C# Signature:

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

VB.NET Signature:

'Imports System.Text
<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function GetWindowText(ByVal hwnd As IntPtr, ByVal lpString As StringBuilder, ByVal cch As Integer) As Integer
End Function

VB.NET Signature Alternative:

'Imports System.Text

<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Ansi)> _
Public Function GetWindowText(hwnd As IntPtr, <MarshalAs(UnManagedType.LPStr)>lpString As System.Text.StringBuilder, cch As Integer) As Integer
End Function

VB Signature:

Public Declare Function GetWindowText Lib "user32.dll" Alias "GetWindowTextA" _
        (ByVal hWnd As Long, _
         ByVal prmstrString As String, _
         ByVal nMaxCount As Long) As Long

User-Defined Types:

None.

Notes:

See also GetWindowTextLength

Tips & Tricks:

Please add some!

Sample Code:

public static string GetText(IntPtr hWnd)
{
    // Allocate correct string length first
    int length       = GetWindowTextLength(hWnd);
    StringBuilder sb = new StringBuilder(length + 1);
    GetWindowText(hWnd, sb, sb.Capacity);
    return sb.ToString();
}

But, if you need to get text from a control in another process, GetWindowText() won't work. Use WM_GETTEXT instead.

Sample Code:

[DllImport("user32.dll", CharSet = CharSet.Auto)]

static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, Out StringBuilder lParam);

public static string GetWindowTextRaw(IntPtr hwnd)

{

    // Allocate correct string length first
    int length = (int)SendMessage(hwnd, WM_GETTEXTLENGTH, IntPtr.Zero, IntPtr.Zero);
    StringBuilder sb = new StringBuilder(length + 1);
    SendMessage(hwnd, WM_GETTEXT, (IntPtr)sb.Capacity, sb);
    return sb.ToString();

}

vb.net sample

Public Function GetText(ByVal hWnd As IntPtr) As String
    Dim length As Integer
    If hWnd.ToInt32 <= 0 Then
        Return Nothing
    End If
    length = GetWindowTextLength(hWnd)
    If length = 0 Then
        Return Nothing
    End If
    Dim sb As New System.Text.StringBuilder("", length + 1)

    GetWindowText(hWnd, sb, sb.Capacity)
    Return sb.ToString()
End Function

Alternative Managed API:

The ManagedWindowsApi project (http://mwinapi.sourceforge.net) provides a

class ManagedWinapi.SystemWindow that has a Title property.