ObjectDataSourceView.OnUpdating(ObjectDataSourceMethodEventArgs) Methode

  • Referenz

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Löst das Updating-Ereignis aus, bevor das ObjectDataSourceView-Objekt einen Aktualisierungsvorgang startet.

protected:
 virtual void OnUpdating(System::Web::UI::WebControls::ObjectDataSourceMethodEventArgs ^ e);
protected virtual void OnUpdating (System.Web.UI.WebControls.ObjectDataSourceMethodEventArgs e);
abstract member OnUpdating : System.Web.UI.WebControls.ObjectDataSourceMethodEventArgs -> unit
override this.OnUpdating : System.Web.UI.WebControls.ObjectDataSourceMethodEventArgs -> unit
Protected Overridable Sub OnUpdating (e As ObjectDataSourceMethodEventArgs)

Parameter

e
ObjectDataSourceMethodEventArgs

Ein ObjectDataSourceMethodEventArgs, das die Ereignisdaten enthält.

Beispiele

Im folgenden Codebeispiel wird veranschaulicht, wie Sie ein DropDownList Steuerelement, TextBox Steuerelemente und mehrere ObjectDataSource Steuerelemente verwenden, um Daten zu aktualisieren. Zeigt DropDownList den Namen eines NorthwindEmployeean, während die TextBox Steuerelemente zum Eingeben und Aktualisieren von Adressinformationen verwendet werden. Da die UpdateParameters Auflistung ein ControlParameter Objekt enthält, das an den ausgewählten Wert von DropDownListgebunden ist, wird die Schaltfläche, die den Update Vorgang auslöst, erst aktiviert, nachdem ein Mitarbeiter ausgewählt wurde.

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS" Assembly="Samples.AspNet.CS" %>
<%@ Page language="c#" %>
<%@ Import namespace="Samples.AspNet.CS" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

// Add parameters and initialize the user interface
// only if an employee is selected.
private void Page_Load(object sender, EventArgs e)
{
  // Be sure the text boxes are initialized with
  // data from the currently selected employee.
  NorthwindEmployee selectedEmployee = EmployeeLogic.GetEmployee(DropDownList1.SelectedValue);
  if (selectedEmployee != null) {
    AddressBox.Text    = selectedEmployee.Address;
    CityBox.Text       = selectedEmployee.City;
    PostalCodeBox.Text = selectedEmployee.PostalCode;

    Button1.Enabled = true;
  }
  else {
    Button1.Enabled = false;
  }
}

// Press the button to update.
private void Btn_UpdateEmployee (object sender, CommandEventArgs e) {
    ObjectDataSource2.Update();
}

// Dynamically add parameters to the InputParameters collection.
private void NorthwindEmployeeUpdating(object source, ObjectDataSourceMethodEventArgs e) {

  // The names of the parameters are the same as
  // the variable names for the method that is invoked to
  // perform the Update. The InputParameters collection is
  // an IDictionary collection of name/value pairs,
  // not a ParameterCollection.
  e.InputParameters.Add("anID",       DropDownList1.SelectedValue);
  e.InputParameters.Add("anAddress"  ,AddressBox.Text);
  e.InputParameters.Add("aCity"      ,CityBox.Text);
  e.InputParameters.Add("aPostalCode",PostalCodeBox.Text);
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>ObjectDataSource - C# Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">

        <!-- The DropDownList is bound to the first ObjectDataSource. -->
        <asp:objectdatasource
          id="ObjectDataSource1"
          runat="server"
          selectmethod="GetAllEmployees"
          typename="Samples.AspNet.CS.EmployeeLogic" />

        <p><asp:dropdownlist
          id="DropDownList1"
          runat="server"
          datasourceid="ObjectDataSource1"
          datatextfield="FullName"
          datavaluefield="EmpID"
          autopostback="True" /></p>

        <!-- The second ObjectDataSource performs the Update. This
             preserves the state of the DropDownList, which otherwise
             would rebind when the DataSourceChanged event is
             raised as a result of an Update operation. -->

        <asp:objectdatasource
          id="ObjectDataSource2"
          runat="server"
          updatemethod="UpdateEmployeeWrapper"
          onupdating="NorthwindEmployeeUpdating"
          typename="Samples.AspNet.CS.EmployeeLogic" />

        <p><asp:textbox
          id="AddressBox"
          runat="server" /></p>

        <p><asp:textbox
          id="CityBox"
          runat="server" /></p>

        <p><asp:textbox
          id="PostalCodeBox"
          runat="server" /></p>

        <asp:button
          id="Button1"
          runat="server"
          text="Update Employee"
          oncommand="Btn_UpdateEmployee" />

    </form>
  </body>
</html>

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB" Assembly="Samples.AspNet.VB" %>
<%@ Page language="vb" %>
<%@ Import namespace="Samples.AspNet.VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

' Add parameters and initialize the user interface
' only if an employee is selected.
Private Sub Page_Load(sender As Object, e As EventArgs)

  ' Be sure the text boxes are initialized with
  ' data from the currently selected employee.
  Dim selectedEmployee As NorthwindEmployee
  selectedEmployee = EmployeeLogic.GetEmployee(DropDownList1.SelectedValue)

  If Not selectedEmployee Is Nothing Then
    AddressBox.Text    = selectedEmployee.Address
    CityBox.Text       = selectedEmployee.City
    PostalCodeBox.Text = selectedEmployee.PostalCode

    Button1.Enabled = True
  Else
    Button1.Enabled = False
  End If
End Sub ' Page_Load

' Press the button to update.
Private Sub Btn_UpdateEmployee (sender As Object, e As CommandEventArgs)
    ObjectDataSource2.Update()
End Sub ' Btn_UpdateEmployee

' Dynamically add parameters to the InputParameters collection.
Private Sub NorthwindEmployeeUpdating(source As Object, e As ObjectDataSourceMethodEventArgs)

  ' The names of the parameters are the same as
  ' the variable names for the method that is invoked to
  ' perform the Update. The InputParameters collection is
  ' an IDictionary collection of name/value pairs,
  ' not a ParameterCollection.
  e.InputParameters.Add("anID",       DropDownList1.SelectedValue)
  e.InputParameters.Add("anAddress"  ,AddressBox.Text)
  e.InputParameters.Add("aCity"      ,CityBox.Text)
  e.InputParameters.Add("aPostalCode",PostalCodeBox.Text)

End Sub ' NorthwindEmployeeUpdating

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>ObjectDataSource - VB Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">

        <!-- The DropDownList is bound to the first ObjectDataSource. -->
        <asp:objectdatasource
          id="ObjectDataSource1"
          runat="server"
          selectmethod="GetAllEmployees"
          typename="Samples.AspNet.VB.EmployeeLogic" />

        <p><asp:dropdownlist
          id="DropDownList1"
          runat="server"
          datasourceid="ObjectDataSource1"
          datatextfield="FullName"
          datavaluefield="EmpID"
          autopostback="True" /></p>

        <!-- The second ObjectDataSource performs the Update. This
             preserves the state of the DropDownList, which otherwise
             would rebind when the DataSourceChanged event is
             raised as a result of an Update operation. -->

        <asp:objectdatasource
          id="ObjectDataSource2"
          runat="server"
          updatemethod="UpdateEmployeeWrapper"
          onupdating="NorthwindEmployeeUpdating"
          typename="Samples.AspNet.VB.EmployeeLogic" />

        <p><asp:textbox
          id="AddressBox"
          runat="server" /></p>

        <p><asp:textbox
          id="CityBox"
          runat="server" /></p>

        <p><asp:textbox
          id="PostalCodeBox"
          runat="server" /></p>

        <asp:button
          id="Button1"
          runat="server"
          text="Update Employee"
          oncommand="Btn_UpdateEmployee" />

    </form>
  </body>
</html>

Hinweise

Durch das Auslösen eines Ereignisses wird der Ereignishandler über einen Delegaten aufgerufen. Weitere Informationen zum Behandeln von Ereignissen finden Sie unter behandeln und Auslösen von Ereignissen.

Mit der OnUpdating-Methode können auch abgeleitete Klassen das Ereignis ohne Anfügen eines Delegaten behandeln. Dies ist das bevorzugte Verfahren für die Behandlung des Ereignisses in einer abgeleiteten Klasse.

Hinweise für Vererber

Wenn Sie die OnUpdating(ObjectDataSourceMethodEventArgs) -Methode in einer abgeleiteten Klasse überschreiben, achten Sie darauf, die OnUpdating(ObjectDataSourceMethodEventArgs) Methode für die Basisklasse aufzurufen, damit registrierte Delegaten das Ereignis empfangen.

Gilt für:

Weitere Informationen