TableCallback Délégué

Référence

Définition

Espace de noms:: System.Web.UI.WebControls.WebParts

Assembly:: System.Web.dll

Important

Certaines informations portent sur la préversion du produit qui est susceptible d’être en grande partie modifiée avant sa publication. Microsoft exclut toute garantie, expresse ou implicite, concernant les informations fournies ici.

Référence la méthode à appeler lors de la récupération de données de table auprès d'un fournisseur.

public delegate void TableCallback(ICollection ^ tableData);

public delegate void TableCallback(ICollection tableData);

type TableCallback = delegate of ICollection -> unit

Public Delegate Sub TableCallback(tableData As ICollection)

Paramètres

tableData: ICollection

Données à récupérer du fournisseur.

Exemples

L’exemple de code suivant contient un contrôle composants WebPart nommé TableProviderWebPart qui sert de fournisseur de données sous la forme d’une table. Le contrôle inclut une implémentation de la GetTableData méthode, qui reçoit un paramètre de type TableCallback. Cette méthode appelle la méthode représentée par le TableCallback délégué qui transmet les données de table.

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Reflection;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
//This sample code creates a Web Parts control that acts as a provider of table data.
namespace Samples.AspNet.CS.Controls
{
    public sealed class TableProviderWebPart : WebPart, IWebPartTable
    {
        DataTable _table;

        public TableProviderWebPart()
        {
            _table = new DataTable();

            DataColumn col = new DataColumn();
            col.DataType = typeof(string);
            col.ColumnName = "Name";
            _table.Columns.Add(col);

            col = new DataColumn();
            col.DataType = typeof(string);
            col.ColumnName = "Address";
            _table.Columns.Add(col);

            col = new DataColumn();
            col.DataType = typeof(int);
            col.ColumnName = "ZIP Code";
            _table.Columns.Add(col);

            DataRow row = _table.NewRow();
            row["Name"] = "John Q. Public";
            row["Address"] = "123 Main Street";
            row["ZIP Code"] = 98000;
            _table.Rows.Add(row);
        }

        public PropertyDescriptorCollection Schema
        {
            get
            {
                return TypeDescriptor.GetProperties(_table.DefaultView[0]);
            }
        }
        
        public void GetTableData(TableCallback callback)
        {
            callback(_table.Rows);
        }

        public bool ConnectionPointEnabled
        {
            get
            {
                object o = ViewState["ConnectionPointEnabled"];
                return (o != null) ? (bool)o : true;
            }
            set
            {
                ViewState["ConnectionPointEnabled"] = value;
            }
        }

        [ConnectionProvider("Table")]
        public IWebPartTable GetConnectionInterface()
        {
            return new TableProviderWebPart();
        }

        public class TableProviderConnectionPoint : ProviderConnectionPoint
        {
            public TableProviderConnectionPoint(MethodInfo callbackMethod, 
                Type interfaceType, Type controlType,
                string name, string id, bool allowsMultipleConnections)
                : base(callbackMethod, interfaceType, controlType,
                    name, id, allowsMultipleConnections)
            {
            }

            public override bool GetEnabled(Control control)
            {
                return ((TableProviderWebPart)control).ConnectionPointEnabled;
            }
        }
    }
}

Imports System.Collections
Imports System.ComponentModel
Imports System.Data
Imports System.Reflection
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts

'This sample code creates a Web Parts control that acts as a provider of table data.
Namespace Samples.AspNet.VB.Controls

    Public NotInheritable Class TableProviderWebPart
        Inherits WebPart
        Implements IWebPartTable

        Private _table As DataTable


        Public Sub New()
            _table = New DataTable()

            Dim col As New DataColumn()
            col.DataType = GetType(String)
            col.ColumnName = "Name"
            _table.Columns.Add(col)

            col = New DataColumn()
            col.DataType = GetType(String)
            col.ColumnName = "Address"
            _table.Columns.Add(col)

            col = New DataColumn()
            col.DataType = GetType(Integer)
            col.ColumnName = "ZIP Code"
            _table.Columns.Add(col)

            Dim row As DataRow = _table.NewRow()
            row("Name") = "John Q. Public"
            row("Address") = "123 Main Street"
            row("ZIP Code") = 98000
            _table.Rows.Add(row)

        End Sub

        <ConnectionProvider("Table")> _
        Public Function GetConnectionInterface() As IWebPartTable
            Return New TableProviderWebPart()

        End Function 'GetConnectionInterface

        Public ReadOnly Property Schema() As PropertyDescriptorCollection _
            Implements IWebPartTable.Schema
            Get
                Return TypeDescriptor.GetProperties(_table.DefaultView(0))
            End Get
        End Property

        Public Property ConnectionPointEnabled() As Boolean
            Get
                Dim o As Object
                o = ViewState("ConnectionPointEnabled")
                If Not (o Is Nothing) Then
                    Return CBool(o)
                Else
                    Return True
                End If

            End Get
            Set(ByVal value As Boolean)
                ViewState("ConnectionPointEnabled") = value
            End Set
        End Property

        Public Sub GetTableData(ByVal callback As TableCallback) _
            Implements IWebPartTable.GetTableData
            callback(_table.Rows)

        End Sub
    End Class

End Namespace

Dans la OnPreRender méthode, le consommateur appelle GetTableData TableProviderWebPart et transmet sa GetTableData méthode en tant que délégué à appeler avec les données de table, comme illustré dans l’exemple de code suivant.

namespace Samples.AspNet.CS.Controls
{
    using System;
    using System.ComponentModel;
    using System.Data;
    using System.Data.SqlClient;
    using System.Reflection;
    using System.Web.UI;
    using System.Web.UI.WebControls;
    using System.Web.UI.WebControls.WebParts;
    using System.Collections;

    public class TableConsumer : WebPart
    {
        private IWebPartTable _provider;
        private ICollection _tableData;

        private void GetTableData(object tableData)
        {
            _tableData = (ICollection)tableData;
        }

        protected override void OnPreRender(EventArgs e)
        {
            if (_provider != null)
            {
                _provider.GetTableData(new TableCallback(GetTableData));
            }
        }

        protected override void RenderContents(HtmlTextWriter writer)
        {
            if (_provider != null)
            {
                PropertyDescriptorCollection props = _provider.Schema;
                int count = 0;
                if (props != null && props.Count > 0 && _tableData != null)
                {
                    foreach (PropertyDescriptor prop in props)
                    {
                        foreach (DataRow o in _tableData)
                        {
                            writer.Write(prop.DisplayName + ": " + o[count]);
                        }
                        writer.WriteBreak();
                        writer.WriteLine();
                        count = count + 1;
                    }
                }
                else
                {
                    writer.Write("No data");
                }
            }
            else
            {
                writer.Write("Not connected");
            }
        }

        [ConnectionConsumer("Table")]
        public void SetConnectionInterface(IWebPartTable provider)
        {
            _provider = provider;
        }
    }
}

Imports System.ComponentModel
Imports System.Reflection
Imports System.Collections
Imports System.Data
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts

Namespace Samples.AspNet.VB.Controls

    Public Class TableConsumerWebPart
        Inherits WebPart

        Private _provider As IWebPartTable
        Private _tableData As ICollection

        Private Sub GetTableData(ByVal tableData As ICollection)
            _tableData = CType(tableData, ICollection)

        End Sub

        Protected Overrides Sub OnPreRender(ByVal e As EventArgs)
            If Not (_provider Is Nothing) Then
                _provider.GetTableData((New TableCallback(AddressOf GetTableData)))
            End If
            'MyBase.OnPreRender(e)

        End Sub

        Protected Overrides Sub RenderContents(ByVal writer As HtmlTextWriter)

            If Not (_provider Is Nothing) Then
                Dim props As PropertyDescriptorCollection = _provider.Schema
                Dim count As Integer = 0

                If Not (props Is Nothing) AndAlso props.Count > 0 _
                  AndAlso Not (_tableData Is Nothing) Then
                    For Each prop As PropertyDescriptor In props
                        For Each o As DataRow In _tableData
                            writer.Write(prop.DisplayName & ": " & o(count).ToString())
                        Next
                        writer.WriteBreak()
                        writer.WriteLine()
                        count = count + 1
                    Next
                Else
                    writer.Write("No data")
                End If
            Else
                writer.Write("Not connected")
            End If

        End Sub

        <ConnectionConsumer("Table")> _
        Public Sub SetConnectionInterface(ByVal provider As IWebPartTable)
            _provider = provider

        End Sub

        Private Class TableConsumerConnectionPoint
            Inherits ConsumerConnectionPoint

            Public Sub New(ByVal callbackMethod As MethodInfo, _
              ByVal interfaceType As Type, ByVal controlType As Type, _
              ByVal name As String, ByVal id As String, _
              ByVal allowsMultipleConnections As Boolean)
                MyBase.New(callbackMethod, interfaceType, controlType, _
                  name, id, allowsMultipleConnections)

            End Sub
        End Class
    End Class

End Namespace

Les deux contrôles et la connexion sont inclus dans une page Web, comme illustré dans l’exemple suivant.

<%@ page language="C#" %>
<%@ Register tagprefix="wp" Namespace="Samples.AspNet.CS.Controls"  %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>ITable Test Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <!-- A static or dynamic connection is required to link two
             Web Parts controls. --->
        <asp:webpartmanager id="WebPartManager1" runat="server">
            <StaticConnections>
                <asp:WebPartConnection id="wp1" ProviderID="provider1" 
                   ConsumerID="consumer1">
                </asp:WebPartConnection>
            </StaticConnections>
        </asp:webpartmanager>
        <asp:webpartzone id="WebPartZone1" runat="server">
            <zoneTemplate>
            <!-- The following two lines define the 
              two connected controls. --->
            <wp:TableProviderWebPart ID="provider1" runat="server" 
               title="Web Parts Table Provider Control" />
            <wp:TableConsumer ID="consumer1" runat="server" 
               title="Web Parts Table Consumer Control"/>
            </zoneTemplate>
        </asp:webpartzone>
    </div>
    </form>
</body>
</html>

<%@ Page Language="VB" %>
<%@ Register tagprefix="wp" Namespace="Samples.AspNet.VB.Controls"  %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>ITable Test Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <!-- A static or dynamic connection is required to 
             link two Web Parts controls. --->
        <asp:webpartmanager id="WebPartManager1" runat="server">
            <StaticConnections>
                <asp:WebPartConnection id="wp1" ProviderID="provider1" 
                   ConsumerID="consumer1">
                </asp:WebPartConnection>
            </StaticConnections>
        </asp:webpartmanager>
        <asp:webpartzone id="WebPartZone1" runat="server">
            <zoneTemplate>
            <!-- The following two lines define the two 
                 connected controls. --->
            <wp:TableProviderWebPart ID="provider1" runat="server" 
               title="Web Parts Table Provider Control" />
            <wp:TableConsumerWebPart ID="consumer1" runat="server" 
               title="Web Parts Table Consumer Control"/>
            </zoneTemplate>
        </asp:webpartzone>
    </div>
    </form>
</body>
</html>

Remarques

Lorsqu’un contrôle composants WebPart implémente l’interface IWebPartTable et sert de fournisseur dans une connexion composants WebPart, le consommateur ou le transformateur doit récupérer et traiter les données de table du fournisseur. Le TableCallback délégué représente la méthode à appeler pour le traitement des données du fournisseur.

La GetTableData méthode contient un TableCallback paramètre délégué.

Méthodes d’extension

GetMethodInfo(Delegate)

Obtient un objet qui représente la méthode représentée par le délégué spécifié.

S’applique à

Partager via