I have xamarin.forms application for android and ios, I want to target UWP as well but i dont want to use Xamarin.Forms generated UWP rather I will reuse ViewModels and resources from XF shared library and design UWP natively.
There are resx files as translation files within the Shared project and I am using in the xaml with help of TranslatorExtension as below like mentioned in the article
[ContentProperty("Text")]
public class TranslateExtension : IMarkupExtension
{
const string ResourceId = "LocalizationSample.Resources.AppResources";
static readonly Lazy resmgr =
new Lazy(() =>
new ResourceManager(ResourceId, typeof(TranslateExtension)
.GetTypeInfo().Assembly));
public string Text { get; set; }
public object ProvideValue(IServiceProvider serviceProvider)
{
if (Text == null)
return "";
var ci = CrossMultilingual.Current.CurrentCultureInfo;
var translation = resmgr.Value.GetString(Text, ci);
if (translation == null)
{
translation = Text; // returns the key, which GETS DISPLAYED TO THE USER
}
return translation;
}
}
And referencing in Xaml code in the ContentPage simply <Label Text="{i18n:Translate HelloWorld}"
This works perfectly fine but I couldnt figure out how to use translationextension in a UWP xaml Page.
Is it only meant to be used for Xamarin.Forms application. Is there something similar for UWP.
So basically how can reuse those resx files without duplicating for UWP?
PS, if i have to use Xamarin.forms nuget and namespace in order to use IMarkupExtension, it is still fine for me.
This works perfectly fine but I couldnt figure out how to use translationextension in a UWP xaml Page. Is it only meant to be used for Xamarin.Forms application. Is there something similar for UWP. So basically how can reuse those resx files without duplicating for UWP?
I'm afraid you can't use above TranslateExtension in UWP Xaml, Because above IMarkupExtension in forms specific, you can't use it in UWP Xaml.
For making UWP native localization, please refer this document and use an x:Uid directive to associate a control or other element in your markup with a string resource identifier.
XAML
<TextBlock x:Uid="Greeting"/>
I have a default theme for my app. I customize this theme using Style file in Android. But I'm creating a login page that I want use other theme just for it. How can I do that?
I am not sure you can do that, because Android theme can be applied to an activity in Android, but Xamarin.Forms run "within" a single activity, so you would have to do the styling either in Xamarin.Forms. Check out this post on Xamarin Forums where the developer was able to change the theme at runtime, which however restarted the activity and in turn also his Xamarin.Forms app.
If your Xamarin Forms app is only using one activity, then this is quite straightforward. This solution is for Lollipop and versions after. You can do this using platform specific Android code:
public class StatusBarStyleManager : IStatusBarStyleManager
{
public void SetStatusBarColor(Android.Graphics.Color color)
{
if (Build.VERSION.SdkInt >= BuildVersionCodes.M)
{
Device.BeginInvokeOnMainThread(() =>
{
var currentWindow = GetCurrentWindow();
currentWindow.DecorView.SystemUiVisibility = (StatusBarVisibility)SystemUiFlags.LightStatusBar;
currentWindow.SetStatusBarColor(color);
});
}
}
Window GetCurrentWindow()
{
//Note this is a nuget package for retrieving the activity.
var window = CrossCurrentActivity.Current.Activity.Window;
// clear FLAG_TRANSLUCENT_STATUS flag:
window.ClearFlags(WindowManagerFlags.TranslucentStatus);
// add FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS flag to the window
window.AddFlags(WindowManagerFlags.DrawsSystemBarBackgrounds);
return window;
}
}
Then just use this implementation in your pages to set their specific status bar colors when they appear.
Inspired by this article when I needed this in my own projects:
https://evgenyzborovsky.com/2018/08/20/dynamically-changing-the-status-bar-appearance-in-xamarin-forms/
I downloaded a copy of the current Xamarin Forms master branch, compiled it, and then I added these compiled assemblies as references to a test project:
Xamarin.Forms.Core
Xamarin.Forms.Platform
Xamarin.Forms.Platform.Android
Xamarin.Forms.Xaml
The test project was created using the Visual Studio Xamarin Forms project template, the only thing I modified is the references in the Core.csproj and Android.csproj to point to the compiled assemblies.
I used the first 3 from the bin\debug\ folder of the Xamarin.Forms.Platform.Android project, and the last one from the Xamarin.Forms.Xaml bin\debug folder.
I run the test project, and it runs fine, I can see the label from the default generated code "Welcome to Xamarin Forms!"
Next, I just modified the MainPage like this:
public partial class App : Application
{
public App()
{
InitializeComponent();
MainPage = new NavigationPage(new ContentPage());
}
}
When I run the app, it gives me an error
System.ArgumentException: element is not of type Xamarin.Forms.View
Parameter name: element
thrown on this line:
void IVisualElementRenderer.SetElement(VisualElement element)
{
if (!(element is TElement))
throw new ArgumentException("element is not of type " + typeof(TElement), nameof(element));
SetElement((TElement)element);
}
which is strange.
The type of the element is Xamarin.Forms.NavigationPage and the stack trace is
Can someone help me running the test project with the compiled assemblies?
UPDATE #1:
The 2nd entry in the call stack shows that it's not able to get the registered renderer(NavigationPageRenderer) for the NavigationPage element and instead it's creating a default renderer(DefaultRenderer), which can't handle the type of element(NavigationPage) so it's throwing the exception I see.
So it appears that for NavigationPage, it doesn't find its renderer(NavigationPageRenderer) in the Registrar.
public static IVisualElementRenderer CreateRenderer(VisualElement element)
{
UpdateGlobalContext(element);
IVisualElementRenderer renderer = Registrar.Registered.GetHandler<IVisualElementRenderer>(element.GetType()) ?? new DefaultRenderer();
renderer.SetElement(element);
return renderer;
}
My feeling is there's a build step I'm not aware about when building Xamarin Forms.
Its crashing as you are calling InitializeComponent on something which doesn't derive from a Forms.Page (i.e. ContentPage etc).
The application itself is not a Page, if you had a page, lets call it 'MyCustomPage' which has some Xaml behind the class would look something like this:
public partial class MyCustomPage : ContentPage
{
public MyCustomPage()
{
InitializeComponent ();
// Some other setup...
}
}
Then in your App constructor you would call
MainPage = new MyCustomPage();
Since you are creating a blank content page from the root of your app, you do not need to call InitializeComponent.
Hope this helps.
You also need to reference
Xamarin.Forms.Platform.Android (Forwarders)
from your Android project.
I'm using Visual Studio to try out Xamarin.Forms. I'm trying to follow the guide:
http://developer.xamarin.com/guides/cross-platform/xamarin-forms/xaml-for-xamarin-forms/getting_started_with_xaml/
In short, I create a Xamarin.Forms solution using a PCL and then try to add a Forms XAML Page to the PCL-project.
The code-behind that gets created looks like this:
public partial class Page1 : ContentPage
{
public Page1()
{
InitializeComponent();
}
}
The problem here is that InitializeComponent(); is red.
When I try to build I get informed that The name 'InitializeComponent' does not exist in the current context
I've been looking around for solutions and even though others have had the same trouble, their solutions wont work for me. Here is one suggestion i tried to use:
http://blog.falafel.com/xamarin-error-initializecomponent-does-not-exist-in-the-current-context/
Please let me know if you have a solution for this problem. Thanks!
Update:
My PCL (which is where I also want to add my XAML-page) contains:
App.cs:
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
}
}
And my XAML-page:
<?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>
Code-behind:
public partial class MyXamlPage : ContentPage
{
public MyXamlPage()
{
InitializeComponent();
}
}
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:
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.
I get this sometimes and here's the checklist that solved them so far:
Make sure the namespace in .xaml and .xaml.cs match
Inherit from the correct parent - ContentPage for a page and ContentView for a control
Set build action of the .xaml file to Embedded Resource if in the shared project.
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.
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:
Open the *.xaml file in the project and click Save button. (There will be applying the correct encoding in VS2015).
Then reopen the project and rebuild it. Now there are no errors.
Updating the Xamarin.Forms NuGet package should do the job
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
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...
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.
I came across this error when;
I removed a ContentPage-cs+xaml and the App-cs+xaml from the project without actually deleting it.
Re-added these to the project in another folder.
This was fixed by;
Select the .xaml file of the class in which the issue is present.
Right click and select properties.
In Build action select "Embedded Resource"
In Custom Tool type "MSBuild:UpdateDesignTimeXaml"
Clean and Build and it was gone.
Check page text x:Class="AppName.Page1". AppName must be your app name
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.
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!
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.
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.
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
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.
Check the version of Xamarin.Forms package referenced in your project.
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 Just updated All packages, works fine.
Change Page properties to :
BuildAction => Embedded resource
CustomTools => MSBuild:UpdateDesignTimeXaml
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.
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.
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.
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.
add using Xamarin.Forms.Xaml
tested on Visual Studio 2017
Select the App.xaml and MainPage.xaml file of the class in which the issue is present.
Right click and select properties.
In Build action select "Embedded Resource"
In Custom Tool type "MSBuild:UpdateDesignTimeXaml"
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>
In Xaml Page Properties only set
Build Action = Embedded resource
It works in visual studio 2017.