Server side:
Imports System.Data
Partial Class Default3
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim empds As DataSet
Dim empTable As DataTable = New DataTable()
Dim dr As DataRow
empTable.Columns.Add(New DataColumn("Id"))
empTable.Columns.Add(New DataColumn("Name"))
empTable.Columns.Add(New DataColumn("Mobile"))
dr = empTable.NewRow()
dr("Id") = "A"
dr("Name") = "A...."
dr("Mobile") = "12345"
empTable.Rows.Add(dr)
dr = empTable.NewRow()
dr("Id") = "B"
dr("Name") = "B...."
dr("Mobile") = "12345656"
empTable.Rows.Add(dr)
dr = empTable.NewRow()
dr("Id") = "C"
dr("Name") = "C...."
dr("Mobile") = "123343445"
empTable.Rows.Add(dr)
GridView1.DataSource = empTable
GridView1.DataBind()
End Sub
Protected Sub GridView1_PreRender(ByVal sender As Object, ByVal e As System.EventArgs) Handles GridView1.PreRender
For Each dr As GridViewRow In GridView1.Rows
If dr.Cells(0).Text <> DropDownList1.SelectedItem.Text Then
dr.Cells(2).Text = ""
End If
Next
End Sub
End Class
Client Side
<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default3.aspx.vb" Inherits="Default3" %>
<!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>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="true">
<asp:ListItem>A</asp:ListItem>
<asp:ListItem>B</asp:ListItem>
<asp:ListItem>C</asp:ListItem>
</asp:DropDownList>
<br />
<asp:GridView ID="GridView1" runat="server" Width="731px">
</asp:GridView>
</div>
</form>
</body>
</html>