VS 2010 Compiler Creates New Variable Automatically When Use If Statement Without Strictly Declared Variable?

Say that i have the following code that parse about 20k records from the DB.

Code #1

vb.net While reader.Read()
list.Add(If(Integer.TryParse(reader(0).ToString, 0), Integer.Parse(reader(0).ToString), 0))
End While

And then another code which does the very same thing but it seems to be a little cleaner.

Code #2

vb.net While reader.Read()
Dim storeowner As Integer = 0
Integer.TryParse(reader(0).ToString, storeowner)
list.Add(storeowner)
End While

This is what i am confused about; does the compiler creates a new variable automatically when i use the if statement without strictly declared variable? What approach is better in sense of performance?