The GetWindowText function copies the text of the specified window's title bar (if it has one) into a buffer. If the specified window is a control, the text of the control is copied. However, GetWindowText cannot retrieve the text of a control in another application.
Syntax
int GetWindowText( HWND hWnd, LPTSTR lpString, int nMaxCount );
Parameters
hWnd [in] Handle to the window or control containing the text. lpString [out] Pointer to the buffer that will receive the text. If the string is as long or longer than the buffer, the string is truncated and terminated with a NULL character. nMaxCount [in] Specifies the maximum number of characters to copy to the buffer, including the NULL character. If the text exceeds this limit, it is truncated.
Return Value
If the function succeeds, the return value is the length, in characters, of the copied string, not including the terminating NULL character. If the window has no title bar or text, if the title bar is empty, or if the window or control handle is invalid, the return value is zero. To get extended error information, call GetLastError. This function cannot retrieve the text of an edit control in another application.
If the function succeeds, the return value is the length, in characters, of the copied string, not including the terminating NULL character. If the window has no title bar or text, if the title bar is empty, or if the window or control handle is invalid, the return value is zero. To get extended error information, call GetLastError.
This function cannot retrieve the text of an edit control in another application.
Remarks
If the target window is owned by the current process, GetWindowText causes a WM_GETTEXT message to be sent to the specified window or control. If the target window is owned by another process and has a caption, GetWindowText retrieves the window caption text. If the window does not have a caption, the return value is a null string. This behavior is by design. It allows applications to call GetWindowText without becoming unresponsive if the process that owns the target window is not responding. However, if the target window is not responding and it belongs to the calling application, GetWindowText will cause the calling application to become unresponsive. To retrieve the text of a control in another process, send a WM_GETTEXT message directly instead of calling GetWindowText. Windows 95/98/Me: GetWindowTextW is supported by the Microsoft Layer for Unicode (MSLU). To use this, you must add certain files to your application, as outlined in Microsoft Layer for Unicode on Windows 95/98/Me Systems.
If the target window is owned by the current process, GetWindowText causes a WM_GETTEXT message to be sent to the specified window or control. If the target window is owned by another process and has a caption, GetWindowText retrieves the window caption text. If the window does not have a caption, the return value is a null string. This behavior is by design. It allows applications to call GetWindowText without becoming unresponsive if the process that owns the target window is not responding. However, if the target window is not responding and it belongs to the calling application, GetWindowText will cause the calling application to become unresponsive.
To retrieve the text of a control in another process, send a WM_GETTEXT message directly instead of calling GetWindowText.
Windows 95/98/Me: GetWindowTextW is supported by the Microsoft Layer for Unicode (MSLU). To use this, you must add certain files to your application, as outlined in Microsoft Layer for Unicode on Windows 95/98/Me Systems.
Example
For an example, see Sending a Message.
Function Information
Minimum DLL Versionuser32.dllHeaderDeclared in Winuser.h, include Windows.hImport libraryUser32.libMinimum operating systems Windows 95, Windows NT 3.1UnicodeImplemented as ANSI and Unicode versions.
See Also
Windows Overview, GetWindowTextLength, SetWindowText, WM_GETTEXT
Friend Declare Auto Function GetWindowText Lib "user32.dll" (ByVal hwnd As Int32, <Out()> ByVal lpString As System.Text.StringBuilder, ByVal cch As Int32) As Int32
Example:
Dim len As Integer = API.GetWindowTextLength(hWnd) If len > 0 Then Dim b As New System.Text.StringBuilder(ChrW(0), len + 1) Dim ret = API.GetWindowText(hWnd, b, b.Capacity) If ret <> 0 Then Return b.ToString Else Throw New API.Win32APIException End If Else Dim ex As New API.Win32APIException If ex.NativeErrorCode <> 0 Then Throw New API.Win32APIException Else Return "" End If End If
<DllImport("user32", CharSet:=CharSet.Auto, SetLastError:=True)> _ Public Shared Function GetWindowText(ByVal hWnd As IntPtr, <Out, MarshalAs(UnmanagedType.LPTStr)> ByVal lpString As StringBuilder, ByVal nMaxCount As Integer) As Integer End Function
[DllImport("user32", CharSet=CharSet.Auto, SetLastError=true)] internal static extern int GetWindowText(IntPtr hWnd, [Out, MarshalAs(UnmanagedType.LPTStr)] StringBuilder lpString, int nMaxCount);