在指定位置打开“ColorDialog”对话框

Question

可能是重复的问题：
如何设置 OpenFileDialog/SaveFileDialog 的起始位置？

我需要显示一个 ColorDialog，就在用户点击的按钮上方。

目前我找不到如何指定此位置的方法：

1. 没有 StartPosition/Location 属性 (使用 ShowDialog 显示对话框时，如何控制其位置？)
2. 构造函数只接受一个窗口参数，并将其放置在中间

我需要将它直接放在我的光标上方，指定一个 X;Y。

有什么办法可以实现这个功能吗？

谢谢！

- J4N

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不同的对话框，但应该是相同的解决方案。 - Jon B

@JonB：我不明白如何通过提供一个IWin32Window来帮助我将对话框定位到正确的位置？ - J4N

@J4N 请查看那个链接到一个codeproject文章的问题的答案。https://dev59.com/0HM_5IYBdhLWcg3wt1rD#1256524 - Rotem

@J4N - 对话框是一个窗口。设置窗口的位置将会实现你想要做的事情。 - Security Hound

Answer 1

我终于找到了一种方法，虽然不是最完美的解决方案，但它可以运作：

public class ColorDialogExtension : ColorDialog
{
    #region private const
    //Windows Message Constants
    private const Int32 WM_INITDIALOG = 0x0110;

    //uFlag Constants
    private const uint SWP_NOSIZE = 0x0001;
    private const uint SWP_SHOWWINDOW = 0x0040;
    private const uint SWP_NOZORDER = 0x0004;
    private const uint UFLAGS = SWP_NOSIZE | SWP_NOZORDER | SWP_SHOWWINDOW;
    #endregion

    #region private readonly
    //Windows Handle Constants
    private static readonly IntPtr HWND_TOPMOST = new IntPtr(-1);
    private static readonly IntPtr HWND_NOTOPMOST = new IntPtr(-2);
    private static readonly IntPtr HWND_TOP = new IntPtr(0);
    private static readonly IntPtr HWND_BOTTOM = new IntPtr(1);
    #endregion

    #region private vars
    //Module vars
    private int _x;
    private int _y;
    private string _title = null;
    #endregion

    #region private static methods imports
    //WinAPI definitions

    /// <summary>
    /// Sets the window text.
    /// </summary>
    /// <param name="hWnd">The h WND.</param>
    /// <param name="text">The text.</param>
    /// <returns></returns>
    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    private static extern bool SetWindowText(IntPtr hWnd, string text);

    /// <summary>
    /// Sets the window pos.
    /// </summary>
    /// <param name="hWnd">The h WND.</param>
    /// <param name="hWndInsertAfter">The h WND insert after.</param>
    /// <param name="x">The x.</param>
    /// <param name="y">The y.</param>
    /// <param name="cx">The cx.</param>
    /// <param name="cy">The cy.</param>
    /// <param name="uFlags">The u flags.</param>
    /// <returns></returns>
    [DllImport("user32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int x, int y, int cx, int cy, uint uFlags);
    #endregion

    #region public constructor
    /// <summary>
    /// Initializes a new instance of the <see cref="ColorDialogExtension"/> class.
    /// </summary>
    /// <param name="x">The X position</param>
    /// <param name="y">The Y position</param>
    /// <param name="title">The title of the windows. If set to null(by default), the title will not be changed</param>
    public ColorDialogExtension(int x, int y, String title = null)
    {
        _x = x;
        _y = y;
        _title = title;
    }
    #endregion

    #region protected override methods
    /// <summary>
    /// Defines the common dialog box hook procedure that is overridden to add specific functionality to a common dialog box.
    /// </summary>
    /// <param name="hWnd">The handle to the dialog box window.</param>
    /// <param name="msg">The message being received.</param>
    /// <param name="wparam">Additional information about the message.</param>
    /// <param name="lparam">Additional information about the message.</param>
    /// <returns>
    /// A zero value if the default dialog box procedure processes the message; a nonzero value if the default dialog box procedure ignores the message.
    /// </returns>
    protected override IntPtr HookProc(IntPtr hWnd, int msg, IntPtr wparam, IntPtr lparam)
    {
        //We do the base initialization
        IntPtr hookProc = base.HookProc(hWnd, msg, wparam, lparam);
        //When we init the dialog
        if (msg == WM_INITDIALOG)
        {
            //We change the title
            if (!String.IsNullOrEmpty(_title))
            {
                SetWindowText(hWnd, _title);
            }
            //We move the position
            SetWindowPos(hWnd, HWND_TOP, _x, _y, 0, 0, UFLAGS); 

        }
        return hookProc;
    }
    #endregion
}

- J4N

Answer 2

你做不到！实际上，这不是ColorDialog或其他Common Dialog的问题。如果你想显示一个模态对话框框，你将直接或间接使用"DialogBox.Show"方法，在这种情况下，操作系统决定位置。 唯一的解决方案是使用非模态对话框框，并使用DialogBox.Show方法，但你还需要重新创建整个dialogBox！

- Stephane Halimi