IWebPartField インターフェイスとは何？わかりやすく解説 Weblio辞書

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

Namespace Samples.AspNet.VB.Controls

  ' This sample code creates a Web Parts control that acts as a 
  ' provider of field data.
  <AspNetHostingPermission(SecurityAction.Demand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  <AspNetHostingPermission(SecurityAction.InheritanceDemand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  Public NotInheritable Class
 FieldProviderWebPart
    Inherits WebPart
    Implements IWebPartField
    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("FieldProvider")> _
    Public Function GetConnectionInterface()
 As IWebPartField
      Return New FieldProviderWebPart()

    End Function


    Public ReadOnly Property
 Schema() As ComponentModel.PropertyDescriptor _
      Implements IWebPartField.Schema
      Get
        ' The two parameters are row and field. Zero is the first record.
 
        ' 0,2 returns the zip code field value.   
        Return TypeDescriptor.GetProperties(_table.DefaultView(0))(2)
      End Get
    End Property


    Sub GetFieldValue(ByVal callback As
 FieldCallback) _
      Implements IWebPartField.GetFieldValue

      callback(Schema.GetValue(_table.DefaultView(0)))

    End Sub

  End Class 'FieldProviderWebPart
 


  ' This sample code creates a Web Parts control that acts as a 
  ' consumer of an IWebPartField interface.
  <AspNetHostingPermission(SecurityAction.Demand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  <AspNetHostingPermission(SecurityAction.InheritanceDemand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  Public Class FieldConsumerWebPart
    Inherits WebPart

    Private _provider As IWebPartField
    Private _fieldValue As Object


    Private Sub GetFieldValue(ByVal
 fieldValue As Object)
      _fieldValue = fieldValue

    End Sub


    Public Property ConnectionPointEnabled()
 As Boolean
      Get
        Dim o As Object
 = ViewState("ConnectionPointEnabled")
        Return IIf(Not (o Is
 Nothing), CBool(o), True)
      End Get
      Set(ByVal value As
 Boolean)
        ViewState("ConnectionPointEnabled") = value
      End Set
    End Property


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

    End Sub


    Protected Overrides Sub
 RenderContents(ByVal writer As _
      HtmlTextWriter)

      If Not (_provider Is
 Nothing) Then
        Dim prop As PropertyDescriptor = _provider.Schema

        If Not (prop Is
 Nothing) AndAlso Not (_fieldValue
 Is Nothing) Then
          writer.Write(prop.DisplayName & ": "
 & _fieldValue)
        Else
          writer.Write("No data")
        End If
      Else
        writer.Write("Not connected")
      End If

    End Sub

    <ConnectionConsumer("FieldConsumer", "Connpoint1",
 _
      GetType(FieldConsumerConnectionPoint), AllowsMultipleConnections:=True)>
 _
    Public Sub SetConnectionInterface(ByVal
 provider As IWebPartField)
      _provider = provider

    End Sub

  End Class 'FieldConsumerWebPart

  Public Class FieldConsumerConnectionPoint
    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


    Public Overrides Function
 GetEnabled(ByVal control As Control) _
      As Boolean

      Return CType(control, FieldConsumerWebPart).ConnectionPointEnabled

    End Function

  End Class 'FieldConsumerConnectionPoint

End Namespace  ' Samples.AspNet.VB.Controls

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Reflection;
using System.Security.Permissions;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;

namespace Samples.AspNet.CS.Controls
{
  // This sample code creates a Web Parts control that acts as a provider
 
  // of field data.
  [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  public sealed class FieldProviderWebPart
 : WebPart, IWebPartField
  {
    private DataTable _table;

    public FieldProviderWebPart() 
    {
        _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);
    }

       [ConnectionProvider("FieldProvider")]
      public IWebPartField GetConnectionInterface()
    {
        return new FieldProviderWebPart();
    }

    public PropertyDescriptor Schema 
    {
        get 
        {
            /* The two parameters are row and field. Zero is the first record. 
                0,2 returns the zip code field value.   */ 
            return TypeDescriptor.GetProperties(_table.DefaultView[0])[2];
        }
    }

      void IWebPartField.GetFieldValue(FieldCallback callback)
 
    {
        callback(Schema.GetValue(_table.DefaultView[0]));
    }

  } // end FieldProviderWebPart

  // This sample code creates a Web Parts control that acts as a consumer
 
  // of an IWebPartField interface.
  [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  public class FieldConsumerWebPart : WebPart
  {

    private IWebPartField _provider;
    private object _fieldValue;

    private void GetFieldValue(object fieldValue)
    {
      _fieldValue = fieldValue;
    }

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

    protected override void OnPreRender(EventArgs
 e)
    {
      if (_provider != null)
      {
        _provider.GetFieldValue(new FieldCallback(GetFieldValue));
      }
      base.OnPreRender(e);
    }

    protected override void RenderContents(HtmlTextWriter
 writer)
    {

      if (_provider != null)
      {
        PropertyDescriptor prop = _provider.Schema;

        if (prop != null && _fieldValue
 != null)
        {
          writer.Write(prop.DisplayName + ": " + _fieldValue);
        }
        else
        {
          writer.Write("No data");
        }
      }
      else
      {
        writer.Write("Not connected");
      }
    }

    [ConnectionConsumer("FieldConsumer", "Connpoint1", 
      typeof(FieldConsumerConnectionPoint), AllowsMultipleConnections = true)]
    public void SetConnectionInterface(IWebPartField
 provider)
    {
      _provider = provider;
    }

    public class FieldConsumerConnectionPoint
 : ConsumerConnectionPoint
    {
      public FieldConsumerConnectionPoint(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 ((FieldConsumerWebPart)control).ConnectionPointEnabled;
      }
    } // end FieldConsumerConnectionPoint

  } // end FieldConsumerWebPart

} // end namespace Samples.AspNet.CS.Controls

コード例の 2 番目の部分は、静的接続を宣言し、コントロールをホストする Web ページです。ページの上部には、App_Code ディレクトリに格納されているソースコードの名前空間を宣言する Register ディレクティブが含まれています。接続は、<asp:webpartconnection> 要素を使用して宣言されます。カスタムコンシューマコントロールとカスタムプロバイダコントロールは、<asp:webpartzone> 要素内の <zonetemplate> 要素で宣言されています。これは、これらのコントロールを接続できるようにするために必要な要素です (これらのコントロールは、WebPartZoneBase クラスから継承されるゾーンに配置されている必要があります)。

Visual Basic

<%@ page language="VB" debug="true"
 %>
<%@ Register tagprefix="IField" 
    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">

<!-- This code sample creates a page with two Web Parts controls
 
and establishes a connection between the controls. -->
<script runat="server">

</script>

<html  >
<head runat="server">
    <title>IWebPartField Test Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:webpartmanager id="WebPartManager1"
 runat="server">
            <StaticConnections>
                <asp:WebPartConnection id="con1"
 ProviderID="provider1" 
                  ConsumerID="consumer1" 
                  ConsumerConnectionPointID="Connpoint1">
                </asp:WebPartConnection>
            </StaticConnections>
        </asp:webpartmanager>
        <asp:webpartzone id="WebPartZone1" runat="server">
            <zoneTemplate>
              <ifield:fieldproviderwebpart runat="Server"
 
                ID="provider1" Title="Provider"
 />
              <ifield:fieldconsumerwebpart runat="Server"
 
                ID="consumer1" Title="Consumer"/>
            </zoneTemplate>
        </asp:webpartzone>
    </div>
    </form>
</body>
</html>

<%@ page language="C#" %>
<%@ Register tagprefix="IField" 
    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">

<!-- This code sample creates a page with two Web Parts controls 
and establishes a connection between the controls. -->
<script runat="server">

</script>

<html  >
<head runat="server">
    <title>IWebPartField Test Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:webpartmanager id="WebPartManager1" runat="server">
            <StaticConnections>
                <asp:WebPartConnection id="con1" ProviderID="provider1"
 
                  ConsumerID="consumer1" 
                  ConsumerConnectionPointID="Connpoint1">
                </asp:WebPartConnection>
            </StaticConnections>
        </asp:webpartmanager>
        <asp:webpartzone id="WebPartZone1" runat="server">
            <zoneTemplate>
              <ifield:fieldproviderwebpart runat="Server" 
                ID="provider1" Title="Provider" />
              <ifield:fieldconsumerwebpart runat="Server" 
                ID="consumer1" Title="Consumer"/>
            </zoneTemplate>
        </asp:webpartzone>
    
    </div>
    </form>
</body>
</html>

ブラウザにページを読み込みます。コンシューマコントロールは、プロバイダが IWebPartField インターフェイスのインスタンスを通じて提供する、特定のフィールドからのデータを表示します。

.NET Framework のセキュリティ

AspNetHostingPermission (ホスト環境での動作に必要なアクセス許可)要求値 : LinkDemand; アクセス許可値 : Minimal。
AspNetHostingPermission (ホスト環境での動作に必要なアクセス許可)要求値 : InheritanceDemand; アクセス許可値 : Minimal。

プラットフォーム

バージョン情報

.NET Framework
サポート対象 : 2.0

参照

関連項目
IWebPartField メンバ
System.Web.UI.WebControls.WebParts 名前空間
IWebPartRow
IWebPartTable
WebPartConnection
その他の技術情報
ASP.NET Web パーツページ
Web パーツ接続の概要

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IWebPartField インターフェイスとは？ わかりやすく解説

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IWebPartField インターフェイスとは？わかりやすく解説