static HwndSubclass()
{
DetachMessage = UnsafeNativeMethods.RegisterWindowMessage("HwndSubclass.DetachMessage");
// Go find the address of DefWindowProc.
IntPtr hModuleUser32 = UnsafeNativeMethods.GetModuleHandle(ExternDll.User32);
IntPtr address = UnsafeNativeMethods.GetProcAddress(new HandleRef(null, hModuleUser32), "DefWindowProcW");
DefWndProc = address;
}
private static IntPtr GetUser32ProcAddress(string export)
{
IntPtr hModule = UnsafeNativeMethods.GetModuleHandle(ExternDll.User32);
if (hModule != IntPtr.Zero)
{
return(UnsafeNativeMethods.GetProcAddress(new HandleRef(null, hModule), export));
}
return(IntPtr.Zero);
}
/// <summary>
/// Unregisters the window class represented by classAtom
/// </summary>
/// <param name="arg">A ushort representing the class atom</param>
internal static object UnregisterClass(object arg)
{
ushort classAtom = (ushort)arg;
if (classAtom != 0)
{
IntPtr hInstance = UnsafeNativeMethods.GetModuleHandle(null);
UnsafeNativeMethods.UnregisterClass(
new IntPtr(classAtom), //* this function is defined as taking a type lpClassName - but this can be an atom. 2 Low Bytes are the atom*/
hInstance);
}
return(null);
}
public HwndWrapper(
int classStyle,
int style,
int exStyle,
int x,
int y,
int width,
int height,
string name,
IntPtr parent,
HwndWrapperHook[] hooks)
{
_ownerThreadID = new SecurityCriticalDataForSet <int>(Thread.CurrentThread.ManagedThreadId);
// First, add the set of hooks. This allows the hooks to receive the
// messages sent to the window very early in the process.
if (hooks != null)
{
for (int i = 0, iEnd = hooks.Length; i < iEnd; i++)
{
if (null != hooks[i])
{
AddHook(hooks[i]);
}
}
}
_wndProc = new SecurityCriticalData <HwndWrapperHook>(new HwndWrapperHook(WndProc));
// We create the HwndSubclass object so that we can use its
// window proc directly. We will not be "subclassing" the
// window we create.
HwndSubclass hwndSubclass = new HwndSubclass(_wndProc.Value);
// Register a unique window class for this instance.
NativeMethods.WNDCLASSEX_D wc_d = new NativeMethods.WNDCLASSEX_D();
IntPtr hNullBrush = UnsafeNativeMethods.CriticalGetStockObject(NativeMethods.NULL_BRUSH);
if (hNullBrush == IntPtr.Zero)
{
throw new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error());
}
IntPtr hInstance = UnsafeNativeMethods.GetModuleHandle(null);
// We need to keep the Delegate object alive through the call to CreateWindowEx().
// Subclass.WndProc will install a better delegate (to the same function) when it
// processes the first message.
// But this first delegate needs be held alive until then.
NativeMethods.WndProc initialWndProc = new NativeMethods.WndProc(hwndSubclass.SubclassWndProc);
// The class name is a concat of AppName, ThreadName, and RandomNumber.
// Register will fail if the string gets over 255 in length.
// So limit each part to a reasonable amount.
string appName;
if (null != AppDomain.CurrentDomain.FriendlyName && 128 <= AppDomain.CurrentDomain.FriendlyName.Length)
{
appName = AppDomain.CurrentDomain.FriendlyName.Substring(0, 128);
}
else
{
appName = AppDomain.CurrentDomain.FriendlyName;
}
string threadName;
if (null != Thread.CurrentThread.Name && 64 <= Thread.CurrentThread.Name.Length)
{
threadName = Thread.CurrentThread.Name.Substring(0, 64);
}
else
{
threadName = Thread.CurrentThread.Name;
}
// Create a suitable unique class name.
_classAtom = 0;
string randomName = Guid.NewGuid().ToString();
string className = String.Format(CultureInfo.InvariantCulture, "HwndWrapper[{0};{1};{2}]", appName, threadName, randomName);
wc_d.cbSize = Marshal.SizeOf(typeof(NativeMethods.WNDCLASSEX_D));
wc_d.style = classStyle;
wc_d.lpfnWndProc = initialWndProc;
wc_d.cbClsExtra = 0;
wc_d.cbWndExtra = 0;
wc_d.hInstance = hInstance;
wc_d.hIcon = IntPtr.Zero;
wc_d.hCursor = IntPtr.Zero;
wc_d.hbrBackground = hNullBrush;
wc_d.lpszMenuName = "";
wc_d.lpszClassName = className;
wc_d.hIconSm = IntPtr.Zero;
// Register the unique class for this instance.
// Note we use a GUID in the name so we are confident that
// the class name should be unique. And RegisterClassEx won't
// fail (for that reason).
_classAtom = UnsafeNativeMethods.RegisterClassEx(wc_d);
// call CreateWindow
_isInCreateWindow = true;
try {
_handle = new SecurityCriticalDataClass <IntPtr>(UnsafeNativeMethods.CreateWindowEx(exStyle,
className,
name,
style,
x,
y,
width,
height,
new HandleRef(null, parent),
new HandleRef(null, IntPtr.Zero),
new HandleRef(null, IntPtr.Zero),
null));
}
finally
{
_isInCreateWindow = false;
if (_handle == null || _handle.Value == IntPtr.Zero)
{
// Because the HwndSubclass is pinned, but the HWND creation failed,
// we need to manually clean it up.
hwndSubclass.Dispose();
}
}
GC.KeepAlive(initialWndProc);
}