C# Signature:
/// <summary>
/// Retrieves a handle to a window that has the specified relationship (Z-Order or owner) to the specified window.
/// </summary>
/// <remarks>The EnumChildWindows function is more reliable than calling GetWindow in a loop. An application that
/// calls GetWindow to perform this task risks being caught in an infinite loop or referencing a handle to a window
/// that has been destroyed.</remarks>
/// <param name="hWnd">A handle to a window. The window handle retrieved is relative to this window, based on the
/// value of the uCmd parameter.</param>
/// <param name="uCmd">The relationship between the specified window and the window whose handle is to be
/// retrieved.</param>
/// <returns>
/// If the function succeeds, the return value is a window handle. If no window exists with the specified relationship
/// to the specified window, the return value is NULL. To get extended error information, call GetLastError.
/// </returns>
[DllImport("user32.dll", SetLastError = true)]
private static extern IntPtr GetWindow(IntPtr hWnd, GetWindowType uCmd);
private enum GetWindowType : uint
{
/// <summary>
/// The retrieved handle identifies the window of the same type that is highest in the Z order.
/// <para/>
/// If the specified window is a topmost window, the handle identifies a topmost window.
/// If the specified window is a top-level window, the handle identifies a top-level window.
/// If the specified window is a child window, the handle identifies a sibling window.
/// </summary>
GW_HWNDFIRST = 0,
/// <summary>
/// The retrieved handle identifies the window of the same type that is lowest in the Z order.
/// <para />
/// If the specified window is a topmost window, the handle identifies a topmost window.
/// If the specified window is a top-level window, the handle identifies a top-level window.
/// If the specified window is a child window, the handle identifies a sibling window.
/// </summary>
GW_HWNDLAST = 1,
/// <summary>
/// The retrieved handle identifies the window below the specified window in the Z order.
/// <para />
/// If the specified window is a topmost window, the handle identifies a topmost window.
/// If the specified window is a top-level window, the handle identifies a top-level window.
/// If the specified window is a child window, the handle identifies a sibling window.
/// </summary>
GW_HWNDNEXT = 2,
/// <summary>
/// The retrieved handle identifies the window above the specified window in the Z order.
/// <para />
/// If the specified window is a topmost window, the handle identifies a topmost window.
/// If the specified window is a top-level window, the handle identifies a top-level window.
/// If the specified window is a child window, the handle identifies a sibling window.
/// </summary>
GW_HWNDPREV = 3,
/// <summary>
/// The retrieved handle identifies the specified window's owner window, if any.
/// </summary>
GW_OWNER = 4,
/// <summary>
/// The retrieved handle identifies the child window at the top of the Z order,
/// if the specified window is a parent window; otherwise, the retrieved handle is NULL.
/// The function examines only child windows of the specified window. It does not examine descendant windows.
/// </summary>
GW_CHILD = 5,
/// <summary>
/// The retrieved handle identifies the enabled popup window owned by the specified window (the
/// search uses the first such window found using GW_HWNDNEXT); otherwise, if there are no enabled
/// popup windows, the retrieved handle is that of the specified window.
/// </summary>
GW_ENABLEDPOPUP = 6
}
VB Signature:
Declare Auto Function GetWindow Lib "user32.dll" ( _
ByVal hWnd As IntPtr, ByVal uCmd As UInt32) As IntPtr
Notes:
None
VB.NET Signature:
<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function GetWindow(ByVal hWnd As IntPtr, ByVal uCmd As UInt32) As IntPtr
End Function
Private Enum GetWindowType As UInteger
GW_HWNDFIRST = 0
GW_HWNDLAST = 1
GW_HWNDNEXT = 2
GW_HWNDPREV = 3
GW_OWNER = 4
GW_CHILD = 5
GW_ENABLEDPOPUP = 6
End Enum
Tips & Tricks:
' (VB.NET): Get the owner of a program. Sometimes works better than using .GetParent. (i.e. when using .GetParent on the Desktop it would return no hWnd; this will return one.)
Dim Owner As IntPtr = GetWindow(hWnd, GW_OWNER)
Sample Code:
// Get the handle to a dialog
IntPtr dlgHandle = GetWindow(myProcess.MainWindowHandle, GW_ENABLEDPOPUP);
Alternative Managed API:
Do you know one? Please contribute it!
