c# - 获取焦点窗口名称

Question

我正在尝试获取当前聚焦窗口的名称。感谢我的研究，我有这个代码:

[DllImport("user32.dll")]
public static extern IntPtr GetForegroundWindow();

[DllImport("user32.dll")]
public static extern int GetWindowText(IntPtr hWnd, StringBuilder lpString, int nMaxCount);

private static bool IsFocused(string name)
{
   StringBuilder buffer = new StringBuilder(256);

   if (GetWindowText(GetForegroundWindow(), buffer, buffer.Length + 1) > 0)
   {
      if (buffer.ToString() == name)
      {
         return true;
      }
   }
   return false;
}

我已经检查过，GetForegroundWindow() 返回的句柄是正确的。但 GetWindowText() 始终返回 null 或负值。

Answer 1

您需要获取文本的长度

[DllImport("user32.dll")]
public static extern IntPtr GetForegroundWindow();

[DllImport("user32.dll")]
public static extern int GetWindowText(IntPtr hWnd, StringBuilder lpString, int nMaxCount);

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

private static bool IsFocused(string name)
{
    var handle = GetForegroundWindow();
    var length = GetWindowTextLength(handle);
    var builder = new StringBuilder(length + 1);

    GetWindowText(handle, builder, builder.Capacity);

    return builder.ToString() == name;
}