c#如何获取windows桌面背景？

#region 获取windows桌面背景
[System.Runtime.InteropServices.DllImport("user32.dll", CharSet = System.Runtime.InteropServices.CharSet.Auto, SetLastError = true)]
public static extern int SystemParametersInfo(int uAction, int uParam, StringBuilder lpvParam, int fuWinIni);
private const int SPI_GETDESKWALLPAPER = 0x0073;
#endregion

void WindowsBtn_Click(object sender, RoutedEventArgs e)
{
//定义存储缓冲区大小
StringBuilder s = new StringBuilder(300);
//获取Window 桌面背景图片地址，使用缓冲区
SystemParametersInfo(SPI_GETDESKWALLPAPER, 300, s, 0);
//缓冲区中字符进行转换
string wallpaper_path = s.ToString(); //系统桌面背景图片路径
 }