重写ColorDialog类从而实现改变ColorDialog显示的位置

在C#程序中如果直接用ColorDialog来实现颜色挑选功能的话，会有个问题，就是ColorDialog显示的位置永远都是屏幕居中的位置，并且这个类没有提供任何函数来改变其显示位置，这是个大坑。
在网上找了半天，终于找到了一个大神重写了ColorDialog类，从而在初始化该类的时候可以设置其显示位置，具体代码如下：

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

namespace TestWPFColorDialog
{
    public class MyColorDlg : 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="MyColorDlg"/> 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 MyColorDlg(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
    }
}

使用的时候如下：

MyColorDlg myPopUpColorEdit  = new MyColorDlg(100，100);

源码下载位置：
download.csdn.net/download/we…