Why I can't find a ResourceDictionary template in my visual studio? - visual-studio

Question

I am a beginner in Xamarin. Now I want to add a ResourceDictionary for making a Theme.
In https://learn.microsoft.com/en-us/dotnet/api/xamarin.forms.resourcedictionary?view=xamarin-forms:
The Namespace of ResourceDictionary is Xamarin.Forms.
Whereas, there is not any ResourceDictionary template.
I tried to search it again:
There is nothing about this. I am using the Visual Studio Community 2019 Version 16.5.4. Why it turns out to be this and how can I solve it?
Thank you.

Answer 1

I think that you are mixing the terms here. Namespaces and assemblies are totally different things than the New item templates inside Visual studio. ResourceDictionary class is inside the Xamarin.Forms, indeed, and in the same time inside the Xamarin.Forms.Core.dll. This doesn't mean that it should be inside the new item template. There are a lot of other classes inside this namespace.
Having said that, you can create ResourceDictionary class in 2 ways:
If you want to write in it entirely in c#, what you will need is a .cs file. The file can be either ContentPage (C#) from the templates above (the second item from your screenshot), or a simple .cs calss file will do the work also. After that, inherit from ResourceDictionary class like so:
public class MyResourceDictionary : Xamarin.Forms.ResourceDictionary
{
}
If you want to write in it in xaml, then simply create a new ContentPage (the first item from your screenshot). Any other type of the combo .xaml together with a .xaml.cs code-behind file will work too. After the files have been created, change their structure from:
MyResoruceDictionary.xaml
<?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="LEUA.Services.MyResourceDictionary">
<ContentPage.Content>
<StackLayout>
<Label Text="Hello, world!"
VerticalOptions="CenterAndExpand"
HorizontalOptions="CenterAndExpand" />
</StackLayout>
</ContentPage.Content>
</ContentPage>
MyResourceDictionary.xaml.cs
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class MyResourceDictionary : ContentPage
{
public MyResourceDictionary()
{
InitializeComponent();
}
}
to this
MyResoruceDictionary.xaml
<?xml version="1.0" encoding="utf-8"?>
<ResourceDictionary xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="LEUA.Services.MyResourceDictionary">
</ResourceDictionary>
MyResourceDictionary.xaml.cs
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class MyResourceDictionary : Xamarin.Forms.ResourceDictionary
{
public MyResourceDictionary()
{
InitializeComponent();
}
}