帮助“?"按钮 [英] Help "?" button

问题描述

如何将此按钮添加到 WPF 中的标题栏，因为它在许多应用程序中如此使用，我认为它会内置或其他东西，但看起来不是.无论如何，如果您对此有所了解，请告诉我.

How can add this button to the title bar in WPF, by it being so used in a lot of applications I thought it would be built in or something, but looks like it isn't. Anyway let me know if you know anything about this.

谢谢.

有没有什么等同于这个?

基本上，要拥有 ?win 表单中的图标，您需要做的就是:

Basically, to have the ? icon in win forms, all you need to do is this:

public Form1()
{
    InitializeComponent();

    this.HelpButton = true;
    this.MaximizeBox = false;
    this.MinimizeBox = false;
}

WPF 没有类似的东西吗?

Doesn't WPF have anything like that?

推荐答案

很简单，只需将此代码插入到您的 Window 类中即可.

It's simple, just inset this code into your Window class.

此代码使用 interop 删除 WS_MINIMIZEBOX 和 WS_MAXIMIZEBOX 样式并添加 WS_EX_CONTEXTHELP 扩展样式(问号仅在您删除最小化和最大化按钮时才会显示).

This code uses interop to remove the WS_MINIMIZEBOX and WS_MAXIMIZEBOX styles and add the WS_EX_CONTEXTHELP extended style (the question mark will only show up if you remove the minimize and maximize buttons).

在帮助按钮上添加了点击检测，这是通过使用 HwndSource.AddHook 连接到 WndProc 并使用 SC_CONTEXTHELP 的 wParam 侦听 WM_SYSCOMMAND 消息来完成的.

added click detection on the help button, this is done by hooking into the WndProc using HwndSource.AddHook and listening for a WM_SYSCOMMAND message with wParam of SC_CONTEXTHELP.

当检测到点击时，此代码将显示一个消息框，将其更改为事件、路由事件甚至命令(对于 MVVM 应用程序)作为练习留给读者.

When a click is detected this code will show a message box, changing this into an event, routed event or even a command (for MVVM apps) is left as an exercise for the reader.

private const uint WS_EX_CONTEXTHELP = 0x00000400;
private const uint WS_MINIMIZEBOX = 0x00020000;
private const uint WS_MAXIMIZEBOX = 0x00010000;
private const int GWL_STYLE = -16;
private const int GWL_EXSTYLE = -20;
private const int SWP_NOSIZE = 0x0001;
private const int SWP_NOMOVE = 0x0002;
private const int SWP_NOZORDER = 0x0004;
private const int SWP_FRAMECHANGED = 0x0020;
private const int WM_SYSCOMMAND = 0x0112;
private const int SC_CONTEXTHELP  = 0xF180;


[DllImport("user32.dll")]
private static extern uint GetWindowLong(IntPtr hwnd, int index);

[DllImport("user32.dll")]
private static extern int SetWindowLong(IntPtr hwnd, int index, uint newStyle);

[DllImport("user32.dll")]
private static extern bool SetWindowPos(IntPtr hwnd, IntPtr hwndInsertAfter, int x, int y, int width, int height, uint flags);


protected override void OnSourceInitialized(EventArgs e)
{
    base.OnSourceInitialized(e);
    IntPtr hwnd = new System.Windows.Interop.WindowInteropHelper(this).Handle;
    uint styles = GetWindowLong(hwnd, GWL_STYLE);
    styles &= 0xFFFFFFFF ^ (WS_MINIMIZEBOX | WS_MAXIMIZEBOX);
    SetWindowLong(hwnd, GWL_STYLE, styles);
    styles = GetWindowLong(hwnd, GWL_EXSTYLE);
    styles |= WS_EX_CONTEXTHELP;
    SetWindowLong(hwnd, GWL_EXSTYLE, styles);
    SetWindowPos(hwnd, IntPtr.Zero, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED);   
    ((HwndSource)PresentationSource.FromVisual(this)).AddHook(HelpHook);
}

private IntPtr HelpHook(IntPtr hwnd,
        int msg,
        IntPtr wParam,
        IntPtr lParam,
        ref bool handled)
{
    if (msg == WM_SYSCOMMAND &&
            ((int)wParam & 0xFFF0) == SC_CONTEXTHELP)
    {
        MessageBox.Show("help");
        handled = true;
    }
    return IntPtr.Zero;
}

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