TableCallback デリゲート
アセンブリ: System.Web (system.web.dll 内)


Web パーツ コントロールが IWebPartTable インターフェイスを実装して Web パーツ接続でプロバイダとして動作する場合、コンシューマまたはトランスフォーマはプロバイダからテーブル データを取得して処理する必要があります。TableCallback デリゲートは、プロバイダのデータを処理するために呼び出すメソッドを表します。

テーブル形式のデータのプロバイダとして動作する、TableProviderWebPart という名前の Web パーツ コントロールのコード例を次に示します。このコントロールには、TableCallback 型のパラメータを受け取る、GetTableData メソッドの実装が含まれます。このメソッドは、テーブル データを渡す TableCallback デリゲートで表されるメソッドを呼び出します。
Imports System 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 'New <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 'GetTableData End Class 'TableProviderWebPart End Namespace
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; } } } }
OnPreRender メソッドで、コンシューマが TableProviderWebPart の GetTableData を呼び出し、その GetTableData メソッドをテーブル データと共に呼び出すデリゲートとして渡すコード例を次に示します。
Imports System 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 'GetTableValue 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 'OnPreRender 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 'RenderContents <ConnectionConsumer("Table")> _ Public Sub SetConnectionInterface(ByVal provider As IWebPartTable) _provider = provider End Sub 'SetConnectionInterface 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 'New End Class 'TableConsumerConnectionPoint End Class 'TableConsumerWebPart End Namespace
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; } } }
Web ページに 2 つのコントロールと接続が含まれている例を次に示します。
<%@ Page Language="VB" %> <%@ Register tagprefix=wp Namespace=Samples.AspNet.VB.Controls %> <script runat="server"> </script> <html> <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>
<%@ page language="C#" %> <%@ Register tagprefix=wp Namespace=Samples.AspNet.CS.Controls %> <script runat="server"> </script> <html> <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>

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
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