C＃WPF如何从已打开的UserControl中设置MainWindow.contentControl.Content

Question

How do I set the MainWindow.contentControl.Content from an already opened UserControl?

In my MainWindow I load an UserControl from where I want to override the MainWindow.contentControl.Content again but when I do so my whole menu disappears which is defined above the ContentControl :(

[CODE] MainWindow

public MainWindow()
    {
        InitializeComponent();
        this.contentControl.Content = new MyUserControl();
    }

[XAML] MainWindow

<Grid>
    <DockPanel>
        <Menu IsMainMenu="True" DockPanel.Dock="Top">
            <MenuItem Header="_Application">
            </MenuItem>
        </Menu>
        <ContentControl x:Name="contentControl"/>
    </DockPanel>
</Grid>

[CODE] MyUserControl

public MyUserControl()
    {
        InitializeComponent();
        Application.Current.MainWindow.Content = new MyUserControlNEW();
    }

Answer 1

When you assign Application.Current.MainWindow.Content you actually remove the root Grid of your window.

One solution is to find the ContentControl by name like this:

(Application.Current.MainWindow.FindName("contentControl") as ContentControl).Content = new MyUserControlNEW();

But you really should avoid manipulating controls in this way for the sake of maintainability of your code. Try to implement MVVM pattern.