how i retrieve pdf files in gridview using mssql 2008

Question

how i retrieve pdf files in gridview using mssql 2008 and in Database i use varchar(max) instead of varbinary(max) in sql 2008 server ; it gives error "how to convert system.string to system.byte[] " .... PLZ HELP

 

 

 

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;
using System.IO;
using System.Text;
using System.Net;

public partial class Defaultpdf : System.Web.UI.Page
{
SqlConnection sqlcon = new SqlConnection("Data Source=;Initial Catalog=;User ID=;Password=");
SqlCommand cmd = new SqlCommand();
SqlDataAdapter da = new SqlDataAdapter();
DataTable dt = new DataTable();
string qstr;
byte[] b = null;



protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
qstr = Request.QueryString["ReqDocId"];

SqlCommand sqlcmd = new SqlCommand("Select ReqDoc from tbl_name where ReqDocId='" + qstr + "'", sqlcon);
sqlcon.Open();
da = new SqlDataAdapter(sqlcmd);
da.Fill(dt);
if (dt.Rows.Count > 0)
{
b =((byte[])dt.Rows[0][0]);


Response.ContentType = "application/pdf";

Response.BinaryWrite(b);
}
}
}



}