GridViewCancelEditEventHandler Delegado

  • Referencia

Definición

Espacio de nombres:
System.Web.UI.WebControls
Ensamblado:
System.Web.dll

Representa el método que controla el evento RowCancelingEdit de un control GridView.

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

Parámetros

sender
Object

Origen del evento.

e
GridViewCancelEditEventArgs

Objeto GridViewCancelEditEventArgs que contiene los datos del evento.

Ejemplos

En el ejemplo siguiente se muestra cómo agregar mediante programación un GridViewCancelEditEventHandler delegado al RowCancelingEdit evento de un GridView control.


<%@ 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 Page_Load(Object sender, EventArgs e)
  {
        
    // Create a new GridView object.
    GridView customerGridView = new GridView();
         
    // Set the GridView object's properties.
    customerGridView.ID = "CustomersGridView";
    customerGridView.DataSourceID = "CustomersSqlDataSource";
    customerGridView.AutoGenerateColumns = true;
    customerGridView.AutoGenerateEditButton = true;
    customerGridView.DataKeyNames = new String[] { "CustomerID" };
        
    // Programmatically register the event-handling methods.
    customerGridView.RowCancelingEdit += new GridViewCancelEditEventHandler(this.CustomersGridView_RowCancelingEdit);
    customerGridView.RowUpdated += new GridViewUpdatedEventHandler(this.CustomersGridView_RowUpdated);
        
    // Add the GridView object to the Controls collection
    // of the PlaceHolder control.
    GridViewPlaceHolder.Controls.Add(customerGridView);
        
  }

  void CustomersGridView_RowCancelingEdit(Object sender, GridViewCancelEditEventArgs e)
  {
    
    // Display a message indicating that the update operation was canceled.
    Message.Text = "Update for row " + e.RowIndex.ToString() + " canceled."; 
    
  }

  void CustomersGridView_RowUpdated(Object sender, GridViewUpdatedEventArgs e)
  {

    // The update operation was successful. Clear the message label.
    Message.Text = "";

  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewCancelEditEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewCancelEditEventHandler Example</h3>
            
      <asp:label id="Message"
        forecolor="Red"
        runat="server"/>
                
      <br/>
            
      <asp:placeholder id="GridViewPlaceHolder"
        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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </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 Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        
    ' Create a new GridView object.
    Dim customerGridView As New GridView()
         
    ' Set the GridView object's properties.
    customerGridView.ID = "CustomersGridView"
    customerGridView.DataSourceID = "CustomersSqlDataSource"
    customerGridView.AutoGenerateColumns = True
    customerGridView.AutoGenerateEditButton = True
    customerGridView.DataKeyNames = New [String]() {"CustomerID"}
        
    ' Programmatically register the event-handling methods.
    AddHandler customerGridView.RowCancelingEdit, AddressOf CustomersGridView_RowCancelingEdit
    AddHandler customerGridView.RowUpdated, AddressOf CustomersGridView_RowUpdated
        
    ' Add the GridView object to the Controls collection
    ' of the PlaceHolder control.
    GridViewPlaceHolder.Controls.Add(customerGridView)
        
  End Sub
    
  Sub CustomersGridView_RowCancelingEdit(ByVal sender As Object, ByVal e As GridViewCancelEditEventArgs)
    
    ' Display a message indicating that the update operation was canceled.
    Message.Text = "Update for row " + e.RowIndex.ToString() + " canceled."
    
  End Sub
    
  Sub CustomersGridView_RowUpdated(ByVal sender As Object, ByVal e As GridViewUpdatedEventArgs)

    ' The update operation was successful. Clear the message label.
    Message.Text = ""

  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewCancelEditEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewCancelEditEventHandler Example</h3>
            
      <asp:label id="Message"
        forecolor="Red"
        runat="server"/>
                
      <br/>
            
      <asp:placeholder id="GridViewPlaceHolder"
        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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>

En el ejemplo siguiente se muestra cómo agregar mediante declaración un GridViewCancelEditEventHandler delegado al RowCancelingEdit evento de un GridView control.


<%@ 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 CustomersGridView_RowCancelingEdit(Object sender, GridViewCancelEditEventArgs e)
  {
    
    // Retrieve the row that raised the event from the Rows
    // collection of the GridView control.
    GridViewRow row = CustomersGridView.Rows[e.RowIndex];
    
    // The update operation was canceled. Display the 
    // primary key of the row. In this example, the primary
    // key is displayed in the second column of the GridView
    // control. To access the text of the column, use the Cells
    // collection of the row.
    Message.Text = "Update for item " + row.Cells[1].Text + " Canceled."; 
    
  }

  void CustomersGridView_RowEditing(Object sender, GridViewEditEventArgs e)
  {

    // The GridView control is entering edit mode. Clear the message label.
    Message.Text = "";

  }
  
  void CustomersGridView_RowUpdated(Object sender, GridViewUpdatedEventArgs e)
  {

    // The update operation was successful. Clear the message label.
    Message.Text = "";

  }
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridView RowCancelingEdit Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridView RowCancelingEdit Example</h3>
            
      <asp:label id="Message"
        forecolor="Red"
        runat="server"/>
                
      <br/>
      
      <!-- The GridView control automatically sets the columns     -->
      <!-- specified in the datakeynames attribute as read-only.   -->
      <!-- No input controls are rendered for these columns in     -->
      <!-- edit mode.                                              -->
      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSqlDataSource" 
        autogeneratecolumns="true"
        autogenerateeditbutton="true"
        allowpaging="true" 
        datakeynames="CustomerID"
        onrowcancelingedit="CustomersGridView_RowCancelingEdit"
        onrowediting="CustomersGridView_RowEditing" 
        onrowupdated="CustomersGridView_RowUpdated"    
        runat="server">
      </asp:gridview>
            
      <!-- 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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </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 CustomersGridView_RowCancelingEdit(ByVal sender As Object, ByVal e As GridViewCancelEditEventArgs)
    
    ' Retrieve the row that raised the event from the Rows
    ' collection of the GridView control.
    Dim row As GridViewRow = CustomersGridView.Rows(e.RowIndex)
    
    ' The update operation was canceled. Display the 
    ' primary key of the row. In this example, the primary
    ' key is displayed in the second column of the GridView
    ' control. To access the text of the column, use the Cells
    ' collection of the row.
    Message.Text = "Update for item " & row.Cells(1).Text & " Canceled."
    
  End Sub

  Sub CustomersGridView_RowEditing(ByVal sender As Object, ByVal e As GridViewEditEventArgs)

    ' The GridView control is entering edit mode. Clear the message label.
    Message.Text = ""

  End Sub
  
  Sub CustomersGridView_RowUpdated(ByVal sender As Object, ByVal e As GridViewUpdatedEventArgs)
    
    ' The update operation was successful. Clear the message label.
    Message.Text = ""

  End Sub
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridView RowCancelingEdit Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridView RowCancelingEdit Example</h3>
            
      <asp:label id="Message"
        forecolor="Red"
        runat="server"/>
                
      <br/>
      
      <!-- The GridView control automatically sets the columns     -->
      <!-- specified in the datakeynames attribute as read-only.   -->
      <!-- No input controls are rendered for these columns in     -->
      <!-- edit mode.                                              -->
      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSqlDataSource" 
        autogeneratecolumns="true"
        autogenerateeditbutton="true"
        allowpaging="true" 
        datakeynames="CustomerID"
        onrowcancelingedit="CustomersGridView_RowCancelingEdit"
        onrowediting="CustomersGridView_RowEditing" 
        onrowupdated="CustomersGridView_RowUpdated"    
        runat="server">
      </asp:gridview>
            
      <!-- 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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>

Comentarios

El RowCancelingEdit evento se genera cuando se hace clic en el botón Cancelar de una fila en modo de edición, pero antes de que la fila salga del modo de edición. Esto le permite proporcionar un método de control de eventos que realice una rutina personalizada, como detener la operación de cancelación si colocaría la fila en un estado no deseado, siempre que se produzca este evento.

Cuando se crea un delegado GridViewCancelEditEventHandler, 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