Question

I am having an ASP.NET Web application that i will deploy to an Internet Information Services (IIS) in integrated pipeline mode. The application contains a photo gallery of images that are stored in a Microsoft SQL Server database. I need to ensure that the application can retrieve images from the database without blocking its worker process. What should i do? Please suggest……

using System;
using System.Web;
using System.Configuration;
using System.Data.SqlClient;

public class Handler : IHttpHandler {

public void ProcessRequest (HttpContext context)
{
SqlConnection con = new SqlConnection();
con.ConnectionString = ConfigurationManager.ConnectionStrings
                      ["ConnectionString"].ConnectionString;

// Create SQL Command
SqlCommand cmd = new SqlCommand();
cmd.CommandText = "Select ImageName,Image from Images" +
                  " where ID =@ID";
cmd.CommandType = System.Data.CommandType.Text;
cmd.Connection = con;

SqlParameter ImageID = new SqlParameter
                    ("@ID", System.Data.SqlDbType.Int);
ImageID.Value = context.Request.QueryString["ID"];
cmd.Parameters.Add(ImageID);
con.Open();
SqlDataReader dReader = cmd.ExecuteReader();
dReader.Read();
context.Response.BinaryWrite((byte[])dReader["Image"]);
dReader.Close();
con.Close();
}

and design code is,

<asp:GridView ID="GridView1" runat="server" 
              AutoGenerateColumns="False" DataKeyNames="ID"
              DataSourceID="SqlDataSource1">
<Columns>
<asp:BoundField DataField="ID" HeaderText="ID" 
                InsertVisible="False" ReadOnly="True"
                               SortExpression="ID" />
<asp:BoundField DataField="ImageName" HeaderText="ImageName" 
                               SortExpression="ImageName" />
<asp:TemplateField HeaderText="Image">
<ItemTemplate>
<asp:Image ID="Image1" runat="server" 
           ImageUrl='<%# "Handler.ashx?ID=" + Eval("ID")%>'/>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" 
ConnectionString="<%$ ConnectionStrings:ConnectionString %>"
SelectCommand="SELECT [ID], [ImageName], [Image] 
              FROM [Images]"></asp:SqlDataSource>

Answer 1

You should just go ahead and write the application, because there’s nothing that’s going to block the worker process. The process is multithreaded, meaning that each connection is going to be handled without interfering with other connections, so you’re fine.