Creating a Basic Windows PowerShell Provider
This topic is the starting point for learning how to create a Windows PowerShell provider. The basic provider described here provides methods for starting and stopping the provider, and although this provider does not provide a means to access a data store or to get or set the data in the data store, it does provide the basic functionality that is required by all providers.
As mentioned previously, the basic provider described here implements methods for starting and stopping the provider. The Windows PowerShell runtime calls these methods to initialize and uninitialize the provider.
Note
You can find a sample of this provider in the AccessDBSampleProvider01.cs file provided by Windows PowerShell.
Defining the Windows PowerShell Provider Class
The first step in creating a Windows PowerShell provider is to define its .NET class. This basic
provider defines a class called AccessDBProvider that derives from the
System.Management.Automation.Provider.Cmdletprovider
base class.
It is recommended that you place your provider classes in a Providers namespace of your API
namespace, for example, xxx.PowerShell.Providers. This provider uses the
Microsoft.Samples.PowerShell.Provider namespace, in which all Windows PowerShell provider samples
run.
Note
The class for a Windows PowerShell provider must be explicitly marked as public. Classes not marked as public will default to internal and will not be found by the Windows PowerShell runtime.
Here is the class definition for this basic provider:
[CmdletProvider("AccessDB", ProviderCapabilities.None)]
public class AccessDBProvider : CmdletProvider
Right before the class definition, you must declare the System.Management.Automation.Provider.Cmdletproviderattribute attribute, with the syntax [CmdletProvider()].
You can set attribute keywords to further declare the class if necessary. Notice that the System.Management.Automation.Provider.Cmdletproviderattribute attribute declared here includes two parameters. The first attribute parameter specifies the default-friendly name for the provider, which the user can modify later. The second parameter specifies the Windows PowerShell-defined capabilities that the provider exposes to the Windows PowerShell runtime during command processing. The possible values for the provider capabilities are defined by the System.Management.Automation.Provider.Providercapabilities enumeration. Because this is a base provider, it supports no capabilities.
Note
The fully qualified name of the Windows PowerShell provider includes the assembly name and other attributes determined by Windows PowerShell upon registration of the provider.
Defining Provider-Specific State Information
The System.Management.Automation.Provider.Cmdletprovider base class and all derived classes are considered stateless because the Windows PowerShell runtime creates provider instances only as required. Therefore, if your provider requires full control and state maintenance for provider-specific data, it must derive a class from the System.Management.Automation.Providerinfo class. Your derived class should define the members necessary to maintain the state so that the provider-specific data can be accessed when the Windows PowerShell runtime calls the System.Management.Automation.Provider.Cmdletprovider.Start* method to initialize the provider.
A Windows PowerShell provider can also maintain connection-based state. For more information about maintaining connection state, see Creating a PowerShell Drive Provider.
Initializing the Provider
To initialize the provider, the Windows PowerShell runtime calls the System.Management.Automation.Provider.Cmdletprovider.Start* method when Windows PowerShell is started. For the most part, your provider can use the default implementation of this method, which simply returns the System.Management.Automation.Providerinfo object that describes your provider. However, in the case where you want to add additional initialization information, you should implement your own System.Management.Automation.Provider.Cmdletprovider.Start* method that returns a modified version of the System.Management.Automation.Providerinfo object that is passed to your provider. In general, this method should return the provided System.Management.Automation.Providerinfo object passed to it or a modified System.Management.Automation.Providerinfo object that contains other initialization information.
This basic provider does not override this method. However, the following code shows the default implementation of this method:
The provider can maintain the state of provider-specific information as described in Defining Provider-specific Data State. In this case, your implementation must override the System.Management.Automation.Provider.Cmdletprovider.Start* method to return an instance of the derived class.
Start Dynamic Parameters
Your provider implementation of the System.Management.Automation.Provider.Cmdletprovider.Start* method might require additional parameters. In this case, the provider should override the System.Management.Automation.Provider.Cmdletprovider.Startdynamicparameters* method and return an object that has properties and fields with parsing attributes similar to a cmdlet class or a System.Management.Automation.Runtimedefinedparameterdictionary object.
This basic provider does not override this method. However, the following code shows the default implementation of this method:
Uninitializing the Provider
To free resources that the Windows PowerShell provider uses, your provider should implement its own System.Management.Automation.Provider.Cmdletprovider.Stop* method. This method is called by the Windows PowerShell runtime to uninitialize the provider at the close of a session.
This basic provider does not override this method. However, the following code shows the default implementation of this method:
Code Sample
For complete sample code, see AccessDbProviderSample01 Code Sample.
Testing the Windows PowerShell Provider
Once your Windows PowerShell provider has been registered with Windows PowerShell, you can test it
by running the supported cmdlets on the command line. For this basic provider, run the new shell and
use the Get-PSProvider cmdlet to retrieve the list of providers and ensure that the AccessDb
provider is present.
Get-PSProvider
The following output appears:
Name Capabilities Drives
---- ------------ ------
AccessDb None {}
Alias ShouldProcess {Alias}
Environment ShouldProcess {Env}
FileSystem Filter, ShouldProcess {C, Z}
Function ShouldProcess {function}
Registry ShouldProcess {HKLM, HKCU}
