Winforms-如何让对话框显示在 MainForm 的中心?这与基于普通窗口默认设置相反,后者将它们显示在屏幕的中心。在我的例子中,我有一个小的
Winforms-如何使对话框显示在 MainForm 的中心?这与基于普通窗口默认设置(将对话框显示在屏幕中心)相反。
在我的例子中,我有一个小的主窗体,例如,它可能被放置在一个角落里,MessageBox 弹出窗口显示在看似很远的地方。
借助 P/Invoke 的一些功能和 Control.BeginInvoke() 提供的魔力,这是有可能实现的。向您的项目添加一个新类并粘贴以下代码:
using System;
using System.Text;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;
class CenterWinDialog : IDisposable {
private int mTries = 0;
private Form mOwner;
public CenterWinDialog(Form owner) {
mOwner = owner;
owner.BeginInvoke(new MethodInvoker(findDialog));
}
private void findDialog() {
// Enumerate windows to find the message box
if (mTries < 0) return;
EnumThreadWndProc callback = new EnumThreadWndProc(checkWindow);
if (EnumThreadWindows(GetCurrentThreadId(), callback, IntPtr.Zero)) {
if (++mTries < 10) mOwner.BeginInvoke(new MethodInvoker(findDialog));
}
}
private bool checkWindow(IntPtr hWnd, IntPtr lp) {
// Checks if <hWnd> is a dialog
StringBuilder sb = new StringBuilder(260);
GetClassName(hWnd, sb, sb.Capacity);
if (sb.ToString() != "#32770") return true;
// Got it
Rectangle frmRect = new Rectangle(mOwner.Location, mOwner.Size);
RECT dlgRect;
GetWindowRect(hWnd, out dlgRect);
MoveWindow(hWnd,
frmRect.Left + (frmRect.Width - dlgRect.Right + dlgRect.Left) / 2,
frmRect.Top + (frmRect.Height - dlgRect.Bottom + dlgRect.Top) / 2,
dlgRect.Right - dlgRect.Left,
dlgRect.Bottom - dlgRect.Top, true);
return false;
}
public void Dispose() {
mTries = -1;
}
// P/Invoke declarations
private delegate bool EnumThreadWndProc(IntPtr hWnd, IntPtr lp);
[DllImport("user32.dll")]
private static extern bool EnumThreadWindows(int tid, EnumThreadWndProc callback, IntPtr lp);
[DllImport("kernel32.dll")]
private static extern int GetCurrentThreadId();
[DllImport("user32.dll")]
private static extern int GetClassName(IntPtr hWnd, StringBuilder buffer, int buflen);
[DllImport("user32.dll")]
private static extern bool GetWindowRect(IntPtr hWnd, out RECT rc);
[DllImport("user32.dll")]
private static extern bool MoveWindow(IntPtr hWnd, int x, int y, int w, int h, bool repaint);
private struct RECT { public int Left; public int Top; public int Right; public int Bottom; }
}
使用示例:
private void button1_Click(object sender, EventArgs e) {
using (new CenterWinDialog(this)) {
MessageBox.Show("Nobugz waz here");
}
}
请注意,此代码适用于任何 Windows 对话框。MessageBox、OpenFormDialog、FolderBrowserDialog、PrintDialog、ColorDialog、FontDialog、PageSetupDialog 和 SaveFileDialog。