net maui 主窗口使用菜单功能打开子窗口的效果类似MID

Question

net maui 主窗口使用菜单功能打开子窗口的效果类似MID

张中伟 80

我想用MAUI实现WINforM 的主从窗口效果。如果实现不了就多窗口也行。结果就是菜单点击后，弹出指定的PAGE。如果本来就存在那么前端显示，不重复显示。安卓上就直接跳转过去就行。如果也可以多窗口就更好。我的代码只能打开一次。还是在WIN下。麻烦给出最简洁的代码，谢谢。。

<ContentPage.MenuBarItems>

 <MenuBarItem Text="pages">

     <MenuFlyoutSubItem Text="all">

         <MenuFlyoutItem Text="page1" Clicked="MenuFlyoutItem_Clicked"/>

         <MenuFlyoutSeparator />

     </MenuFlyoutSubItem>

 </MenuBarItem>
``` </ContentPage.MenuBarItems>

namespace MauiApp1;

public partial class MainPage : ContentPage

{

```scala
public MainPage()

{

    InitializeComponent();

}

public Window? win1 = null;

private void MenuFlyoutItem_Clicked(object sender, EventArgs e)

{

    if (win1 == null)

    {

        win1 = new(new pages.Page1());

        if (DeviceInfo.Platform == DevicePlatform.WinUI)

        {

            App.Current?.OpenWindow(win1);

        }

        else if (DeviceInfo.Platform == DevicePlatform.Android)

        {

            //安卓怎么打开

        }

        else

        {

            //

        }

    }

    else

    {

        if (DeviceInfo.Platform == DevicePlatform.WinUI)

        {

            //这里无法再打开也会报错

            //var winUIWindow = win1.Handler?.PlatformView as Microsoft.UI.Xaml.Window;

            //if (winUIWindow != null)

            //{

            //    winUIWindow.Activate();

            //}

        }


        

    }

}
```}

1 个答案

你的答案

Answer 1

Hello,

首先 MenuBarItem 只能用于Mac Catalyst 和Windows. Android 系统上没有 MenuBarItem且无法触发MenuFlyoutItem_Clicked 事件

对于windows 或者Mac Catalyst，我们可以通过在Microsoft.Maui.Controls.Application.Current.Windows 中去查找是否有相同title的page, 如果有，就利用 Microsoft.Maui.Controls.Application.Current?.ActivateWindow(window)，把打开过的windows 调到前台，注意请加一个Task.Delay(100),如果不加这个delay, 我这边测下来，当window 在后台，没有最小化的情况下无法调到前台。

如果在Microsoft.Maui.Controls.Application.Current.Windows 中没有相同title的page，就去OpenWindow.

private async void MenuFlyoutItem_Clicked(object sender, EventArgs e)
      {
          LoginPage login = new LoginPage();
          Microsoft.Maui.Controls.Window secondWindow = new Microsoft.Maui.Controls.Window(login);

 
          if (Microsoft.Maui.Controls.Application.Current.Windows.Any(t => t.Page.Title.Equals(login.Title)))
          {
             var window = Microsoft.Maui.Controls.Application.Current.Windows.Where(t => t.Page.Title.Equals(login.Title)).FirstOrDefault();
             await Task.Delay(100);
             Microsoft.Maui.Controls.Application.Current?.ActivateWindow(window);
          }
          else
          {
              Microsoft.Maui.Controls.Application.Current?.OpenWindow(secondWindow);
 
          }
      }

对于Android 平台，你可以在button 点击事件中尝试以上代码，并且不要忘了把MainActivity 的LaunchMode 设置成LaunchMode.Multiple。

[Activity(Theme = "@style/Maui.SplashTheme", MainLauncher = true, LaunchMode = LaunchMode.Multiple, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation | ConfigChanges.UiMode | ConfigChanges.ScreenLayout | ConfigChanges.SmallestScreenSize | ConfigChanges.Density)]
public class MainActivity : MauiAppCompatActivity
{
}

Best Regards,

Leon Lu

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