private void SetWindowBottommost(bool value)
{
IntPtr hWnd = new WindowInteropHelper(this).Handle;
IntPtr hWndDesktop = FindDesktopWindow();
if (hWndDesktop == IntPtr.Zero) return;
RECT desktopRect = new RECT();
WINDOWPLACEMENT wp = new WINDOWPLACEMENT();
if (GetWindowRect(hWndDesktop, out desktopRect) == false) return;
if (NativeMethods.GetWindowPlacement(hWnd, out wp) == false) return;
Debug.Write("DesktopRect=(" +
desktopRect.Left + ", " + desktopRect.Top + ", " +
desktopRect.Right + ", " + desktopRect.Bottom + "), ");
Debug.Write("[Before]WindowRect=(" +
wp.normalPosition.Left + ", " + wp.normalPosition.Top + ", " +
wp.normalPosition.Right + ", " + wp.normalPosition.Bottom + "), ");
if (value)
{
// WS_CHILDを追加
var wl = GetWindowLongPtr(hWnd, (int)WindowLongFlags.GWL_STYLE);
wl = (UIntPtr)(wl.ToUInt32() | (uint)WindowStyles.WS_CHILD);
SetWindowLongPtr(hWnd, (int)WindowLongFlags.GWL_STYLE, wl);
// Desktopウィンドウの子ウィンドウにして最背面に配置する
SetParent(hWnd, hWndDesktop);
// ウィンドウの位置を調整
AdjustWindowPosition(ref wp, -desktopRect.Left, -desktopRect.Top);
}
else
{
// Desktopウィンドウから切り離す
SetParent(hWnd, IntPtr.Zero);
// WS_CHILDを削除
var wl = GetWindowLongPtr(hWnd, (int)WindowLongFlags.GWL_STYLE);
wl = (UIntPtr)(wl.ToUInt32() & ~(uint)WindowStyles.WS_CHILD);
SetWindowLongPtr(hWnd, (int)WindowLongFlags.GWL_STYLE, wl);
// ウィンドウの位置を調整
AdjustWindowPosition(ref wp, desktopRect.Left, desktopRect.Top);
}
NativeMethods.SetWindowPlacement(hWnd, ref wp);
Debug.Write("[After]WindowRect=(" +
wp.normalPosition.Left + ", " + wp.normalPosition.Top + ", " +
wp.normalPosition.Right + ", " + wp.normalPosition.Bottom + ")\r\n");
}
public static extern bool GetWindowPlacement(
IntPtr hWnd,
out WINDOWPLACEMENT lpwndpl);
private static void AdjustWindowPosition(ref WINDOWPLACEMENT wp, int offsetX, int offsetY)
{
wp.normalPosition.Left += offsetX;
wp.normalPosition.Top += offsetY;
wp.normalPosition.Right += offsetX;
wp.normalPosition.Bottom += offsetY;
}