ListItemCollection.Clear 方法

  • 參考

定義

命名空間:
System.Web.UI.WebControls
組件:
System.Web.dll

從集合中移除所有 ListItem 物件。

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

實作

Clear()

範例

// Copy the items in the ListItemCollection to an array before 
// deleting them.     
ListItem[] myListItemArray = new ListItem[ListBox1.Items.Count];
ListBox1.Items.CopyTo(myListItemArray, 0);

// Delete all the items from the ListBox.
ListBox1.Items.Clear();
DeleteLabel.Text = "<b>All items in the ListBox were deleted successfully." 
    + "</b><br /><b>The deleted items are:";
String listResults="";
    foreach(ListItem myItem in myListItemArray)
    {
        listResults = listResults + myItem.Text + "<br />";
    }
ResultsLabel.Text = listResults;

' Copy the items in the ListListBox1.Items to an array before 
' deleting them.     
Dim myListItemArray(ListBox1.Items.Count - 1) As ListItem
ListBox1.Items.CopyTo(myListItemArray, 0)

' Delete all the items from the ListBox.
ListBox1.Items.Clear()
DeleteLabel.Text = "<b>All items in the ListBox were deleted successfully." & _
                   "</b><br /><b>The deleted items are:"
Dim listResults As [String] = ""
Dim myItem2 As ListItem
For Each myItem2 In myListItemArray
    listResults = listResults & myItem2.Text & "<br />"
Next myItem2
ResultsLabel.Text = listResults

備註

Clear使用 方法來移除所有 ListItem 物件。 屬性 Count 也會設定為 0 。

警告

當您使用此方法時，所有 ListItem 物件都會從集合中移除。 您無法復原此動作。

適用於

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