How to Binding data to User Control loaded in Control Template?-CodePudding

My CMainViewModel has a property called AnalogGaugeValue1

On my Window I have a data template as shown below. I use this template to load a user control named AnalogIOView and try to binding the dependency property, GaugeValue1DP, inside AnalogIOView to the AnalogGaugeValue1

<Window>

  <Window.Resources>

    <DataTemplate x:Key="AnalogIOViewTemplate" DataType="{x:Type local:CMainViewModel}">
        <local:AnalogIOView 
               GaugeValue1DP="{Binding Path=AnalogGaugeValue1}"   />
   </DataTemplate>

  </Window.Resources>

<Window>

I use the ContentControl to load the AnalogIOViewTemplate in my Window as shown below

<Grid>

                        <ContentControl>
                            <ContentControl.Style>
                                <Style TargetType="{x:Type ContentControl}">
                                    <Setter Property="ContentTemplate" Value=" 
                                    {StaticResource AnalogIOViewTemplate }" />
                                </Style>
                            </ContentControl.Style>
                        </ContentControl>

</Grid>

The user control displays correctly on my Window but I could not set the Analog Gauge value through binding in CMainViewModel.

However, If I just load the user control directly (without using Control Template) then it is working correctly as shown below

<Grid>
   <local:AnalogIOView GaugeValue1DP="{Binding Path=AnalogGaugeValue1}" />
</Grid>

My question is why it does not work when loading the user control using Content Control template and data template

Thanks for your help

CodePudding user response：

You have to set the Content property, and it would also be simpler not set an x:Key on the DataTemplate. It would then automatically be selected as the ContentTemplate of the ContentControl.

<Window>
    <Window.Resources>
        <DataTemplate DataType="{x:Type local:CMainViewModel}">
            <local:AnalogIOView GaugeValue1DP="{Binding AnalogGaugeValue1}"/>
        </DataTemplate>
    </Window.Resources>

    <Grid>
        <ContentControl Content="{Binding}"/>
    </Grid>
<Window>