This post originated from an RSS feed registered with .NET Buzz by Peter G Provost. Original Post: Passing Function Pointer to SendMessage with P/Invoke Feed Title: Peter Provost's Geek Noise Feed URL: /error.aspx?aspxerrorpath=/Rss.aspx Feed Description: Technology news, development articles, Microsoft .NET, and other stuff... Latest .NET Buzz Posts Latest .NET Buzz Posts by Peter G Provost Latest Posts From Peter Provost's Geek Noise

I decided to try sorting the list before tackling positions. From my Win32 and MFC days, I knew exactly how to do this. Or so I thought.

As soon as I tried to pass a delegate as the LPARAM of SendMessage, I started crashing the Explorer.exe process. Does anyone out there know what is wrong with this code?

public delegate int CompareFunc(int lParam1, int lParam2, int lParamSort);

[DllImport("user32.dll", EntryPoint="SendMessage")] 


public static extern int SendMessage(IntPtr hWnd, uint Msg, uint wParam, [MarshalAs(UnmanagedType.FunctionPtr)]
CompareFunc compareFunc); 

[DllImport("user32.dll",EntryPoint="FindWindow")]

private static extern int FindWindow(string _ClassName, string _WindowName);

[DllImport ("user32.dll")]

public static extern IntPtr GetWindow( IntPtr handle, int cmd );

private void button1_Click(object sender, System.EventArgs e)

{

 // const int LVA_DEFAULT = 0x0000;

 const int LVM_FIRST = 0x1000;      // ListView messages

 // const int LVM_ARRANGE = (LVM_FIRST + 22);

 const int LVM_SORTITEMS = (LVM_FIRST + 48);

 const int GW_CHILD = 5;

 int tmp = FindWindow( "ProgMan", null );

 IntPtr handle = new IntPtr(tmp);

 handle = GetWindow( handle, GW_CHILD );

 handle = GetWindow( handle, GW_CHILD );

 CompareFunc f = new CompareFunc(Compare);

 SendMessage( handle, LVM_SORTITEMS, 0, f );

}

public static int Compare( int lp1, int lp2, int lpSort )

{

 return 0;

}

Read: Passing Function Pointer to SendMessage with P/Invoke