PSDefaultVariablizer – I didn’t know what else to name it!

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public class PSDefaultVariablizer<T> where T: class
{
    string variableName;
    T innerValue;
    PSCmdlet cmdlet;
 
    public PSDefaultVariablizer(string _variableName, PSCmdlet _cmdlet)
        : this(_variableName, null, _cmdlet) { }
 
    public PSDefaultVariablizer(string _variableName, T _innerValue, PSCmdlet _cmdlet)
    {
        variableName = _variableName;
        innerValue = _innerValue;
        cmdlet = _cmdlet;
    }
 
    public T Value
    {
        get
        {
            if(innerValue != null)
            {
                return innerValue;
            }
            else
            {
                return (T)cmdlet.SessionState.PSVariable.GetValue(variableName, null);
            }
        }
        set
        {
            innerValue = value;
        }
    }
}

Here is the use case for the class. You have a parameter that a user can input, otherwise it attempts to use a value of a variable in the same scope (think how $ErrorActionPreference works). This class allows you to very simply reuse that functionality.

[Cmdlet("Some", "Command")]
public class SomeCommand : PSCmdlet
{
    private PSDefaultVariablizer<string> someParam;
 
    public SomeCommand ()
    {
        someParam = new PSDefaultVariablizer<string>("SomeParam", this);
    }
 
    [Parameter()]
    public string SomeParam
    {
        get
        {
            return someParam.Value;
        }
        set
        {
            someParam.Value = value;
        }
    }
}

And you would use it from Powershell with the following.

Some-Command -SomeParam 'hello'
#or
$SomeParam = 'hello'
Some-Command

Pretty simple really. I just posted it because I thought the name was hilarious, but I didn’t really know what else to call it.

Let me know if anyone knows of an easier way to this. Unfortunately, there aren’t too many people I can talk to about SnapIn development :)

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