Whether we can get WM_IME_* messages when we’re ty

First, thanks for reading this thread and provide your suggestion.

Here’s the detailed description of my question: Due to large scale of legacy code, we need to use Win32 messages. And for UI part, we need to use WPF to modernize our appearance. That part of UI need to direct keyboard messages into the old legacy component. For input messages without IME, we have used ComponentDispatcher.ThreadFilterMessage to get these messages like WM_KEYDOWN, WM_CHAR, ect. But for IME input, we can’t get the corresponding WM_IME_* messages. Do we have a way to get these messages, or at least, get all the input text which corresponds to WM_IME_* messages?

We have tried several ways for that: First, WPF native methods, like OnPreviewKeyDown(), OnTextInput(). One lackage of that solution is that we can’t get the Win32 messages. And I’ve found that WPF will not respond for some special key, e.g. Space key will not cause OnTextInput() to be invoked. Second, different hooks, like SetWindowLong(), HwndSource.AddHook(). These solutions will not get the WM_IME_* messages as well. Third, use InputMethod class. I’ve tried to use InputMethod.ImeConversionMode to determine whether the user input corresponds to WM_IME_* messages. But you know it is a different way with ComponentDispatcher.ThreadFilterMessage, and against several basic laws. At the same time, I’m not sure whether there may be cases overlapped for these two ways, and whether there’re missed cases. There’re so many languages and so many kinds of input methods, each of them has different character set and punctuation (They can be combined separately), then that solution will be risky.

When I’m investigating with class ImmComposition, which can be created by TextBoxBase.OnGotKeyboardFocus(), I’ve seen the hook ImmCompositionFilterMessage() is dealing with WM_IME_CHAR(0x0286), but failed to get it in my hook added after base. OnGotKeyboardFocus():

public class HookedTextBox : TextBox
{
    protected override void OnGotKeyboardFocus(KeyboardFocusChangedEventArgs e)
    {
        base.OnGotKeyboardFocus(e);

        InstallHook();
    }
}