GridViewSelectEventHandler Gedelegeerde
Definitie
Belangrijk
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Vertegenwoordigt de methode die de SelectedIndexChanging gebeurtenis van een GridView besturingselement afhandelt.
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)Parameters
- sender
- Object
De bron van de gebeurtenis.
Een GridViewSelectEventArgs object dat de gebeurtenisgegevens bevat.
Voorbeelden
In het volgende voorbeeld ziet u hoe u programmatisch een GridViewSelectEventHandler gemachtigde toevoegt aan de SelectedIndexChanging gebeurtenis van een GridView besturingselement.
<%@ 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>
In het volgende voorbeeld ziet u hoe u declaratief een GridViewSelectEventHandler gedelegeerde toevoegt aan de SelectedIndexChanging gebeurtenis van een GridView besturingselement.
<%@ 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>
Opmerkingen
De SelectedIndexChanging gebeurtenis wordt gegenereerd wanneer op een knop Selecteren (een knop met CommandName de eigenschap 'Selecteren' is ingesteld), maar voordat het GridView besturingselement de selectiebewerking afhandelt. Hiermee kunt u een methode voor gebeurtenisafhandeling opgeven waarmee een aangepaste routine wordt uitgevoerd, zoals het annuleren van de selectiebewerking wanneer deze gebeurtenis plaatsvindt.
Wanneer u een GridViewSelectEventHandler gemachtigde maakt, identificeert u de methode die de gebeurtenis verwerkt. Als u de gebeurtenis wilt koppelen aan uw gebeurtenis-handler, voegt u een exemplaar van de gemachtigde toe aan de gebeurtenis. De gebeurtenis-handler wordt aangeroepen wanneer de gebeurtenis plaatsvindt, tenzij u de gemachtigde verwijdert. Zie Afhandeling en het genereren van gebeurtenissen voor meer informatie over gedelegeerden voor gebeurtenissen.
Extensiemethoden
| Name | Description |
|---|---|
| GetMethodInfo(Delegate) |
Hiermee haalt u een object op dat de methode vertegenwoordigt die wordt vertegenwoordigd door de opgegeven gemachtigde. |