Question

Most common way I encountered of specifying a value converter for a binding is to:
1. Create an instance of the value converter as a resource with a key.
2. Reference the instance using StaticResource markup extension:

<TextBlock Text="{Binding Converter={StaticResource myFormatter}" />  

Q: Is there anything wrong with using static instance as follows:

<TextBlock Text="{Binding Path=Description, Converter={x:Static local:MyFormatter.Instance}}"/>

// where Instance is declared as:
public readonly static MyFormatter Instance = new MyFormatter();

In my case value converter is immutable.

Edit: another way is to turn the converter into an extension
so that you specify the converter using markup extension format:

<TextBlock Text="{Binding Converter={local:MyFormatter}}"/>

Answer 1

Technically it will be fine, but in practice I don’t like it:

1. If you declare the converter as a resource, then you have a single point of reference. If you change the namespace or class name of the converter, then you only have a single place to update.

2. If you declare it as static, then you need to bring the clr-namespace in at the top of each and every xaml file that uses the converter. If you declare it as a resource, you don’t.

3. {Binding Converter={StaticResource myFormatter} is much shorter and easier to read than the static one. In the long run, this will help you more than you might think.