C# Getting window's title by handle in Hebrew return question marks

Question

I am using this: to get window's title by its handle:

[DllImport("user32.dll")] private static extern int GetWindowText(int hWnd, StringBuilder title, int size);

StringBuilder title = new StringBuilder(256);
GetWindowText(hWnd, title, 256);

If the title has hebrew chars, it replaces them by question marks.
I guess the problem is related to econding or something... how can I solve it?

Windows 8 Pro 64 bit, doesnt matter - works same in all versions (I assume, if I tested in my windows and windows xp) — Ron, Oct 02 '13 at 19:00

score 9 · Answer 1 · edited Mar 12 '21 at 03:30

9

Your question contains a little error, that might not occurs very often. You assume, that the title has a max length of 256 characters, which might be enough for most cases. But as this post shows, the length could be at 100K characters, maybe more. So I would use another helper function: GetWindowTextLength

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

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

public static string GetWindowTitle(IntPtr hWnd)
{
    var length = GetWindowTextLength(hWnd) + 1;
    var title = new StringBuilder(length);
    GetWindowText(hWnd, title, length);
    return title.ToString();
}

edited Mar 12 '21 at 03:30

Julio Nobre

4,196
3
46
49

answered Sep 06 '19 at 09:59

0xBADF00D

980
1
12
25

6

For me length always equals (real length -1). Not sure why, but simple `var length = GetWindowTextLength(hwnd) + 1;` fixes my problem. – Alex Wyler May 25 '20 at 17:12
@alexWyler I stumbled upon the same issue but forget to update my answer. I assume GetWindowTitle returns the length without the terminator \0 that is used in C and C++ to mark the end of the string. But its only a guess – 0xBADF00D Mar 12 '21 at 07:36

score 7 · Accepted Answer · edited May 27 '20 at 10:58

7

Use this:

[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern int GetWindowText(int hWnd, StringBuilder title, int size);

edited May 27 '20 at 10:58

Louis Go

2,213
2
16
29

answered Oct 02 '13 at 19:00

Hamlet Hakobyan

32,965
6
52
68

DAMN that was fast and pretty easy. Thank you! :D – Ron Oct 02 '13 at 19:01
I think there is an error here. The `int hWnd` should be changed to `IntPtr hWnd` – John Henckel Apr 14 '22 at 14:38

C# Getting window's title by handle in Hebrew return question marks

2 Answers2

Linked