The Microsoft .NET Framework 4 Platform Update 1 released today, 4/18/2011.

The Microsoft .NET Framework 4 Platform Update 1 is a platform update that is a set of new features that provides additional functionality for top customer requests and important scenarios.

The features that are enabled in this update are:

• State machine workflows
  • New classes added: StateMachine, State, FinalState, Transition, StateMachineStateQuery, StateMachineStateRecord
  • Getting Started Tutorial: How to Create a State Machine Workflow
  • Windows Workflow Foundation (WF4) - Introduction to State Machine Hands On Lab
  • State Machine Activity Designers
  • State Machine Workflows
  • WF4 State Machine User Experience
• SqlWorkflowInstanceStore support for SQL Azure
  • The scripts that create the persistence database are modified to be compatible with Sql Azure
  • Retry semantics have been added and new error codes added that are specific to SQL Azure scenarios
  • For more information, see the More Information section of KB2478063
• CompensationExtension class, which enables custom workflow hosts to use WF4 compensation

The Microsoft .NET Platform Update 1 consists of three packages:

• Microsoft .NET Framework 4 Platform Update 1 (KB2478063)
  • This package contains the runtime files for the platform update. This package must be deployed on systems where applications that target the platform update are deployed.
• Multi-Targeting Pack for Microsoft .NET Framework 4 Platform Update 1 (KB2495638)
  • This package contains reference assemblies and intellisense files for the platform update. This package is installed as part of the next package.
• Microsoft .NET Framework 4 Platform Update 1 – Design-time Package for Visual Studio 2010 SP1 (KB2495593)
  • This package installs the previous two packages and configures Visual Studio 2010 SP1 with new .NET Framework targeting profiles, intellisense, and adds the state machine activities to the toolbox.

To develop workflow applications in Visual Studio 2010 SP1 that target the new Platform Update 1 functionality, the Microsoft .NET Framework 4 Platform Update 1 – Design-time Package for Visual Studio 2010 SP1 (KB2495593) must be installed. Once it is installed, the .NET Framework 4 Platform Update 1 (KB2478063) profile can be chosen when creating a new .NET application.

There are two new profiles added to Visual Studio when the Design-time Package for Visual Studio 2010 SP1 (KB2495593) is installed.

•  .NET Framework 4 Platform Update 1 (KB2478063)
•  .NET Framework 4 Client Profile Platform Update 1 (KB2478063)

When a new project is created with the platform update profile selected, the .NET Framework 4 Client Profile Platform Update 1 (KB2478063) is used. The .NET Framework 4 Platform Update 1 (KB2478063) profile builds on the .NET Framework 4 profile, and the .NET Framework 4 Client Profile Platform Update 1 (KB2478063) profile builds on the .NET Framework 4 Client Profile. The .NET Framework 4 Client Profile is a subset of the .NET Framework 4 that is optimized for client applications. For more information, see .NET Framework Client Profile.

To choose either profile or change the profile after a project has been created, right-click the project in Solution Explorer, choose Properties, and select the desired profile from the Target framework drop-down.

When either of these profiles is selected, the features in the platform update are available and the State Machine activities are available in the Toolbox.

To configure .NET Framework 4 Platform Update 1 on computers with Visual Studio 2010 SP1 that are going to be used to develop applications that target the functionality in the platform update, install Microsoft .NET Framework 4 Platform Update 1 – Design-time Package for Visual Studio 2010 SP1 (KB2495593).

• Note: Microsoft Visual Studio 2010 Service Pack 1 is required to install the Design-time Package for Visual Studio 2010 SP1 (KB2495593)

To configure a computer on which applications that target the .NET Framework 4 Platform Update 1 are to be deployed, deploy Microsoft .NET Framework 4 Platform Update 1 (KB2478063) and the appropriate version of the .NET Framework 4.

• If the application targets .NET Framework 4 Client Profile Platform Update 1 (KB2478063), you must also deploy either:
  • Microsoft .NET Framework 4
  • Microsoft .NET Framework 4 Client Profile
• If the application targets .NET Framework 4 Platform Update 1 (KB2478063), you must also deploy:
  • Microsoft .NET Framework 4

For information on how to use the new state machine functionality in .NET Framework 4 Platform Update 1, see:

• Getting Started Tutorial: How to Create a State Machine Workflow
• Windows Workflow Foundation (WF4) - Introduction to State Machine Hands On Lab
• State Machine Activity Designers
• State Machine Workflows