Sql数据库读取文件下载

using(SqlConnection sqlCon = new SqlConnection(Config.sqlConnectionString))
   {    
    sqlCon.Open();
    SqlCommand sqlComm = sqlCon.CreateCommand();
    sqlComm.CommandText = "Update Lesson_Data_Table set Lesson_Click = Lesson_Click + 1 where Lesson_ID =" +LessonID;
    sqlComm.ExecuteNonQuery();

    sqlComm.CommandText = "select * from Lesson_Data_Table where Lesson_ID = "+LessonID;
    SqlDataReader sqlReader = sqlComm.ExecuteReader();
    byte[] buffer;
    if(sqlReader.Read())
    {
     Response.Clear();
     buffer = (byte[])sqlReader["Lesson_Data"];
     Response.AddHeader("Content-Length",buffer.Length.ToString());
     Response.AddHeader("Content-Type",sqlReader["Lesson_File_Type"].ToString());
     Response.AddHeader("Content-Disposition", "attachment; filename="+sqlReader["Lesson_File_Name"].ToString());
     Response.BinaryWrite(buffer);
     Response.End();
    }
    sqlReader.Close();

   }