ObjectDataSourceView.Updating Event
Definition
Important
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Occurs before an Update operation.
public:
event System::Web::UI::WebControls::ObjectDataSourceMethodEventHandler ^ Updating;public event System.Web.UI.WebControls.ObjectDataSourceMethodEventHandler Updating;member this.Updating : System.Web.UI.WebControls.ObjectDataSourceMethodEventHandler Public Custom Event Updating As ObjectDataSourceMethodEventHandler Event Type
Examples
The following code example demonstrates how to use a DropDownList control, TextBox controls, and several ObjectDataSource controls to update data. The DropDownList displays the name of a NorthwindEmployee, while the TextBox controls are used to enter and update address information. Because the UpdateParameters collection contains a ControlParameter object that is bound to the selected value of the DropDownList, the button that triggers the Update operation is enabled only after an employee is selected.
<%@ 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>
Remarks
Handle the Updating event to perform additional initialization operations that are specific to your application, to validate the values of parameters, or to change the parameter values before the ObjectDataSource control performs the Update operation. The parameters are available as an IDictionary collection, accessed by the InputParameters property, which is exposed by the ObjectDataSourceMethodEventArgs object.
For more information about how to handle events, see Handling and Raising Events.
Applies to
See also
Met ons samenwerken op GitHub
De bron voor deze inhoud vindt u op GitHub, waar u ook problemen en pull-aanvragen kunt maken en controleren. Bekijk onze gids voor inzenders voor meer informatie.
