Control.ClearChildState Método

Definição

Exclui as informações de estado de exibição e de estado de controle para todos os controles filho do controle de servidor.Deletes the view-state and control-state information for all the server control's child controls.

protected:
 void ClearChildState();
protected void ClearChildState ();
member this.ClearChildState : unit -> unit
Protected Sub ClearChildState ()

Exemplos

O exemplo de código a seguir demonstra como substituir o OnDataBinding método para um controle vinculado a dados de modelo.The following code example demonstrates how to override the OnDataBinding method for a templated data-bound control. Se a fonte de dados à qual o controle está associado for populada, a coleção do controle ControlCollection será esvaziada usando o Clear método e o ClearChildState método será usado para remover todas as informações de estado que foram salvas para os controles filho.If the data source that the control binds to is populated, the control's ControlCollection collection is emptied using the Clear method, and the ClearChildState method is used to remove any state information that had been saved for the child controls.

// Override to create the repeated items from the DataSource.
protected override void OnDataBinding(EventArgs e) {
    base.OnDataBinding(e);

    if (DataSource != null) {
        // Clear any existing child controls.
        Controls.Clear();
        // Clear any previous state for the existing child controls.
        ClearChildState();

        // Iterate over the DataSource, creating a new item for each data item.
        IEnumerator dataEnum = DataSource.GetEnumerator();
        int i = 0;
        while(dataEnum.MoveNext()) {

            // Create an item.
            RepeaterItem item = new RepeaterItem(i, dataEnum.Current);
            // Initialize the item from the template.
            ItemTemplate.InstantiateIn(item);
            // Add the item to the ControlCollection.
            Controls.Add(item);

            i++;
        }

        // Prevent child controls from being created again.
        ChildControlsCreated = true;
        // Store the number of items created in view state for postback scenarios.
        ViewState["NumItems"] = i;
    }
}
' Override to create the repeated items from the DataSource.
Protected Overrides Sub OnDataBinding(E As EventArgs)
    MyBase.OnDataBinding(e)

    If Not DataSource Is Nothing
        ' Clear any existing child controls.
        Controls.Clear()
        ' Clear any previous view state for the existing child controls.
        ClearChildState()

        ' Iterate over the DataSource, creating a new item for each data item.
        Dim DataEnum As IEnumerator = DataSource.GetEnumerator()
        Dim I As Integer = 0
        Do While (DataEnum.MoveNext())

            ' Create an item.
            Dim Item As RepeaterItemVB = New RepeaterItemVB(I, DataEnum.Current)
            ' Initialize the item from the template.
            ItemTemplate.InstantiateIn(Item)
            ' Add the item to the ControlCollection.
            Controls.Add(Item)

            I = I + 1
        Loop

        ' Prevent child controls from being created again.
        ChildControlsCreated = true
        ' Store the number of items created in view state for postback scenarios.
        ViewState("NumItems") = I
    End If
End Sub

Comentários

O ClearChildState método limpa todas as informações de estado de exibição e de estado de controle para controles filho.The ClearChildState method clears all view-state and control-state information for child controls. É equivalente a chamar o ClearChildViewState método e o ClearChildControlState método.It is equivalent to calling both the ClearChildViewState method and the ClearChildControlState method.

Ao recriar controles filho de um Control objeto, use o ClearChildState método para limpar o estado filho para que ele não seja aplicado aos novos controles inadvertidamente.When recreating child controls of a Control object, use the ClearChildState method to clear child state so that it does not get applied to the new controls inadvertently.

Aplica-se a

Confira também