Transaction Class

Artigo
07/22/2011

A transaction makes sure that changes that were made to the store are treated as a group that can be committed or rolled back.

Inheritance Hierarchy

System.Object
System.MarshalByRefObject
Microsoft.VisualStudio.Modeling.Transaction

Namespace: Microsoft.VisualStudio.Modeling
Assembly: Microsoft.VisualStudio.Modeling.Sdk.10.0 (in Microsoft.VisualStudio.Modeling.Sdk.10.0.dll)

Syntax

'Declaração
Public Class Transaction _
    Inherits MarshalByRefObject _
    Implements IDisposable

public class Transaction : MarshalByRefObject, 
    IDisposable

public ref class Transaction : public MarshalByRefObject, 
    IDisposable

type Transaction =  
    class
        inherit MarshalByRefObject
        interface IDisposable
    end

public class Transaction extends MarshalByRefObject implements IDisposable

The Transaction type exposes the following members.

Properties

	Name	Description
	Context	Gets the transaction and enables clients to append user data to the transaction.
	ContextInstance	Gets the Context for this transaction.
	ForceAllRulesToCommitTime	Gets or sets a flag that forces all nested rules to occur at LocalCommit time for the current transaction.
	HasPendingChanges	Gets the transaction and verifies whether changes to the store have been made during this transaction.
	HaveCommitTimeRulesFired	Indicates whether the commit time rules have been fired or not
	Id	Gets the ID for this transaction.
	InRollback	Gets the transaction and verifies whether this transaction is being rolled back.
	IsActive	Gets the transaction and verifies whether this transaction is processing.
	IsHidden	Gets the transaction and verifies whether the transaction is hidden.
	IsNested	Gets the transaction and verifies whether a transaction is nested within another transaction.
	IsSerializing	Gets the transaction and verifies whether the transaction is currently serializing.
	Name	Gets or sets the name of the transaction.
	Parent	Gets the top-level transaction that is assigned to the nested transaction.
	PartitionStates	Gets information about the state of all partitions in the store.
	SequenceNumber	Gets the sequence number for the transaction.
	Store	Gets the store to which the transaction belongs.
	TopLevelTransaction	Gets the top-level transaction of the transaction hierarchy.
	TransactionDepth	Gets the number of transactions in which this transaction is nested.

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Methods

	Name	Description
	Commit	Commits the transaction.
	CreateObjRef	Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject.)
	Dispose	Disposes the state of the transaction.
	Equals	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Finalizes the transaction. (Overrides Object.Finalize().)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetLifetimeService	Retrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	InitializeLifetimeService	Obtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
	MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object.)
	MemberwiseClone(Boolean)	Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject.)
	Rollback	The Store will be set back to the state that it was in when the transaction was created.
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Extension Methods

	Name	Description
	GetSerializationContext	Get the SerializationContext active in the context of the specified transaction. The SerializationContext is stored in the TranactionContext of serializing transactions. If the transaction is nested the transaction stack is searched to find the nearest enclosing serialization transaction with a SerializationContext. (Defined by SerializationContextTransactionExtensions.)

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Remarks

A transaction enables you to group changes. It also keeps track of the actions that are performed in a transaction so that they can be undone at a later stage.

Changes to the store must be done in a transaction. Changes to the store are made only if the transaction commits. A transaction can have the store accept the changes when the local transaction is committed or when the top-level transaction is committed. Local transactions are nested in a top-level transaction. A nested transaction must commit or roll back before the next top-level transaction can commit or roll back. For more information, see the example for the TransactionDepth property.

A transaction also keeps track of the actions that have occurred. This enables a group of actions to be undone or redone at a later stage with the UndoManager property.

A transaction should be disposed. This can be done by using the Dispose method or by creating the transaction in a Using construct. If the transaction has not been committed when it is disposed, the transaction is automatically rolled back and any changes are canceled.

Examples

The following example shows a transaction that modifies the store. The transaction is committed. If the transaction is rolled back, any changes to the store are canceled. The transaction is disposed automatically at the end of the using block.

using (Transaction txCreateElem =  model.Store.TransactionManager.BeginTransaction("Create named element")
{
  A a = new A(store);
  a.Name = "Fred";
  // Commit the transaction and add the named element to the model
  txCreateElem.Commit();
}

For examples and more information, see Using Transactions.

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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