C# 如何自定义Windows窗体的系统菜单？

我想将“关于”菜单项添加到我的应用程序中。我想把它添加到应用程序的“系统菜单”中，当我们点击左上角的应用程序图标时，它会弹出。那么，我怎样才能在.NET中做到这一点呢？

对于您所需要的pinvoke数量来说，附加值相当小。但这是可能的。使用GetSystemMenu检索系统菜单句柄。然后插入菜单项以添加条目。必须在OnHandleCreated的重写中执行此操作，以便在重新创建窗口时重新创建菜单

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重写WndProc以识别用户单击时生成的WM_SYSCOMMAND消息。请访问pinvoke.net以获取所需的pinvoke声明。

Windows可以非常轻松地获取表单系统菜单副本的句柄，以便使用进行自定义。困难的部分是，您需要自己对它返回的菜单执行适当的修改，使用函数，如，并且就像您直接针对Win32 API编程一样

然而，如果你想做的只是添加一个简单的菜单项，其实并不难。例如，您只需要使用AppendMenu函数，因为您只需要在菜单的末尾添加一两个项目。做任何更高级的事情，比如在菜单中间插入一个项目，在菜单项上显示位图，显示选中的菜单项，设置默认菜单项等等。但一旦你知道怎么做，你就可以发疯了。这件事说明了一切

下面是一个表单的完整代码，该表单在其系统菜单（也称为窗口菜单）的底部添加分隔线和“关于”项：

using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;

public class CustomForm : Form
{
    // P/Invoke constants
    private const int WM_SYSCOMMAND = 0x112;
    private const int MF_STRING = 0x0;
    private const int MF_SEPARATOR = 0x800;

    // P/Invoke declarations
    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr GetSystemMenu(IntPtr hWnd, bool bRevert);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern bool AppendMenu(IntPtr hMenu, int uFlags, int uIDNewItem, string lpNewItem);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern bool InsertMenu(IntPtr hMenu, int uPosition, int uFlags, int uIDNewItem, string lpNewItem);


    // ID for the About item on the system menu
    private int SYSMENU_ABOUT_ID = 0x1;

    public CustomForm()
    {
    }

    protected override void OnHandleCreated(EventArgs e)
    {
        base.OnHandleCreated(e);

        // Get a handle to a copy of this form's system (window) menu
        IntPtr hSysMenu = GetSystemMenu(this.Handle, false);

        // Add a separator
        AppendMenu(hSysMenu, MF_SEPARATOR, 0, string.Empty);

        // Add the About menu item
        AppendMenu(hSysMenu, MF_STRING, SYSMENU_ABOUT_ID, "&About…");
    }

    protected override void WndProc(ref Message m)
    {
        base.WndProc(ref m);

        // Test if the About item was selected from the system menu
        if ((m.Msg == WM_SYSCOMMAND) && ((int)m.WParam == SYSMENU_ABOUT_ID))
        {
            MessageBox.Show("Custom About Dialog");
        }

    }
}

以下是成品的外观：

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我进一步采用了Cody Gray的解决方案，并从中创建了一个可重用的类。它是我的应用程序日志提交工具的一部分，应该在系统菜单中隐藏其关于信息

它可以很容易地像这样使用：

class MainForm : Form
{
    private SystemMenu systemMenu;

    public MainForm()
    {
        InitializeComponent();

        // Create instance and connect it with the Form
        systemMenu = new SystemMenu(this);

        // Define commands and handler methods
        // (Deferred until HandleCreated if it's too early)
        // IDs are counted internally, separator is optional
        systemMenu.AddCommand("&About…", OnSysMenuAbout, true);
    }

    protected override void WndProc(ref Message msg)
    {
        base.WndProc(ref msg);

        // Let it know all messages so it can handle WM_SYSCOMMAND
        // (This method is inlined)
        systemMenu.HandleMessage(ref msg);
    }

    // Handle menu command click
    private void OnSysMenuAbout()
    {
        MessageBox.Show("My about message");
    }
}

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我知道这个答案很古老，但我真的很喜欢LonelyPixel的答案。然而，它需要一些工作来正确使用WPF。以下是我编写的WPF版本，因此您不必：

/// <summary>
/// Extends the system menu of a window with additional commands.
/// Adapted from:
/// https://github.com/dg9ngf/FieldLog/blob/master/LogSubmit/Unclassified/UI/SystemMenu.cs
/// </summary>
public class SystemMenuExtension
{
    #region Native methods

    private const int WM_SYSCOMMAND = 0x112;
    private const int MF_STRING = 0x0;
    private const int MF_SEPARATOR = 0x800;

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr GetSystemMenu(IntPtr hWnd, bool bRevert);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern bool AppendMenu(IntPtr hMenu, int uFlags, int uIDNewItem, string lpNewItem);

    #endregion Native methods

    #region Private data
    private Window window;
    private IntPtr hSysMenu;
    private int lastId = 0;
    private List<Action> actions = new List<Action>();
    private List<CommandInfo> pendingCommands;

    #endregion Private data

    #region Constructors

    /// <summary>
    /// Initialises a new instance of the <see cref="SystemMenu"/> class for the specified
    /// <see cref="Form"/>.
    /// </summary>
    /// <param name="window">The window for which the system menu is expanded.</param>
    public SystemMenuExtension(Window window)
    {
        this.window = window;
        if(this.window.IsLoaded)
        {
            WindowLoaded(null, null);
        }
        else
        {
            this.window.Loaded += WindowLoaded;
        }
    }

    #endregion Constructors

    #region Public methods

    /// <summary>
    /// Adds a command to the system menu.
    /// </summary>
    /// <param name="text">The displayed command text.</param>
    /// <param name="action">The action that is executed when the user clicks on the command.</param>
    /// <param name="separatorBeforeCommand">Indicates whether a separator is inserted before the command.</param>
    public void AddCommand(string text, Action action, bool separatorBeforeCommand)
    {
        int id = ++this.lastId;
        if (!this.window.IsLoaded)
        {
            // The window is not yet created, queue the command for later addition
            if (this.pendingCommands == null)
            {
                this.pendingCommands = new List<CommandInfo>();
            }
            this.pendingCommands.Add(new CommandInfo
            {
                Id = id,
                Text = text,
                Action = action,
                Separator = separatorBeforeCommand
            });
        }
        else
        {
            // The form is created, add the command now
            if (separatorBeforeCommand)
            {
                AppendMenu(this.hSysMenu, MF_SEPARATOR, 0, "");
            }
            AppendMenu(this.hSysMenu, MF_STRING, id, text);
        }
        this.actions.Add(action);
    }

    #endregion Public methods

    #region Private methods

    private void WindowLoaded(object sender, RoutedEventArgs e)
    {
        var interop = new WindowInteropHelper(this.window);
        HwndSource source = PresentationSource.FromVisual(this.window) as HwndSource;
        source.AddHook(WndProc);

        this.hSysMenu = GetSystemMenu(interop.EnsureHandle(), false);

        // Add all queued commands now
        if (this.pendingCommands != null)
        {
            foreach (CommandInfo command in this.pendingCommands)
            {
                if (command.Separator)
                {
                    AppendMenu(this.hSysMenu, MF_SEPARATOR, 0, "");
                }
                AppendMenu(this.hSysMenu, MF_STRING, command.Id, command.Text);
            }
            this.pendingCommands = null;
        }
    }

    private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
    {
        if (msg == WM_SYSCOMMAND)
        {
            if ((long)wParam > 0 && (long)wParam <= lastId)
            {
                this.actions[(int)wParam - 1]();
            }
        }

        return IntPtr.Zero;
    }

    #endregion Private methods

    #region Classes

    private class CommandInfo
    {
        public int Id { get; set; }
        public string Text { get; set; }
        public Action Action { get; set; }
        public bool Separator { get; set; }
    }

    #endregion Classes

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接受答案的VB.NET版本：

Imports System.Windows.Forms
Imports System.Runtime.InteropServices

Public Class CustomForm
    Inherits Form
    ' P/Invoke constants
    Private Const WM_SYSCOMMAND As Integer = &H112
    Private Const MF_STRING As Integer = &H0
    Private Const MF_SEPARATOR As Integer = &H800

    ' P/Invoke declarations
    <DllImport("user32.dll", CharSet := CharSet.Auto, SetLastError := True)> _
    Private Shared Function GetSystemMenu(hWnd As IntPtr, bRevert As Boolean) As IntPtr
    End Function

    <DllImport("user32.dll", CharSet := CharSet.Auto, SetLastError := True)> _
    Private Shared Function AppendMenu(hMenu As IntPtr, uFlags As Integer, uIDNewItem As Integer, lpNewItem As String) As Boolean
    End Function

    <DllImport("user32.dll", CharSet := CharSet.Auto, SetLastError := True)> _
    Private Shared Function InsertMenu(hMenu As IntPtr, uPosition As Integer, uFlags As Integer, uIDNewItem As Integer, lpNewItem As String) As Boolean
    End Function


    ' ID for the About item on the system menu
    Private SYSMENU_ABOUT_ID As Integer = &H1

    Public Sub New()
    End Sub

    Protected Overrides Sub OnHandleCreated(e As EventArgs)
        MyBase.OnHandleCreated(e)

        ' Get a handle to a copy of this form's system (window) menu
        Dim hSysMenu As IntPtr = GetSystemMenu(Me.Handle, False)

        ' Add a separator
        AppendMenu(hSysMenu, MF_SEPARATOR, 0, String.Empty)

        ' Add the About menu item
        AppendMenu(hSysMenu, MF_STRING, SYSMENU_ABOUT_ID, "&About…")
    End Sub

    Protected Overrides Sub WndProc(ByRef m As Message)
        MyBase.WndProc(m)

        ' Test if the About item was selected from the system menu
        If (m.Msg = WM_SYSCOMMAND) AndAlso (CInt(m.WParam) = SYSMENU_ABOUT_ID) Then
            MessageBox.Show("Custom About Dialog")
        End If

    End Sub
End Class

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这很有效。但是，如何显示About条目的加速键？就像Close有Alt+F4一样，我想显示Alt+A大约。不过，我找到了我评论的答案。您只需添加类似&About…\t+A的字符串，并使用制表符\t分隔。酷！，但是我可以在多项目库、dll中重复使用这个吗？@123iamking您是在询问代码的许可证吗？它与堆栈溢出上的所有内容一样。这意味着您可以自由使用它，并根据需要修改它，只要您提供属性，即包括我的名字。源代码中的注释就足够了。如果您询问的是实现问题，当然可以：您可以将自定义表单类打包到DLL或LIB或任何东西中，然后从中继承所有表单。@Yoda，现在轮到我为迟到道歉了…：-要向菜单项添加图标，请设置MENUITEMINFO的hbmpItem字段。在Vista和更高版本中，您可以指定PARGB32位图以获得一个漂亮的alpha混合图标。将来，当你有一个新问题时，请提出一个新问题，而不是将其作为评论发布。你会得到一个更好的答案。我想试试你的技巧，但我找不到SystemMenu的参考资料。它在哪里？@John它是链接处提供上述函数并处理P/Invoke的类。@John Oops，我是否错过了那条评论……我还更新了链接，使其更适合未来。我必须通知您，您的代码GitHub存储库的修改版本已被用作示例，而不是答案本身的一部分。您的代码已被修改，添加了允许在系统菜单中插入位图的操作。但是，如果你不同意，我会删除它。让我知道你的想法。@Jimi，没关系！我在我的本地参考文件副本中注意到了一个指向你文章的链接，这样我就知道有一天我需要图标支持时应该去哪里查看了-