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FormViewModeEventHandler Delegado

Definición

Representa el método que controla el evento ModeChanging de un control FormView.

public delegate void FormViewModeEventHandler(System::Object ^ sender, FormViewModeEventArgs ^ e);
public delegate void FormViewModeEventHandler(object sender, FormViewModeEventArgs e);
type FormViewModeEventHandler = delegate of obj * FormViewModeEventArgs -> unit
Public Delegate Sub FormViewModeEventHandler(sender As Object, e As FormViewModeEventArgs)

Parámetros

sender
Object

Origen del evento.

e
FormViewModeEventArgs

Objeto FormViewModeEventArgs que contiene los datos del evento.

Ejemplos

En el ejemplo siguiente se muestra cómo agregar mediante programación un FormViewModeEventHandler delegado al ModeChanging evento de un FormView control.

Importante

El control de este ejemplo tiene un cuadro de texto que acepta la entrada del usuario, que es una amenaza de seguridad potencial. De forma predeterminada, ASP.NET Web Pages valida que los datos proporcionados por el usuario no incluyen elementos HTML ni de script. Para más información, consulte Información general sobre los ataques mediante scripts.


<%@ 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 
    // the FormView control.
    employeesFormView.ModeChanging += new FormViewModeEventHandler(EmployeeFormView_ModeChanging);
    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_ModeChanging(Object sender, FormViewModeEventArgs e)
  {

    // Use the sender argument to retrieve the FormView
    // control that raised the event.
    FormView employeeFormView = (FormView)sender;

    // Use the NewMode property to determine the mode to which the 
    // FormView control is transitioning.
    switch (e.NewMode)
    {
      case FormViewMode.Edit:
        // Hide the pager row and clear the Label control
        // when transitioning to edit mode.
        employeeFormView.AllowPaging = false;
        MessageLabel.Text = "";
        break;
      case FormViewMode.ReadOnly:
        // Display the pager row and confirmation message
        // when transitioning to edit mode.
        employeeFormView.AllowPaging = true;
        if (e.CancelingEdit)
        {
          MessageLabel.Text = "Update canceled.";
        }
        else
        {
          MessageLabel.Text = "Update completed.";
        }
        break;
      case FormViewMode.Insert:
        // Cancel the mode change if the FormView
        // control attempts to transition to insert 
        // mode.
        e.Cancel = true;
        break;
      default:
        MessageLabel.Text = "Unsupported mode.";
        break;
    }

  }

</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 
    ' the FormView control.
    AddHandler employeesFormView.ModeChanging, AddressOf EmployeeFormView_ModeChanging
    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_ModeChanging(ByVal sender As Object, ByVal e As FormViewModeEventArgs)

    ' Use the sender argument to retrieve the FormView
    ' control that raised the event.
    Dim employeeFormView As FormView = CType(sender, FormView)
    
    ' Use the NewMode property to determine the mode to which the 
    ' FormView control is transitioning.
    Select Case e.NewMode
   
      Case FormViewMode.Edit
        ' Hide the pager row and clear the Label control
        ' when transitioning to edit mode.
        employeeFormView.AllowPaging = False
        MessageLabel.Text = ""

      Case FormViewMode.ReadOnly
        ' Display the pager row and confirmation message
        ' when transitioning to edit mode.
        employeeFormView.AllowPaging = True
        If e.CancelingEdit Then
        
          MessageLabel.Text = "Update canceled."
        
        Else
        
          MessageLabel.Text = "Update completed."
        
        End If
        
      Case FormViewMode.Insert
        ' Cancel the mode change if the FormView
        ' control attempts to transition to insert 
        ' mode.
        e.Cancel = True

      Case Else
        MessageLabel.Text = "Unsupported mode."

    End Select

  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>

En el ejemplo siguiente se muestra cómo agregar mediante declaración un FormViewModeEventHandler delegado al ModeChanging evento de un FormView control.

Importante

El control de este ejemplo tiene un cuadro de texto que acepta la entrada del usuario, que es una amenaza de seguridad potencial. De forma predeterminada, ASP.NET Web Pages valida que los datos proporcionados por el usuario no incluyen elementos HTML ni de script. Para más información, consulte Información general sobre los ataques mediante scripts.


<%@ 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_ModeChanging(Object sender, FormViewModeEventArgs e)
  {

    // Use the NewMode property to determine the mode to which the 
    // FormView control is transitioning.
    switch (e.NewMode)
    {
      case FormViewMode.Edit:
        // Hide the pager row and clear the Label control
        // when transitioning to edit mode.
        EmployeeFormView.AllowPaging = false;
        MessageLabel.Text = "";
        break;
      case FormViewMode.ReadOnly:
        // Display the pager row and confirmation message
        // when transitioning to edit mode.
        EmployeeFormView.AllowPaging = true;
        if (e.CancelingEdit)
        {
          MessageLabel.Text = "Update canceled.";
        }
        else
        {
          MessageLabel.Text = "Update completed.";
        }
        break;
      case FormViewMode.Insert:
        // Cancel the mode change if the FormView
        // control attempts to transition to insert 
        // mode.
        e.Cancel = true;
        break;
      default:
        MessageLabel.Text = "Unsupported mode.";
        break;
    }

  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>FormViewModeEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>FormViewModeEventArgs Example</h3>
                       
      <asp:formview id="EmployeeFormView"
        datasourceid="EmployeeSource"
        allowpaging="true"
        datakeynames="EmployeeID"
        emptydatatext="No employees found."
        onmodechanging="EmployeeFormView_ModeChanging"  
        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>
              <td>
                <b>Hire Date:</b>                 
              </td>
              <td>
                <%# Eval("HireDate","{0:d}") %>
              </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_ModeChanging(ByVal sender As Object, ByVal e As FormViewModeEventArgs)

    ' Use the NewMode property to determine the mode to which the 
    ' FormView control is transitioning.
    Select Case e.NewMode
   
      Case FormViewMode.Edit
        ' Hide the pager row and clear the Label control
        ' when transitioning to edit mode.
        EmployeeFormView.AllowPaging = False
        MessageLabel.Text = ""

      Case FormViewMode.ReadOnly
        ' Display the pager row and confirmation message
        ' when transitioning to edit mode.
        EmployeeFormView.AllowPaging = True
        If e.CancelingEdit Then
        
          MessageLabel.Text = "Update canceled."
        
        Else
        
          MessageLabel.Text = "Update completed."
        
        End If
        
      Case FormViewMode.Insert
        ' Cancel the mode change if the FormView
        ' control attempts to transition to insert 
        ' mode.
        e.Cancel = True

      Case Else
        MessageLabel.Text = "Unsupported mode."

    End Select

  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>FormViewModeEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>FormViewModeEventArgs Example</h3>
                       
      <asp:formview id="EmployeeFormView"
        datasourceid="EmployeeSource"
        allowpaging="true"
        datakeynames="EmployeeID"
        emptydatatext="No employees found."
        onmodechanging="EmployeeFormView_ModeChanging"  
        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>
              <td>
                <b>Hire Date:</b>                 
              </td>
              <td>
                <%# Eval("HireDate","{0:d}") %>
              </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>

Comentarios

El ModeChanging evento se genera cuando un FormView control intenta cambiar entre el modo de edición, inserción y solo lectura, pero antes de que el modo cambie realmente. Esto le permite proporcionar un método de control de eventos que realiza una rutina personalizada, como configurar el FormView control para un modo específico o cancelar el cambio de modo, siempre que se produzca este evento.

Cuando se crea un delegado FormViewModeEventHandler, se identifica el método que controlará el evento. Para asociar el evento al controlador, se debe agregar una instancia del delegado al evento. Siempre que se produce el evento, se llama a su controlador, a menos que se quite el delegado. Para obtener más información sobre los delegados del controlador de eventos, consulte Control y generación de eventos.

Métodos de extensión

GetMethodInfo(Delegate)

Obtiene un objeto que representa el método representado por el delegado especificado.

Se aplica a

Consulte también