DataConnectionSupport Class

Article
02/23/2011

Provides properties and methods that enable you to work directly with connections to a data source.

Inheritance Hierarchy

System.Object
  Microsoft.VisualStudio.Data.ServiceProvider
    Microsoft.VisualStudio.Data.ServiceProviderWithSite
      Microsoft.VisualStudio.Data.DataConnectionSupport
        Microsoft.VisualStudio.Data.AdoDotNet.AdoDotNetConnectionSupport

Namespace: Microsoft.VisualStudio.Data
Assembly: Microsoft.VisualStudio.Data (in Microsoft.VisualStudio.Data.dll)

Syntax

'Declaration
Public MustInherit Class DataConnectionSupport _
    Inherits ServiceProviderWithSite _
    Implements IDisposable

public abstract class DataConnectionSupport : ServiceProviderWithSite, 
    IDisposable

public ref class DataConnectionSupport abstract : public ServiceProviderWithSite, 
    IDisposable

[<AbstractClass>]
type DataConnectionSupport =  
    class
        inherit ServiceProviderWithSite
        interface IDisposable
    end

public abstract class DataConnectionSupport extends ServiceProviderWithSite implements IDisposable

The DataConnectionSupport type exposes the following members.

Constructors

	Name	Description
	DataConnectionSupport	Class constructor. Instantiates a nonparameterized instance of the DataConnectionSupport class.

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Properties

	Name	Description
	ConnectionString	Retrieves or sets a string representation of information required to establish a given data source connection.
	ConnectionTimeout	Retrieves or sets the amount of time, in seconds, to wait to establish a connection before terminating the attempt and generating a timeout error.
	ProviderObject	Retrieves the underlying data provider object for the specified connection.
	ServiceTypes	Retrieves a list of service types used to convert the unmanaged QueryService method call, in which a service GUID is specified, into a managed IServiceProvider.GetService method call, in which a managed type is specified. (Inherited from ServiceProvider.)
	Site	Retrieves or sets the site object instance. (Inherited from ServiceProviderWithSite.)
	State	Retrieves the state of the data connection.

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Methods

	Name	Description
	Close	Closes the specified connection.
	Dispose()	Performs tasks associated with freeing, releasing, or resetting resources.
	Dispose(Boolean)	Performs tasks associated with freeing, releasing, or resetting resources.
	Equals	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Finalizes the connection. (Overrides Object.Finalize().)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetService(Guid)	Retrieves a service with a specified service GUID. (Inherited from ServiceProvider.)
	GetService(Type)	Retrieves a service of the specified type. (Inherited from ServiceProvider.)
	GetServiceImpl(Type)	Allows you to obtain implementation services. (Overrides ServiceProvider.GetServiceImpl(Type).)
	GetServiceImpl(Guid)	Provides the implementation for retrieving a service with a specific GUID. (Inherited from ServiceProvider.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	Initialize	Initializes the specified connection, optionally from an existing data provider object.
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	OnSiteChanged	Raises the SiteChanged event. (Inherited from ServiceProviderWithSite.)
	Open	Opens the specified connection.
	RaiseMessageReceived	Raises the MessageReceivedevent on the enclosing DataConnection instance.
	RaiseStateChanged	Raises the state changed event on the enclosing DataConnection instance.
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Events

	Name	Description
	SiteChanged	Event raised when the Site property has changed. (Inherited from ServiceProviderWithSite.)

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Explicit Interface Implementations

	Name	Description
	IObjectWithSite.GetSite	Retrieves the last site set using the IObjectWithSite.SetSite method. If there is no known site, an exception is thrown. (Inherited from ServiceProviderWithSite.)
	IServiceProvider.QueryService	Performs as a factory for services that are exposed through an implementation of IServiceProvider. (Inherited from ServiceProvider.)
	IObjectWithSite.SetSite	Provides a site's IUnknown pointer to a given object. (Inherited from ServiceProviderWithSite.)

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Remarks

The DataConnectionSupport class represents the data provider implementation to support a data connection. The DDEX architecture implements the DataConnection class by calling into a provider specific DataConnectionSupport implementation.

The properties and methods on this class provide basic functionality that allows the data provider to communicate with the data source, performing such tasks as opening and closing connections and retrieving connection state. A data provider can also expose more specialized services by overriding the GetServiceImpl method. These connection-related services are summarized following:

DataViewSupport: Provides a method for retrieving XML that describes data source specific views of data objects to be shown in the Visual Studio Server Explorer.
DataObjectSupport: Provides a method for retrieving XML that describes types of data objects supported by the data source and actions that can be performed on them.
DataObjectIdentifierResolver: Provides a method for resolving data object identifiers.
DataObjectIdentifierConverter: Provides methods for converting between string and array representations of data object identifiers.
DataObjectItemComparer: Provides methods for comparing data object identifier parts and property values.
DataCommand: Provides the ability to derive and execute various types of commands.
DataAsyncCommand: Enables executing data commands in an asynchronous manner.
DataTransaction: Provides the ability to begin, commit, and roll back transactions.
DataSourceVersionComparer: Provides a method for comparing two data-source-specific version strings.
DataSourceInformation: Provides a set of well-defined name-value pairs that describe the data source.

This class implements the IObjectWithSite interface, which allows DDEX to site a data provider's DataConnectionSupport implementation with the DataConnection object that is calling into it. This provides the implementation with context, as well as with a means for retrieving Visual Studio services.

Any derived class should implement the various abstract properties and methods to support their connection. A derived class should also override the protected GetServiceImplmethod to provide its connection services. When a state-change or message-received event occurs, a derived class should, where possible, call the protected RaiseStateChanged and RaiseMessageReceived methods, which the base class then passes on to the sited DataConnection object.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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