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Subklassen in XAML ansprechen

In the realm of XAML, crafting DataTemplates for classes is a routine task. But what if we need to specify a subclass as the DataType? This scenario can present a unique set of challenges, as I discovered during my recent endeavor.

I set out to create a DataTemplate in a XAML Resource file for my class, specifying my subclass as the DataType. Here’s the code I used:

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
   xmlns:local="clr-namespace:Project;assembly=Project">
   <DataTemplate x:Key="myTaskTemplate" DataType="{x:Type local:Subclass}">
[..]
   </DataTemplate>
</ResourceDictionary> 

However, during compilation, I was consistently greeted with the error message “The type Subclass was not found”. This was a roadblock I hadn’t anticipated. I attempted various alternatives, such as Class.Subclass, but these efforts proved fruitless.

The error message indicated that the compiler was unable to find the subclass. This was puzzling because the subclass was defined in the same namespace as the class. After some research, I discovered that the issue was with how I was referencing the subclass in the DataType attribute.

In XAML, when specifying a subclass as a DataType, the syntax requires a + symbol to denote the subclass. This is a less-known aspect of XAML syntax, and it’s easy to overlook if you’re not aware of it.

So, the correct approach to specify a subclass as a DataType in XAML is as follows:

DataType="{x:Type local:class+subclass}"

This experience served as a reminder that even seemingly straightforward tasks can present unexpected challenges. But with a bit of persistence and a deep dive into the nuances of XAML syntax, I was able to find the solution. I hope this exploration helps others who might encounter a similar issue.