VAR - The type of the variable is decided by the compiler at compile time.
DYNAMIC - The type of the variable is decided at run time.
The var and dynamic keywords in C# are both used for implicit typing, but they have different behaviors and use cases.
varkeyword: Thevarkeyword allows the compiler to infer the type of a variable based on the expression used to initialize it. Once the type is inferred, it becomes a strongly typed variable. The type of the variable is determined at compile-time and cannot be changed.
Example:
var number = 10; // Compiler infers that 'number' is of type int
var message = "Hello"; // Compiler infers that 'message' is of type string
In this example, the compiler automatically determines the types of the variables number and message based on the assigned values.
The var keyword is useful when you want the convenience of implicit typing while still maintaining static type safety. It allows you to write more concise code without sacrificing type checking.
dynamickeyword: Thedynamickeyword is used to declare a variable whose type is determined at runtime. It enables late binding and dynamic behavior, where the type and member resolution occur at runtime rather than at compile-time. The type of adynamicvariable is resolved dynamically when the code is executed.
Example:
dynamic value = 10; // 'value' can hold any type at runtime
value = "Hello"; // 'value' can now hold a string at runtime
In this example, the value variable is declared as dynamic, allowing it to hold different types of values at runtime.
The dynamic keyword is useful in scenarios where you need to work with dynamically typed objects, such as when interacting with dynamic languages, dealing with COM interop, or performing late-bound operations. It provides more flexibility but sacrifices compile-time type checking and can result in runtime errors if the operations performed on the dynamic variable are not supported.
In summary, the var keyword is used for implicit typing with static type checking at compile-time, while the dynamic keyword is used for late binding and dynamic behavior at runtime. var is resolved at compile-time, and its type cannot change, while dynamic is resolved at runtime and allows dynamic typing and late binding.