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Unit 8: Creating More Advanced ASP.NET
<html> Notes
<body>
<form runat= “server”>
<asp:ListBox id= “drop1” rows= “3” runat= “server”>
<asp:ListItem selected= “true”>Item 1</asp:ListItem>
<asp:ListItem>Item 2</asp:ListItem>
<asp:ListItem>Item 3</asp:ListItem>
<asp:ListItem>Item 4</asp:ListItem>
<asp:ListItem>Item 5</asp:ListItem>
<asp:ListItem>Item 6</asp:ListItem>
</asp:ListBox>
<asp:Button Text= “Submit” OnClick= “submit” runat= “server”/>
<p><asp:label id= “mess” runat= “server”/></p>
</form>
</body>
</html>
Write a program for code binding.
8.4 Understanding Two-Way Data Binding
One common example of two-way data binding is the DataSet/DataAdapter grouping. You
can update the data in the DataSet, and then update the underlying data cause using the
DataAdapter, or, if changes occur to the underlying data, you can refresh the DataSet using
the Fill() method.
With ASP.NET 2.0’s bi-directional data binding, you can eliminate the code required to update
a data store by binding the data controls in your presentation layer to the data sources. Because
the binding is bi-directional, when users modify the data in the controls the underlying data
sources update when users post the web form back to the server. Typically, you have had to
use code similar to the following to manage displayed data binding:
//Populate the data controls from a business object
txtCode.Text = emp.Code;
txtName.Text = emp.Name;
//Populate a business object from the data controls
emp.Code = txtCode.Text;
emp.Name = txtName.Text;
<%# Bind( “FieldName”) %>
8.4.1 Sample Two-Way Data Binding Application
To test the framework, you need to build an application that uses it. As a simple example, suppose
you have an Employee entity, represented by an EmployeeDO class. This class contains three
private fields and corresponding exposed public properties. It implements the IBusinessEntity
interface and extends the Component class. IBusinessEntity is a base interface that all entities in
this application extend, but this sample application deals exclusively with the Employee entity.
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