Binding with a DataTemplate for System DataType
This may either be a silly question or i've searched for the wrong words:<br>
I have a ComboBox and want to display doubles using a custom converter (showing the equivalent fraction).<br>
In the DataTemplate i have to specify a DataType, which is Double, but i don't know how to specity it. I'm sure there is a simple way to do so!

Adding the System-namespace to the window doesn't work

    <Window ... xmlns:sys="clr-namespace:System" ...>

Simply typing Double or System.Double in DataType doesn't either.

And defining a ViewModel for a simple Double-Type can't be the solution either, can it?!

This is my code so far:

    <ComboBox ItemsSource="{Binding Gains}" SelectedItem="{Binding Gain, Mode=TwoWay}">
    	<ComboBox.Resources>
    		<DataTemplate DataType=" ??????? fract">
    			<TextBlock Text="{Binding ., Converter=fractConverter}"/>
    		</DataTemplate>
    	</ComboBox.Resources>
    </ComboBox>
Binding with a DataTemplate for System DataType
===

This may either be a silly question or i've searched for the wrong words:<br>
I have a ComboBox and want to display doubles using a custom converter (showing the equivalent fraction).<br>
In the DataTemplate i have to specify a DataType, which is Double, but i don't know how to specity it. I'm sure there is a simple way to do so!

Adding the System-namespace to the window doesn't work

    <Window ... xmlns:sys="clr-namespace:System" ...>

Simply typing Double or System.Double in DataType doesn't either.

And defining a ViewModel for a simple Double-Type can't be the solution either, can it?!

This is my code so far:

    <ComboBox ItemsSource="{Binding Gains}" SelectedItem="{Binding Gain, Mode=TwoWay}">
    	<ComboBox.Resources>
    		<DataTemplate DataType=" ??????? fract">
    			<TextBlock Text="{Binding ., Converter=fractConverter}"/>
    		</DataTemplate>
    	</ComboBox.Resources>
    </ComboBox>