c# - 在 WPF MVVM 中添加新的用户控件按钮单击命令

Question

您好，我正在尝试动态显示用户控件，但它不起作用...请帮助我改进代码。在 MainWindowViewModel 的 cunstructor 中，我试图设置 contentcontrol 的初始属性。提前谢谢你

<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>

查看模型代码:-

    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

您需要将 LoadedControl 设置为您的 ViewModel 类型的实例，而不是字符串!

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

private ViewModelBase _LoadedControl;

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