RowToFieldTransformer Classe

Definição

public ref class RowToFieldTransformer sealed : System::Web::UI::WebControls::WebParts::WebPartTransformer, System::Web::UI::WebControls::WebParts::IWebPartField

[System.Web.UI.WebControls.WebParts.WebPartTransformer(typeof(System.Web.UI.WebControls.WebParts.IWebPartRow), typeof(System.Web.UI.WebControls.WebParts.IWebPartField))]
public sealed class RowToFieldTransformer : System.Web.UI.WebControls.WebParts.WebPartTransformer, System.Web.UI.WebControls.WebParts.IWebPartField

[<System.Web.UI.WebControls.WebParts.WebPartTransformer(typeof(System.Web.UI.WebControls.WebParts.IWebPartRow), typeof(System.Web.UI.WebControls.WebParts.IWebPartField))>]
type RowToFieldTransformer = class
    inherit WebPartTransformer
    interface IWebPartField

Public NotInheritable Class RowToFieldTransformer
Inherits WebPartTransformer
Implements IWebPartField

Herança

Object

WebPartTransformer

RowToFieldTransformer

Atributos

WebPartTransformerAttribute

Implementações

IWebPartField

Exemplos

O exemplo de código a seguir demonstra como usar um RowToFieldTransformer objeto para conectar um provedor e um consumidor com pontos de conexão incompatíveis. A primeira seção do exemplo mostra um controle de Web Parts que serve como um provedor. A classe de provedor, chamada RowProviderWebPart, fornece dados por meio da IWebPartRow interface .

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 row data.
namespace Samples.AspNet.CS.Controls
{
    public sealed class RowProviderWebPart : WebPart, IWebPartRow
    {
        private DataTable _table;

        public RowProviderWebPart()
        {
            _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("Row")]
        public IWebPartRow GetConnectionInterface()
        {
            return new RowProviderWebPart();
        }
        
        public PropertyDescriptorCollection Schema
        {
            get
            {
                return TypeDescriptor.GetProperties(_table.DefaultView[0]);
            }
        }
        
        public void GetRowData(RowCallback callback)
        {
            callback(_table.DefaultView[0]);
        }          
    }
}

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 row data.
Namespace Samples.AspNet.VB.Controls

    Public NotInheritable Class RowProviderWebPart
        Inherits WebPart
        Implements IWebPartRow

        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("Row")> _
        Public Function GetConnectionInterface() As IWebPartRow
            Return New RowProviderWebPart()

        End Function 'GetConnectionInterface

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

        Public Sub GetRowData(ByVal callback As RowCallback) _
            Implements IWebPartRow.GetRowData
            callback(_table.DefaultView(0))

        End Sub
    End Class

End Namespace

A segunda seção do exemplo contém um controle de Web Parts que é um consumidor de uma conexão de Web Parts. A classe de consumidor, chamada FieldConsumerWebPart, espera dados da IWebPartField interface .

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Reflection;
using System.Web;
using System.Web.UI;
using System.Security.Permissions;
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 consumer of an IField interface.

    // A consumer WebPart control that consumes strings.
    [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["ConnectionPointeEnabled"] = 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("Field")]
        public void SetConnectionInterface(IWebPartField provider)
        {
            _provider = provider;
        }

        private 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;
            }
        }
    }
}

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
    ' This sample code creates a Web Parts control that acts as 
    ' a consumer of an IField interface.

    Public Class FieldConsumerWebPart
        Inherits WebPart

        Private _provider As IWebPartField
        Private _fieldValue As Object

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

        End Sub

        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("Field")> _
        Public Sub SetConnectionInterface(ByVal provider As IWebPartField)
            _provider = provider

        End Sub

        Private 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
        End Class
    End Class

A terceira seção do exemplo mostra uma página que contém os dois controles e define o RowToFieldTransformer objeto para conectar os dois controles.

<%@ Page Language="C#" %>
<%@ register tagprefix="uc1" 
    tagname="DisplayModeMenuCS" 
    src="~/displaymodemenucs.ascx" %>
<%@ 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>Untitled Page</title>
</head>
<body>
  <form id="form1" runat="server">
    <asp:webpartmanager id="manager" runat="server">
    <staticconnections>
      <asp:WebPartConnection ID="conn1" ProviderID="rp1" ConsumerID="fc1">
        <asp:RowToFieldTransformer FieldName="Zip Code"/>
      </asp:WebPartConnection>
    </staticconnections>
    </asp:webpartmanager>
  <uc1:displaymodemenucs id="menu1" runat="server" />
  <table>
  <tr valign="top">
    <td>
      <asp:webpartzone id="zone1" headertext="zone1" runat="server">
        <zonetemplate>
          <wp:RowProviderWebPart Title="provider" ID="rp1" runat="server" />
          <wp:FieldConsumerWebPart Title="consumer" ID="fc1" runat="server" />
        </zonetemplate>
      </asp:webpartzone>
    </td>
    <td>
      <asp:connectionszone id="connectionszone1" runat="server" />
    </td>
  </tr>
  </table>
    
  </form>
</body>
</html>

<%@ Page Language="VB" %>
<%@ register tagprefix="uc1" 
    tagname="DisplayModeMenuVB" 
    src="~/displaymodemenuvb.ascx" %>
<%@ 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>Untitled Page</title>
</head>
<body>
  <form id="form1" runat="server">
    <asp:webpartmanager id="manager" runat="server">
    <staticconnections>
      <asp:WebPartConnection ID="conn1" ProviderID="rp1" ConsumerID="fc1">
        <asp:RowToFieldTransformer FieldName="Zip Code"/>
      </asp:WebPartConnection>
    </staticconnections>
    </asp:webpartmanager>
  <uc1:displaymodemenuvb id="menu1" runat="server" />
  <table>
  <tr valign="top">
    <td>
      <asp:webpartzone id="zone1" headertext="zone1" runat="server">
        <zonetemplate>
          <wp:RowProviderWebPart Title="provider" ID="rp1" runat="server" />
          <wp:FieldConsumerWebPart Title="consumer" ID="fc1" runat="server" />
        </zonetemplate>
      </asp:webpartzone>
    </td>
    <td>
      <asp:connectionszone id="connectionszone1" runat="server" />
    </td>
  </tr>
  </table>
    
  </form>
</body>
</html>

O exemplo de código inclui um controle de usuário que permite alterar os modos de exibição em uma página de Web Parts. O código-fonte para o controle do usuário vem de outro tópico. Você pode obter o arquivo .ascx para o controle de usuário de Passo a passo : alterando modos de exibição em uma página de Web Parts e ele deve ser colocado na mesma pasta que a página .aspx.

Comentários

Os transformadores são usados para traduzir dados entre dois controles de Web Parts com pontos de conexão incompatíveis. Um RowToFieldTransformer objeto transforma dados de um provedor implementando a IWebPartRow interface para um consumidor que exige dados da IWebPartField interface. A RowToFieldTransformer classe permite que controles com esses pontos de conexão incompatíveis sejam conectados.

Construtores

Propriedades

Métodos

Implantações explícitas de interface

Aplica-se a