This is one of the most common query I saw in Microsoft forums when a beginner start coding. So I thought I will take some time and post a simple and useful code here.
<html>
<head id="Head1" runat="server">
<title>Untitled Page</title>
<script type="text/javascript"> function CheckAllRow(chkBox) {var gridViewCtlId = '<%=GridView1.ClientID%>';
var grid = document.getElementById(gridViewCtlId); var gridLength = grid.rows.length;for (var i = 1; i < gridLength; i++) {
cell = grid.rows[i].cells[1];
for (var j = 0; j < cell.childNodes.length; j++) {
if (cell.childNodes[j].type == 'checkbox') {
cell.childNodes[j].checked = chkBox;}
}
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:LinkButton ID="chkAll" Text="Check all" OnClientClick=" CheckAllRow(true); return false;"
runat="server"></asp:LinkButton><br /><asp:LinkButton ID="lnkUncheck" Text="Uncheck all" OnClientClick=" CheckAllRow(false); return false;"
runat="server"></asp:LinkButton><br /><asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" AutoGenerateSelectButton="True"
OnSelectedIndexChanged="GridView1_SelectedIndexChanged"OnDataBound="GridView1_DataBound" OnRowDataBound="GridView1_RowDataBound">
<Columns>
<asp:TemplateField>
<HeaderTemplate>
Select All
<asp:CheckBox ID="chkBoxAll" runat="server" onclick="CheckAllRow(this.checked);" />
</HeaderTemplate>
<ItemTemplate>
<asp:CheckBox ID="chkBoxSel" runat="server" />
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Course ID"><ItemTemplate>
<%# Eval("ID") %></ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Course Name"><ItemTemplate>
<%# Eval("Name")%></ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Title"><ItemTemplate>
<%# Eval("Address")%></ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Description"><ItemTemplate>
<%# Eval("Phone")%></ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Course Type"><ItemTemplate>
<%# Eval("Description") %></ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</div>
</form>
</body>
</html>