More SendMessage work

PInvoke/User32/WinUser.Message.cs

@@ -3104,10 +3104,35 @@ namespace Vanara.PInvoke
 
 		private static IntPtr SendMessage<TLP>(HWND hWnd, uint msg, IntPtr wParam, ref TLP lParam)
 		{
-			using var lmem = SafeCoTaskMemHandle.CreateFromStructure(lParam);
-			var lret = SendMessage(hWnd, msg, wParam, lmem);
-			lParam = lmem.ToStructure<TLP>();
-			return lret;
+			// If this must mbe manually marshaled, do it
+			if (typeof(IVanaraMarshaler).IsAssignableFrom(typeof(TLP)))
+				return ManualMarshalSM(hWnd, msg, wParam, ref lParam);
+
+			// Try to pin first as this is most efficient.
+			// This will fail just like checking for blit-ability, so take the hit once.
+			try
+			{
+				using var lpin = new PinnedObject(lParam);
+				return SendMessage(hWnd, msg, wParam, lpin);
+			}
+			catch (ArgumentException)
+			{
+				// If not blitable, manually marshal
+				return ManualMarshalSM(hWnd, msg, wParam, ref lParam);
+			}
+			catch
+			{
+				// For all other exceptions, throw error.
+				throw;
+			}
+
+			static IntPtr ManualMarshalSM(HWND hWnd, uint msg, IntPtr wParam, ref TLP lParam)
+			{
+				using var lmem = SafeCoTaskMemHandle.CreateFromStructure(lParam);
+				var lret = SendMessage(hWnd, msg, wParam, lmem);
+				lParam = lmem.ToStructure<TLP>();
+				return lret;
+			}
 		}
 
 		/// <summary>