I have a need to enumerate all the windows found by the external method GetWindows() and retrieve the various caption text from each window. As I enumerate each window I call GetWindowTextLength to retreive the length of the text before calling GetWindowText. I am faced with catch 22: 1) If I use SendMessage to send the GetWindowTextLength message many windows do not process the message and my C# app hangs. 2) If I use SendNotifyMessage or PostMessage to send the GetWindowTextLength message my app does not hang but the value never returns a valid length (always zero). This causes GetWindowText to always return an empty string. I have found that in most cases the windows that do not process the message fall into one of these categories: 1) The window has the WS_EX_TOOLWINDOW extended style (which I can successfully detect). For example most "tooltips_class32" class windows. -OR- 2) In Spy++ the "Window Proc" field on the "General" tab of the Window Properties dialog has "(Unavailable)" for a value for that window. (The window does not have the WS_EX_TOOLWINDOW ex style). It is important to note that the "Window Proc" field on the "Class" tab does show a handle value. It is ok to skip these types of windows in my enumeration, the trouble I am having though is that I do not know how to determine in C# whether the Window Proc in item 2 above is set to "Unavailable" or not. I have tried using GetWindowLong with an index of GWL_WNDPROC = -4 but this does not return a value reliably and I am not sure if that is really the function that Spy++ is calling anyway. Is my assumption that items 1 and 2 are the cause of the hang up correct? If so how do you determine if the Window Proc is available or not? (so I can skip that window) Thanks, Matt
