Hi @arjunrvasisht,
Please look at the example.
Example
<%@ Page Language="C#" %>
<!DOCTYPE html>
<html>
<head runat="server">
<title>Ext.NET v2 Example</title>
<style>
.my-checkbox-header .x-column-header-text span {
font-size: 11px;
padding-left: 18px;
}
</style>
<script>
Ext.selection.CheckboxModel.override({
getHeaderConfig: function() {
var config = this.callParent(arguments);
if (this.headerText) {
config.text = "<span>" + this.headerText + "</span>";
config.cls += " my-checkbox-header";
}
return config;
}
});
</script>
</head>
<body>
<form runat="server">
<ext:ResourceManager runat="server" />
<ext:GridPanel ID="GridPanel1" runat="server">
<Store>
<ext:Store runat="server">
<Model>
<ext:Model runat="server">
<Fields>
<ext:ModelField Name="test1" />
<ext:ModelField Name="test2" />
</Fields>
</ext:Model>
</Model>
</ext:Store>
</Store>
<ColumnModel runat="server">
<Columns>
<ext:Column runat="server" Text="Test 1" DataIndex="test1" />
<ext:Column runat="server" Text="Test 2" DataIndex="test2" />
</Columns>
</ColumnModel>
<SelectionModel>
<ext:CheckboxSelectionModel runat="server" HeaderWidth="60">
<CustomConfig>
<ext:ConfigItem Name="headerText" Value="In Use" Mode="Value" />
</CustomConfig>
</ext:CheckboxSelectionModel>
</SelectionModel>
</ext:GridPanel>
</form>
</body>
</html>