I have the following variable declarations at the top of my main function
string brand;
double price;
var itemList6 = from i in myStore.items
where i.pri
You have to assign a value to the variables before you construct the LINQ query.
The reason is that the compiler is using the variables to construct the query. Even though the query won't be executed, the compiler requires variables to be assigned before use, and the compiler sees building the query expression as use.
My recommendation is just to put some nominal default/temp value in there.