ProviderConnectionPoint 建構函式

public:
 ProviderConnectionPoint(System::Reflection::MethodInfo ^ callbackMethod, Type ^ interfaceType, Type ^ controlType, System::String ^ displayName, System::String ^ id, bool allowsMultipleConnections);

public ProviderConnectionPoint(System.Reflection.MethodInfo callbackMethod, Type interfaceType, Type controlType, string displayName, string id, bool allowsMultipleConnections);

new System.Web.UI.WebControls.WebParts.ProviderConnectionPoint : System.Reflection.MethodInfo * Type * Type * string * string * bool -> System.Web.UI.WebControls.WebParts.ProviderConnectionPoint

Public Sub New (callbackMethod As MethodInfo, interfaceType As Type, controlType As Type, displayName As String, id As String, allowsMultipleConnections As Boolean)

參數

例外狀況

範例

以下程式碼範例示範如何從 ProviderConnectionPoint 類別推導出，建立自訂的提供者連接點。

該程式碼範例包含三個部分：

• 一個包含提供者 WebPart 控制、消費者 WebPart 控制和自訂 ProviderConnectionPoint 物件的原始碼檔案。

• 一個以靜態連線方式承載控制項的網頁。

• 說明如何執行範例程式碼。

程式碼範例的第一部分是提供者與消費者WebPart控制的原始碼，以及一個名為 ProviderConnectionPoint的自訂TableProviderConnectionPoint類別。 請注意， TableProviderConnectionPoint 類別的建構子會呼叫基礎建構子，並依參數章節所示傳遞所需的參數。 另外請注意，在類別TableProviderWebPartGetConnectionInterface中，該方法被指定為連線的回調方法，屬性ConnectionProvider則以參數宣告自訂TableProviderConnectionPoint。 這示範了如何建立自訂的提供者連接點，並將其與提供者控制連結。 這個例子假設原始碼是動態編譯的，所以你應該把原始碼檔案放在網頁應用程式的App_Code子資料夾裡。

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;

//This sample code creates a Web Parts control that acts as a provider of table data.
namespace Samples.AspNet.CS.Controls
{
  [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]
    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", typeof(TableProviderConnectionPoint), AllowsMultipleConnections = true)]
        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;
            }
        }
    }
    
    // This code sample demonstrates a custom WebPart controls that acts as 
    // a consumer in a Web Parts connection.
  [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  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;
    }

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

程式碼範例的第二部分是將自訂控制項置於靜態 Web Parts 連線中的網頁。 頁面頂端有一個 Register 指令，要宣告前綴以及自訂控制項的命名空間。 連線透過元素 <asp:webpartconnection> 宣告，提供者與消費者控制則在元素 <asp:webpartzone> 中宣告。

<%@ page language="C#" %>
<%@ register tagprefix="aspSample" 
    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">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>IField Test Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <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>
            <aspSample:TableProviderWebPart ID="provider1" runat="server" 
              ToolTip="Web Parts Table Provider Control" />
            <aspSample:TableConsumer ID="consumer1" runat="server" 
              ToolTip="Web Parts Table Consumer Control"/>
          </zoneTemplate>
        </asp:webpartzone>
    </div>
    </form>
</body>
</html>

在瀏覽器中載入該頁面。 控制項間的連線已經存在，消費者會顯示提供者的資料，因為該連線在頁面中被宣告為靜態連線。

備註

該類別的 ProviderConnectionPoint 建構子 ProviderConnectionPoint 只需呼叫基底建構子，將各種參數傳達給它，並初始化基底類別。

基底類別建構子會檢查連接點的多個參數，並可拋出多個例外。 有關可能例外的清單，請參閱例外部分。

你可以呼叫 ProviderConnectionPoint 建構子來建立你自己的類別實例 ProviderConnectionPoint 。 然而，如果你只是建立一個連線，而非擴充類別，你應該呼叫該 GetProviderConnectionPoints 方法，從提供者回傳現有的連接點物件。

另請參閱

• GetProviderConnectionPoints(WebPart)
• ASP.NET 網頁零件控制