getting text entered in textbox of other applications using c#

问题

I am fighting with this thing for the whole day. Still i couldn't figure out the exact solution for this. Help me out.

My objective is very simple. I want to get the text which is in textbox of other application. It may be a textbox of gtalk client or a soap UI screen.

I googled and most of the forums suggested winapi is the concept that i have to use to achieve this. I never used this concept and also i didn't get any good examples. Please help me on how to approach this and get this thing done. Is there any another way to achieve this ?

Waiting for your response guys...

回答1:

Here is an example of how to grab all the text from a window by it's window title.

Please see the comments for an explanation on how this works.

public class GetWindowTextExample
{
    // Example usage.
    public static void Main()
    {
        var allText = GetAllTextFromWindowByTitle("Untitled - Notepad");
        Console.WriteLine(allText);
        Console.ReadLine();
    }

    // Delegate we use to call methods when enumerating child windows.
    private delegate bool EnumWindowProc(IntPtr hWnd, IntPtr parameter);

    [DllImport("user32")]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool EnumChildWindows(IntPtr window, EnumWindowProc callback, IntPtr i);

    [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
    private static extern IntPtr FindWindowByCaption(IntPtr zeroOnly, string lpWindowName);

    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    private static extern IntPtr SendMessage(IntPtr hWnd, uint msg, IntPtr wParam, [Out] StringBuilder lParam);

    // Callback method used to collect a list of child windows we need to capture text from.
    private static bool EnumChildWindowsCallback(IntPtr handle, IntPtr pointer)
    {
        // Creates a managed GCHandle object from the pointer representing a handle to the list created in GetChildWindows.
        var gcHandle = GCHandle.FromIntPtr(pointer);

        // Casts the handle back back to a List<IntPtr>
        var list = gcHandle.Target as List<IntPtr>;

        if (list == null)
        {
            throw new InvalidCastException("GCHandle Target could not be cast as List<IntPtr>");
        }

        // Adds the handle to the list.
        list.Add(handle);

        return true;
    }

    // Returns an IEnumerable<IntPtr> containing the handles of all child windows of the parent window.
    private static IEnumerable<IntPtr> GetChildWindows(IntPtr parent)
    {
        // Create list to store child window handles.
        var result = new List<IntPtr>();

        // Allocate list handle to pass to EnumChildWindows.
        var listHandle = GCHandle.Alloc(result);

        try
        {
            // Enumerates though all the child windows of the parent represented by IntPtr parent, executing EnumChildWindowsCallback for each. 
            EnumChildWindows(parent, EnumChildWindowsCallback, GCHandle.ToIntPtr(listHandle));
        }
        finally
        {
            // Free the list handle.
            if (listHandle.IsAllocated)
                listHandle.Free();
        }

        // Return the list of child window handles.
        return result;
    }

    // Gets text text from a control by it's handle.
    private static string GetText(IntPtr handle)
    {
        const uint WM_GETTEXTLENGTH = 0x000E;
        const uint WM_GETTEXT = 0x000D;

        // Gets the text length.
        var length = (int)SendMessage(handle, WM_GETTEXTLENGTH, IntPtr.Zero, null);

        // Init the string builder to hold the text.
        var sb = new StringBuilder(length + 1);

        // Writes the text from the handle into the StringBuilder
        SendMessage(handle, WM_GETTEXT, (IntPtr)sb.Capacity, sb);

        // Return the text as a string.
        return sb.ToString();
    }

    // Wraps everything together. Will accept a window title and return all text in the window that matches that window title.
    private static string GetAllTextFromWindowByTitle(string windowTitle)
    {
        var sb = new StringBuilder();

        try
        {
            // Find the main window's handle by the title.
            var windowHWnd = FindWindowByCaption(IntPtr.Zero, windowTitle);

            // Loop though the child windows, and execute the EnumChildWindowsCallback method
            var childWindows = GetChildWindows(windowHWnd);

            // For each child handle, run GetText
            foreach (var childWindowText in childWindows.Select(GetText))
            {
                // Append the text to the string builder.
                sb.Append(childWindowText);
            }

            // Return the windows full text.
            return sb.ToString();
        }
        catch (Exception e)
        {
            Console.Write(e.Message);
        }

        return string.Empty;
    }
}

回答2:

You are correct. You will need to use the Windows API. For example:

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern int GetWindowText(IntPtr hWnd, StringBuilder lpString, int nMaxCount);

But first, you'll probably need to use FindWindow or FindWindowEx(?) recursively from the desktop down to where the text box is in the window hieracrchy to get the right window handle.

It looks like http://www.pinvoke.net/ has a good database of Win API's.

Hope that helps.