C# knowledge point: the characteristic argument must be a constant expression, typeof expression or array creation expression of the characteristic parameter type

Description:

       For example, when I was using the MenuItem feature of Unity, I reported an error "The feature argument must be a constant expression, typeof expression, or array creation expression of the feature parameter type"

        

       

​​​​​​​ After several positioning, the reason is because my string is not defined with const. For characteristics, the actual parameter must be a constant value, and what I define is a variable; in addition, there is no readonly declaration. Used, the reasons can be seen: C# knowledge series: the difference between readonly and const

public static string CustomEidorMenu = "CustomEidorMenu";
public static readonly string CustomEidorMenu = "CustomEidorMenu";

​​​​​​​ After testing, the following line of code does not work. In C#, only "+" string concatenation string constants can be determined during compilation, and the others are dynamic concatenation.

[MenuItem($"{EditorConfig.CustomEidorMenu}/window")]

 

So the solution is as follows, compiled through

public const string CustomEidorMenu = "CustomEidorMenu";
[MenuItem(EditorConfig.CustomEidorMenu + "/window")]