What's the Difference Between 'string' and 'String' in C#?

The difference between "string" and "string" in the c#

In C#, "String" and "String" look different, but what are the differences between them? Let's take a closer look.

The essential equivalent

"String" in C# is the alias of the class, a abbreviation form. From the bottom level, the following code fragments are equivalent:

System.String Therefore, from a technical point of view, there is no inherent difference between the two. They all point to the same object, similar to the relationship between "int" and "System.int32".

<code class="language-csharp">string s = "Hello world!";
String s = "Hello world!";</code>

Usage Guide

Although the technical difference is small, for the clearness and consistency of the code, it is generally recommended to follow some agreements:

Use "string" as an object reference:

When the string object is referenced as a variable, "String" is usually used.

• Use "string" as a class reference:

  If you need to explicitly reference the

  <code class="language-csharp">  string place = "world";</code>

  class, such as using a class static method or attribute, it is recommended to use "String".

• This method is consistent with the style used by Microsoft in its code example. System.String

  Current suggestions

  <code class="language-csharp">  string greet = String.Format("Hello {0}!", place);</code>

The latest guidelines, especially the guidelines for StyleCop forced execution, tend to use C# specific aliases, such as "String", not a completely limited type name, such as "System.string".

Conclusion

Although "String" and "String" look different, their bottom layer is equivalent because "string" is an alias. By observing the recommendation of the recommended usage, developers can improve the readability and maintenance of the C# code, especially when processing string.

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