String vs String In C#

Introduction

Many times, developers try to understand what is actually the difference in String vs string in C#. For that, we need to know that C# is a language used with the CLR.

String is a type in the CLR
string is a type in C#
we can't use String without using System; namespace
string is also known as an alias in C# for String.

So from a technical point of view, there is no difference.

For the best practice in C#, the recommendation is to use string when you refer to the object.

Like: string name = "Smith";

And when we need to refer the class then the recommendation is to use String

Like: string welcomeName = String.Format("Welcome {0}!", name);

If we talk about from compilation point of view so they compile the same code and take some time for execution

Key Difference

string is provided by Microsoft so it is a reserved word, while String is just a class name.

This is the reason that string cannot be used as a variable name.

//this is compile code
StringBuilder String = new StringBuilder(); // valid
// this is incompile code
StringBuilder string = new StringBuilder(); // invalid

Note

Only string and object are reference types, the other aliases are all value types.

The complete list is:

SN	Alias	Type
1	object:	Object
2	string:	String
3	char:	Char
4	bool:	Boolean
5	byte:	Byte
6	sbyte:	SByte
7	short:	Int16
8	ushort:	UInt16
9	int:	Int32
10	uint:	UInt32
11	long:	Int64
12	ulong:	UInt64
13	float:	Single
14	double:	Double
15	decimal:	Decimal

Thank you for taking your valuable time to read the full article.