Getting type information at runtime in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of getting type information at runtime in C#?

It helps you find out what kind of object you have while the program is running. This is useful when you don't know the type in advance and want to make decisions based on the object's type.

beginner

Which C# keyword or method returns the runtime type of an object?

The GetType() method returns the exact type of an object at runtime.

intermediate

How do you compare the runtime type of an object to a known type in C#?

Use obj.GetType() == typeof(SomeType) to check if the object's runtime type matches SomeType.

intermediate

What is the difference between GetType() and typeof() in C#?

GetType() is called on an object instance to get its runtime type. typeof() is used with a type name to get the Type object representing that type at compile time.

beginner

How can you get the name of an object's type at runtime?

Call obj.GetType().Name to get the simple name of the object's type as a string.

Which method do you use to get the runtime type of an object in C#?

A TypeOfObject()

B typeof()

C GetType()

D GetRuntimeType()

GetType() is called on an object instance to get its runtime type.

What does typeof(int) return in C#?

A The Type object representing the int type

B The runtime type of an int variable

C The string "int"

D An instance of int

typeof(int) returns the Type object representing the int type at compile time.

How do you check if an object is exactly of type string at runtime?

A obj is string

B obj.GetType() == typeof(string)

C obj.GetType().Name == "string"

D obj == string

Use obj.GetType() == typeof(string) to check exact type equality.

Which property gives you the simple name of a type in C#?

A Type.FullName

B Type.ToString()

C Type.SimpleName

D Type.Name

Type.Name returns the simple name of the type as a string.

If you want to get the full namespace and name of a type, which property do you use?

A Type.FullName

B Type.Namespace

C Type.Name

D Type.ToString()

Type.FullName returns the full namespace and type name.

Explain how to get and compare the runtime type of an object in C#.

Think about how you find out an object's type and then check if it matches a known type.

Describe the difference between GetType() and typeof() in C#.

One works on objects, the other works on type names.