ControlCollection.Clear ControlCollection.Clear ControlCollection.Clear ControlCollection.Clear Method

定义

从当前服务器控件的 ControlCollection 对象中移除所有控件。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 ()

示例

下面的代码示例演示如何重Control.CreateChildControls写方法,并Clear使用方法删除以前在ControlCollection对象中的所有子控件。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. 在这种情况下,您必须执行此操作,以使控件的ControlCollection过期对象不会被不当地显示。In this case, you must do this so that outdated objects in your control's ControlCollection are not displayed inappropriately.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

注解

重写ControlCollectionDataBind方法时,请使用此方法为自定义控件空。 Control.CreateChildControlsUse this method to empty a custom control's ControlCollection when you override the Control.CreateChildControls and DataBind methods. 当开发复合模板、模板化控件或模板化数据绑定控件时,请执行此操作。Do this when you develop composite, templated controls or templated data-bound controls.

适用于

另请参阅