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MVVM DataTemplate Binding Issue

开发者 https://www.devze.com 2023-02-05 00:01 出处:网络
Perhaps this is a case of too much cold medicine, but I just can\'t seem to get this Binding correct.

Perhaps this is a case of too much cold medicine, but I just can't seem to get this Binding correct.

Here is the (simplified) Window, with the a DataTemplate for each ViewModel type, which should just show an associated View:

<Window ...>
    <Window.Resources>
        <DataTemplate DataType="{x:Type local:DefaultViewViewModel">
            <local:DefaultView />
        </DataTemplate>

        <DataTemplate DataType="{x:Type other:AnotherViewModel">
            <other:AnotherView />
        </DataTemplate>
    </Window.Resources>

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

Here is some of the MainViewModel (the actual ShowABCView methods are Command functions that do more than is shown here, for brevity):

class MainViewModel : ViewModelBase
{
    private Stack<ViewModelBase> mContentViewStack;

    public MainViewModel()
    {
        mContentViewStack = new Stack<ViewModelBase>();
        ShowDefaultView();
    }   

    public ViewModelBase CurrentViewModel
    {
        get { return mContentViewStack.Peek(); }
    }

    private ShowDefaultView()
    {
        DefaultViewViewModel viewModel = new DefaultViewViewModel();
        mContentViewStack.Push(viewModel);
        NotifyPropertyChanged("CurrentViewModel");
    }

    private ShowAnotherView()
    {
        AnotherViewModel viewModel = new AnotherViewModel();
        mContentViewStack.Push(viewModel);
        NotifyPropertyChanged("CurrentViewModel");
    }
}

And the MainWindow startup code:

public MainWindow()
{
    this.DataContext = new MainViewModel();
}

When I run this, I get the error

System.Windows.Data.Error: 40: BindingExpression path error: 'Content' property not found on 'object' 'DefaultViewViewModel'

I know I'm missing something obvious here, but the Nyquil and friends betray me...

*EDIT - DefaultViewViewModel and DefaultView *

DefaultViewViewModel:

// ViewModelBase is basically just a wrapper for INotifyPropertyChanged,
// plus some other common-to-my-project properties 
// (NOT INCLUDING A Content PROPERTY)
class DefaultViewViewModel : ViewModelBase
{
    public DefaultViewViewModel() : base()
   {
   }
}

DefaultView:

<UserControl ...>
    <TextBlock Text="Some Hard Coded Text Formatted To My开发者_开发问答 Liking" />
</UserControl>


Well you haven't shown the code for the DefaultViewViewModel yet but my guess is you defined "Content" as a field and not as a property.

to make sure that it will fix it, go ahead and overkill it by making Content a dependency property hope that helps


Found the answer upstream from where I was looking. There was an incorrect binding (used regular Binding without RelativeSource of the TemplatedParent) in the base View control that all of our Views use.

No more Nyquil for me...

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