.NET equivalent of the old vb left(string, length) function

Here's an extension method that will do the job.

<System.Runtime.CompilerServices.Extension()> _
Public Function Left(ByVal str As String, ByVal length As Integer) As String
    Return str.Substring(0, Math.Min(str.Length, length))
End Function

This means you can use it just like the old VB Left function (i.e. Left("foobar", 3) ) or using the newer VB.NET syntax, i.e.

Dim foo = "f".Left(3) ' foo = "f"
Dim bar = "bar123".Left(3) ' bar = "bar"

Another one line option would be something like the following:

myString.Substring(0, Math.Min(length, myString.Length))

Where myString is the string you are trying to work with.

Add a reference to the Microsoft.VisualBasic library and you can use the Strings.Left which is exactly the same method.