Question

In C# there is a a problem: there is no case insensitive String.Contains method (see Case insensitive 'Contains(string)').

In VB.NET the problem is the same, but there are a workaround:

Dim Str As String = "UPPERlower"
Dim b As Boolean = InStr(Str, "UpperLower") 

However, I have little “problems” with it :

1) In the Immediate Window of Visual Studio this method appear as
“not declared”;

2) How can I call this method dynamically (what
should be the “caller” object) ? Say actually I should call it like this:

expr = Expression.Call(myStringParam, "Contains", Nothing, constantExpression, Expression.Constant(StringComparison.InvariantCultureIgnoreCase))

3) Where is located (who owns, what assembley) the InStr Function?

Answer 1

Having seen your edit, it makes more sense – you can’t call an extension method like that. The extension method is just a static method, so call it that way. For example:

expr = Expression.Call(GetType(MyExtensions), "Contains", Nothing, _
           myStringParam, constantExpression, _
           Expression.Constant(StringComparison.InvariantCultureIgnoreCase))

where MyExtensions is the class declaring the Contains extension method.