C# WebBrowser控件 下载文件不弹下载提示框的办法

    public class MyWebBrowser : WebBrowser
    {
        /// 

        /// 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.
        /// 
        /// Pointer to caller object (AX).
        /// String of the URL.
        /// String of the destination filename/path.
        /// [reserved].
        /// A callback function to monitor progress or abort.
        /// 0 for okay.
        /// 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);


        /// 

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

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