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ControlCollection.Add Method
.NET Framework 1.1
Adds the specified Control object to the collection.
[Visual Basic] Public Overridable Sub Add( _ ByVal child As Control _ ) [C#] public virtual void Add( Control child ); [C++] public: virtual void Add( Control* child ); [JScript] public function Add( child : Control );
Parameters
- child
- The Control object to add to the collection.
Exceptions
| Exception Type | Condition |
|---|---|
| ArgumentNullException | Thrown if the child parameter does not specifiy a control. |
| HttpException | Thrown if the ControlCollection object is read-only. |
Remarks
The new control is added to the end of an ordinal index array. The control can be an instance of any ASP.NET server control, a custom server control you create, or a literal control.
To add a control to the collection at a specific index location, use the AddAt method.
Example
The following example uses the Add method to add a series of template items, the number of which are taken from the server control's view state, to a custom templated control.
[Visual Basic] ' 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 [C#] // 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); } } } [C++] // Override to create repeated items. void CreateChildControls() { Object* o = ViewState->Item[S"NumItems"]; if (o != 0) { // Clear any existing child controls. Controls->Clear(); int numItems = *dynamic_cast<int __gc *>(o); for (int i = 0; i < numItems; i++) { // Create an item. RepeaterItem* item = new RepeaterItem(i, 0); // Initialize the item from the template. ItemTemplate->InstantiateIn(item); // Add the item to the ControlCollection. Controls->Add(item); } } } [JScript] // Override to create repeated items. protected override function CreateChildControls() { var o = ViewState["NumItems"]; if (o != null) { // clear any existing child controls Controls.Clear(); var numItems : int = int(o); for (var i : int =0; i < numItems; i++) { // Create an item. var item : RepeaterItem = new RepeaterItem(i, null); // Initialize the item from the template. ItemTemplate.InstantiateIn(item); // Add the item to the ControlCollection. Controls.Add(item); } } }
Requirements
Platforms: Windows 2000, Windows XP Professional, Windows Server 2003 family
See Also
ControlCollection Class | ControlCollection Members | System.Web.UI Namespace | Controls | AddAt
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