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WebPartConnection.Provider Property

Gets a WebPart control that acts as the provider in a Web Parts connection.

Namespace:  System.Web.UI.WebControls.WebParts
Assembly:  System.Web (in System.Web.dll)

[BrowsableAttribute(false)]
public WebPart Provider { get; }

Property Value

Type: System.Web.UI.WebControls.WebParts.WebPart
A WebPart that acts as the provider of data.

ExceptionCondition
InvalidOperationException

The length of the ProviderID property value is zero.

Every Web Parts connection consists of two WebPart controls--a consumer and a provider--and the Provider property returns a reference to the provider control in a connection.

Like its counterpart in a connection (the consumer control), the provider control is required to establish a connection. Whether you create the connection programmatically, or by declaring it in page persistence format, you must specify a control to act as the provider for a connection.

The following code example demonstrates use of the Provider property.

The code example has three parts:

  • Source code for an interface and two WebPart controls acting as the provider and the consumer for a connection.

  • A Web page to host the controls and run the code example.

  • An explanation of how to run the example page.

The first part of the code example is the source code for the interface, and the consumer and provider controls. For the code example to run, you must compile this source code. You can compile it explicitly and put the resulting assembly in your Web site's Bin folder or the global assembly cache. Alternatively, you can put the source code in your site's App_Code folder, where it will be dynamically compiled at run time. This code example uses dynamic compilation. For a walkthrough that demonstrates how to compile, see Walkthrough: Developing and Using a Custom Web Server Control.

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 Provider", "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 (input.Text != String.Empty)
      {
        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 Consumer", "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);
    }

  }
}

The second part of the code example is the Web page. Near the top is a Register directive that refers to the source code for the two dynamically compiled WebPart controls. The static connection is declared within the <StaticConnections> element on the page. Notice that in the <asp:webpartconnection> element, the ProviderID attribute has the ID of the provider control assigned to it. This is required to identify the provider for the static connection. The Button1_Click method accesses the Provider property and writes some of its details to a label.

<%@ 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">

<script runat="server">

  protected void Button1_Click(object sender, EventArgs e)
  {
    WebPartConnection conn = mgr.StaticConnections[0];

    lbl1.Text = "<h3>Provider Details</h3><br />" +
      "ID: " + conn.Provider.ID + 
      "<br />" + 
      "Display Title: " + conn.Provider.Title + 
      "<br />" + 
      "Control type: " + conn.Provider.GetType().FullName;
  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      <asp:WebPartManager ID="mgr" runat="server">
        <StaticConnections>
          <asp:WebPartConnection ID="conn1"
            ConsumerConnectionPointID="ZipCodeConsumer"
            ConsumerID="weather1" 
            ProviderConnectionPointID="ZipCodeProvider" 
            ProviderID="zip1" />
        </StaticConnections>      
      </asp:WebPartManager>
      <asp:WebPartZone ID="WebPartZone1" runat="server">
        <ZoneTemplate>
          <aspSample:ZipCodeWebPart ID="zip1" runat="server"
            Title="Zip Code Provider"   />
          <aspSample:WeatherWebPart ID="weather1" runat="server" 
            Title="Zip Code Consumer" />
        </ZoneTemplate>
      </asp:WebPartZone>
      <asp:ConnectionsZone ID="ConnectionsZone1" runat="server">
      </asp:ConnectionsZone>
      <asp:Button ID="Button1" runat="server" 
        Text="Provider Details" 
        OnClick="Button1_Click" />
      <br />
      <asp:Label ID="lbl1" runat="server" />
    </div>
    </form>
</body>
</html>

Load the page in a browser. The static connection is already created. Enter some text in the provider control, and note that the text is displayed in the consumer control. Click the Provider Details button to display some of the property values accessed through the Provider property.

.NET Framework

Supported in: 4.5.3, 4, 3.5, 3.0, 2.0

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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