C# Signature:
// This static method is required because legacy OSes do not support
// GetWindowLongPtr
public static IntPtr GetWindowLongPtr(HandleRef hWnd, int nIndex)
{
if (IntPtr.Size == 8)
return GetWindowLongPtr64(hWnd, nIndex);
else
return new IntPtr(GetWindowLong32(hWnd, nIndex));
}
[DllImport("user32.dll", EntryPoint="GetWindowLong")]
private static extern int GetWindowLong32(HandleRef hWnd, int nIndex);
[DllImport("user32.dll", EntryPoint="GetWindowLongPtr")]
private static extern IntPtr GetWindowLongPtr64(HandleRef hWnd, int nIndex);
VB .NET Signature:
' This static method is required because legacy OSes do not support GetWindowLongPtr
Public Shared Function GetWindowLongPtr(ByVal hWnd As HandleRef, ByVal nIndex As Integer) As IntPtr
If IntPtr.Size = 8 Then
Return GetWindowLongPtr64(hWnd, nIndex)
Else
Return New IntPtr(GetWindowLong32(hWnd, nIndex))
End If
End Function
<DllImport("user32.dll", EntryPoint:="GetWindowLong")> _
Private Shared Function GetWindowLong32(ByVal hWnd As HandleRef, ByVal nIndex As Integer) As Integer
End Function
<DllImport("user32.dll", EntryPoint:="GetWindowLongPtr")> _
Private Shared Function GetWindowLongPtr64(ByVal hWnd As HandleRef, ByVal nIndex As Integer) As IntPtr
End Function
User-Defined Types:
To access the values referred to on MSDN declare the following enumeration.
C# enumeration:
public enum GWL
{
GWL_WNDPROC = (-4),
GWL_HINSTANCE = (-6),
GWL_HWNDPARENT = (-8),
GWL_STYLE = (-16),
GWL_EXSTYLE = (-20),
GWL_USERDATA = (-21),
GWL_ID = (-12)
}
Notes:
None.
Tips & Tricks:
Please add some!
Sample Code:
C# Sample:
//Returns the ID for a window given the handle for that window as returned by EnumChildWindows.
//note that for this to work you will need to change the signature from 'int nIndex' to 'GWL nIndex' in all three places
private string GetID(IntPtr winhandle)
{
IntPtr result;
result = GetWindowLongPtr(winhandle, GWL.GWL_ID);
return result.ToString();
}
Alternative Managed API:
Do you know one? Please contribute it!
