C# WebBrowser控件 下载文件不弹下载提示框的办法

    public class MyWebBrowser : WebBrowser
    {
        /// <summary>
        /// The URLMON library contains this function, URLDownloadToFile, which is a way
        /// to download files without user prompts.  The ExecWB( _SAVEAS ) function always
        /// prompts the user, even if _DONTPROMPTUSER parameter is specified, for "internet
        /// security reasons".  This function gets around those reasons.
        /// </summary>
        /// <param name="callerPointer">Pointer to caller object (AX).</param>
        /// <param name="url">String of the URL.</param>
        /// <param name="filePathWithName">String of the destination filename/path.</param>
        /// <param name="reserved">[reserved].</param>
        /// <param name="callBack">A callback function to monitor progress or abort.</param>
        /// <returns>0 for okay.</returns>
        /// source: http://www.pinvoke.net/default.aspx/urlmon/URLDownloadToFile%20.html
        [DllImport("urlmon.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern Int32 URLDownloadToFile(
            [MarshalAs(UnmanagedType.IUnknown)] object callerPointer,
            [MarshalAs(UnmanagedType.LPWStr)] string url,
            [MarshalAs(UnmanagedType.LPWStr)] string filePathWithName,
            Int32 reserved,
            IntPtr callBack);


        /// <summary>
        /// Download a file from the webpage and save it to the destination without promting the user
        /// </summary>
        /// <param name="url">the url with the file</param>
        /// <param name="destinationFullPathWithName">the absolut full path with the filename as destination</param>
        /// <returns></returns>
        public FileInfo DownloadFile(string url, string destinationFullPathWithName)
        {
            URLDownloadToFile(null, url, destinationFullPathWithName, 0, IntPtr.Zero);
            return new FileInfo(destinationFullPathWithName);
        }
    }

webBrowser1.DownloadFile(downloadUrl,"test.csv");