Extract Unicode Text from External application's textbox in C# using user32.dll api.

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Hello,
I have developed an Application in C# which extract text from external application's textbox , I am using user32.dll, The application is working fine but my problem is this - The external application's textbox contains text in unicode format, so whenever I extract text in my application it shows "??????" text. I have tried setting charset.unicode , and also used RichTextBox to show text in my application.
Please let me know how to exract unicode text from external application.

Here is code I am using

C#

private void button1_Click(object sender, EventArgs e)
        { 
IntPtr MytestHandle = new IntPtr(0x00060342);

            HandleRef hrefHWndTarget = new HandleRef(null, MytestHandle);
          
         // encode text into 
            richTextBox1.Text = ModApi.GetText(hrefHWndTarget.Handle);
        }

public static class ModApi
        {
          [DllImport("user32.dll", EntryPoint = "SendMessageTimeout", SetLastError = true, CharSet = CharSet.Unicode)]

         public static extern uint SendMessageTimeoutText(IntPtr hWnd, int Msg, int countOfChars, StringBuilder text, uint flags, uint uTImeoutj, uint result); 
           
                                 
          public static string GetText(IntPtr hwnd)
            {
                var text = new StringBuilder(1024);
                
                if (SendMessageTimeoutText(hwnd, 0xd, 1024, text, 0x2, 1000, 0) != 0)
                {
                    return text.ToString();
                }

                MessageBox.Show(text.ToString());
                return "";
            }
        }

Posted 13-Aug-13 16:55pm

shreesoft

Updated 13-Aug-13 17:18pm

User 59241

v5

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Sergey Alexandrovich Kryukov · Answer 1 · 2013-08-13T18:27:00

Solution 1

I'm not sure if this is the only problem, but probably the "real" (mangles) method names are SendMessageTimeoutA and SendMessageTimeoutW for ANSI/Unicode. So, you should either use SendMessageTimeoutW explicitly, or use the parameter CharSet=CharSet.Auto. Such parameter value takes care of mangling automatically, effectively giving you the Unicode version. Please see:
http://www.pinvoke.net/default.aspx/user32.sendmessagetimeout[^].

Your P/Invoke, without it, might be is incorrect, because the default is CharSet.Unicode, and it would require "W".

—SA

Posted 13-Aug-13 18:27pm

Sergey Alexandrovich Kryukov

Comments

[no name] 14-Aug-13 1:43am

I may be wrong but shouldn't SendMessageTimeoutText be Unicode function by default?

Sergey Alexandrovich Kryukov 14-Aug-13 1:46am

I'm not sure. Not in this default form. Defaults to Unicode with CharSet.Unicode, that's for sure. I used to use APIs with char *, they don't work correctly without "W"...
—SA

shreesoft 14-Aug-13 1:46am

I think it can work , but could you create little program to describe more.

Sergey Alexandrovich Kryukov 14-Aug-13 1:50am

Describe what? You can do exact same thing, only add CharSet=CharSet.Auto parameter to your [DLLImport]. That would be the only change. Just spend a minute, try it. And tell us what happens.
—SA

Sergey Alexandrovich Kryukov 14-Aug-13 1:52am

This is another option, but I would start with adding CharSet=CharSet.Auto...
OP can also try to change signature to that written in pinvoke.net, and marshal to string explicitly...
—SA

shreesoft 14-Aug-13 1:57am

[DllImport("user32.dll", EntryPoint = "SendMessageTimeoutW", SetLastError = true, CharSet = CharSet.Auto)]
public static extern uint SendMessageTimeoutW(IntPtr hWnd, int Msg, int countOfChars, StringBuilder text, uint flags, uint uTImeoutj, uint result);
public static string GetText(IntPtr hwnd)
{
var text = new StringBuilder(1024);

if (SendMessageTimeoutW(hwnd, 0xd, 1024, text, 0x2, 1000, 0) != 0)
{
return text.ToString();
}

MessageBox.Show(text.ToString());
return "";
}

Nothing happened ? Still I am Receiving "???".

Sergey Alexandrovich Kryukov 14-Aug-13 2:29am

No, no! 1) if you use CharSet.Auto, remove "W". 2) Or add "W", but with with Charset.Unicode.
But we already got one positive result: you've proven that the name with "W" already exists (we could see it by simply dumping the P/Invoked DLL, by I did not have time for that; this is often a good idea).
So, please try again... 1) and 2)...
—SA

Sergey Alexandrovich Kryukov 14-Aug-13 2:32am

By the way, there is another possibility: what if your target application (the one you call "external application") is not Unicode one. Is it possible? If you think it is, how do you know?
—SA

shreesoft 14-Aug-13 2:42am

yes , it is showing "Window is ANSI", but how the window is showing unicode. I also tried WM_SETTEXT to send text(unicode) from my application to external application. which also showing "????" in external application's textbox. It seems both sending and receiving text is showing "????".

Sergey Alexandrovich Kryukov 14-Aug-13 2:59am

Oh! that changes things. You approach may not work at all. This could be exotic application which is basically ANSI, but it uses some explicit Win32 calls to support Unicode. In other words, some messages or APIs would work as Unicode, some not. I know because I used to develop something like that, in a very tricky situation needed a runtime patch of non-Unicode UI library to Unicode functionality.

Look, you are already moving in a wrong way. First, you should develop some sample application with is certainly Unicode. Test your technique on it, make it working. And only them move to some unknown applications.

—SA

shreesoft 14-Aug-13 3:10am

But I tried same process with another program , which window also showing "Window is ANSI" in winspector, gave perfect result, it's text is showing unicode character in my C# Application.

Sergey Alexandrovich Kryukov 14-Aug-13 3:12am

Too many unknowns. Unicode character can be shown in "ANSI Window", in different ways. Better first do what I advised.
—SA

shreesoft 14-Aug-13 2:01am

I also examined external application window in winspector , please look at detail , if you can find solution.
Properties for window 0x000D05F8
Item Value
Class Name RichEdit20A
Text (1) ?????? ?? ?? ???? ?? ?????? ????? ????-???? ???? ??? ??????????? ???? ??, ????? ??????? ???????? ??? ?? ???????? ?????????? ???? ?? ?????? ????? ?? ??????? ??? ??????????? ???? ?? ? ???????? ?? ?? ?????? ?? ?? ??????? ????????? ???? ?????????? ?? ??
Rectangle 0, 560, 1366, 709
Size 1366, 149
Client Rectangle 0, 0, 1349, 149
Client Size 1349, 149
Styles
WS_CHILD
WS_VISIBLE
WS_VSCROLL
WS_TABSTOP
0x00004420
StylesEx
WS_EX_LEFT
WS_EX_LTRREADING
WS_EX_RIGHTSCROLLBAR
ID
1
Properties
Atom: #43288 0x00E7CC30 (15191088)
OleDropTargetInterface 0x0031C9D0 (3262928)
OleDropTargetMarshalHwnd 0x001C04C4 (1836228)
ThemePropScrollBarCtl 0x083DA570 (138257776)
Class specific
Window is Ansi

[no name] 14-Aug-13 2:10am

are you using the debugger to look at what is coming back?

shreesoft 14-Aug-13 2:34am

no I am using winspector program to look window property.

[no name] 14-Aug-13 2:40am

Forget about winspector. If you are using visual studio you have an excellent debugger. Examine "text" after the function call.

Sergey Alexandrovich Kryukov 14-Aug-13 3:01am

Agree, but I got dramatic news: the target application is not Unicode. This is very tricky. Please see OP's and my comments on it.
—SA

[no name] 14-Aug-13 3:09am

Yes I agree it seems absolute and I think your solution is on the money but by examining text one confirms what is there. Best not to leave a stoned unturned. Your further valid suggestions may also need testing.

Sergey Alexandrovich Kryukov 14-Aug-13 3:10am

:-)

shreesoft 14-Aug-13 2:48am

Is there anyway to get bytes from sendtimeoutmessage function instead of string, then we can convert byte to unicode, I think this can work, but how I can get bytes instead of string.

Sergey Alexandrovich Kryukov 14-Aug-13 2:53am

Yes, you should treat is as the array of bytes and use UTF-16LE encoding to read it as string.
This encoding is used internally by Windows and is called "Unicode" in dirty jargon of Windows API (actually, evokes great confusion on what Unicode is; no, Unicode is NOT encoding).

Here is what you should use: GetChars.

For a string, use new string(UnicodeEncoding.GetChars(rawData));

Is it clear?

—SA

User 59241 · Answer 2 · 2013-08-13T19:28:00

You could convert the Unicode to Ascii or vice versa.

http://msdn.microsoft.com/en-us/library/system.text.encoding.convert%28v=vs.71%29.aspx[^]

C#

// Perform the conversion from one encoding to the other.
         byte[] asciiBytes = Encoding.Convert(unicode, ascii, text.toString());
            
         // Convert the new byte[] into a char[] and then into a string.
         // This is a slightly different approach to converting to illustrate
         // the use of GetCharCount/GetChars.
         char[] asciiChars = new char[ascii.GetCharCount(asciiBytes, 0, asciiBytes.Length)];
         ascii.GetChars(asciiBytes, 0, asciiBytes.Length, asciiChars, 0);
         string asciiString = new string(asciiChars);
         return asciiString;