DataBoundControl.PerformDataBinding(IEnumerable) Método

Definición

Cuando se reemplaza en una clase derivada, enlaza los datos del origen de datos al control.When overridden in a derived class, binds data from the data source to the control.

protected public:
 virtual void PerformDataBinding(System::Collections::IEnumerable ^ data);
protected internal virtual void PerformDataBinding (System.Collections.IEnumerable data);
abstract member PerformDataBinding : System.Collections.IEnumerable -> unit
override this.PerformDataBinding : System.Collections.IEnumerable -> unit
Protected Friend Overridable Sub PerformDataBinding (data As IEnumerable)

Parámetros

data
IEnumerable

La lista IEnumerable de los datos devueltos por una llamada al método PerformSelect().The IEnumerable list of data returned from a PerformSelect() method call.

Ejemplos

En el ejemplo de código siguiente se muestra cómo PerformDataBinding implementar el método en una clase DataBoundControlderivada de.The following code example demonstrates how to implement the PerformDataBinding method in a class derived from DataBoundControl. El TextBoxSet control crea un TextBox control para cada elemento de datos al que está enlazado.The TextBoxSet control creates a TextBox control for each data item it is bound to. Este ejemplo de código forma parte de un ejemplo más extenso proporcionado DataBoundControl para la clase.This code example is part of a larger example provided for the DataBoundControl class.

protected override void PerformDataBinding(IEnumerable retrievedData) {
    base.PerformDataBinding(retrievedData);

    // If the data is retrieved from an IDataSource as an 
    // IEnumerable collection, attempt to bind its values to a 
    // set of TextBox controls.
    if (retrievedData != null) {

        foreach (object dataItem in retrievedData) {
            
            TextBox box = new TextBox();
            
            // The dataItem is not just a string, but potentially
            // a System.Data.DataRowView or some other container. 
            // If DataTextField is set, use it to determine which 
            // field to render. Otherwise, use the first field.                    
            if (DataTextField.Length > 0) {
                box.Text = DataBinder.GetPropertyValue(dataItem, 
                    DataTextField, null);
            }
            else {
                PropertyDescriptorCollection props = 
                    TypeDescriptor.GetProperties(dataItem);

                // Set the "default" value of the TextBox.
                box.Text = String.Empty;
                
                // Set the true data-bound value of the TextBox,
                // if possible.
                if (props.Count >= 1) {                        
                    if (null != props[0].GetValue(dataItem)) {
                        box.Text = props[0].GetValue(dataItem).ToString();
                    }
                }
            }                                        
            
            BoxSet.Add(box);
        }
    }
}
Protected Overrides Sub PerformDataBinding(ByVal retrievedData As IEnumerable)
    MyBase.PerformDataBinding(retrievedData)

    ' If the data is retrieved from an IDataSource as an IEnumerable 
    ' collection, attempt to bind its values to a set of TextBox controls.
    If Not (retrievedData Is Nothing) Then

        Dim dataItem As Object
        For Each dataItem In retrievedData

            Dim box As New TextBox()

            ' The dataItem is not just a string, but potentially
            ' a System.Data.DataRowView or some other container. 
            ' If DataTextField is set, use it to determine which 
            ' field to render. Otherwise, use the first field.                    
            If DataTextField.Length > 0 Then
                box.Text = DataBinder.GetPropertyValue( _
                dataItem, DataTextField, Nothing)
            Else
                Dim props As PropertyDescriptorCollection = _
                    TypeDescriptor.GetProperties(dataItem)

                ' Set the "default" value of the TextBox.
                box.Text = String.Empty

                ' Set the true data-bound value of the TextBox,
                ' if possible.
                If props.Count >= 1 Then
                    If props(0).GetValue(dataItem) IsNot Nothing Then
                        box.Text = props(0).GetValue(dataItem).ToString()
                    End If
                End If
            End If

            BoxSet.Add(box)
        Next dataItem
    End If

End Sub

Comentarios

Implemente este método en lugar del DataBind método al derivar un control enlazado a datos de DataBoundControl la clase.Implement this method instead of the DataBind method when you derive a data-bound control from the DataBoundControl class. Colocar la lógica de enlace de datos del control PerformDataBinding en le permite evitar que DataBinding los DataBound eventos y se produzcan en el orden equivocado.Placing your control's data-binding logic in PerformDataBinding enables you to avoid the DataBinding and DataBound events being raised in the wrong order.

Mientras que la DataBoundControl clase base no proporciona una implementación específica para este método PerformDataBinding , el método llama PerformSelect al método para enlazar los valores de cualquier control de la interfaz de usuario (IU) con los datos recuperados por el PerformSelect forma.While the base DataBoundControl class provides no specific implementation for this method, the PerformDataBinding method is called by the PerformSelect method to bind the values of any user interface (UI) controls to the data that is retrieved by the PerformSelect method.

Se aplica a