在“添加新的用户控件”按钮上单击“在WPF MVVM中单击命令”

Question

Hi i am trying to display usercontrol Dynamically But it is not working ...please help me to improve code . In cunstructor of MainWindowViewModel i tried to set initial property of contentcontrol. Thank you in advance

<Window x:Class="WpfApplication1.MainWindow"
            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
            xmlns:VM="clr-namespace:WpfApplication1.ViewModel"
            xmlns:View="clr-namespace:WpfApplication1.View"
            Title="MainWindow" Height="350" Width="525">
        <Window.Resources>
            <DataTemplate DataType="{x:Type VM:FirstControlViewModel}">
                <View:FirstControl></View:FirstControl>
            </DataTemplate>
            <DataTemplate DataType="{x:Type VM:SecondControlViewModel}">
                <View:SecondControl></View:SecondControl>
            </DataTemplate>

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

View Model Code :-

    public class MainViewModel: INotifyPropertyChanged        
    {
       public MainViewModel()
       {
           LoadedControl = "FirstControlViewModel";// here i am setting property  
                                                   //But not working
       }

       private string _LoadedControl;

       public string LoadedControl
       {
           get { return _LoadedControl; }
           set { _LoadedControl = value;

           NotifyPropertyChanged("LoadedControl");

           }
       }

Answer 1

You need to set LoadedControl to an instance of your ViewModel type, not a string!

public MainViewModel()
{
   LoadedControl = new FirstControlViewModel();
}

private ViewModelBase _LoadedControl;

public ViewModelBase LoadedControl
{
    get { return _LoadedControl; }
    set { _LoadedControl = value;
          NotifyPropertyChanged("LoadedControl");
    }
}