Introduction
Provides a way of reading a forward-only stream of rows from a SQL Server database (according to msdn library). Means you can say a SqlDataReader class read DataRows in forward only stream. SqlDataReader class available in System.Data.SqlClient namespace.
There are some useable public properties available in Library
1.
HasRows : You can check that your DataReader either empty or take some DataRows.
2. FieldCount : Obtains numbers of fields in current rows.
There are some public method available in Library
Read( ) : Read Next record from the database table.
GetValue( ) : Gets the value of the specified column in its native format.
Lets take an simple example to read data from database_table using SqlDataReader class.
Algorithm behind the example
Step-1 : Create a SqlConnection( ) with proper connection string parameter.
SqlConnection con = new
SqlConnection();
con.ConnectionString =ConfigurationManager.ConnectionStrings
["ConnectionString"].ToString ();
con.Open ();
Step-2 : Retrieve data from Database table using SqlCommand Class.
SqlCommand cmd = new
SqlCommand();
cmd.CommandText = "select * from
deltable";
cmd.Connection = con;
Step-3 : Create a SqlDataReader, you must call the ExecuteReader method of the SqlCommand object, instead of directly using a constructor.
SqlDataReader rd = cmd.ExecuteReader();
Step-4: Read data from Read() method
while (rd.Read())
{
snolabel.Text += "sno=" +
rd.GetValue(0) + "<br/>";
name.Text += "name=" +
rd.GetValue(1) + "<br/>";
Addlabel.Text += "Address="
+ rd.GetValue(2) + "<br/>";
}
Step-5: Close reader.
Complete code
<%@ Page Language="C#"
AutoEventWireup="true"
CodeFile="binding.aspx.cs"
Inherits="binding"
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD
XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<asp:Button ID="Button1"
runat="server"
onclick="Button1_Click"
Text="GetData"
Width="123px"
/>
<br />
<br />
<asp:Label ID="snolabel"
runat="server"></asp:Label>
<br />
<div>
<asp:Label ID="name" runat="server"></asp:Label>
<br />
</div>
<p>
<asp:Label ID="Addlabel"
runat="server"></asp:Label>
</p>
</form>
</body>
</html>
Codebehind
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;
using System.IO;
public partial class binding :
System.Web.UI.Page
{
int sno = 0;
string Name = String.Empty;
String Address = String.Empty;
protected void
Page_Load(object sender, EventArgs e)
{
}
protected void
Button1_Click(object sender, EventArgs e)
{
SqlConnection con = new
SqlConnection();
con.ConnectionString =ConfigurationManager.ConnectionStrings
["ConnectionString"].ToString ();
con.Open ();
SqlCommand cmd = new
SqlCommand();
cmd.CommandText = "select * from
deltable";
cmd.Connection = con;
SqlDataReader rd = cmd.ExecuteReader();
while (rd.Read())
{
snolabel.Text += "sno=" +
rd.GetValue(0) + "<br/>";
name.Text += "name=" +
rd.GetValue(1) + "<br/>";
Addlabel.Text += "Address="
+ rd.GetValue(2) + "<br/>";
}
rd.Close();
}
}
Output
