Convert String to Double - VB

Is there an efficient method in VB to check if a string can be converted to a double?

I'm currently doing this by trying to convert the string to a double and then seeing if it throws an exception. But this seems to be slowing down my application.

    ' if number then format it.
    current = CDbl(x)
    current = Math.Round(current, d)
    Return current
Catch ex As System.InvalidCastException
    ' item is not a number, do not format... leave as a string
    Return x
End Try


Try looking at Double.TryParse() if you are using .NET 1.1/2.0/3.0/3.5/4.0/4.5