C#

object obj = myBrowser.ActiveXInstance;
IOleObject oc = obj as IOleObject;
oc.SetClientSite(this as IOleClientSite);

string authHeader = "WWW-Authenticate: Negotiate\r\n";
myBrowser.Navigate(_URL, "", null, authHeader);

public int Authenticate(ref IntPtr phwnd, ref IntPtr pszUsername, ref IntPtr pszPassword)
{
  pszUsername = Marshal.StringToCoTaskMemAuto("user");
  pszPassword = Marshal.StringToCoTaskMemAuto("pass");
  return S_OK;
}

pszUsername = Marshal.StringToCoTaskMemAuto(@"domain\user");
pszUsername = Marshal.StringToCoTaskMemAuto("user@domain");

private void fnLoadSignature()
       {
           try
           {
               SqlConnection con = new SqlConnection(conString);
               con.Open();

               string sql = "SELECT SignatureOfMember FROM CIF WHERE CIFKey = '" + txtcifkey.Text + "'";
               cmd = new SqlCommand(sql, con);
               object value = cmd.ExecuteScalar();

               byte[] data = (byte[])cmd.ExecuteScalar();
               //MemoryStream - creates a Stream whose backing store is memory. Library: System.IO
               MemoryStream strm = new MemoryStream();

               strm.Write(data, 0, data.Length);

               strm.Position = 0;

               System.Drawing.Image img = System.Drawing.Image.FromStream(strm);

               BitmapImage bi = new BitmapImage();

               bi.BeginInit();

               MemoryStream ms = new MemoryStream();

               img.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);

               ms.Seek(0, SeekOrigin.Begin);

               bi.StreamSource = ms;
    error is her------ bi = SigPics.Cursor;
               bi.EndInit();

               //SigPics.Source = bi;
           }
           catch (Exception ex)
           {
               MessageBox.Show(ex.Message);
           }
       }