How to bind DataTemplates to ContentPresenter

Question

I have read some questions-answers explaining this topic (1,2,3) but i'm still missing something.

I have defined a `ResourceDictionary` with several `DataTemplate` for exmaple :

 <ResourceDictionary
        xmlns:wvm="clr-namespace:Octopus.Widgets.ViewModels;assembly=Octopus.Widgets"
        xmlns:wuc="clr-namespace:Octopus.Widgets.Controls;assembly=Octopus.Widgets">
    
    <DataTemplate DataType="{x:Type wvm:ClockViewModel}">
        <wuc:Clock />
    </DataTemplate>
</ResourceDictionary>

And merge it in the Application.Resources ResourceDictionary.MergedDictionaries section.
Now comes the part i don't understand.
How do I show a template in other control? I saw the use of <ContentPresenter Content="{Binding CurrentView}"/> but can't really understand it. Does the ViewModel of the container(parent) has a CurrentView property ? and what type it is then?
this is the parent-container control-view :

<Grid>
<!-- hard coded control - i want to change it -->
<Button>
    <wuc:Clock VerticalAlignment="Center" HorizontalAlignment="Center"> 
        <wuc:Clock.DataContext>
            <wvm:ClockViewModel/>
        </wuc:Clock.DataContext>
    </wuc:Clock>
</Button>

<!-- another try -->
<!--<ContentControl>
    <ContentControl.Style>
        <Style TargetType="{x:Type ContentControl}">
            <Setter Property="ContentTemplate" Value="{Binding WidgetTemplate}" />
        </Style>
    </ContentControl.Style>
</ContentControl>-->
</Grid>

Thanks
EDIT
My goal is to be able to switch widget based on key comming from DB.
Container control has a ViewModel with some properties not related to question. But maybe missing one that does and this is my question.

please clearly describe which data (viewmodels) you have and which behavior(scenarios, use-cases) you want to achive with them. — ASh, Jan 26 '22 at 08:41
You may just want to read the [documentation](https://learn.microsoft.com/en-us/dotnet/api/system.windows.datatemplate.datatype?view=windowsdesktop-6.0). It clearly explains how a DataTemplate is automatically chosen by its DataType. You would of course not explicitly assign a Clock to the Content of a Button, but a ClockViewModel instead. The Clock would then be created by the automatically applied DataTemplate. — Clemens, Jan 26 '22 at 08:45
"switch widget based on key comming from DB" - ok, I can think of half a dozen ways. One of them will probably work for you. — ASh, Jan 26 '22 at 08:59
Thanks you very much. Sometimes what might seen clear to one is chaos to another. — gilad, Jan 26 '22 at 09:00

score 1 · Answer 1 · answered Jan 26 '22 at 09:09

For the generations to come here is my solution:(thanks to @clemens for putting me on track)

In the container ViewModel i added a property to hold the selected widget type

public object Content
    {
        get { return content; }
        set
        {
            content = value;
            this.RaisePropertyChanged("Content");
        }
    }

and according to Widget i needed i initialized a new ViewModel (defined in DataTemplate)
And the xaml i used :

<ContentPresenter Content="{Binding Content}"/>

Simple enough....

How to bind DataTemplates to ContentPresenter

1 Answers1