FormViewUpdateEventHandler Delegar
Definição
Importante
Algumas informações se referem a produtos de pré-lançamento que podem ser substancialmente modificados antes do lançamento. A Microsoft não oferece garantias, expressas ou implícitas, das informações aqui fornecidas.
Representa o método que manipula o evento ItemUpdating de um controle FormView.
public delegate void FormViewUpdateEventHandler(System::Object ^ sender, FormViewUpdateEventArgs ^ e);public delegate void FormViewUpdateEventHandler(object sender, FormViewUpdateEventArgs e);type FormViewUpdateEventHandler = delegate of obj * FormViewUpdateEventArgs -> unitPublic Delegate Sub FormViewUpdateEventHandler(sender As Object, e As FormViewUpdateEventArgs)Parâmetros
- sender
- Object
A fonte do evento.
Um FormViewUpdateEventArgs que contém os dados do evento.
Exemplos
O exemplo a seguir demonstra como adicionar programaticamente um FormViewUpdateEventHandler delegado ao ItemUpdating evento de um FormView controle .
Importante
Este exemplo tem uma caixa de texto que aceita a entrada do usuário, que é uma possível ameaça à segurança. Por padrão, ASP.NET páginas da Web validam que a entrada do usuário não inclui elementos html ou script. Para obter mais informações, consulte Visão geral de explorações de script.
<%@ Page language="C#" %>
<%@ import namespace="System.Data"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
// To dynamically create a template for a FormView control,
// you must create a custom template class to represent
// the template. This template class represents the item
// template for a FormView control.
private sealed class EmployeeItemTemplate : ITemplate
{
// When implementing the ITemplate interface, you must
// implement the InstantiateIn method. The FormView
// control calls this method to create the template's
// content.
void ITemplate.InstantiateIn(Control container)
{
// Create the child controls contained in the template.
// For this example, the item template displays the
// FirstName and LastName fields from the data source.
// To support data binding, create event handlers
// for the DataBinding event of each child control.
// The event handlers must bind the appropriate value
// to each control.
Label firstNameLabel = new Label();
firstNameLabel.ID = "FirstNameLabel";
firstNameLabel.DataBinding += new EventHandler(FirstNameLabel_DataBinding);
LiteralControl nameLineBreak = new LiteralControl("<br/>");
LiteralControl buttonLineBreak = new LiteralControl("<br/>");
Label lastNameLabel = new Label();
lastNameLabel.ID = "LastNameLabel";
lastNameLabel.DataBinding += new EventHandler(LastNameLabel_DataBinding);
Button editButton = new Button();
editButton.ID = "EditButton";
editButton.CommandName = "Edit";
editButton.Text = "Edit";
// Add the controls to the Controls collection of the
// container control.
container.Controls.Add(firstNameLabel);
container.Controls.Add(nameLineBreak);
container.Controls.Add(lastNameLabel);
container.Controls.Add(buttonLineBreak);
container.Controls.Add(editButton);
}
// This event handler binds the value of the FirstName field
// to the FirstNameLabel Label control displayed in the template.
private void FirstNameLabel_DataBinding(Object sender, EventArgs e)
{
// Use the sender parameter to retrieve the Label control
// being bound to data.
Label firstNameLabelControl = (Label)sender;
// Retrieve the value to bind to the Label control. First,
// use the NamingContainer property to retrieve the parent
// control of the Label control. In this example, the parent
// control is the FormView control.
FormView formViewContainer = (FormView)firstNameLabelControl.NamingContainer;
// Get the data item bound to the FormView control.
DataRowView rowView = (DataRowView)formViewContainer.DataItem;
// Use the data item to retrieve the value of the FirstName field.
// Set the Text property of the Label control to this value.
firstNameLabelControl.Text = rowView["FirstName"].ToString();
}
// This event handler binds the value of the LastName field
// to the LastNameLabel Label control displayed in the template.
private void LastNameLabel_DataBinding(Object sender, EventArgs e)
{
// Use the sender parameter to retrieve the Label control
// being bound to data.
Label lastNameLabelControl = (Label)sender;
// Retrieve the value to bind to the Label control. First,
// use the NamingContainer property to retrieve the parent
// control of the Label control. In this example, the parent
// control is the FormView control.
FormView formViewContainer = (FormView)lastNameLabelControl.NamingContainer;
// Get the data item bound to the FormView control.
DataRowView rowView = (DataRowView)formViewContainer.DataItem;
// Use the data item to retrieve the value of the LastName field.
// Set the Text property of the Label control to this value.
lastNameLabelControl.Text = rowView["LastName"].ToString();
}
}
// This template class represents the edit item
// template for a FormView control.
private sealed class EmployeeEditItemTemplate : ITemplate
{
void ITemplate.InstantiateIn(Control container)
{
// Create the child controls contained in the template.
// The edit item template should contain the input
// controls for the user to edit a record.
TextBox firstNameTextBox = new TextBox();
firstNameTextBox.ID = "FirstNameTextBox";
LiteralControl nameLineBreak = new LiteralControl("<br/>");
LiteralControl buttonLineBreak = new LiteralControl("<br/>");
TextBox lastNameTextBox = new TextBox();
lastNameTextBox.ID = "LastNameTextBox";
Button updateButton = new Button();
updateButton.ID = "UpdateButton";
updateButton.CommandName = "Update";
updateButton.Text = "Update";
Button cancelButton = new Button();
cancelButton.ID = "CancelButton";
cancelButton.CommandName = "Cancel";
cancelButton.Text = "Cancel";
// Add the controls to the Controls collection of the
// container control.
container.Controls.Add(firstNameTextBox);
container.Controls.Add(nameLineBreak);
container.Controls.Add(lastNameTextBox);
container.Controls.Add(buttonLineBreak);
container.Controls.Add(updateButton);
container.Controls.Add(cancelButton);
}
}
void Page_Load(Object sender, EventArgs e)
{
// Create a new FormView object.
FormView employeesFormView = new FormView();
// Set the FormView object's properties.
employeesFormView.ID = "EmployeesFormView";
employeesFormView.DataSourceID = "EmployeeSource";
employeesFormView.AllowPaging = true;
employeesFormView.HeaderText = "Employee Name";
employeesFormView.DataKeyNames = new String[1] { "EmployeeID" };
// Programmatically register the event handlers for the
// FormView control.
employeesFormView.ItemUpdated += new FormViewUpdatedEventHandler(EmployeeFormView_ItemUpdated);
employeesFormView.ItemUpdating += new FormViewUpdateEventHandler(EmployeeFormView_ItemUpdating);
// Create the dynamic templates using the custom template classes.
employeesFormView.ItemTemplate = new EmployeeItemTemplate();
employeesFormView.EditItemTemplate = new EmployeeEditItemTemplate();
// Add the FormView object to the Controls collection
// of the PlaceHolder control.
FormViewPlaceHolder.Controls.Add(employeesFormView);
}
void EmployeeFormView_ItemUpdating(Object sender, FormViewUpdateEventArgs e)
{
// Because the FormView control is dynamically generated,
// the NewValues collection must be programmatically populated
// with the values for the record to update.
// Use the sender argument to retrieve the FormView
// control that raised the event.
FormView employeeFormView = (FormView)sender;
// Retrieve the data row from the FormView control.
FormViewRow row = employeeFormView.Row;
// Retrieve the TextBox controls that contain the updated values
// entered by the user.
TextBox firstNameTextBox = (TextBox)row.FindControl("FirstNameTextBox");
TextBox lastNameTextBox = (TextBox)row.FindControl("LastNameTextBox");
if (firstNameTextBox != null && lastNameTextBox != null)
{
// Add the new values to the NewValues collections.
e.NewValues.Add("FirstName", firstNameTextBox.Text);
e.NewValues.Add("LastName", lastNameTextBox.Text);
}
}
void EmployeeFormView_ItemUpdated(Object sender, FormViewUpdatedEventArgs e)
{
// Use the Exception property to determine whether an exception
// occurred during the update operation.
if (e.Exception == null)
{
// Use the AffectedRows property to determine whether the
// record was updated. Sometimes an error might occur that
// does not raise an exception, but prevents the update
// operation from completing.
if (e.AffectedRows == 1)
{
MessageLabel.Text = "Record updated successfully.";
}
else
{
MessageLabel.Text = "An error occurred during the update operation.";
// Use the KeepInUpdateMode property to keep the control in edit mode
// when an error occurs during the update operation.
e.KeepInEditMode = true;
}
}
else
{
// Insert the code to handle the exception.
MessageLabel.Text = e.Exception.Message;
// Use the ExceptionHandled property to indicate that the
// exception has already been handled.
e.ExceptionHandled = true;
e.KeepInEditMode = true;
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>FormView Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>FormView Example</h3>
<!-- Use a PlaceHolder control as the container for the -->
<!-- dynamically generated FormView control. -->
<asp:placeholder id="FormViewPlaceHolder"
runat="server"/>
<br/><br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="EmployeeSource"
selectcommand="Select [EmployeeID], [LastName], [FirstName] From [Employees]"
updatecommand="Update [Employees] Set [LastName]=@LastName, [FirstName]=@FirstName Where [EmployeeID]=@EmployeeID"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
<%@ Page language="VB" %>
<%@ import namespace="System.Data"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
' To dynamically create a template for a FormView control,
' you must create a custom template class to represent
' the template. This template class represents the item
' template for a FormView control.
Private NotInheritable Class EmployeeItemTemplate
Implements ITemplate
' When implementing the ITemplate interface, you must
' implement the InstantiateIn method. The FormView
' control calls this method to create the template's
' content.
Sub InstantiateIn(ByVal container As Control) Implements ITemplate.InstantiateIn
' Create the child controls contained in the template.
' For this example, the item template displays the
' FirstName and LastName fields from the data source.
' To support data binding, create event handlers
' for the DataBinding event of each child control.
' The event handlers must bind the appropriate value
' to each control.
Dim firstNameLabel As New Label()
firstNameLabel.ID = "FirstNameLabel"
AddHandler firstNameLabel.DataBinding, AddressOf FirstNameLabel_DataBinding
Dim nameLineBreak As New LiteralControl("<br/>")
Dim buttonLineBreak As New LiteralControl("<br/>")
Dim lastNameLabel As New Label()
lastNameLabel.ID = "LastNameLabel"
AddHandler lastNameLabel.DataBinding, AddressOf LastNameLabel_DataBinding
Dim editButton As New Button()
editButton.ID = "EditButton"
editButton.CommandName = "Edit"
editButton.Text = "Edit"
' Add the controls to the Controls collection of the
' container control.
container.Controls.Add(firstNameLabel)
container.Controls.Add(nameLineBreak)
container.Controls.Add(lastNameLabel)
container.Controls.Add(buttonLineBreak)
container.Controls.Add(editButton)
End Sub
' This event handler binds the value of the FirstName field
' to the FirstNameLabel Label control displayed in the template.
Private Sub FirstNameLabel_DataBinding(ByVal sender As Object, ByVal e As EventArgs)
' Use the sender parameter to retrieve the Label control
' being bound to data.
Dim firstNameLabelControl As Label = CType(sender, Label)
' Retrieve the value to bind to the Label control. First,
' use the NamingContainer property to retrieve the parent
' control of the Label control. In this example, the parent
' control is the FormView control.
Dim formViewContainer As FormView = CType(firstNameLabelControl.NamingContainer, FormView)
' Get the data item bound to the FormView control.
Dim rowView As DataRowView = CType(formViewContainer.DataItem, DataRowView)
' Use the data item to retrieve the value of the FirstName field.
' Set the Text property of the Label control to this value.
firstNameLabelControl.Text = rowView("FirstName").ToString()
End Sub
' This event handler binds the value of the LastName field
' to the LastNameLabel Label control displayed in the template.
Private Sub LastNameLabel_DataBinding(ByVal sender As Object, ByVal e As EventArgs)
' Use the sender parameter to retrieve the Label control
' being bound to data.
Dim lastNameLabelControl As Label = CType(sender, Label)
' Retrieve the value to bind to the Label control. First,
' use the NamingContainer property to retrieve the parent
' control of the Label control. In this example, the parent
' control is the FormView control.
Dim formViewContainer As FormView = CType(lastNameLabelControl.NamingContainer, FormView)
' Get the data item bound to the FormView control.
Dim rowView As DataRowView = CType(formViewContainer.DataItem, DataRowView)
' Use the data item to retrieve the value of the LastName field.
' Set the Text property of the Label control to this value.
lastNameLabelControl.Text = rowView("LastName").ToString()
End Sub
End Class
' This template class represents the edit item
' template for a FormView control.
Private NotInheritable Class EmployeeEditItemTemplate
Implements ITemplate
Sub InstantiateIn(ByVal container As Control) Implements ITemplate.InstantiateIn
' Create the child controls contained in the template.
' The edit item template should contain the input
' controls for the user to edit a record.
Dim firstNameTextBox As New TextBox()
firstNameTextBox.ID = "FirstNameTextBox"
Dim nameLineBreak As New LiteralControl("<br/>")
Dim buttonLineBreak As New LiteralControl("<br/>")
Dim lastNameTextBox As New TextBox()
lastNameTextBox.ID = "LastNameTextBox"
Dim updateButton As New Button()
updateButton.ID = "UpdateButton"
updateButton.CommandName = "Update"
updateButton.Text = "Update"
Dim cancelButton As New Button()
cancelButton.ID = "CancelButton"
cancelButton.CommandName = "Cancel"
cancelButton.Text = "Cancel"
' Add the controls to the Controls collection of the
' container control.
container.Controls.Add(firstNameTextBox)
container.Controls.Add(nameLineBreak)
container.Controls.Add(lastNameTextBox)
container.Controls.Add(buttonLineBreak)
container.Controls.Add(updateButton)
container.Controls.Add(cancelButton)
End Sub
End Class
Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
' Create a new FormView object.
Dim employeesFormView As New FormView()
' Set the FormView object's properties.
employeesFormView.ID = "EmployeesFormView"
employeesFormView.DataSourceID = "EmployeeSource"
employeesFormView.AllowPaging = True
employeesFormView.HeaderText = "Employee Name"
Dim keyArray() As String = {"EmployeeID"}
employeesFormView.DataKeyNames = keyArray
' Programmatically register the event handlers for the
' FormView control.
AddHandler employeesFormView.ItemUpdated, AddressOf EmployeeFormView_ItemUpdated
AddHandler employeesFormView.ItemUpdating, AddressOf EmployeeFormView_ItemUpdating
' Create the dynamic templates using the custom template classes.
employeesFormView.ItemTemplate = New EmployeeItemTemplate()
employeesFormView.EditItemTemplate = New EmployeeEditItemTemplate()
' Add the FormView object to the Controls collection
' of the PlaceHolder control.
FormViewPlaceHolder.Controls.Add(employeesFormView)
End Sub
Sub EmployeeFormView_ItemUpdating(ByVal sender As Object, ByVal e As FormViewUpdateEventArgs)
' Because the FormView control is dynamically generated,
' the NewValues collection must be programmatically populated
' with the values for the record to update.
' Use the sender argument to retrieve the FormView
' control that raised the event.
Dim employeeFormView As FormView = CType(sender, FormView)
' Retrieve the data row from the FormView control.
Dim row As FormViewRow = employeeFormView.Row
' Retrieve the TextBox controls that contain the updated values
' entered by the user.
Dim firstNameTextBox As TextBox = CType(row.FindControl("FirstNameTextBox"), TextBox)
Dim lastNameTextBox As TextBox = CType(row.FindControl("LastNameTextBox"), TextBox)
If firstNameTextBox IsNot Nothing And lastNameTextBox IsNot Nothing Then
' Add the new values to the NewValues collections.
e.NewValues.Add("FirstName", firstNameTextBox.Text)
e.NewValues.Add("LastName", lastNameTextBox.Text)
End If
End Sub
Sub EmployeeFormView_ItemUpdated(ByVal sender As Object, ByVal e As FormViewUpdatedEventArgs)
' Use the Exception property to determine whether an exception
' occurred during the update operation.
If e.Exception Is Nothing Then
' Use the AffectedRows property to determine whether the
' record was updated. Sometimes an error might occur that
' does not raise an exception, but prevents the update
' operation from completing.
If e.AffectedRows = 1 Then
MessageLabel.Text = "Record updated successfully."
Else
MessageLabel.Text = "An error occurred during the update operation."
' Use the KeepInUpdateMode property to keep the control in edit mode
' when an error occurs during the update operation.
e.KeepInEditMode = True
End If
Else
' Insert the code to handle the exception.
MessageLabel.Text = e.Exception.Message
' Use the ExceptionHandled property to indicate that the
' exception has already been handled.
e.ExceptionHandled = True
e.KeepInEditMode = True
End If
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>FormView Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>FormView Example</h3>
<!-- Use a PlaceHolder control as the container for the -->
<!-- dynamically generated FormView control. -->
<asp:placeholder id="FormViewPlaceHolder"
runat="server"/>
<br/><br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="EmployeeSource"
selectcommand="Select [EmployeeID], [LastName], [FirstName] From [Employees]"
updatecommand="Update [Employees] Set [LastName]=@LastName, [FirstName]=@FirstName Where [EmployeeID]=@EmployeeID"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
O exemplo a seguir demonstra como adicionar declarativamente um FormViewUpdateEventHandler delegado ao ItemUpdating evento de um FormView controle .
<%@ Page language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
void EmployeeFormView_ItemUpdating(Object sender, FormViewUpdateEventArgs e)
{
// Validate the field values entered by the user. This
// example determines whether the user left any fields
// empty. The names of the empty fields are added to
// an ArrayList object.
// Use the NewValues property to access the new
// values entered by the user.
ArrayList emptyFieldList = ValidateFields((OrderedDictionary)e.NewValues);
if (emptyFieldList.Count > 0)
{
// The user left some fields empty. Display an error message.
// Use the Keys property to retrieve the key field value.
String keyValue = e.Keys["EmployeeID"].ToString();
MessageLabel.Text = "You must enter a value for each field of record " +
keyValue + ".<br/>The following fields are missing:<br/><br/>";
// Display the missing fields.
foreach (String value in emptyFieldList)
{
// Use the OldValues property to access the original value
// of a field.
MessageLabel.Text += value + " - Original Value = " +
e.OldValues[value].ToString() + "<br />";
}
// Cancel the update operation.
e.Cancel = true;
}
else
{
// The field values passed validation. Clear the
// error message label.
MessageLabel.Text = "";
}
}
ArrayList ValidateFields(OrderedDictionary list)
{
// Create an ArrayList object to store the
// names of any empty fields.
ArrayList emptyFieldList = new ArrayList();
// Iterate though the field values entered by
// the user and check for an empty field.
foreach (DictionaryEntry entry in list)
{
if (entry.Value.Equals(""))
{
// Add the field name to the ArrayList object.
emptyFieldList.Add(entry.Key.ToString());
}
}
return emptyFieldList;
}
void EmployeeFormView_ModeChanged(Object sender, EventArgs e)
{
// Clear the error message label.
MessageLabel.Text = "";
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>FormViewUpdateEventArgs Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>FormViewUpdateEventArgs Example</h3>
<asp:formview id="EmployeeFormView"
datasourceid="EmployeeSource"
allowpaging="true"
datakeynames="EmployeeID"
emptydatatext="No employees found."
onitemupdating="EmployeeFormView_ItemUpdating"
onmodechanged="EmployeeFormView_ModeChanged"
runat="server">
<itemtemplate>
<table>
<tr>
<td rowspan="6">
<asp:image id="EmployeeImage"
imageurl='<%# Eval("PhotoPath") %>'
alternatetext='<%# Eval("LastName") %>'
runat="server"/>
</td>
<td colspan="2">
</td>
</tr>
<tr>
<td>
<b>Name:</b>
</td>
<td>
<%# Eval("FirstName") %> <%# Eval("LastName") %>
</td>
</tr>
<tr>
<td>
<b>Title:</b>
</td>
<td>
<%# Eval("Title") %>
</td>
</tr>
<tr style="height:150" valign="top">
<td>
<b>Address:</b>
</td>
<td>
<%# Eval("Address") %><br/>
<%# Eval("City") %> <%# Eval("Region") %>
<%# Eval("PostalCode") %><br/>
<%# Eval("Country") %>
</td>
</tr>
<tr>
<td colspan="2">
<asp:linkbutton id="Edit"
text="Edit"
commandname="Edit"
runat="server"/>
</td>
</tr>
</table>
</itemtemplate>
<edititemtemplate>
<table>
<tr>
<td rowspan="6">
<asp:image id="EmployeeEditImage"
imageurl='<%# Eval("PhotoPath") %>'
alternatetext='<%# Eval("LastName") %>'
runat="server"/>
</td>
<td colspan="2">
</td>
</tr>
<tr>
<td>
<b><asp:Label runat="server"
AssociatedControlID="FirstNameUpdateTextBox"
Text="Name" />:</b>
</td>
<td>
<asp:textbox id="FirstNameUpdateTextBox"
text='<%# Bind("FirstName") %>'
accesskey="n" tabindex="1" runat="server"/>
<asp:textbox id="LastNameUpdateTextBox"
text='<%# Bind("LastName") %>'
accesskey="l" tabindex="2" runat="server"/>
</td>
</tr>
<tr>
<td>
<b><asp:Label runat="server"
AssociatedControlID="TitleUpdateTextBox"
Text="Title" />:</b>
</td>
<td>
<asp:textbox id="TitleUpdateTextBox"
text='<%# Bind("Title") %>'
accesskey="t" tabindex="3" runat="server"/>
</td>
</tr>
<tr>
<b><asp:Label runat="server"
AssociatedControlID="HireDateUpdateTextBox"
Text="Hire Date" />:</b>
<td>
<asp:textbox id="HireDateUpdateTextBox"
text='<%# Bind("HireDate", "{0:d}") %>'
accesskey="h" tabindex="4" runat="server" />
</td>
</tr>
<tr style="height:150" valign="top">
<td>
<b><asp:Label runat="server"
AssociatedControlID="AddressUpdateTextBox"
Text="Address" />:</b>
</td>
<td>
<asp:textbox id="AddressUpdateTextBox"
text='<%# Bind("Address") %>'
accesskey="a" tabindex="5" runat="server"/>
<br/>
<asp:textbox id="CityUpdateTextBox"
text='<%# Bind("City") %>'
accesskey="c" tabindex="6" runat="server"/>
<asp:textbox id="RegionUpdateTextBox"
text='<%# Bind("Region") %>'
width="40"
accesskey="r" tabindex="7" runat="server"/>
<asp:textbox id="PostalCodeUpdateTextBox"
text='<%# Bind("PostalCode") %>'
width="60"
accesskey="p" tabindex="8" runat="server"/>
<br/>
<asp:textbox id="CountryUpdateTextBox"
text='<%# Bind("Country") %>'
accesskey="u" tabindex="9" runat="server"/>
</td>
</tr>
<tr>
<td colspan="2">
<asp:linkbutton id="UpdateButton"
text="Update" tabindex="10"
commandname="Update"
runat="server"/>
<asp:linkbutton id="CancelButton"
text="Cancel" tabindex="11"
commandname="Cancel"
runat="server"/>
</td>
</tr>
</table>
</edititemtemplate>
</asp:formview>
<br/><br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="EmployeeSource"
selectcommand="Select [EmployeeID], [LastName], [FirstName], [Title], [Address], [City], [Region], [PostalCode], [Country], [HireDate], [PhotoPath] From [Employees]"
updatecommand="Update [Employees] Set [LastName]=@LastName, [FirstName]=@FirstName, [Title]=@Title, [Address]=@Address, [City]=@City, [Region]=@Region, [PostalCode]=@PostalCode, [Country]=@Country Where [EmployeeID]=@EmployeeID"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
<%@ Page language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Sub EmployeeFormView_ItemUpdating(ByVal sender As Object, ByVal e As FormViewUpdateEventArgs) Handles EmployeeFormView.ItemUpdating
' Validate the field values entered by the user. This
' example determines whether the user left any fields
' empty. The names of the empty fields are added to
' an ArrayList object.
' Use the NewValues property to access the new
' values entered by the user.
Dim emptyFieldList As ArrayList = ValidateFields(CType(e.NewValues, OrderedDictionary))
If emptyFieldList.Count > 0 Then
' The user left some fields empty. Display an error message.
' Use the Keys property to retrieve the key field value.
Dim keyValue As String = e.Keys("EmployeeID").ToString()
MessageLabel.Text = "You must enter a value for each field of record " & _
keyValue & ".<br/>The following fields are missing:<br/><br/>"
' Display the missing fields.
Dim value As String
For Each value In emptyFieldList
' Use the OldValues property access the original value
' of a field.
MessageLabel.Text &= value & " - Original Value = " & _
e.OldValues(value).ToString() & "<br />"
Next
' Cancel the update operation.
e.Cancel = True
Else
' The field values passed validation. Clear the
' error message label.
MessageLabel.Text = ""
End If
End Sub
Function ValidateFields(ByVal list As OrderedDictionary) As ArrayList
' Create an ArrayList object to store the
' names of any empty fields.
Dim emptyFieldList As New ArrayList()
' Iterate though the field values entered by
' the user and check for an empty field.
Dim entry As DictionaryEntry
For Each entry In list
If entry.Value.Equals("") Then
' Add the field name to the ArrayList object.
emptyFieldList.Add(entry.Key.ToString())
End If
Next
Return emptyFieldList
End Function
Sub EmployeeFormView_ModeChanged(ByVal sender As Object, ByVal e As EventArgs) Handles EmployeeFormView.ModeChanged
' Clear the error message label.
MessageLabel.Text = ""
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>FormViewUpdateEventArgs Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>FormViewUpdateEventArgs Example</h3>
<asp:formview id="EmployeeFormView"
datasourceid="EmployeeSource"
allowpaging="true"
datakeynames="EmployeeID"
emptydatatext="No employees found."
runat="server">
<itemtemplate>
<table>
<tr>
<td rowspan="6">
<asp:image id="EmployeeImage"
imageurl='<%# Eval("PhotoPath") %>'
alternatetext='<%# Eval("LastName") %>'
runat="server"/>
</td>
<td colspan="2">
</td>
</tr>
<tr>
<td>
<b>Name:</b>
</td>
<td>
<%# Eval("FirstName") %> <%# Eval("LastName") %>
</td>
</tr>
<tr>
<td>
<b>Title:</b>
</td>
<td>
<%# Eval("Title") %>
</td>
</tr>
<tr style="height:150" valign="top">
<td>
<b>Address:</b>
</td>
<td>
<%# Eval("Address") %><br/>
<%# Eval("City") %> <%# Eval("Region") %>
<%# Eval("PostalCode") %><br/>
<%# Eval("Country") %>
</td>
</tr>
<tr>
<td colspan="2">
<asp:linkbutton id="Edit"
text="Edit"
commandname="Edit"
runat="server"/>
</td>
</tr>
</table>
</itemtemplate>
<edititemtemplate>
<table>
<tr>
<td rowspan="6">
<asp:image id="EmployeeEditImage"
imageurl='<%# Eval("PhotoPath") %>'
alternatetext='<%# Eval("LastName") %>'
runat="server"/>
</td>
<td colspan="2">
</td>
</tr>
<tr>
<td>
<b><asp:Label runat="server"
AssociatedControlID="FirstNameUpdateTextBox"
Text="Name" />:</b>
</td>
<td>
<asp:textbox id="FirstNameUpdateTextBox"
text='<%# Bind("FirstName") %>'
accesskey="n" tabindex="1" runat="server"/>
<asp:textbox id="LastNameUpdateTextBox"
text='<%# Bind("LastName") %>'
accesskey="l" tabindex="2" runat="server"/>
</td>
</tr>
<tr>
<td>
<b><asp:Label runat="server"
AssociatedControlID="TitleUpdateTextBox"
Text="Title" />:</b>
</td>
<td>
<asp:textbox id="TitleUpdateTextBox"
text='<%# Bind("Title") %>'
accesskey="t" tabindex="3" runat="server"/>
</td>
</tr>
<tr>
<b><asp:Label runat="server"
AssociatedControlID="HireDateUpdateTextBox"
Text="Hire Date" />:</b>
<td>
<asp:textbox id="HireDateUpdateTextBox"
text='<%# Bind("HireDate", "{0:d}") %>'
accesskey="h" tabindex="4" runat="server" />
</td>
</tr>
<tr style="height:150" valign="top">
<td>
<b><asp:Label runat="server"
AssociatedControlID="AddressUpdateTextBox"
Text="Address" />:</b>
</td>
<td>
<asp:textbox id="AddressUpdateTextBox"
text='<%# Bind("Address") %>'
accesskey="a" tabindex="5" runat="server"/>
<br/>
<asp:textbox id="CityUpdateTextBox"
text='<%# Bind("City") %>'
accesskey="c" tabindex="6" runat="server"/>
<asp:textbox id="RegionUpdateTextBox"
text='<%# Bind("Region") %>'
width="40"
accesskey="r" tabindex="7" runat="server"/>
<asp:textbox id="PostalCodeUpdateTextBox"
text='<%# Bind("PostalCode") %>'
width="60"
accesskey="p" tabindex="8" runat="server"/>
<br/>
<asp:textbox id="CountryUpdateTextBox"
text='<%# Bind("Country") %>'
accesskey="u" tabindex="9" runat="server"/>
</td>
</tr>
<tr>
<td colspan="2">
<asp:linkbutton id="UpdateButton"
text="Update" tabindex="10"
commandname="Update"
runat="server"/>
<asp:linkbutton id="CancelButton"
text="Cancel" tabindex="11"
commandname="Cancel"
runat="server"/>
</td>
</tr>
</table>
</edititemtemplate>
</asp:formview>
<br/><br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="EmployeeSource"
selectcommand="Select [EmployeeID], [LastName], [FirstName], [Title], [Address], [City], [Region], [PostalCode], [Country], [HireDate], [PhotoPath] From [Employees]"
updatecommand="Update [Employees] Set [LastName]=@LastName, [FirstName]=@FirstName, [Title]=@Title, [Address]=@Address, [City]=@City, [Region]=@Region, [PostalCode]=@PostalCode, [Country]=@Country Where [EmployeeID]=@EmployeeID"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
Comentários
O FormView controle aciona o ItemUpdating evento quando um botão Atualizar (um botão com sua CommandName propriedade definida como "Atualização") dentro do controle é clicado, mas antes que o FormView controle atualize o registro. Isso permite que você forneça um método de manipulação de eventos que executa uma rotina personalizada, como codificação HTML ou validação dos valores de um registro antes de atualizá-lo na fonte de dados, sempre que esse evento ocorrer.
Ao criar um FormViewUpdateEventHandler delegado, você identifica o método que manipulará o evento. Para associar o evento ao manipulador de eventos, adicione uma instância do delegado ao evento. O manipulador de eventos é chamado sempre que o evento ocorre, a menos que você remova o representante. Para obter mais informações sobre delegados do manipulador de eventos, consulte Manipulando e gerando eventos.
Métodos de Extensão
| GetMethodInfo(Delegate) |
Obtém um objeto que representa o método representado pelo delegado especificado. |
Aplica-se a
Confira também
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