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.
  1. //this is compile code
  2. StringBuilder String = new StringBuilder(); // valid
  4. // this is incompile code
  5. StringBuilder string = new StringBuilder(); // invalid
String Vs String In C#
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.