asp.net 3.5中的datalist
问题描述:
如何在按钮上访问数据列表DataListCommandEventArgs单击
how to access data list DataListCommandEventArgs on button click
答
所有事件处理程序都有两个参数:
1)Anobject
名为sender
,它是发起事件的类实例。例如,在Button.Click处理程序中,sender
将是用户单击的按钮。
2)EventArgs
(或派生)类实例,名为e
,它包含事件参数(如果有)。通常,如果这是派生的EventArgs类,那么事件将被声明为将派生类作为参数而不是标准的默认EventArgs,但是您可以将EventArgs转换为派生类并检查它是否有效:
All event handlers have two parameters:
1) Anobject
calledsender
which is the class instance which originated the event. For example, in a Button.Click handler,sender
would be the button the user clicked.
2) AnEventArgs
(or derived) class instance callede
which holds the event arguments if any. Normally, if this is a derived EventArgs class, then the event will be declared as having the derived class as a parameter instead of the standard default EventArgs, but you can cast the EventArgs to a derived class and check if it is valid:
void mySource_Event(object sender, EventArgs e)
{
MyEventArgs args = e as MyEventArgs;
if (args != null)
{
// You can use args here.
}
}
在VB中可能是这样的:
In VB is would be something like:
Private Sub mySource_Event(sender As Object, e As EventArgs) Handles ...
Dim args As MyEventArgs = TryCast(e, MyEventArgs)
If args IsNot Nothing Then
' You can use args here.
End If
End Sub