How to correctly hook and return GetDlgItemTextA from C++ to C# to C++ from EasyHook
- by Gbps
I'm using EasyHook, a C# library for injecting and detouring functions from unmanaged applications. I'm trying to hook onto GetDlgItemTextA, which takes the arguments:
UINT WINAPI GetDlgItemText(
__in HWND hDlg,
__in int nIDDlgItem,
__out LPTSTR lpString,
__in int nMaxCount
);`
In my hook, I am casting it as:
[DllImport("user32.dll",
// CharSet = CharSet.Unicode,
SetLastError = true,
CallingConvention = CallingConvention.StdCall)]
static extern uint GetDlgItemTextA(IntPtr hWin, int nIDDlgItem, StringBuilder text, int MaxCount);
And my hook is:
static uint DGetDlgItemText_Hooked(IntPtr hWin, int nIDDlgItem, StringBuilder text, int MaxCount)
{
// call original API...
uint ret = GetDlgItemTextA(hWin, nIDDlgItem, text, MaxCount);
MessageBox.Show(text.ToString());
return ret;
}
Unfortunately, the moment this is called, the hooked application crashes. Is there a better cast I can use to successfully hook onto this function? Thanks!
I've compiled, editted, and confirmed the working condition of my EasyHook setup. This is just casing and hooking only.
