CODEWITHSUNDEEP
xamlxamarin.formsdatatemplateselector
Peri Hartman
Peri Hartman

Reputation: 19484

xamarin datatemplateselector: not valid XAML name

I'm trying to do a very common usage of Xamarin.Forms ListView, where I have multiple types of items.

I'm using a DataTemplateSelector and defining the different (two at this point) views in my XAML file. That requires referencing the c# code from the XAML code through a namesspace definition. And, that's where I'm stuck.

The error I'm getting is

XFC0000 Cannot resolve type "local:NodeTemplateSelector".

Here is my XAML, condensed:

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

  <ContentPage.Resources>
    <ResourceDictionary>
      
      <DataTemplate x:Key="NoteItem">
      ...
      </DataTemplate>

      <local:NodeTemplateSelector x:Key="NodeTemplateKey">
        NoteTemplate = "{StaticResource NoteItem}"
        ImageTemplate = "{StaticResource ImageItem}"
      </local:NodeTemplateSelector>

    </ResourceDictionary>
  </ContentPage.Resources>
</ContentPage>

And, here is C#, also condensed:

namespace varlist
{
  [XamlCompilation(XamlCompilationOptions.Compile)]
  public partial class ListViewPage : ContentPage
  {
    ...
    public class NodeTemplateSelector : DataTemplateSelector
    {
      public DataTemplate NoteTemplate { get; set; }
      public DataTemplate ImageTemplate { get; set; }

      protected override DataTemplate OnSelectTemplate (object item, BindableObject container)
      {
        ListView list = (ListView)container;
        if (item is NoteData)
          return NoteTemplate;
        else // item is ImageData
          return ImageTemplate;
      }
    }
  }
}

What do I need to change to get the XAML to recognize NodeTemplateSelector ?

Upvotes: 0

Views: 193

Answers (1)

Peri Hartman
Peri Hartman

Reputation: 19484

As Jason and Shaw suggested, the NodeTemplateSelector must be in top level class.

Also, another problem I ran into is the syntax in the DataTemplate XAML file. Might as well add this note, in case anyone else has the same trouble:

The NodeTemplateSelector in XAML must be defined as direct content; must be like this:

  <local:NodeTemplateSelector 
    x:Key="NodeTemplate"
    NoteItemTemplate="{StaticResource NoteTemplate}"
    ImageItemTemplate="{StaticResource ImageTemplate}"
  />

Otherwise you get a rather undecipherable runtime error.

Upvotes: 0

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