, here's my original answer:

Found the solution! Right click on the .XAML file, select Properties.

You will see a Property called Custom Tool. Change its value from MSBuild:Compile to MSBuild:UpdateDesignTimeXaml

This will solve the problem. Dont know about the downvote, but here's my screenshot:

Screenshot UPDATE:

It reappears rarely. If it does, just open the Xaml and code behind files and save them. I know, its not the best solution, but it gets the job done.

It looks like the (re)generation of the blah.xaml.g.cs files is actually the problem. I get this a LOT in shared projects (which is why I don't use them unless I have no other choice). It happens way more in Xamarin Studio than Visual Studio, for me, for some reason. I try not to use XS at all.

Often unloading one of the other platforms (e.g. if you're building droid, unload ios) and doing a clean and rebuild will fix it.

You can also try doing something like opening one of the offending .xaml files and changing some of the xaml markup (e.g. adding or changing an x:Name to one of the controls or views). This will force a regeneration of the xaml.g.cs file, and (for me at least) usually solves the problem.

This really shouldn't be a thing tho.

This is probably not your case but I had similar problem and mine was xaml and code behind name missmatching. for example according to your sample, if code behind namespace is XamaTest(name of your app in most cases) and class is called MyXamlPage, your xaml class name must be XamaTest.MyXamlPage ([namespace].[classname])

I was silly after creating an empty xaml with code behind, I changed name of the class in xaml and i was getting this error.

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="XamaTest.MyXamlPage">
<Label Text="{Binding MainText}" VerticalOptions="Center" HorizontalOptions="Center" />
</ContentPage>

Code-behind:

public partial class MyXamlPage : ContentPage

I get this sometimes and here's the checklist that solved them so far:

  1. Make sure the namespace in .xaml and .xaml.cs match

  2. Inherit from the correct parent - ContentPage for a page and ContentView for a control

  3. Set build action of the .xaml file to Embedded Resource if in the shared project.

I don't know if this is solved, but for me, the only thing I had to do is remove the first line of the XAML ("xml version="1.0" encoding="utf-8")

Sometimes source version control, tries to identify which type of file is and add this kind of stuff.

I have met this problem. It's associated with the encoding of XAML files in VS. I'm using VS2015.

I solved this problem as follows:

  1. Open the *.xaml file in the project and click Save button. (There will be applying the correct encoding in VS2015).

  2. Then reopen the project and rebuild it. Now there are no errors.

As far as my observation is concerned, in Visual Studio 2015, XAML properties are already set as suggested by highly-voted answers here by default, specifically :

  • Custom Tool = MSBuild:UpdateDesignTimeXaml
  • Build Action = Embedded Resource

but the error still appears sometimes... (like in this other question).

Editing the corresponding XAML file and then hit CTRL+S should work fine, but you don't have to. A cleaner way to force Custom Tools to be run is by right-clicking on the XAML file and then click on "Run Custom Tool" context menu.

enter image description here

Right click *.xaml and click properties,and change "Custom Tool" value to "MSBuild:UpdateDesignTimeXaml", next change "Build Action" properties to "Embedded Resource", build project works.

In my case the problem was the project path. The generated code file gets a name including the absolute path encoded to make it a valid filename. The path was "D:\Projekt C#\ProjectRootFolder\Project". The filename generated by the build tool was "Project.Droid.D_.Projekt_C_. Namespace etc." Moving the project to a path like "D:\project\ProjectRootFolder" helped in my case.

I'm using Visual Studio 2015, I got the same problem, and found none of the answers on the net was a full solution. Here I'll explain what worked for me.

My primary goal here was to eliminate the red error message that kept coming up

The name InitializeComponent does not exist in the current context

Basically I created a function called InitializeComponent2() that does exactly the same thing as InitializeComponent() and used that instead, I literally copied the code for InitializeComponent(). Does the job.

It looks like this (and I'll explain):

[System.CodeDom.Compiler.GeneratedCodeAttribute("Xamarin.Forms.Build.Tasks.XamlG", "0.0.0.0")]
private void InitializeComponent2()
{
// Change to:
//   this.LoadFromXaml(typeof(Page2)); // for Page2
//   this.LoadFromXaml(typeof(Page3)); // for Page3
// and put
//   using Xamarin.Forms.Xaml;
// at the top of each source file.
this.LoadFromXaml(typeof(Page1));
}

Put the function in the definition of each of your pages (.cs files) e.g.

public partial class Page1 : ContentPage
{
[System.CodeDom.Compiler.GeneratedCodeAttribute("Xamarin.Forms.Build.Tasks.XamlG", "0.0.0.0")]
private void InitializeComponent2()
{
// Change to:
//   this.LoadFromXaml(typeof(Page2)); // for Page2
//   this.LoadFromXaml(typeof(Page3)); // for Page3
// and put
//   using Xamarin.Forms.Xaml;
// at the top of each source file.
this.LoadFromXaml(typeof(Page1));
}
}

Also you need to put using Xamarin.Forms.Xaml; at the top of each .cs page where LoadFromXaml(..) is used.

And then of course change InitializeComponent() to InitializeComponent2() to call the new function. i.e. you have put the function into the same context as the page making the error go away. I can't imagine the real InitializeComponent function will get anything added to it as you modify your project but that is a possibility. It's been fine for me so far.

I tried many things, changing the Build Action, the XAML namespace, restarting vs, cleaning+rebuilding, looking for NuGet package updates.

Basically, Visual Studio compiled and ran the program fine on my android device + emulator, but that error message wouldn't go away. My solution is for Android, but it may also work for iOS etc.

I went back to the root of the problem InitializeComponent() The actual code for this function is generated in a file called <Your Project Name>.Page1.xaml.g.cs or Page2.xaml.g.cs for example. However, it (the file) is only generated when a certain event gets fired. I was lucky to discover it by typing text into "Custom Tool Namespace", which fired that event, for one of the xaml pages(a file ending in .xaml, not .cs - make sure you have .xaml file selected), type some text and press enter and the file will be created.

Then I had the great idea of making InitializeComponent2(), a function exactly the same as InitializeComponent() and putting it in each cs file so it exists without having to generate the .xaml.g.cs every time you want the error to go away.

Check the version of Xamarin.Forms package referenced in your project.

.csproj file Xamarin.Forms nuget package

Very simple solution that worked for me:

  • Copy contents of the xaml/cs file
  • Delete the xaml/cs file
  • Create a new class and paste the contents

Now the InitializeComponent() function appears without red underline.

Hope this helps someone.

I have been having the same issue now and then, and this is what I have been doing to fix it: When in the PCL project, I add a new cross-platform XAML page to the project. Adding a new XAML page takes a few seconds for the references to "hook". After the new XAML page is successfully added to the project, the red underlines on the XAML Pages (with issues) will get cleared. Once the problem is solved, I simply delete the XAML file that I have just added. - So, in summary, adding a new XAML page then deleting it has been solving the issue for me.

I came across this error when;

  1. I removed a ContentPage-cs+xaml and the App-cs+xaml from the project without actually deleting it.
  2. Re-added these to the project in another folder.

This was fixed by;

  1. Select the .xaml file of the class in which the issue is present.
  2. Right click and select properties.
  3. In Build action select "Embedded Resource"
  4. In Custom Tool type "MSBuild:UpdateDesignTimeXaml"
  5. Clean and Build and it was gone.

I Just updated All packages, works fine.

If you get intellisense errors such InitializeComponent in your Xamarin.Forms pages but the project actually builds and runs fine, just add a new Forms page using the wizard to fix all errors...

Then you can delete that new page.

Check page text x:Class="AppName.Page1". AppName must be your app name

add using Xamarin.Forms.Xaml

tested on Visual Studio 2017

I had a caching issue when I encountered this error.

To get this fixed, simply uninstall last version of Xamarin.Forms package and reinstall a previous working version.

When the rebuild is successful, then update the package again to the latest version.

  1. Select the App.xaml and MainPage.xaml file of the class in which the issue is present.
  2. Right click and select properties.
  3. In Build action select "Embedded Resource"
  4. In Custom Tool type "MSBuild:UpdateDesignTimeXaml"
  5. Clean and Build and it was gone.

Ultimate solution would be to edit the project file in a text editor and just copy the pattern from another non-conflicting file. This solution worked for me. Usually, you would look for this syntax:

<Compile Update="Your\Path\YourContentPage.xaml.cs">
<DependentUpon>YourContentPage.xaml</DependentUpon>
</Compile>

Change Page properties to :

BuildAction => Embedded resource
CustomTools => MSBuild:UpdateDesignTimeXaml

In Xaml Page Properties only set
Build Action = Embedded resource
It works in visual studio 2017.

Tried all of the above and no luck, what did work for me was force reinstalling the Xamarin.Forms packages. In package manager console prompt;

update-package xamarin.forms -reinstall

It does not update packages, just removes and re-adds

I was missing a specific reference attribute (util in my case) in the root element:

<ContentPage
xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="MyProject.Views.HomePage"
xmlns:util="clr-namespace:Porject.Library.Util;assembly=Library"
>

Check the class name properly.

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="{AppName}.{ClassName}">
</ContentPage>

The class name should be a combination of App name and partial class name

It appears this is caused by many things so if you've read all of these and haven't resolved it yet:

Mine was caused by the Solution Configuration being set to Release. Changed to Debug and error resolved.

I Had the same issue with VS community edition 2019, i just used regenerate solution and the problem was fixed

For me it was just one rogue XAML with a leading space before <?xml version="1.0" encoding="utf-8" ?>, i.e.

 <?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
...

resulting in a bunch of CS0103 The name 'InitializeComponent' does not exist in the current context errors.