GridViewSelectEventHandler Delegado
Definición
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 SelectedIndexChanging de un control GridView.
public delegate void GridViewSelectEventHandler(System::Object ^ sender, GridViewSelectEventArgs ^ e);public delegate void GridViewSelectEventHandler(object sender, GridViewSelectEventArgs e);type GridViewSelectEventHandler = delegate of obj * GridViewSelectEventArgs -> unitPublic Delegate Sub GridViewSelectEventHandler(sender As Object, e As GridViewSelectEventArgs)Parámetros
- sender
- Object
Origen del evento.
Objeto GridViewSelectEventArgs que contiene los datos del evento.
Ejemplos
En el ejemplo siguiente se muestra cómo agregar mediante programación un GridViewSelectEventHandler delegado al SelectedIndexChanging 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 authorGridView = new GridView();
// Set the GridView object's properties.
authorGridView.ID = "AuthorGridView";
authorGridView.DataSourceID = "AuthorsSqlDataSource";
authorGridView.AutoGenerateColumns = true;
authorGridView.AutoGenerateSelectButton = true;
authorGridView.AllowPaging = true;
authorGridView.SelectedIndex = 1;
authorGridView.SelectedRowStyle.BackColor = System.Drawing.Color.LightCyan;
authorGridView.SelectedRowStyle.ForeColor = System.Drawing.Color.DarkBlue;
authorGridView.SelectedRowStyle.Font.Bold = true;
// Programmatically register the event-handling methods.
authorGridView.SelectedIndexChanged += new EventHandler(this.AuthorsGridView_SelectedIndexChanged);
authorGridView.SelectedIndexChanging += new GridViewSelectEventHandler(this.AuthorsGridView_SelectedIndexChanging);
// Add the GridView object to the Controls collection
// of the PlaceHolder control.
GridViewPlaceHolder.Controls.Add(authorGridView);
}
void AuthorsGridView_SelectedIndexChanged(Object sender, EventArgs e)
{
// Get the currently selected row using the SelectedRow property.
GridView AuthorsGridView = (GridView)sender;
GridViewRow row = AuthorsGridView.SelectedRow;
// Display the author's name from the selected row.
// In this example, the second and third columns contain
// the author's last and first name, respectively.
Message.Text = "You selected " + row.Cells[2].Text +
" " + row.Cells[1].Text + ".";
}
void AuthorsGridView_SelectedIndexChanging(Object sender, GridViewSelectEventArgs e)
{
// Get the currently selected row. Because the SelectedIndexChanging event
// occurs before the select operation in the GridView control, the
// SelectedRow property cannot be used. Instead, use the Rows collection
// and the NewSelectedIndex property of the e argument passed to this
// event handler.
GridView AuthorsGridView = (GridView)sender;
GridViewRow row = AuthorsGridView.Rows[e.NewSelectedIndex];
// If the user selects an author with the last name White,
// cancel the selection operation and display an error message.
if(row.Cells[1].Text == "White")
{
e.Cancel = true;
Message.Text = "You cannot select " + row.Cells[2].Text +
" " + row.Cells[1].Text + ".";
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridViewSelectEventHandler Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridViewSelectEventHandler Example</h3>
<asp:placeholder id="GridViewPlaceHolder"
runat="Server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Pubs sample database. -->
<asp:sqldatasource id="AuthorsSqlDataSource"
selectcommand="SELECT [au_lname], [au_fname], [address], [city], [state], [zip], [contract] FROM [authors]"
connectionstring="server=localhost;database=pubs;integrated security=SSPI"
runat="server">
</asp:sqldatasource>
<br/>
<asp:label id="Message"
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 object.
Dim authorGridView As GridView = New GridView
' Set the GridView object's properties.
authorGridView.ID = "AuthorGridView"
authorGridView.DataSourceID = "AuthorsSqlDataSource"
authorGridView.AutoGenerateColumns = True
authorGridView.AutoGenerateSelectButton = True
authorGridView.AllowPaging = True
authorGridView.SelectedIndex = 1
authorGridView.SelectedRowStyle.BackColor = System.Drawing.Color.LightCyan
authorGridView.SelectedRowStyle.ForeColor = System.Drawing.Color.DarkBlue
authorGridView.SelectedRowStyle.Font.Bold = True
' Programmatically register the event-handling methods.
AddHandler authorGridView.SelectedIndexChanged, AddressOf AuthorsGridView_SelectedIndexChanged
AddHandler authorGridView.SelectedIndexChanging, AddressOf AuthorsGridView_SelectedIndexChanging
' Add the GridView object to the Controls collection
' of the PlaceHolder control.
GridViewPlaceHolder.Controls.Add(authorGridView)
End Sub
Sub AuthorsGridView_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
' Get the currently selected row using the SelectedRow property.
Dim AuthorsGridView As GridView = CType(sender, GridView)
Dim row As GridViewRow = AuthorsGridView.SelectedRow
' Display the author's name from the selected row.
' In this example, the second and third columns contain
' the author's last and first name, respectively.
Message.Text = "You selected " & row.Cells(2).Text & _
" " & row.Cells(1).Text & "."
End Sub
Sub AuthorsGridView_SelectedIndexChanging(ByVal sender As Object, ByVal e As GridViewSelectEventArgs)
' Get the currently selected row. Because the SelectedIndexChanging event
' occurs before the select operation in the GridView control, the
' SelectedRow property cannot be used. Instead, use the Rows collection
' and the NewSelectedIndex property of the e argument passed to this
' event handler.
Dim AuthorsGridView As GridView = CType(sender, GridView)
Dim row As GridViewRow = AuthorsGridView.Rows(e.NewSelectedIndex)
' If the user selects an author with the last name White,
' cancel the selection operation and display an error message.
If row.Cells(1).Text = "White"
e.Cancel = true
Message.Text = "You cannot select " & row.Cells(2).Text & _
" " & row.Cells(1).Text & "."
End If
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridViewSelectEventHandler Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridViewSelectEventHandler Example</h3>
<asp:placeholder id="GridViewPlaceHolder"
runat="Server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Pubs sample database. -->
<asp:sqldatasource id="AuthorsSqlDataSource"
selectcommand="SELECT [au_lname], [au_fname], [address], [city], [state], [zip], [contract] FROM [authors]"
connectionstring="server=localhost;database=pubs;integrated security=SSPI"
runat="server">
</asp:sqldatasource>
<br/>
<asp:label id="Message"
runat="server"/>
</form>
</body>
</html>
En el ejemplo siguiente se muestra cómo agregar mediante declaración un GridViewSelectEventHandler delegado al SelectedIndexChanging 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_SelectedIndexChanged(Object sender, EventArgs e)
{
// Get the currently selected row using the SelectedRow property.
GridViewRow row = CustomersGridView.SelectedRow;
// Display the first name from the selected row.
// In this example, the third column (index 2) contains
// the first name.
MessageLabel.Text = "You selected " + row.Cells[2].Text + ".";
}
void CustomersGridView_SelectedIndexChanging(Object sender, GridViewSelectEventArgs e)
{
// Get the currently selected row. Because the SelectedIndexChanging event
// occurs before the select operation in the GridView control, the
// SelectedRow property cannot be used. Instead, use the Rows collection
// and the NewSelectedIndex property of the e argument passed to this
// event handler.
GridViewRow row = CustomersGridView.Rows[e.NewSelectedIndex];
// You can cancel the select operation by using the Cancel
// property. For this example, if the user selects a customer with
// the ID "ANATR", the select operation is canceled and an error message
// is displayed.
if (row.Cells[1].Text == "ANATR")
{
e.Cancel = true;
MessageLabel.Text = "You cannot select " + row.Cells[2].Text + ".";
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridView Select Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridView Select Example</h3>
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSource"
autogeneratecolumns="False"
autogenerateselectbutton="True"
selectedindex="1"
onselectedindexchanged="CustomersGridView_SelectedIndexChanged"
onselectedindexchanging="CustomersGridView_SelectedIndexChanging"
runat="server" DataKeyNames="CustomerID">
<Columns>
<asp:BoundField DataField="CustomerID"
HeaderText="CustomerID"
InsertVisible="False" ReadOnly="True"
SortExpression="CustomerID" />
<asp:BoundField DataField="FirstName"
HeaderText="FirstName"
SortExpression="FirstName" />
<asp:BoundField DataField="MiddleName"
HeaderText="MiddleName"
SortExpression="MiddleName" />
<asp:BoundField DataField="LastName"
HeaderText="LastName"
SortExpression="LastName" />
<asp:BoundField DataField="Phone"
HeaderText="Phone"
SortExpression="Phone" />
</Columns>
<selectedrowstyle backcolor="LightCyan"
forecolor="DarkBlue"
font-bold="true"/>
</asp:gridview>
<br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the 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, FirstName, MiddleName, LastName, Phone FROM SalesLT.Customer"
connectionstring="<%$ ConnectionStrings:AdventureWorksLTConnectionString %>"
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_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
' Get the currently selected row using the SelectedRow property.
Dim row As GridViewRow = CustomersGridView.SelectedRow
' Display the first name from the selected row.
' In this example, the third column (index 2) contains
' the first name.
MessageLabel.Text = "You selected " & row.Cells(2).Text & "."
End Sub
Sub CustomersGridView_SelectedIndexChanging(ByVal sender As Object, ByVal e As GridViewSelectEventArgs)
' Get the currently selected row. Because the SelectedIndexChanging event
' occurs before the select operation in the GridView control, the
' SelectedRow property cannot be used. Instead, use the Rows collection
' and the NewSelectedIndex property of the e argument passed to this
' event handler.
Dim row As GridViewRow = CustomersGridView.Rows(e.NewSelectedIndex)
' You can cancel the select operation by using the Cancel
' property. For this example, if the user selects a customer with
' the ID "ANATR", the select operation is canceled and an error message
' is displayed.
If row.Cells(1).Text = "ANATR" Then
e.Cancel = True
MessageLabel.Text = "You cannot select " + row.Cells(2).Text & "."
End If
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridView Select Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridView Select Example</h3>
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSource"
autogeneratecolumns="False"
autogenerateselectbutton="True"
selectedindex="1"
onselectedindexchanged="CustomersGridView_SelectedIndexChanged"
onselectedindexchanging="CustomersGridView_SelectedIndexChanging"
runat="server" DataKeyNames="CustomerID">
<Columns>
<asp:BoundField DataField="CustomerID"
HeaderText="CustomerID"
InsertVisible="False" ReadOnly="True"
SortExpression="CustomerID" />
<asp:BoundField DataField="FirstName"
HeaderText="FirstName"
SortExpression="FirstName" />
<asp:BoundField DataField="MiddleName"
HeaderText="MiddleName"
SortExpression="MiddleName" />
<asp:BoundField DataField="LastName"
HeaderText="LastName"
SortExpression="LastName" />
<asp:BoundField DataField="Phone"
HeaderText="Phone"
SortExpression="Phone" />
</Columns>
<selectedrowstyle backcolor="LightCyan"
forecolor="DarkBlue"
font-bold="true"/>
</asp:gridview>
<br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the 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, FirstName, MiddleName, LastName, Phone FROM SalesLT.Customer"
connectionstring="<%$ ConnectionStrings:AdventureWorksLTConnectionString %>"
runat="server"/>
</form>
</body>
</html>
Comentarios
El SelectedIndexChanging evento se genera cuando se hace clic en un botón Seleccionar (un botón con su CommandName propiedad establecida en "Seleccionar"), pero antes de que el GridView control control controle la operación de selección. Esto le permite proporcionar un método de control de eventos que realiza una rutina personalizada, como cancelar la operación de selección, siempre que se produzca este evento.
Cuando se crea un delegado GridViewSelectEventHandler, 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
Consulte también
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