i am new to the developnment currently i am working on datagrid
i just want to know how to select a row on a datagrid using check boxes

You can try following code for ASP:

//HTML part of DemoPage1.aspx
         <%@ Page Language="C#" AutoEventWireup="true" CodeFile="DemoPage1.aspx.cs" Inherits="DemoPage1" %>
      <!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 id="Head1" runat="server">
       <title>GridView Sample By Ramesh S</title>
        <script type="text/javascript">
        function selectUnselectCheckboxes(chkBoxHeaderId, chkBoxIdInGrid, gridViewId) {
       var gridViewElem = document.getElementById(gridViewId);
      //get the no of rows<tr> generated by the gridview
        var gridRowsCount = gridViewElem.rows.length;
        //the controls in the gridview will have the following suffix in their ids 'GridView1_ctl0n'
      //the first element starts with 2 e.g. GridView1_ctl02_chkEmployee(first element)... GridView1_ctl10_chkEmployee(9th element)
      for (i = 2; i <= gridRowsCount; i++) {
       var ctlIndex = eval(i);
        if (ctlIndex < 10)
        ctlIndex = '0' + i;
        var chkBoxIdFull = gridViewElem.id + '_ctl' + ctlIndex + '_' + chkBoxIdInGrid;
        var chkBoxElem = document.getElementById(chkBoxIdFull);
        if (chkBoxElem != null) {
        //if the header checkbox is checked, then check the checkboxes in the grid
        if (document.getElementById(chkBoxHeaderId).checked)
        chkBoxElem.checked = true;
        chkBoxElem.checked = false;
        <form id="form1" runat="server">
        <table width="100%">
      <asp:GridView ID="GridView1" runat="server" Width="500px" BackColor="White" BorderColor="#3366CC"
        BorderStyle="None" BorderWidth="1px" CellPadding="4" OnRowDataBound="GridView1_RowDataBound"
        <RowStyle BackColor="White" ForeColor="#003399" />
        <asp:CheckBox ID="chkSelectAll" ToolTip="Select/Unselect all employees" onclick="selectUnselectCheckboxes(this.id, 'chkEmployee', 'GridView1');"
        runat="server" />
        <asp:CheckBox ID="chkEmployee" runat="server" Checked='<%# Bind("Is_Eligible") %>' />
        <HeaderStyle HorizontalAlign="Center" />
        <ItemStyle HorizontalAlign="Center" Width="50px" />
        <asp:BoundField DataField="EmpName" HeaderText="Name">
        <HeaderStyle HorizontalAlign="Left" />
        <asp:BoundField DataField="EmpCode" HeaderText="Code">
        <HeaderStyle HorizontalAlign="Left" />
        <asp:TemplateField HeaderText="Dept">
        <asp:DropDownList ID="ddlDept" DataTextField="Dname" DataValueField="Deptno" DataSource="<%#GetAllDept()%>"
        <FooterStyle BackColor="#99CCCC" ForeColor="#003399" />
        <PagerStyle BackColor="#99CCCC" ForeColor="#003399" HorizontalAlign="Left" />
        <SelectedRowStyle BackColor="#009999" Font-Bold="True" ForeColor="#CCFF99" />
        <HeaderStyle BackColor="#003399" Font-Bold="True" ForeColor="#CCCCFF" />
      //Code behind part of DemoPage1.aspx.cs
      using System;
      using System.Web.UI.WebControls;
      using System.Data;
      public partial class DemoPage1 : System.Web.UI.Page
       protected void Page_Load(object sender, EventArgs e)
        if (!IsPostBack)
       //Bind gridview with employee details
      //This method binds DataTable to GridView
       //I have created a DataTable with sample data here
       //You can fetch records from database, store it in a DataTable and bind it
       private void BindGridView()
       DataTable dtEmp = new DataTable();
       dtEmp.Columns.Add("Is_Eligible", System.Type.GetType("System.Boolean"));
       dtEmp.Columns.Add("EmpName", System.Type.GetType("System.String"));
       dtEmp.Columns.Add("EmpCode", System.Type.GetType("System.Int16"));
       dtEmp.Columns.Add("Deptno", System.Type.GetType("System.Int16"));
       dtEmp.Rows.Add(new object[] { true, "Kannan", 1001, 10 });
       dtEmp.Rows.Add(new object[] { true, "Arun", 1001, 10 });
      dtEmp.Rows.Add(new object[] { false, "Jackson", 1001, 30 });
       dtEmp.Rows.Add(new object[] { true, "Raja", 1001, 20 });
       dtEmp.Rows.Add(new object[] { false, "John", 1001, 30 });
       GridView1.DataSource = dtEmp;
    //This method returns a DataTable having department details to be
      //bind with DropDownList for each record in the GridView
       public DataTable GetAllDept()
       DataTable dtDept = new DataTable();
     dtDept.Columns.Add("Deptno", System.Type.GetType("System.Int16"));
       dtDept.Columns.Add("Dname", System.Type.GetType("System.String"));
    dtDept.Rows.Add(new object[] { 10, "Accounts" });
    dtDept.Rows.Add(new object[] { 20, "Sales" });
    dtDept.Rows.Add(new object[] { 30, "Operations" });
    return dtDept;
    //This event is handled to bind DropDownList in the GridView
    //with department details
    protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
      if (e.Row.RowType == DataControlRowType.DataRow)
      DropDownList ddlDeptNo = (DropDownList)e.Row.FindControl("ddlDept");
       string deptNo = ((System.Data.DataRowView)(e.Row.DataItem)).Row.ItemArray[3].ToString();
     if (ddlDeptNo != null)
       ddlDeptNo.SelectedValue = deptNo;

Hello, just to make sure .. you have WinForms Project or Web-vased?

first add a check box column to the datagridview.
to do this click on the datagridview control on ur form.
click on the right arrow on the top of ur datagrid.
click edit columns
add a column and set its type to check box column

private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
            if (e.ColumnIndex == //column index of check box column)
                if (Convert.ToBoolean(dataGridView1.CurrentCell.Value) == true)
                    dataGridView1.CurrentCell.Value = false;
                    dataGridView1.CurrentCell.Value = true;