[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern int GetWindowText(IntPtr hWnd, StringBuilder lpString, int nMaxCount);
[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
static extern int GetWindowTextLength(IntPtr hWnd);
[DllImport("user32", SetLastError = true)]
public static extern int EnumWindows(CallBack x, int y);
[DllImport("user32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool EnumChildWindows(IntPtr hwndParent, CallBack lpEnumFunc, IntPtr lParam);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern IntPtr SendMessage(HandleRef hWnd, uint Msg, IntPtr wParam, string lParam);
public const uint WM_SETTEXT = 0x000C;
public delegate bool CallBack(int hwnd, int lParam);
public static void Main()
{
CallBack windowsCallback = new CallBack(IterateWindows);
EnumWindows(windowsCallback, 0);
}
public static bool IterateChildren(int hwnd, int lParam)
{
string newButtonText = "Some text";
bool continueIteratingChildren = true;
//Console.WriteLine("Child handle: " + hwnd);
int length = GetWindowTextLength((IntPtr)hwnd);
StringBuilder sb = new StringBuilder(length + 1);
GetWindowText((IntPtr)hwnd, sb, sb.Capacity);
//Console.WriteLine(sb);
if (sb.ToString().StartsWith("My Button Text "))
{
HandleRef hrefHWndTarget = new HandleRef(null, (IntPtr)hwnd);
SendMessage(hrefHWndTarget, WM_SETTEXT, IntPtr.Zero, newButtonText);
continueIteratingChildren = false;
}
return continueIteratingChildren;
}
public static bool IterateWindows(int hwnd, int lParam)
{
bool continueIteratingWindows = true;
int windowTextLength = GetWindowTextLength((IntPtr)hwnd);
StringBuilder sb = new StringBuilder(windowTextLength + 1);
GetWindowText((IntPtr)hwnd, sb, sb.Capacity);
if (sb.ToString().StartsWith("My Window Caption"))
{
//Console.Write("Window handle is ");
//Console.WriteLine(hwnd);
//Console.WriteLine(sb);
//Console.WriteLine(Marshal.GetLastWin32Error());
var childrenCallback = new CallBack(IterateChildren);
EnumChildWindows((IntPtr)hwnd, childrenCallback, IntPtr.Zero);
continueIteratingWindows = false;
}
return continueIteratingWindows;
}