RowToFieldTransformer 类

参考

定义

命名空间:: System.Web.UI.WebControls.WebParts

程序集:: System.Web.dll

重要

一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。

通过 IWebPartField 接口，将 Web 部件连接中的数据从实现 IWebPartRow 接口的提供程序转换为客户期望的数据。

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

继承: Object

WebPartTransformer
RowToFieldTransformer

属性: WebPartTransformerAttribute

实现: IWebPartField

示例

下面的代码示例演示如何使用 RowToFieldTransformer 对象将提供程序和使用者与不兼容的连接点连接起来。本示例的第一部分演示用作提供程序的 Web 部件控件。名为 RowProviderWebPart的提供程序类通过 IWebPartRow 接口提供数据。

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

本示例的第二部分包含一个 Web 部件控件，该控件是 Web 部件连接的使用者。名为的 FieldConsumerWebPart使用者类需要接口中的数据 IWebPartField 。

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

该示例的第三部分显示了一个包含两个控件的页面，并定义 RowToFieldTransformer 用于连接这两个控件的对象。

<%@ 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>

该代码示例包含一个用户控件，可用于更改 Web 部件页上的显示模式。用户控件的源代码来自另一个主题。可以从演练：更改 Web 部件页上的显示模式中获取用户控件的 .ascx 文件，该文件必须与 .aspx 页放在同一文件夹中。

注解

转换器用于在具有不兼容连接点的两个 Web 部件控件之间转换数据。 RowToFieldTransformer对象将数据从实现 IWebPartRow 接口的提供程序转换为需要接口中的数据的IWebPartField使用者。类 RowToFieldTransformer 允许连接具有这些不兼容连接点的控件。

构造函数

RowToFieldTransformer()

初始化 RowToFieldTransformer 类的新实例。

属性

FieldName

获取或设置要转换的值的名称。

方法

CreateConfigurationControl()	在 RowToFieldTransformer 区域中显示配置 ConnectionsZone 转换器的 ASP.NET 控件。
Equals(Object)	确定指定对象是否等于当前对象。 (继承自 Object)
GetHashCode()	作为默认哈希函数。 (继承自 Object)
GetType()	获取当前实例的 Type。 (继承自 Object)
LoadConfigurationState(Object)	加载通过 SaveConfigurationState() 方法保存的配置状态。 (继承自 WebPartTransformer)
MemberwiseClone()	创建当前 Object 的浅表副本。 (继承自 Object)
SaveConfigurationState()	将用户设置的配置状态保存在 ASP.NET 配置控件中。 (继承自 WebPartTransformer)
ToString()	返回表示当前对象的字符串。 (继承自 Object)
Transform(Object)	提供用于转换数据的对象。

显式接口实现

IWebPartField.GetFieldValue(FieldCallback)	返回字段的值，该字段由接口用作两个 Web 部件控件之间的连接基础。
IWebPartField.Schema	获取用于在两个 Web 部件控件之间共享数据的数据字段的架构信息。

适用于

RowToFieldTransformer 类

定义

示例

注解

构造函数

属性

方法

显式接口实现

适用于

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其他资源