Evento DataGrid.SortCommand
.NET Framework 3.5
Aggiornamento: novembre 2007
Si verifica quando viene ordinata una colonna.
Assembly: System.Web (in System.Web.dll)
L'evento SortCommand viene generato quando si ordina una colonna.
In genere, un gestore per l'evento SortCommand ordina l'elenco, quindi esegue nuovamente l'associazione dei dati al controllo DataGrid.
Per ulteriori informazioni sulla gestione degli eventi, vedere Utilizzo degli eventi.
Nell'esempio di codice riportato di seguito viene illustrato come specificare e scrivere il codice di un gestore per l'evento SortCommand allo scopo di ordinare un controllo DataGrid.
<%@ Page Language="C#" AutoEventWireup="True" %> <%@ 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"> ICollection CreateDataSource() { // Create a Random object to mix up the // order of items in the sample data. Random randNum = new Random(); // Create sample data for the DataGrid control. DataTable dt = new DataTable(); // Define the columns of the table. dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32))); dt.Columns.Add(new DataColumn("StringValue", typeof(String))); dt.Columns.Add(new DataColumn("CurrencyValue", typeof(Double))); // Populate the table with sample values. for (int i = 0; i <= 8; i++) { DataRow dr = dt.NewRow(); dr[0] = i; dr[1] = "Item " + randNum.Next(1, 15).ToString(); dr[2] = 1.23 * randNum.Next(1, 15); dt.Rows.Add(dr); } // To persist the data source between posts to the server, // store it in session state. Session["Source"] = dt; DataView dv = new DataView(dt); return dv; } void Page_Load(Object sender, EventArgs e) { // Load sample data only once, when the page is first loaded. if (!IsPostBack) { ItemsGrid.DataSource = CreateDataSource(); ItemsGrid.DataBind(); } } void Sort_Grid(Object sender, DataGridSortCommandEventArgs e) { // Retrieve the data source from session state. DataTable dt = (DataTable)Session["Source"]; // Create a DataView from the DataTable. DataView dv = new DataView(dt); // The DataView provides an easy way to sort. Simply set the // Sort property with the name of the field to sort by. dv.Sort = e.SortExpression; // Rebind the data source and specify that it should be sorted // by the field specified in the SortExpression property. ItemsGrid.DataSource = dv; ItemsGrid.DataBind(); } void Check_Change(Object sender, EventArgs e) { // Allow or prevent sorting depending on the user's selection. ItemsGrid.AllowSorting = AllowSortingCheckBox.Checked; // After changing the property, rebind the data to // refresh the DataGrid control. // Retrieve the data source from session state. DataTable dt = (DataTable)Session["Source"]; // Create a DataView from the DataTable. DataView dv = new DataView(dt); // Rebind the data source. ItemsGrid.DataSource = dv; ItemsGrid.DataBind(); } </script> <html xmlns="http://www.w3.org/1999/xhtml" > <head id="Head1" runat="server"> <title> ExtractTemplateRows Example </title> </head> <body> <form id="form1" runat="server"> <div> <h3>DataGrid AllowSorting Example</h3> <p>Select whether to allow sorting in the DataGrid control.<br /> <asp:CheckBox id="AllowSortingCheckBox" Text="Allow sorting" AutoPostBack="True" Checked="True" OnCheckedChanged="Check_Change" runat="server"/></p> <hr /> <b>Product List</b> <asp:DataGrid id="ItemsGrid" BorderColor="black" BorderWidth="1" CellPadding="3" OnSortCommand="Sort_Grid" UseAccessibleHeader="true" AutoGenerateColumns="False" AllowSorting="True" runat="server"> <HeaderStyle BackColor="#00aaaa" /> <Columns> <asp:BoundColumn DataField="IntegerValue" SortExpression="IntegerValue" HeaderText="Item"/> <asp:BoundColumn DataField="StringValue" SortExpression="StringValue" HeaderText="Description"/> <asp:BoundColumn DataField="CurrencyValue" HeaderText="Price" SortExpression="CurrencyValue" DataFormatString="{0:c}"> <ItemStyle HorizontalAlign="Right"> </ItemStyle> </asp:BoundColumn> </Columns> </asp:DataGrid> </div> </form> </body> </html>
<%@ Page Language="C#" AutoEventWireup="True" %> <%@ Import Namespace="System.Data" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <script runat="server"> ICollection CreateDataSource() { // Create a Random object to mix up the order of items in the sample data. Random Rand_Num = new Random(); // Create sample data for the DataGrid control. DataTable dt = new DataTable(); DataRow dr; // Define the columns of the table. dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32))); dt.Columns.Add(new DataColumn("StringValue", typeof(String))); dt.Columns.Add(new DataColumn("CurrencyValue", typeof(Double))); // Populate the table with sample values. for (int i=0; i<=8; i++) { dr = dt.NewRow(); dr[0] = i; dr[1] = "Item " + Rand_Num.Next(1, 15).ToString(); dr[2] = 1.23 * Rand_Num.Next(1, 15); dt.Rows.Add(dr); } // To persist the data source between posts to the server, store it // in session state. Session["Source"] = dt; DataView dv = new DataView(dt); return dv; } void Page_Load(Object sender, EventArgs e) { // Load sample data only once, when the page is first loaded. if (!IsPostBack) { ItemsGrid.DataSource = CreateDataSource(); ItemsGrid.DataBind(); } // Manually register the event-handling method for the PageIndexChanged // event of the DataGrid control. ItemsGrid.SortCommand += new DataGridSortCommandEventHandler(this.Sort_Grid); } void Sort_Grid(Object sender, DataGridSortCommandEventArgs e) { // Retrieve the data source from session state. DataTable dt = (DataTable)Session["Source"]; // Create a DataView from the DataTable. DataView dv = new DataView(dt); // The DataView provides an easy way to sort. Simply set the Sort property with // the name of the field to sort by. dv.Sort = e.SortExpression; // Re-bind the data source and specify that it should be sorted // by the field specified in the SortExpression property. ItemsGrid.DataSource = dv; ItemsGrid.DataBind(); } void Check_Change(Object sender, EventArgs e) { // Allow or prevent sorting depending on the user's selection. if (AllowSortingCheckBox.Checked) { ItemsGrid.AllowSorting = true; } else { ItemsGrid.AllowSorting = false; } // After changing the property, re-bind the data to // refresh the DataGrid control. // Retrieve the data source from session state. DataTable dt = (DataTable)Session["Source"]; // Create a DataView from the DataTable. DataView dv = new DataView(dt); // Re-bind the data source. ItemsGrid.DataSource = dv; ItemsGrid.DataBind(); } </script> <head runat="server"> <title>DataGrid SortCommand Example</title> </head> <body> <form id="form1" runat="server"> <h3>DataGrid SortCommand Example</h3> Select whether to allow sorting in the DataGrid control. <br /><br /> <b>Product List</b> <asp:DataGrid id="ItemsGrid" BorderColor="black" BorderWidth="1" CellPadding="3" AutoGenerateColumns="False" AllowSorting="True" runat="server"> <HeaderStyle BackColor="#00aaaa"> </HeaderStyle> <Columns> <asp:BoundColumn DataField="IntegerValue" SortExpression="IntegerValue" HeaderText="Item"/> <asp:BoundColumn DataField="StringValue" SortExpression="StringValue" HeaderText="Description"/> <asp:BoundColumn DataField="CurrencyValue" HeaderText="Price" SortExpression="CurrencyValue" DataFormatString="{0:c}"> <ItemStyle HorizontalAlign="Right"> </ItemStyle> </asp:BoundColumn> </Columns> </asp:DataGrid> <hr /> <asp:CheckBox id="AllowSortingCheckBox" Text="Allow sorting" AutoPostBack="True" Checked="True" OnCheckedChanged="Check_Change" runat="server"/> </form> </body> </html>
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