ObjectDataSourceEventArgs 类

定义

ObjectCreating 控件的 ObjectCreatedObjectDataSource 事件提供数据。Provides data for the ObjectCreating and ObjectCreated events of the ObjectDataSource control.

public ref class ObjectDataSourceEventArgs : EventArgs
public class ObjectDataSourceEventArgs : EventArgs
type ObjectDataSourceEventArgs = class
    inherit EventArgs
Public Class ObjectDataSourceEventArgs
Inherits EventArgs
继承
ObjectDataSourceEventArgs

示例

本部分包含两个代码示例。This section contains two code examples. 第一个代码示例演示如何将ObjectDataSource控件与业务对象GridView和控件结合使用来检索和显示信息。The first code example demonstrates how to use an ObjectDataSource control with a business object and a GridView control to retrieve and display information. 第二个代码示例提供了第一个代码示例使用的示例基本业务对象。The second code example provides the example basic business object that the first code example uses.

下面的代码示例演示如何将ObjectDataSource控件与业务对象GridView和控件结合使用来检索和显示信息。The following code example demonstrates how to use an ObjectDataSource control with a business object and a GridView control to retrieve and display information. 在此示例中, 与在许多真实情况下一样, 这可能是不可能的, 也可能不适合将业务对象ObjectDataSource的默认实例用于控件。In this example, as in many real-world scenarios, it might not be possible nor appropriate to use a default instance of the business object with the ObjectDataSource control. 在此示例中, ObjectDataSource无法成功调用无参数的构造函数, 因为它将引发异常。In this example, the ObjectDataSource cannot successfully call the parameterless constructor because it will throw an exception. 在某些情况下, 无参数的构造函数可能是受保护的, 在其他情况下, 它可能不会将业务对象初始化为所需状态。In some cases, the parameterless constructor might be protected and in others it might not initialize the business object to a desired state. 无论原因是什么, 您都可以自己创建业务对象的实例, 并将实例设置为ObjectInstance传递给该ObjectDataSourceEventArgs处理程序的对象的属性。Whatever the reason, you can create an instance of the business object yourself and set the instance to the ObjectInstance property of the ObjectDataSourceEventArgs object that is passed to the handler. 这是ObjectDataSource将用于执行其工作的业务对象实例。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>
<%@ Import namespace="Samples.AspNet.VB" %>
<%@ Page language="vb" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Private Sub NorthwindLogicCreating(sender As Object, e As ObjectDataSourceEventArgs)

    ' Create an instance of the business object using a non-default constructor.
    Dim eLogic As EmployeeLogic = New EmployeeLogic("Not created by the default constructor!")
    
    ' Set the ObjectInstance property so that the ObjectDataSource uses the created instance.
    e.ObjectInstance = eLogic
    
End Sub ' NorthwindLogicCreating

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>ObjectDataSource - VB 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.VB.EmployeeLogic" >
        </asp:objectdatasource>

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

下面的代码示例演示前面的代码示例使用的示例基本业务对象。The following code example demonstrates the example basic business object that the preceding code example uses.

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;
    }
    
  }

}
Imports System.Collections
Imports System.Web.UI
Imports System.Web.UI.WebControls

Namespace Samples.AspNet.VB
  Public Class EmployeeLogic
    
    
    Public Sub New() 
        Throw New NotSupportedException("Initialize data.")
    
    End Sub
    
    
    Public Sub New(ByVal data As String) 
        _data = data
    
    End Sub
    
    Private _data As String
    
    
    ' Returns a collection of NorthwindEmployee objects.
    Public Function GetAllEmployees() As ICollection 
        Dim al As New ArrayList()
        al.Add(_data)
        Return al
    
    End Function 'GetAllEmployees
  End Class
End Namespace ' Samples.AspNet.VB

注解

OnObjectCreating ObjectDataSource在和ObjectDataSourceEventArgs 方法中使用类,以在执行任何使用控件和业务对象的数据操作之前提供对业务对象实例的访问。OnObjectCreatedThe ObjectDataSourceEventArgs class is used in the OnObjectCreating and OnObjectCreated methods to provide access to the business object instance before any data operations that are using the ObjectDataSource control and business object are performed. 使用ObjectInstance属性设置和访问业务对象。The business object is set and accessed using the ObjectInstance property. 通过添加事件处理程序委托来处理ObjectCreating事件, 可以在自定义代码中创建业务对象的实例, 而不是ObjectDataSource执行实例化。By adding an event handler delegate to handle the ObjectCreating event, you can create an instance of the business object in custom code instead of the ObjectDataSource performing the instantiation. 当你需要业务对象的非默认实例或调用非参数构造函数来创建实例时, 这会很有用;ObjectDataSource始终调用无参数的构造函数来创建它所使用的业务对象的实例。This is useful when you want a non-default instance of your business object or to call a non-parameterless constructor to create the instance; the ObjectDataSource always calls the parameterless constructor to create an instance of the business object it works with. 你还可以添加一个事件处理程序委托来处理ObjectCreated事件, 这使你能够访问业务对象的任何公开显示的成员以执行任何附加的初始化或工作。You can also add an event handler delegate to handle the ObjectCreated event, which enables you to access any publicly exposed members of the business object to perform any additional initialization or work.

如果执行OnObjectCreated数据操作的业务对象方法ObjectDataSourcestatic, 则控件不会调用和方法。OnObjectCreatingThe OnObjectCreating and OnObjectCreated methods are not called by the ObjectDataSource control, if the business object method that performs the data operations is static.

ObjectDataSource控件公开了许多事件, 您可以处理这些事件, 以便在其生命周期中的不同时间使用基础业务对象。The ObjectDataSource control exposes many events that you can handle to work with the underlying business object at various times in its lifecycle. 下表列出了事件以及关联EventArgs的类和事件处理程序委托。The following table lists the events and the associated EventArgs classes and event handler delegates.

事件Event EventArgsEventArgs EventHandlerEventHandler
ObjectCreatingObjectCreating.

在创建业务对象的实例之前立即发生。Occurs immediately before the instance of the business object is created.
ObjectDataSourceEventArgs ObjectDataSourceObjectEventHandler
ObjectCreatedObjectCreated.

在创建业务对象的实例之后立即发生。Occurs immediately after the instance of the business object is created.
ObjectDataSourceEventArgs ObjectDataSourceObjectEventHandler
SelectingSelecting.

在检索数据之前发生。Occurs before the data is retrieved.
ObjectDataSourceSelectingEventArgs ObjectDataSourceSelectingEventHandler
InsertingUpdatingDeletingInserting, Updating, and Deleting.

在执行插入、更新或删除操作之前发生。Occur before an insert, update, or delete operation is performed.
ObjectDataSourceMethodEventArgs ObjectDataSourceMethodEventHandler
SelectedSelected.

在检索数据后发生。Occurs after the data is retrieved.
ObjectDataSourceStatusEventArgs ObjectDataSourceStatusEventHandler
Inserted, Updated, Deleted.Inserted, Updated, Deleted.

完成插入、更新或删除操作后发生。Occur after the insert, update, or delete operation is completed.
ObjectDataSourceStatusEventArgs ObjectDataSourceStatusEventHandler
ObjectDisposingObjectDisposing.

在销毁业务对象之前发生。Occurs before a business object is destroyed.
ObjectDataSourceDisposingEventArgs ObjectDataSourceDisposingEventHandler

构造函数

ObjectDataSourceEventArgs(Object)

使用指定的对象初始化 ObjectDataSourceEventArgs 类的新实例。Initializes a new instance of the ObjectDataSourceEventArgs class using the specified object.

属性

ObjectInstance

获取或设置表示一个业务对象的对象,ObjectDataSource 控件使用该业务对象执行数据操作。Gets or sets an object that represents the business object with which the ObjectDataSource control performs data operations.

方法

Equals(Object)

确定指定的对象是否等于当前对象。Determines whether the specified object is equal to the current object.

(继承自 Object)
GetHashCode()

用作默认哈希函数。Serves as the default hash function.

(继承自 Object)
GetType()

获取当前实例的 TypeGets the Type of the current instance.

(继承自 Object)
MemberwiseClone()

创建当前 Object 的浅表副本。Creates a shallow copy of the current Object.

(继承自 Object)
ToString()

返回一个表示当前对象的 string。Returns a string that represents the current object.

(继承自 Object)

适用于

另请参阅