SQL SPLIT STRING

Question

I wanted to know if it would be possible to do something like this in t-sql.
I want to create a stored procedure which takes a list of invoice numbers and uses it as a parameter for my stored procedure
PARAMETER = @INVOICES NVARCHAR
UPDATE INVOICES SET STATUS = 'INVOICE' WHERE INVOICE IN(@INVOICES)
and in my c# code I will fill the parameter with a list of invoices separated by a comma I need those to be able to go in the IN of the update command but the problem is that the invoice column is an int column so it doesn't recognize all the invoices with
the comma in middle.
Debra has a question

Answer 1

I will go one step further. Do not use XML and make the maintenance programmer have to learn XML, maintain XML when it changes, etc.  Mixed languages are a disaster. My favorite was the MOD() function in procedural languages; Pascal FORTRAN, BASIC favors,
etc. all defined non-integers and non-positive parameters differently! Yet, you would think that a basic math function would be the same. 
The TVP is nice, but proprietary. When SQL/PSM gets it so it will port, I migfht use it. 
I prefer to use the long parameter list so I get all the benefits of the SQL engine, save disk access and give the optimizer something.
https://www.simple-talk.com/sql/learn-sql-server/values()-and-long-parameter-lists/
https://www.simple-talk.com/sql/learn-sql-server/values()-and-long-parameter-lists---part-ii/
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