I found that DataFormDataField.ContentTemplate doesn't work since version "RadControls for WPF Q2 2013", actually i only have the latest 3 versions. I've tried each one, all the same, just display the default textbox. My code is simple, just copy from your online documentation, as below:
<Grid x:Name="LayoutRoot" Background="White">
<Grid.Resources>
<DataTemplate x:Key="MyTemplate">
<StackPanel Orientation="Horizontal" >
<telerik:DataFormDataField>
<telerik:DataFormDataField.LabelTemplate>
<DataTemplate>
<Label Foreground="Orange">Title:</Label>
</DataTemplate>
</telerik:DataFormDataField.LabelTemplate>
<telerik:DataFormDataField.ContentTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBox Text="25" Margin="0,0,10,0" />
<TextBlock Text="years" Foreground="Green" VerticalAlignment="Bottom" />
</StackPanel>
</DataTemplate>
</telerik:DataFormDataField.ContentTemplate>
</telerik:DataFormDataField>
</StackPanel>
</DataTemplate>
</Grid.Resources>
<telerik:RadDataForm x:Name="DataForm1"
AutoGenerateFields="False"
ReadOnlyTemplate="{StaticResource MyTemplate}">
</telerik:RadDataForm>
</Grid>
MOST URGENT, PLEASE ANSWER IT QUICKLY, THANK YOU!!
<Grid x:Name="LayoutRoot" Background="White">
<Grid.Resources>
<DataTemplate x:Key="MyTemplate">
<StackPanel Orientation="Horizontal" >
<telerik:DataFormDataField>
<telerik:DataFormDataField.LabelTemplate>
<DataTemplate>
<Label Foreground="Orange">Title:</Label>
</DataTemplate>
</telerik:DataFormDataField.LabelTemplate>
<telerik:DataFormDataField.ContentTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBox Text="25" Margin="0,0,10,0" />
<TextBlock Text="years" Foreground="Green" VerticalAlignment="Bottom" />
</StackPanel>
</DataTemplate>
</telerik:DataFormDataField.ContentTemplate>
</telerik:DataFormDataField>
</StackPanel>
</DataTemplate>
</Grid.Resources>
<telerik:RadDataForm x:Name="DataForm1"
AutoGenerateFields="False"
ReadOnlyTemplate="{StaticResource MyTemplate}">
</telerik:RadDataForm>
</Grid>
MOST URGENT, PLEASE ANSWER IT QUICKLY, THANK YOU!!