Errors When Writing Or Delete A File Using System.io - Array Bounds Cannot Appear In Type Specifier

why i get these followinf error in the following codes please

'Delet the file on the path, it does exist
Dim deletfile As System.IO.FileStream
deletfile = System.IO.File.Delete("C: emp.txt")

i get error underlining in blue the part

System.IO.File.Delete("C: emp.txt")

and the error is "express does not produce a value" second error i get is in this code

Dim datawriter As System.IO.StreamWriter("C: emp.txt")

where
("C: emp.txt")

is underlined in blue n the error says "array bounds cannot appear in type specifier"