Once upon the time there is a group of .NET developer just want to use var to declare all the variable.
MSDN has written “Beginning in Visual C# 3.0, variables that are declared at method scope can have an implicit type
var. An implicitly typed local variable is strongly typed just as if you had declared the type yourself, but the compiler determines the type.” So if you read the code without the compiler then you need to use your best guess to guess what data the var is.
There is one new refactor feature in Visual Studio 2017. The feature suggest that Use explicit type instead of ‘var’, cool feature.