dynamic vs object type

Question

I have used the dynamic and the object type interchangeably. Is there any difference between these two types? Is there any performance implications of using one over the oth

Answer 1

There is an article explaining the different types, including object and dynamic types. The article also explains the difference between the two with a nice example.

https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/reference-types

I shall give a short gist of the difference explained in the article:

• The object type is an alias for System.Object in .NET. In the unified type system of C#, all types, predefined and user-defined, reference types and value types, inherit directly or indirectly from System.Object. You can assign values of any type to variables of type object.

• The dynamic type indicates that use of the variable and references to its members bypass compile-time type checking. Instead, these operations are resolved at run time. The dynamic type simplifies access to COM APIs such as the Office Automation APIs, to dynamic APIs such as IronPython libraries, and to the HTML Document Object Model (DOM).

• Type dynamic behaves like type object in most circumstances. In particular, any non-null expression can be converted to the dynamic type. The dynamic type differs from object in that operations that contain expressions of type dynamic are not resolved or type checked by the compiler. The compiler packages together information about the operation, and that information is later used to evaluate the operation at run time. As part of the process, variables of type dynamic are compiled into variables of type object. Therefore, type dynamic exists only at compile time, not at run time.

Summary:

What this essentially means is object is a type and all other types inherit from it. Dynamic is not really a type, it is more like a pointer or representation of some other type, which will be resolved at run time.