AddingNewEventHandler 代理人

定義

代表將處理 AddingNew 事件的方法。Represents the method that will handle the AddingNew event.

public delegate void AddingNewEventHandler(System::Object ^ sender, AddingNewEventArgs ^ e);
public delegate void AddingNewEventHandler(object sender, AddingNewEventArgs e);
type AddingNewEventHandler = delegate of obj * AddingNewEventArgs -> unit
Public Delegate Sub AddingNewEventHandler(sender As Object, e As AddingNewEventArgs)

參數

sender
Object

事件的來源,通常為資料容器或資料繫結集合。The source of the event, typically a data container or data-bound collection.

e
AddingNewEventArgs

AddingNewEventArgs,其中包含事件資料。A AddingNewEventArgs that contains the event data.

繼承
AddingNewEventHandler

範例

下列程式碼範例示範如何使用AddingNewEventHandler委派來BindingSource.AddingNew處理事件。The following code example demonstrates how to use the AddingNewEventHandler delegate to handle the BindingSource.AddingNew event. 這個程式碼範例是如何:使用 Windows Forms BindingSource自訂加入專案。This code example is part of a larger example provided in How to: Customize Item Addition with the Windows Forms BindingSource.

// This event handler provides custom item-creation behavior.
void OnCustomersBindingSourceAddingNew(Object^ sender, 
    AddingNewEventArgs^ e)
{
    e->NewObject = DemoCustomer::CreateNewCustomer();
}
// This event handler provides custom item-creation behavior.
void customersBindingSource_AddingNew(
    object sender, 
    AddingNewEventArgs e)
{
    e.NewObject = DemoCustomer.CreateNewCustomer();
}
' This event handler provides custom item-creation behavior.
 Private Sub customersBindingSource_AddingNew( _
 ByVal sender As Object, _
 ByVal e As AddingNewEventArgs) _
 Handles customersBindingSource.AddingNew

     e.NewObject = DemoCustomer.CreateNewCustomer()

 End Sub

備註

BindingSource.AddingNew將新專案加入集合之前, 通常會在資料系結案例中發生此事件。The BindingSource.AddingNew event occurs prior to adding a new item to a collection, typically in data-binding scenarios. 這個事件的處理常式可以提供要新增的新專案, 並覆寫集合類別的標準動作。The handler of this event can supply the new item to be added, overriding the standard action of the collection class. NewObject AddingNewEventArgs參數的e屬性設定為這個新專案, 即可完成此作業。This is accomplished by setting the NewObject property of the AddingNewEventArgs parameter e to this new item. 此專案通常必須是收件者集合所預期的類型, 否則集合將會擲回類型InvalidCastException的例外狀況。Typically this item must be of a type expected by the recipient collection, or the collection will throw an exception of type InvalidCastException.

這個事件通常用於資料系結案例中, 例如System.Windows.Forms.BindingSourceSystem.ComponentModel.BindingList<T>之類的類別。This event is commonly used in data-binding scenarios, within classes such as System.Windows.Forms.BindingSource and System.ComponentModel.BindingList<T>.

當您建立 AddingNewEventHandler 委派 (Delegate) 時,就可以識別即將處理此事件的方法。When you create an AddingNewEventHandler delegate, you identify the method that will handle the event. 若要使事件與您的事件處理常式產生關聯,請將委派的執行個體 (Instance) 加入至事件。To associate the event with your event handler, add an instance of the delegate to the event. 除非您移除委派,否則每當事件發生時就會呼叫事件處理常式。The event handler is called whenever the event occurs, unless you remove the delegate. 如需事件處理常式委派的詳細資訊, 請參閱處理和引發事件For more information about event-handler delegates, see Handling and Raising Events.

擴充方法

GetMethodInfo(Delegate)

取得表示特定委派所代表之方法的物件。Gets an object that represents the method represented by the specified delegate.

適用於

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