如何从Windows控件的文本框中获取文本？ 我怎么知道这是一个文本框？

Question

I've used spy++ to find the right handle of the wanted windows control, which belongs to a standalone application which isn't managed. Note that the spy++ "property inspector" mentions that this window doesn't have any child (or parent) windows.

I've also managed to get back the name of the window with the following code:

   //the invokes are included aswell
    const int WM_GETTEXT = 0x000D;
    static void Main(string[] args)
    {
        IntPtr handle = new IntPtr(Convert.ToInt32("00070818", 16)); 
        int nChars = GetWindowTextLength(handle); //win32 function
        int length = 200;
        StringBuilder sb = new StringBuilder(length);
        SendMessage(handle, WM_GETTEXT, length, sb);
        Console.WriteLine(sb.ToString());           

    }

This window has a lot more information than it's title, and that's all I seem to get back with WM_GETTEXT (changing the value of length to 200 didnt help, was a long shot anyway).

Next, I've tried a different approach using UI Automation:

static void Main(string[] args)
{
    AutomationElement target = AutomationElement.FromHandle(handle);
    TextPattern textPattern = target.GetCurrentPattern(TextPattern.Pattern) as TextPattern;
}

but I got this error back:

An unhandled exception of type 'System.InvalidOperationException' occurred in UIAutomationClient.dll

Additional information: Unsupported Pattern.

To top it off, I've also tried using Microsoft Inspect.exe, but it failed to focus on the text in the window, both in UI automation and MSAA mode.

---

Does it mean that the data cant be achieved with UI Automation?? or should am I just using the wrong methods/types?

Is there another way to get the data from this window other than using GetWindowText, WM_GETTEXT, or UI automation??

I'm fairly new to this stuff, but I'm trying my best to learn. In addition I've have no current leads so any helpful comment/answer would be much appreciated!! if you do answer please be sure to include helpful keywords so i'll be able to learn more about your solutions

Answer 1

Labels (ie static controls) and text boxes are child windows with their own handles, hence they are visible to Spy++. If your target Window has no children then it's not using a label or text box, it's painting the text itself, and you won't be able to retrieve it using GetWindowText or WM_GETTEXT .

The text might be exposed through UI Automation , the API used by screen readers. Use UISpy.exe or Inspect.exe to see if the text is accessible.