(VB.NET) Have a DLL with a single function. Calling this function throws a nullreferenceexception and I can't understand what causes it

Question

This is the code that calls the function:

Imports Peasantlish

    Public Class main
        Dim TranslateLib As Peasantlish.PeasantlishLib
        Private Sub Translate()
            Label2.Text = "Translator - working"
            TextBox1.Text = TranslateLib.TranslateToEng(TextBox2.Text)
        End Sub

TextBox2 is the textbox that contains the text to translate. TextBox1 contains the result.

And this is the function itself:

Imports System.Text.RegularExpressions

Public Class PeasantlishLib
    Public Function TranslateToEng(ByVal input As String)
        Dim output As String = "test string please ignore"
        output = input
        output = Regex.Replace(output, "full hd", "720p", RegexOptions.IgnoreCase)
        output = Regex.Replace(output, "fullhd", "720p", RegexOptions.IgnoreCase)
        output = Regex.Replace(output, "xbox live", "free service that I paid for", RegexOptions.IgnoreCase)
        output = Regex.Replace(output, "\bxbl\b", "free service that I paid for", RegexOptions.IgnoreCase)
        ' next are single words after phrases
        output = Regex.Replace(output, "\bhd\b", "720p", RegexOptions.IgnoreCase)
        output = Regex.Replace(output, "next gen", "already-was-on-pc-3-years-ago gen", RegexOptions.IgnoreCase)
        output = Regex.Replace(output, "censored", "bundle of sticks", RegexOptions.IgnoreCase)
        output = Regex.Replace(output, "gddr5", "high latency RAM", RegexOptions.IgnoreCase)
        output = Regex.Replace(output, "esram", "level 4 cache", RegexOptions.IgnoreCase)
        output = Regex.Replace(output, "Controller", "poo-ey excuse for an output device", RegexOptions.IgnoreCase)
        output = Regex.Replace(output, "console", "potato", RegexOptions.IgnoreCase)
        output = Regex.Replace(output, "cloud", "butt", RegexOptions.IgnoreCase)
        output = Regex.Replace(output, "optimization", "ultra low settings", RegexOptions.IgnoreCase)
        output = Regex.Replace(output, "optimized", "with ultra low settings", RegexOptions.IgnoreCase)
        ' and a bunch more of these
        Return output
    End Function
End Class

It throws the exception at the TextBox1.Text = TranslateLib.TranslateToEng(TextBox1.Text) line. But I don't see anything wrong there. It worked fine before I migrated the bunch of Regex.Replace's to a .dll for tidiness purposes. Before the output variable was TextBox1.Text

Answer 1

Did you instantiate TranslateLib? My VB is a bit rusty, but I thought you needed the New keyword to instantiate a new object:

Dim TranslateLib As New Peasantlish.PeasantlishLib

You can confirm this in your debugger by seeing which object is Nothing (or null). If it's TranslateLib then you never instantiated it.

Answer 2

You need to instantiate your TranslateLib before using it:

Dim TranslateLib As Peasantlish.PeasantlishLib
...
TranslateLib = New Peasantlish.PeasantlishLib