ObjectCreating Event

ObjectDataSource::ObjectCreating Event

 

Occurs before the object that is identified by the TypeName property is created.

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

public:
event ObjectDataSourceObjectEventHandler^ ObjectCreating {
	void add(ObjectDataSourceObjectEventHandler^ value);
	void remove(ObjectDataSourceObjectEventHandler^ value);
}

If the method that is identified to perform the data operation is static (Shared in Visual Basic), the ObjectCreating and ObjectCreated events are never raised.

The ObjectDataSource control automatically calls the default constructor of a business object to create an instance of it using reflection. Handle the ObjectCreating event to explicitly call another constructor, and set the instance of the object that results to the ObjectInstance property of the associated ObjectDataSourceEventArgs object.

For more information about handling events, see NIB: Consuming Events.

This section contains two code examples. The first code example demonstrates how to use an ObjectDataSource object with a business object and a GridView control to display information. The second code example provides the middle-tier business object that is used in the first code example.

The following code example demonstrates how to use an ObjectDataSource control with a business object and a GridView control to display information. You might work with a business object that is very expensive to create (in terms of time or resources) for every data operation your Web page performs. One way to work with an expensive object might be to create an instance of it once, and then cache it for subsequent operations instead of creating and destroying it for every data operation.

System_CAPS_noteNote

In a production application, multiple requests might end up simultaneously using the same instance. Therefore, the object needs to be implemented in a thread-safe manner.

This code example demonstrates this pattern. You can handle the ObjectCreating event to check the cache for an object first, and only create an instance of the object, if one is not already cached. Then, handle the ObjectDisposing event to cache the business object for future use, instead of destroying it. In this code example, the CancelEventArgs::Cancel property of the ObjectDataSourceDisposingEventArgs object is set to true to direct the ObjectDataSource to not call Dispose method on the object.

No code example is currently available or this language may not be supported.

The following code example provides the example middle-tier business object that the preceding code example uses. The code example consists of a basic business object, defined by the EmployeeLogic class, which is a stateful class that encapsulates business logic. For a complete working example, you must compile this code as a library and use these classes from an ASP.NET page (.aspx file).

No code example is currently available or this language may not be supported.

.NET Framework
Available since 2.0
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