WebPartManager.CanConnectWebParts 方法

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。

检查将参与连接的 WebPart 控件，以确定它们是否能够被连接。

重载

CanConnectWebParts(WebPart, ProviderConnectionPoint, WebPart, ConsumerConnectionPoint)	当使用者和提供者控件有兼容接口且不需要 WebPart 对象时，请检查将参与连接的 WebPartTransformer 控件，以确定它们是否能够被连接。
CanConnectWebParts(WebPart, ProviderConnectionPoint, WebPart, ConsumerConnectionPoint, WebPartTransformer)	检查将参与连接的 WebPart 控件，以确定这些控件是否能够连接，并使用 WebPartTransformer 对象在不兼容的使用者和提供者之间创建连接。

注解

方法 CanConnectWebParts 用于确定是否可以连接两个 WebPart 控件。方法通常在调用 ConnectWebParts 方法之前用作条件检查。

方法 CanConnectWebParts 检查在两个控件可以形成连接之前必须满足的多个条件。以下列表汇总了建立连接的主要条件。如果满足所有这些条件 (以及) 的一些其他内部条件，则方法返回 true，这意味着可以连接控件：

提供程序和使用者控件不能是 null，它们必须包含在属性引用的控件的集合中 WebParts 。
提供程序和使用者不能是同一控件。换句话说，控件 WebPart 无法连接到自身。
ConnectionPoint提供程序和使用者) (连接点的对象不能是 null。
不能关闭提供程序和使用者， (两个控件的 IsClosed 属性都 true 不能) 。
ControlType连接点控件的属性必须与使用者和提供程序的控件的类型匹配。
连接点必须同时启用， (其 GetEnabled 方法必须返回 true) 。
每个连接点不得尝试形成超过其属性 AllowsMultipleConnections 中指定的连接数。
如果需要 (WebPartTransformer 转换器) 的对象来连接不兼容的控件，则它不能为 null。但是，如果控件已兼容，则转换器必须为 null。
转换器 (（如果使用) 必须在集合中 AvailableTransformers 引用）。
转换器 (如果使用) 必须具有与提供程序和使用者兼容的接口，以便它可以在两个控件之间转换数据。使用者和提供程序的辅助接口也必须兼容。

CanConnectWebParts(WebPart, ProviderConnectionPoint, WebPart, ConsumerConnectionPoint)

当使用者和提供者控件有兼容接口且不需要 WebPart 对象时，请检查将参与连接的 WebPartTransformer 控件，以确定它们是否能够被连接。

public:
 bool CanConnectWebParts(System::Web::UI::WebControls::WebParts::WebPart ^ provider, System::Web::UI::WebControls::WebParts::ProviderConnectionPoint ^ providerConnectionPoint, System::Web::UI::WebControls::WebParts::WebPart ^ consumer, System::Web::UI::WebControls::WebParts::ConsumerConnectionPoint ^ consumerConnectionPoint);

public bool CanConnectWebParts (System.Web.UI.WebControls.WebParts.WebPart provider, System.Web.UI.WebControls.WebParts.ProviderConnectionPoint providerConnectionPoint, System.Web.UI.WebControls.WebParts.WebPart consumer, System.Web.UI.WebControls.WebParts.ConsumerConnectionPoint consumerConnectionPoint);

member this.CanConnectWebParts : System.Web.UI.WebControls.WebParts.WebPart * System.Web.UI.WebControls.WebParts.ProviderConnectionPoint * System.Web.UI.WebControls.WebParts.WebPart * System.Web.UI.WebControls.WebParts.ConsumerConnectionPoint -> bool

Public Function CanConnectWebParts (provider As WebPart, providerConnectionPoint As ProviderConnectionPoint, consumer As WebPart, consumerConnectionPoint As ConsumerConnectionPoint) As Boolean

参数

provider: WebPart

在控件连接时为 consumer 提供数据的控件。

providerConnectionPoint: ProviderConnectionPoint

使 provider 能够参与连接的 ConnectionPoint。

consumer: WebPart

控件连接时从 provider 接收数据的控件。

consumerConnectionPoint: ConsumerConnectionPoint

一个 ConnectionPoint，它作为回调方法，以便 consumer 可以参与连接。

Boolean

一个布尔值，指示是否能连接 provider 和 consumer。

示例

下面的代码示例演示如何使用此方法。

该代码示例包含四个部分：

一个用户控件，可用于更改 Web 部件页上的显示模式。
一个网页，其中包含两个可以连接的自定义 WebPart 控件、一个 <asp:webpartmanager> 元素和一些使用 CanConnectWebParts 方法创建连接的事件处理代码。
一个源代码文件，其中包含两个自定义 WebPart 控件和一个自定义接口。
说明该示例在浏览器中的工作原理。

代码示例的第一部分是用于更改显示模式的用户控件。可以从类概述的“示例”部分获取用户控件的 WebPartManager 源代码。有关显示模式和用户控件工作原理的详细信息，请参阅演练：更改 Web 部件页上的显示模式。

网页的声明性标记包含 Register 用户控件和自定义控件的指令。有一个 <asp:webpartmanager> 元素、一个 <asp:webpartzone> 用于包含自定义控件的元素和一个 <asp:connectionszone> 元素。请注意，在方法中 Page_Load ，代码检查是否可以建立连接，如果是，则定义提供程序、使用者及其各自的连接点，然后将新连接添加到由属性引用 StaticConnections 的静态连接集。

<%@ Page Language="C#" %>
<%@ register TagPrefix="uc1" 
  TagName="DisplayModeMenuCS" 
  Src="DisplayModeMenuCS.ascx" %>
<%@ register tagprefix="aspSample" 
  Namespace="Samples.AspNet.CS.Controls" 
  Assembly="ConnectionSampleCS"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

  protected void Page_Load(object sender, EventArgs e)
  {
    
    // Define provider, consumer, and connection points.
    WebPart provider = mgr.WebParts["zip1"];
    ProviderConnectionPoint provConnPoint =
      mgr.GetProviderConnectionPoints(provider)["ZipCodeProvider"];
    WebPart consumer = mgr.WebParts["weather1"];
    ConsumerConnectionPoint consConnPoint =
      mgr.GetConsumerConnectionPoints(consumer)["ZipCodeConsumer"];
    
    // Check whether the connection already exists.
    if (mgr.CanConnectWebParts(provider, provConnPoint,
      consumer, consConnPoint))
    {
      // Create a new static connection.
      WebPartConnection conn = new WebPartConnection();
      conn.ID = "staticConn1";
      conn.ConsumerID = "weather1";
      conn.ConsumerConnectionPointID = "ZipCodeConsumer";
      conn.ProviderID = "zip1";
      conn.ProviderConnectionPointID = "ZipCodeProvider";
      mgr.StaticConnections.Add(conn);
    }
 }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">
      <!-- Reference the WebPartManager control. -->
      <asp:WebPartManager ID="mgr" runat="server" />   
    <div>
      <uc1:DisplayModeMenuCS ID="displaymode1" 
        runat="server" />
      <!-- Reference consumer and provider controls 
           in a zone. -->
      <asp:WebPartZone ID="WebPartZone1" runat="server">
        <ZoneTemplate>
          <aspSample:ZipCodeWebPart ID="zip1" 
            runat="server" 
            Title="Zip Code Control"/>
          <aspSample:WeatherWebPart ID="weather1" 
            runat="server" 
            Title="Weather Control" />
        </ZoneTemplate>
      </asp:WebPartZone>
      <hr />
      <!-- Add a ConnectionsZone so users can connect 
           controls. -->
      <asp:ConnectionsZone ID="ConnectionsZone1" 
        runat="server" />
    </div>
    </form>
</body>
</html>

<%@ Page Language="vb" %>
<%@ register TagPrefix="uc1" 
  TagName="DisplayModeMenuVB" 
  Src="DisplayModeMenuVB.ascx" %>
<%@ register tagprefix="aspSample" 
  Namespace="Samples.AspNet.VB.Controls" 
  Assembly="ConnectionSampleVB"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

  Protected Sub Page_Load(ByVal sender As Object, _
    ByVal e As System.EventArgs)
    
    ' Define provider, consumer, and connection points.
    Dim provider As WebPart = mgr.WebParts("zip1")
    Dim provConnPoint As ProviderConnectionPoint = _
      mgr.GetProviderConnectionPoints(provider)("ZipCodeProvider")
    Dim consumer As WebPart = mgr.WebParts("weather1")
    Dim consConnPoint As ConsumerConnectionPoint = _
      mgr.GetConsumerConnectionPoints(consumer)("ZipCodeConsumer")
    
    ' Check whether the connection already exists.
    If mgr.CanConnectWebParts(provider, provConnPoint, _
      consumer, consConnPoint) Then
      ' Create a new static connection.
      Dim conn As New WebPartConnection()
      conn.ID = "staticConn1"
      conn.ConsumerID = "weather1"
      conn.ConsumerConnectionPointID = "ZipCodeConsumer"
      conn.ProviderID = "zip1"
      conn.ProviderConnectionPointID = "ZipCodeProvider"
      mgr.StaticConnections.Add(conn)
    End If
    
  End Sub
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">
      <!-- Reference the WebPartManager control. -->
      <asp:WebPartManager ID="mgr" runat="server" />   
    <div>
      <uc1:DisplayModeMenuVB ID="displaymode1" 
        runat="server" />
      <!-- Reference consumer and provider controls 
           in a zone. -->
      <asp:WebPartZone ID="WebPartZone1" runat="server">
        <ZoneTemplate>
          <aspSample:ZipCodeWebPart ID="zip1" 
            runat="server" 
            Title="Zip Code Control"/>
          <aspSample:WeatherWebPart ID="weather1" 
            runat="server" 
            Title="Weather Control" />
        </ZoneTemplate>
      </asp:WebPartZone>
      <hr />
      <!-- Add a ConnectionsZone so users can connect 
           controls. -->
      <asp:ConnectionsZone ID="ConnectionsZone1" 
        runat="server" />
    </div>
    </form>
</body>
</html>

该示例的第三部分是控件的源代码。它包含一个接口和两个自定义 WebPart 控件，一个充当提供程序，另一个充当使用者。由于它们具有兼容的连接点 (两者都识别 IZipCode 接口) ，因此不需要转换器来建立连接。若要运行代码示例，必须编译此源代码。可以显式编译它，并将生成的程序集放入网站的 Bin 文件夹或全局程序集缓存中。或者，可以将源代码放入站点的“App_Code”文件夹中，并在运行时动态编译源代码。有关演示如何编译的演练，请参阅演练：开发和使用自定义 Web 服务器控件。

namespace Samples.AspNet.CS.Controls
{
  using System;
  using System.Web;
  using System.Web.Security;
  using System.Security.Permissions;
  using System.Web.UI;
  using System.Web.UI.WebControls;
  using System.Web.UI.WebControls.WebParts;

  [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  public interface IZipCode
  {
    string ZipCode { get; set;}
  }

  [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  public class ZipCodeWebPart : WebPart, IZipCode
  {
    string zipCodeText = String.Empty;
    TextBox input;
    Button send;

    public ZipCodeWebPart()
    {
    }

    // Make the implemented property personalizable to save 
    // the Zip Code between browser sessions.
    [Personalizable()]
    public virtual string ZipCode
    {
      get { return zipCodeText; }
      set { zipCodeText = value; }
    }

    // This is the callback method that returns the provider.
    [ConnectionProvider("Zip Code", "ZipCodeProvider")]
    public IZipCode ProvideIZipCode()
    {
      return this;
    }

    protected override void CreateChildControls()
    {
      Controls.Clear();
      input = new TextBox();
      this.Controls.Add(input);
      send = new Button();
      send.Text = "Enter 5-digit Zip Code";
      send.Click += new EventHandler(this.submit_Click);
      this.Controls.Add(send);
    }

    private void submit_Click(object sender, EventArgs e)
    {
      if (!string.IsNullOrEmpty(input.Text))
      {
        zipCodeText = Page.Server.HtmlEncode(input.Text);
        input.Text = String.Empty;
      }
    }
  }

  [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  public class WeatherWebPart : WebPart
  {
    private IZipCode _provider;
    string _zipSearch;
    Label DisplayContent;

    // This method is identified by the ConnectionConsumer 
    // attribute, and is the mechanism for connecting with 
    // the provider. 
    [ConnectionConsumer("Zip Code", "ZipCodeConsumer")]
    public void GetIZipCode(IZipCode Provider)
    {
      _provider = Provider;
    }
    
    protected override void OnPreRender(EventArgs e)
    {
      EnsureChildControls();

      if (this._provider != null)
      {
        _zipSearch = _provider.ZipCode.Trim();
        DisplayContent.Text = "My Zip Code is:  " + _zipSearch;
      }
    }

    protected override void CreateChildControls()
    {
      Controls.Clear();
      DisplayContent = new Label();
      this.Controls.Add(DisplayContent);
    }
  }
}

Imports System.Web
Imports System.Web.Security
Imports System.Security.Permissions
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts

Namespace Samples.AspNet.VB.Controls

  <AspNetHostingPermission(SecurityAction.Demand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  <AspNetHostingPermission(SecurityAction.InheritanceDemand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  Public Interface IZipCode

    Property ZipCode() As String

  End Interface

  <AspNetHostingPermission(SecurityAction.Demand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  <AspNetHostingPermission(SecurityAction.InheritanceDemand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  Public Class ZipCodeWebPart
    Inherits WebPart
    Implements IZipCode
    Private zipCodeText As String = String.Empty
    Private input As TextBox
    Private send As Button

    Public Sub New()
    End Sub

    ' Make the implemented property personalizable to save 
    ' the Zip Code between browser sessions.
    <Personalizable()> _
    Public Property ZipCode() As String _
      Implements IZipCode.ZipCode

      Get
        Return zipCodeText
      End Get
      Set(ByVal value As String)
        zipCodeText = value
      End Set
    End Property

    ' This is the callback method that returns the provider.
    <ConnectionProvider("Zip Code", "ZipCodeProvider")> _
    Public Function ProvideIZipCode() As IZipCode
      Return Me
    End Function


    Protected Overrides Sub CreateChildControls()
      Controls.Clear()
      input = New TextBox()
      Me.Controls.Add(input)
      send = New Button()
      send.Text = "Enter 5-digit Zip Code"
      AddHandler send.Click, AddressOf Me.submit_Click
      Me.Controls.Add(send)

    End Sub


    Private Sub submit_Click(ByVal sender As Object, _
      ByVal e As EventArgs)

      If input.Text <> String.Empty Then
        zipCodeText = Page.Server.HtmlEncode(input.Text)
        input.Text = String.Empty
      End If

    End Sub

  End Class

  <AspNetHostingPermission(SecurityAction.Demand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  <AspNetHostingPermission(SecurityAction.InheritanceDemand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  Public Class WeatherWebPart
    Inherits WebPart
    Private _provider As IZipCode
    Private _zipSearch As String
    Private DisplayContent As Label

    ' This method is identified by the ConnectionConsumer 
    ' attribute, and is the mechanism for connecting with 
    ' the provider. 
    <ConnectionConsumer("Zip Code", "ZipCodeConsumer")> _
    Public Sub GetIZipCode(ByVal Provider As IZipCode)
      _provider = Provider
    End Sub


    Protected Overrides Sub OnPreRender(ByVal e As EventArgs)
      EnsureChildControls()

      If Not (Me._provider Is Nothing) Then
        _zipSearch = _provider.ZipCode.Trim()
                DisplayContent.Text = "My Zip Code is:  " + _zipSearch
      End If

    End Sub

    Protected Overrides Sub CreateChildControls()
      Controls.Clear()
      DisplayContent = New Label()
      Me.Controls.Add(DisplayContent)

    End Sub

  End Class

End Namespace

在浏览器中加载网页后，单击“ 显示模式 ”下拉列表控件，然后选择“ 连接 ”将页面切换到连接模式。连接模式使用 <asp:connectionszone> 元素在控件之间创建连接。在连接模式下，单击 “邮政编码” 控件标题栏中的向下箭头以激活其谓词菜单，然后单击“ 连接”。显示连接用户界面 (UI) 后，请注意，方法中包含的 Page_Load 代码已创建连接。

注解

此方法用于连接 provider ，以及 consumer 当两个 WebPartTransformer 控件都具有兼容的连接点类型时，因此不需要对象。在调用 ConnectWebParts 创建编程连接之前，你可能想要使用此方法验证是否可以连接两个控件。

此重载使用与方法重载相同的实现 CanConnectWebParts(WebPart, ProviderConnectionPoint, WebPart, ConsumerConnectionPoint, WebPartTransformer) ，唯一的例外是此重载不需要转换器。

另请参阅

ASP.NET Web 部件控件

适用于

CanConnectWebParts(WebPart, ProviderConnectionPoint, WebPart, ConsumerConnectionPoint, WebPartTransformer)

检查将参与连接的 WebPart 控件，以确定这些控件是否能够连接，并使用 WebPartTransformer 对象在不兼容的使用者和提供者之间创建连接。

public:
 virtual bool CanConnectWebParts(System::Web::UI::WebControls::WebParts::WebPart ^ provider, System::Web::UI::WebControls::WebParts::ProviderConnectionPoint ^ providerConnectionPoint, System::Web::UI::WebControls::WebParts::WebPart ^ consumer, System::Web::UI::WebControls::WebParts::ConsumerConnectionPoint ^ consumerConnectionPoint, System::Web::UI::WebControls::WebParts::WebPartTransformer ^ transformer);

public virtual bool CanConnectWebParts (System.Web.UI.WebControls.WebParts.WebPart provider, System.Web.UI.WebControls.WebParts.ProviderConnectionPoint providerConnectionPoint, System.Web.UI.WebControls.WebParts.WebPart consumer, System.Web.UI.WebControls.WebParts.ConsumerConnectionPoint consumerConnectionPoint, System.Web.UI.WebControls.WebParts.WebPartTransformer transformer);

abstract member CanConnectWebParts : System.Web.UI.WebControls.WebParts.WebPart * System.Web.UI.WebControls.WebParts.ProviderConnectionPoint * System.Web.UI.WebControls.WebParts.WebPart * System.Web.UI.WebControls.WebParts.ConsumerConnectionPoint * System.Web.UI.WebControls.WebParts.WebPartTransformer -> bool
override this.CanConnectWebParts : System.Web.UI.WebControls.WebParts.WebPart * System.Web.UI.WebControls.WebParts.ProviderConnectionPoint * System.Web.UI.WebControls.WebParts.WebPart * System.Web.UI.WebControls.WebParts.ConsumerConnectionPoint * System.Web.UI.WebControls.WebParts.WebPartTransformer -> bool

Public Overridable Function CanConnectWebParts (provider As WebPart, providerConnectionPoint As ProviderConnectionPoint, consumer As WebPart, consumerConnectionPoint As ConsumerConnectionPoint, transformer As WebPartTransformer) As Boolean

参数

provider: WebPart

在控件连接时为 consumer 提供数据的控件。

providerConnectionPoint: ProviderConnectionPoint

一个 ConnectionPoint，它作为回调方法，以便 provider 可以参与连接。

consumer: WebPart

控件连接时从 provider 接收数据的控件。

consumerConnectionPoint: ConsumerConnectionPoint

一个 ConnectionPoint，它作为回调方法，以便 consumer 可以参与连接。

transformer: WebPartTransformer

一个 WebPartTransformer，它使不兼容的 provider 和 consumer 能够进行连接。

Boolean

一个布尔值，它指示 provider 和 consumer 是否可以形成连接。

注解

当两个控件都有不兼容的连接点类型时，此方法用于连接providerconsumer，因此需要对象WebPartTransformer。在调用 ConnectWebParts 创建编程连接之前，你可能想要使用此方法验证是否可以连接两个控件。

此重载使用与方法重载相同的实现 CanConnectWebParts(WebPart, ProviderConnectionPoint, WebPart, ConsumerConnectionPoint) ，唯一的例外是此重载需要转换器。

适用于

通过

WebPartManager.CanConnectWebParts 方法

定义

重载

注解

CanConnectWebParts(WebPart, ProviderConnectionPoint, WebPart, ConsumerConnectionPoint)

参数

返回

示例

注解

另请参阅

适用于

CanConnectWebParts(WebPart, ProviderConnectionPoint, WebPart, ConsumerConnectionPoint, WebPartTransformer)

参数

返回

注解

适用于

其他资源