title: Download file from sql server using c#
body: <p>I developed an application, one web app, and one c#, the file upload is done in the web application, here is my code for that: </p>
  
  <pre><code> protected void ImageButton2_Click(object sender, ImageClickEventArgs e) // upload documents to database 
      {
          foreach (HttpPostedFile upFile in FileUpload1.PostedFiles)
          {
  
              // Read the file and convert it to Byte Array
              string filename = Path.GetFileName(upFile.FileName);
              string ext = Path.GetExtension(filename);
              string contenttype = String.Empty;
  
  
              //Set the contenttype based on File Extension
              switch (ext)
              {
                  case ".doc":
                      contenttype = "application/vnd.ms-word";
                      break;
                  case ".docx":
                      contenttype = "application/vnd.ms-word";
                      break;
                  case ".xls":
                      contenttype = "application/vnd.ms-excel";
                      break;
                  case ".xlsx":
                      contenttype = "application/vnd.ms-excel";
                      break;
                  case ".jpg":
                      contenttype = "image/jpg";
                      break;
                  case ".png":
                      contenttype = "image/png";
                      break;
                  case ".gif":
                      contenttype = "image/gif";
                      break;
                  case ".pdf":
                      contenttype = "application/pdf";
                      break;
                  case ".rar":
                      contenttype = "application/rar";
                      break;
              }
  
              if (contenttype != String.Empty)
              {
  
                  Stream fs = FileUpload1.PostedFile.InputStream;
                  BinaryReader br = new BinaryReader(fs);
                  Byte[] bytes = br.ReadBytes((Int32)fs.Length);
  
                  //insert the file into database
                  string strQuery = "insert into UploadFile(referencenumber, Name, ContentType, Data, id)" +
                     " values (@referencenumber, @Name, @ContentType, @Data, @id)";
                  SqlCommand cmd = new SqlCommand(strQuery);
                  cmd.Parameters.Add("@referencenumber", SqlDbType.VarChar).Value = disprefno.Text;
                  cmd.Parameters.Add("@id", SqlDbType.VarChar).Value = 1;
                  cmd.Parameters.Add("@Name", SqlDbType.VarChar).Value = filename;
                  cmd.Parameters.Add("@ContentType", SqlDbType.VarChar).Value
                    = contenttype;
                  cmd.Parameters.Add("@Data", SqlDbType.Binary).Value = bytes;
                  InsertUpdateData(cmd);
              }
          }
      }
      private Boolean InsertUpdateData(SqlCommand cmd)
      {
          //upload class
          String strConnString = System.Configuration.ConfigurationManager
          .ConnectionStrings["AIConnectionString"].ConnectionString;
          SqlConnection con = new SqlConnection(strConnString);
          cmd.CommandType = CommandType.Text;
          cmd.Connection = con;
          try
          {
              lblUploadStat.Visible = true;
              con.Open();
              cmd.ExecuteNonQuery();
              return true;
          }
          catch (Exception ex)
          {
              Response.Write(ex.Message);
              return false;
          }
          finally
          {
              string myStringVariable1 = string.Empty;
              myStringVariable1 = "Documents Was Successfully Sent ";
              ClientScript.RegisterStartupScript(this.GetType(), "myalert", "alert('" + myStringVariable1 + "');", true);
              lblUploadStat.Visible = false;
              con.Close();
              con.Dispose();
          }
      }
  </code></pre>
  
  <p>Now, I want to retrieve the upload files via my c# application from the sql database, how can I achieve this </p>