用一个键声明多个值的字典

Question

C# I am using a dictionary like:

var dict = new Dictionary<byte, Tuple<string, string>>();           
Tuple<string, string> t = new Tuple<string, string>(label, unit);

I want to declare it as a data member of the class. but it says

The contextual keyword 'var' may only appear within a local variable declaration or in script code

How do I solve this?

Answer 1

The error message is pretty clear. You cannot use var to declare class members, only for local variables.

For class members you need to use the explicit type:

public class MyClass
{
    Dictionary<byte, Tuple<string, string>> dict = new Dictionary<byte, Tuple<string, string>>();

    // ...
}

Answer 2

in C# you cannot use var to declare class members:

here are technical issues with implementing this feature. The common cases seem simple but the tougher cases (eg, fields referencing other fields in chains or cycles, expressions which contain anonymous types) are not.

taken from the blog post Why no var on fields? and from this post .

In such case, you need to declare explicit types:

Dictionary<byte, Tuple<string, string>> dict = new Dictionary<byte, Tuple<string, string>>();