ConnectionsZone Class
Provides a user interface (UI) that enables users to form connections between WebPart and other server controls that reside in WebPartZoneBase zones.
Assembly: System.Web (in System.Web.dll)
[AspNetHostingPermissionAttribute(SecurityAction::LinkDemand, Level = AspNetHostingPermissionLevel::Minimal)] [AspNetHostingPermissionAttribute(SecurityAction::InheritanceDemand, Level = AspNetHostingPermissionLevel::Minimal)] public ref class ConnectionsZone : public ToolZone
<asp:ConnectionsZone />
Using the Web Parts control set, you can enable two server controls to form a connection and share data, with one control acting as the provider, and the other acting as the consumer of the data. The two controls can be WebPart controls or any other type of server control, provided that they are designed to handle connections, and that they are residing in a WebPartZoneBase zone. To learn more about Web Parts connections, see the WebPartConnection and ConnectionPoint class overviews, as well as Web Parts Connections Overview.
Provided that the requisite controls and conditions exist to form a Web Parts connection, it is still necessary to actually connect the controls. There are three ways to form a connection between server controls: declaring a connection in a Web page, creating a connection in code, or adding a ConnectionsZone control to the page so that users can connect the controls on demand. The ConnectionsZone control generates a UI that enables users to connect or disconnect any server controls on a page that meet the conditions necessary to form a connection. It is an optional control that is not necessary to form connections, but is useful in the case where you want to give users control over which server controls are connected or disconnected.
The ConnectionsZone control is one of the Web Parts tool zone controls that inherit from the ToolZone base class. As a tool zone, the ConnectionsZone control is designed to be visible only when its Web page is in a certain display mode. In this case, the display mode is named connect mode (a page is in this mode when the WebPartManager control on the page has its DisplayMode property value set to ConnectDisplayMode). After users switch a page into connect mode, they must click a connect verb on the verbs menu of one of the server controls, and then the connection UI becomes visible.
As a Web Parts zone control, the ConnectionsZone control is a type of WebZone zone (which inherits from the CompositeControl class) designed to contain other controls. In general, a ConnectionsZone zone has most of the same elements as other Web Parts tool zones: a header, a body or contents area, and a footer. For a complete discussion of what a Web Parts zone is, and the different parts of a zone, see the WebZone class overview.
Important Note: |
|---|
Unlike most other Web Parts zones, it is important to note that a ConnectionsZone zone does not contain a unique type of server control associated with it. For a list of zones and the associated controls they contain, see the chart in the WebZone class overview. But the ConnectionsZone zone does not contain WebPartConnection controls. Instead, it serves a very limited purpose of providing a UI for users to connect or disconnect server controls that exist in some WebPartZoneBase zone on the page. The only controls contained in a ConnectionsZone control are the standard ASP.NET server controls that it generates as part of its UI for forming connections. |
When the ConnectionsZone control is rendered, it generates a UI based on the server controls on the page that are capable of forming connections. The ConnectionsZone control determines which server controls in the WebPartZoneBase zone on the page are providers, which are consumers, which connection points are available, and whether the server controls are currently connected or disconnected, and then it generates the UI accordingly.
For example, suppose there is one WebPart control capable of being a provider, one WebPart control capable of being a consumer, they are declared in a WebPartZone on the page, and they are currently disconnected. When a user switches the page to connect mode and clicks the connect verb on one of the controls, the ConnectionsZone control generates a UI with a link that, when clicked, displays a form in which users can choose options to create a connection. (If the controls were previously connected, the initial view instead presents users with a button to disconnect the controls). In the connection UI for creating new connections, users are shown which control is a provider, and which control is a consumer. A drop-down list control appears below each server control, listing the available ConnectionPoint objects for the control. From the respective drop-down lists, users must select one ProviderConnectionPoint object for the provider (to determine what interface and data will be shared with consumers), and one ConsumerConnectionPoint object for each consumer (to determine what interface and data the consumer will consume) that will be connected to the provider.
Note: |
|---|
In the Web Parts control set default implementation, one provider can connect to many consumers, but a consumer can have only one provider. |
To use the ConnectionsZone control, you can declare it within the <form> element on a Web page (but not nested within another Web Parts zone element), using the <asp:connectionszone> element, or you can add it to the page programmatically. If you declare the element in a page, unlike the other Web Parts zones, you cannot declare any other type of server controls between the tags of the <asp:connectionszone> element. You can declare elements within it that relate to its own properties and style details, but it is a standalone element and is not a template control within which other server controls can be declared.
Note: |
|---|
To improve accessibility, the ConnectionsZone control is rendered within a <fieldset> element. The <fieldset> element groups the related set of controls used for establishing connections in the ConnectionsZone control, and it facilitates tabbed navigation among those controls for both visual user agents (such as ordinary Web browsers) and speech-oriented user agents (such as screen-reading software). |
The ConnectionsZone control has a number of properties it uses for rendering the connection UI. One set of properties includes several verbs--used only in relation to connections--that carry out actions in the UI: ConfigureVerb, ConnectVerb, and DisconnectVerb. A large set of properties, used especially for the connections zone UI, consists of text strings displayed at various places (or in certain situations, such as when errors occur) in the UI: ConfigureConnectionTitle, ConnectToConsumerInstructionText, ConnectToConsumerText, ConnectToConsumerTitle, ConnectToProviderInstructionText, ConnectToProviderText, ConnectToProviderTitle, ConsumersInstructionText, ConsumersTitle, ExistingConnectionErrorMessage, GetFromText, GetText, InstructionTitle, NewConnectionErrorMessage, NoExistingConnectionInstructionText, NoExistingConnectionTitle, ProvidersInstructionText, ProvidersTitle, SendText, and SendToText. The ConnectionsZone class also contains a number of common properties found in other Web Parts zones: CancelVerb, CloseVerb, Display, EmptyZoneText, HeaderText, InstructionText, and PartChromeType. Finally, the WebPartToConnect property is unique to the class, referencing the control that initiates the connection (this is the control on which the user clicks the connect verb in its verbs menu, which is also the control referenced in the WebPartManager control's SelectedWebPart property).
The ConnectionsZone class also has a number of methods, all of which are inherited and overridden from base classes, and most of them come from the base Web Parts zone classes. For details, see the individual methods.
Notes to Inheritors:The ConnectionsZone class can be extended, if developers want to change its behavior or the default UI that it provides for working with connections.
The following code example demonstrates how to use the ConnectionsZone control on a Web Parts page. The example has four parts:
A user control that enables you to switch display modes on the Web page.
A source file that contains the code for a ZIP Code interface, and two WebPart controls acting as the provider and the consumer for a connection.
A Web page that hosts all the controls, demonstrates how to declare an <asp:connectionszone> element, and sets a number of properties on the connections zone declaratively and programmatically.
An explanation of how the example works in a browser.
The first part of this code example is the user control that enables users to switch display modes on a Web page. For details about display modes and a description of the source code in this control, see Walkthrough: Changing Display Modes on a Web Parts Page.
The second part of the example is the source file with the interface and custom controls. Notice that the ZipCodeWebPart control implements the IZipCode interface, adding a ConnectionProvider attribute so that the control can act as a provider for a connection. The WeatherWebPart control has a method marked with a ConnectionConsumer attribute, where it consumes the IZipCode interface, so it can act as a consumer in a connection.
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 example uses dynamic compilation. For a walkthrough that demonstrates how to compile, see Walkthrough: Developing and Using a Custom Web Server Control.
The third part of the example code is the Web page. Near the top are Register directives for the user control and the custom controls used in the connection. An <asp:connectionszone> element is declared in the page as an example of using the ConnectionsZone control declaratively. Within the element, a number of properties are set declaratively. Other properties on the connections zone are set programmatically in the <script> section of the page.
Load the Web page in a browser. Use the Display Mode drop-down list control to switch the page to connect mode. On the verbs menu of the ZIP Code Provider control (the verbs menu is indicated by the downward arrow in the control's title bar), click the connect verb. A ConnectionsZone control appears. Note that in the connection UI, an End Connection button appears; the connection has already been declared in the markup of the page, so the controls are already connected. Click End Connection, and then use the Display Mode control again to return the page to browse mode. Next, return the page to connect mode again, click the connect verb on one of the controls, and note that the connection UI now displays a hyperlink that enables you to form a connection between the controls. Click the link, and use the connection UI to select connection points and establish the connection.
- AspNetHostingPermission
for operating in a hosted environment. Demand value: LinkDemand; Permission value: Minimal.
- AspNetHostingPermission
for operating in a hosted environment. Demand value: InheritanceDemand; Permission value: Minimal.
System.Web.UI::Control
System.Web.UI.WebControls::WebControl
System.Web.UI.WebControls::CompositeControl
System.Web.UI.WebControls.WebParts::WebZone
System.Web.UI.WebControls.WebParts::ToolZone
System.Web.UI.WebControls.WebParts::ConnectionsZone
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Important Note:
Note: