Just about every C# doc you find can be adapted for VB.NET, the syntax when it comes to LINQ to Object changes, but everything else is near identical.
I’m confused, what you posted is near syntax that vb.net honors, so there is nothing to alter, it is simply doing an equality check. Does txbAddress.Text equal the the line we’re iterating on from the multiline textbox.
By the way, you can develop windows forms in C# if you want to, then you don’t have to interpret the syntax.