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ObjectDataSourceObjectEventHandler Delegate

Represents the method that will handle the ObjectCreating and ObjectCreated events of the ObjectDataSource control.

Namespace:  System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

public delegate void ObjectDataSourceObjectEventHandler(
	Object sender,
	ObjectDataSourceEventArgs e
)

Parameters

sender
Type: System.Object

The source of the event.

e
Type: System.Web.UI.WebControls.ObjectDataSourceEventArgs

An ObjectDataSourceEventArgs that contains the event data.

When you create an ObjectDataSourceObjectEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event handler delegates, see Consuming Events.

The following code example demonstrates how to use an ObjectDataSource control with a business object and a GridView control to retrieve and display information. In this example, as in many real-world scenarios, it might not be possible or appropriate to use a default instance of the business object with the ObjectDataSource control. In this example, the ObjectDataSource cannot successfully call the default constructor because it will throw an exception. In some cases, the default constructor might be protected, and in others it might not initialize the business object to a desired state. Whatever the reason, you can instantiate the business object yourself and set the instance to the ObjectInstance property of the ObjectDataSourceEventArgs object that is passed to the handler. This is the business object instance that the ObjectDataSource will use to perform its work.

<%@ Import namespace="Samples.AspNet.CS" %>
<%@ Page language="c#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
private void NorthwindLogicCreating(object sender, ObjectDataSourceEventArgs e)
{
    // Create an instance of the business object using a non-default constructor.
    EmployeeLogic eLogic = new EmployeeLogic("Not created by the default constructor!");

    // Set the ObjectInstance property so that the ObjectDataSource uses the created instance.
    e.ObjectInstance = eLogic;
}

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>ObjectDataSource - C# Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">

        <asp:gridview
          id="GridView1"
          runat="server"
          datasourceid="ObjectDataSource1">
        </asp:gridview>

        <asp:objectdatasource
          id="ObjectDataSource1"
          runat="server"
          selectmethod="GetAllEmployees"
          onobjectcreating="NorthwindLogicCreating"
          typename="Samples.AspNet.CS.EmployeeLogic" >
        </asp:objectdatasource>

    </form>
  </body>
</html>

The following code example demonstrates the example basic business object used in the preceding example.

namespace Samples.AspNet.CS {

using System;
using System.Collections;
using System.Web.UI;
using System.Web.UI.WebControls;

  public class EmployeeLogic {

    public EmployeeLogic() {  
        throw new NotSupportedException("Initialize data.");
    }

    public EmployeeLogic(string data) {
        _data = data;
    }

    private string _data;

    // Returns a collection of NorthwindEmployee objects. 
    public ICollection GetAllEmployees () {
      ArrayList al = new ArrayList();      
      al.Add(_data);        
      return al;
    }

  }

}

.NET Framework

Supported in: 4.5.3, 4, 3.5, 3.0, 2.0

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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