ControlCollection.Clear 方法

定義

從目前伺服器控制項的 ControlCollection 物件中移除所有控制項。Removes all controls from the current server control's ControlCollection object.

public:
 virtual void Clear();
public virtual void Clear ();
abstract member Clear : unit -> unit
override this.Clear : unit -> unit
Public Overridable Sub Clear ()

範例

下列程式碼範例將示範如何Control.CreateChildControls覆寫方法,並Clear使用方法來刪除先前在物件中的ControlCollection所有子控制項。The following code example demonstrates overriding the Control.CreateChildControls method, and using the Clear method to delete all child controls previously in the ControlCollection object. 在這種情況下,您必須這麼做,才能使控制項ControlCollection中過期的物件無法適當地顯示。In this case, you must do this so that outdated objects in your control's ControlCollection are not displayed inappropriately.

// Override to create repeated items.
protected override void CreateChildControls() {
    object o = ViewState["NumItems"];
    if (o != null) {
       // Clear any existing child controls.
       Controls.Clear();

       int numItems = (int)o;
       for (int i=0; i < numItems; i++) {
          // Create an item.
          RepeaterItem item = new RepeaterItem(i, null);
          // Initialize the item from the template.
          ItemTemplate.InstantiateIn(item);
          // Add the item to the ControlCollection.
          Controls.Add(item);
       }
    }
}
' Override to create repeated items.
Protected Overrides Sub CreateChildControls()
    Dim O As Object = ViewState("NumItems")
    If Not (O Is Nothing)
       ' Clear any existing child controls.
       Controls.Clear()

       Dim I As Integer
       Dim NumItems As Integer = CInt(O)
       For I = 0 To NumItems - 1
          ' Create an item.
          Dim Item As RepeaterItemVB = New RepeaterItemVB(I, Nothing)
          ' Initialize the item from the template.
          ItemTemplate.InstantiateIn(Item)
          ' Add the item to the ControlCollection.
          Controls.Add(Item)
       Next
    End If
End Sub

備註

當您覆ControlCollection Control.CreateChildControls寫和DataBind方法時,請使用這個方法來清空自訂控制項的。Use this method to empty a custom control's ControlCollection when you override the Control.CreateChildControls and DataBind methods. 當您開發複合、樣板化控制項或樣板化資料繫結控制項時,請執行此動作。Do this when you develop composite, templated controls or templated data-bound controls.

適用於

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