PowerShell type cast using type stored in variable

Question

I\'d like to cast a .NET object to another .NET type, but:

• The target .NET type (class) is stored in a variable
• I don\'t want to use the -as

Answer 1

You can roughly emulate a cast using the following method:

[System.Management.Automation.LanguagePrimitives]::ConvertTo($Value, $TargetType)

A true cast may behave differently than the above method for dynamic objects that provide their own conversions. Otherwise, the only other difference I can think of is performance - a true cast may perform better because of optimizations not available in the ConvertTo static method.

To precisely emulate a cast, you'll need to generate a script block with something like:

function GenerateCastScriptBlock
{
    param([type]$Type)

    [scriptblock]::Create('param($Value) [{0}]$Value' -f
        [Microsoft.PowerShell.ToStringCodeMethods]::Type($Type))
}

You can then assign this script block to a function or invoke it directly, e.g.:

(& (GenerateCastScriptBlock ([int])) "42").GetType()