GridViewPageEventHandler Delegado

Referencia

Definición

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

Ensamblado:: System.Web.dll

Importante

Parte de la información hace referencia a la versión preliminar del producto, que puede haberse modificado sustancialmente antes de lanzar la versión definitiva. Microsoft no otorga ninguna garantía, explícita o implícita, con respecto a la información proporcionada aquí.

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

public delegate void GridViewPageEventHandler(System::Object ^ sender, GridViewPageEventArgs ^ e);

public delegate void GridViewPageEventHandler(object sender, GridViewPageEventArgs e);

type GridViewPageEventHandler = delegate of obj * GridViewPageEventArgs -> unit

Public Delegate Sub GridViewPageEventHandler(sender As Object, e As GridViewPageEventArgs)

Parámetros

sender: Object

Origen del evento.

e: GridViewPageEventArgs

Objeto GridViewPageEventArgs que contiene los datos del evento.

Ejemplos

En el ejemplo siguiente se muestra cómo agregar mediante programación un GridViewPageEventHandler delegado al PageIndexChanging 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 control.
    GridView customersGridView = new GridView();

    // Set the GridView object's properties.
    customersGridView.ID = "CustomersGridView";
    customersGridView.DataSourceID = "CustomersSource";
    customersGridView.AutoGenerateColumns = true;
    customersGridView.EmptyDataText = "No data available.";
    customersGridView.AllowPaging = true;
    customersGridView.AutoGenerateEditButton = true;
    customersGridView.PagerSettings.Mode = PagerButtons.Numeric;
    customersGridView.PagerSettings.Position = PagerPosition.Bottom;
    customersGridView.PagerSettings.PageButtonCount = 10;
    customersGridView.PagerStyle.BackColor = System.Drawing.Color.LightBlue;
    customersGridView.DataKeyNames = new String[] { "CustomerID" };

    // Programmatically register the event-handling methods.
    customersGridView.PageIndexChanging += new GridViewPageEventHandler(this.CustomersGridView_PageIndexChanging);
    customersGridView.RowCancelingEdit += new GridViewCancelEditEventHandler(this.CustomersGridView_RowCancelingEdit);

    // Add the GridView control to the Controls collection
    // of the PlaceHolder control.
    GridViewPlaceHolder.Controls.Add(customersGridView);
    
  }          

  void CustomersGridView_PageIndexChanging(Object sender, GridViewPageEventArgs e)
  {

    // User the sender parameter to retrieve the GridView control
    // that raised the event.
    GridView customersGridView = (GridView)sender;
    
    // Cancel the paging operation if the user attempts to navigate
    // to another page while the GridView control is in edit mode. 
    if (customersGridView.EditIndex != -1)
    {
      // Use the cancel property to cancel the paging operation.
      e.Cancel = true;
      
      // Display an error message.
      int newPageNumber = e.NewPageIndex + 1;
      Message.Text = "Please update the record before moving to page " +
        newPageNumber.ToString() + ".";
    }
    else
    {
      // Clear the error message.
      Message.Text = "";
    }
    
  }

  void CustomersGridView_RowCancelingEdit(Object sender, GridViewCancelEditEventArgs e)
  {
    // Clear the error message.
    Message.Text = "";
  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewPageEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewPageEventHandler 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="CustomersSource"
        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"/>
            
    </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 control.
    Dim customersGridView As New GridView()

    ' Set the GridView object's properties.
    customersGridView.ID = "CustomersGridView"
    customersGridView.DataSourceID = "CustomersSource"
    customersGridView.AutoGenerateColumns = True
    customersGridView.EmptyDataText = "No data available."
    customersGridView.AllowPaging = True
    customersGridView.AutoGenerateEditButton = True
    customersGridView.PagerSettings.Mode = PagerButtons.Numeric
    customersGridView.PagerSettings.Position = PagerPosition.Bottom
    customersGridView.PagerSettings.PageButtonCount = 10
    customersGridView.PagerStyle.BackColor = System.Drawing.Color.LightBlue
    Dim keyArray() As String = {"CustomerID"}
    customersGridView.DataKeyNames = keyArray

    ' Programmatically register the event-handling methods.
    AddHandler customersGridView.PageIndexChanging, AddressOf CustomersGridView_PageIndexChanging
    AddHandler customersGridView.RowCancelingEdit, AddressOf CustomersGridView_RowCancelingEdit

    ' Add the GridView control to the Controls collection
    ' of the PlaceHolder control.
    GridViewPlaceHolder.Controls.Add(customersGridView)
    
  End Sub

  Sub CustomersGridView_PageIndexChanging(ByVal sender As Object, ByVal e As GridViewPageEventArgs)

    ' User the sender parameter to retrieve the GridView control
    ' that raised the event.
    Dim customersGridView As GridView = CType(sender, GridView)
    
    ' Cancel the paging operation if the user attempts to navigate
    ' to another page while the GridView control is in edit mode. 
    If customersGridView.EditIndex <> -1 Then
    
      ' Use the cancel property to cancel the paging operation.
      e.Cancel = True
      
      ' Display an error message.
      Dim newPageNumber As Integer = e.NewPageIndex + 1
      Message.Text = "Please update the record before moving to page " & _
        newPageNumber.ToString() & "."
    
    Else
    
      ' Clear the error message.
      Message.Text = ""
    
    End If
    
  End Sub

  Sub CustomersGridView_RowCancelingEdit(ByVal sender As Object, ByVal e As GridViewCancelEditEventArgs)
  
    ' Clear the error message.
    Message.Text = ""
    
  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewPageEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewPageEventHandler 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="CustomersSource"
        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"/>
            
    </form>
  </body>
</html>

En el ejemplo siguiente se muestra cómo agregar mediante declaración un GridViewPageEventHandler delegado al PageIndexChanging 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_PageIndexChanging(Object sender, GridViewPageEventArgs e)
  {
    
    // Cancel the paging operation if the user attempts to navigate
    // to another page while the GridView control is in edit mode. 
    if (CustomersGridView.EditIndex != -1)
    {
      // Use the Cancel property to cancel the paging operation.
      e.Cancel = true;
      
      // Display an error message.
      int newPageNumber = e.NewPageIndex + 1;
      Message.Text = "Please update the record before moving to page " +
        newPageNumber.ToString() + ".";
    }
    else
    {
      // Clear the error message.
      Message.Text = "";
    }
    
  }

  void CustomersGridView_RowCancelingEdit(Object sender, GridViewCancelEditEventArgs e)
  {
    // Clear the error message.
    Message.Text = "";
  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridView PageIndexChanging Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridView PageIndexChanging Example</h3>
            
      <asp:label id="Message"
        forecolor="Red"
        runat="server"/>
                
      <br/>  

      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSource" 
        autogeneratecolumns="true"
        emptydatatext="No data available." 
        allowpaging="true"
        autogenerateeditbutton="true"
        datakeynames="CustomerID"  
        onpageindexchanging="CustomersGridView_PageIndexChanging"
        onrowcancelingedit="CustomersGridView_RowCancelingEdit" 
        runat="server">
                
        <pagersettings mode="Numeric"
          position="Bottom"           
          pagebuttoncount="10"/>
                      
        <pagerstyle backcolor="LightBlue"/>
                
      </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="CustomersSource"
        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"/>
            
    </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_PageIndexChanging(ByVal sender As Object, ByVal e As GridViewPageEventArgs)
    
    ' Cancel the paging operation if the user attempts to navigate
    ' to another page while the GridView control is in edit mode. 
    If CustomersGridView.EditIndex <> -1 Then
    
      ' Use the Cancel property to cancel the paging operation.
      e.Cancel = True
      
      ' Display an error message.
      Dim newPageNumber As Integer = e.NewPageIndex + 1
      Message.Text = "Please update the record before moving to page " & _
        newPageNumber.ToString() & "."
    
    Else
    
      ' Clear the error message.
      Message.Text = ""
    
    End If
    
  End Sub

  Sub CustomersGridView_RowCancelingEdit(ByVal sender As Object, ByVal e As GridViewCancelEditEventArgs)
  
    ' Clear the error message.
    Message.Text = ""
    
  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridView PageIndexChanging Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridView PageIndexChanging Example</h3>
            
      <asp:label id="Message"
        forecolor="Red"
        runat="server"/>
                
      <br/>  

      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSource" 
        autogeneratecolumns="true"
        emptydatatext="No data available." 
        allowpaging="true"
        autogenerateeditbutton="true"
        datakeynames="CustomerID"  
        onpageindexchanging="CustomersGridView_PageIndexChanging"
        onrowcancelingedit="CustomersGridView_RowCancelingEdit" 
        runat="server">
                
        <pagersettings mode="Numeric"
          position="Bottom"           
          pagebuttoncount="10"/>
                      
        <pagerstyle backcolor="LightBlue"/>
                
      </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="CustomersSource"
        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"/>
            
    </form>
  </body>
</html>

Comentarios

El GridView control genera el PageIndexChanging evento cuando se hace clic en un botón de buscapersonas (un botón con su CommandName propiedad establecida en "Page") dentro del control, pero antes de que el GridView control control controle la operación de paginación. Esto le permite proporcionar un método de control de eventos que realiza una rutina personalizada, como cancelar la operación de paginación, siempre que se produzca este evento.

Nota

Los botones de buscapersonas normalmente se encuentran en la fila del buscapersonas de un GridView control.

Cuando se crea un delegado GridViewPageEventHandler, 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, vea 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

Comparteix a través de