.NET Array Dictionary List String 2D Async DataTable Dates DateTime Enum File For Foreach Format IEnumerable If IndexOf Lambda LINQ Parse Path Process Property Regex Replace Row Sort Split Static StringBuilder Substring Switch Tuple

Strings. Nearly every program uses strings. In strings, we find characters, words and textual data. The string type allows us to test and manipulate character data.

Methods. Here are the methods and properties on strings. Some are static. We access them on the string type (like string.Empty). Complex algorithms often use many string methods.


Constructor. Strings are often reused, and passed around within a program. Methods like Replace() create new strings. But we can also create new ones with a constructor.

String Constructor

Literals. These specify string data. We use quotes around literal data (characters). Literals are embedded in the program executable.


Comparisons. Are two strings equal? In a Dictionary, we can use a StringComparer to change how keys are compared. We can ignore case.


Parse, TryParse. These methods transform strings into other types. Many parsing routines are built-in. Usually it is a bad idea to create our own if one already exists.


TextInfo. This type provides some helpful methods. We can convert a string To Title Case with ToTitleCase. No custom methods are needed.

TextInfoTextInfo: ToTitleCase

Whitespace. Strings often contain newline or whitespace. We often need to check for these values. We use methods like IsNullOrWhitespace.

NewLineLine CountWhitespace

Empty. An empty string has zero characters. Meanwhile a null string is no string at all. It is a reference that points to no memory location.

Empty StringsNull Strings

Chars. A string contains data made up of individual characters. We deal with these chars in looping constructs. Accessing chars is a fast way to test strings.

CharString Chars

Loops. We can loop over a string with any style of loop. When no index is required, a foreach-loop will result in the clearest code.

ForeachFor, string

Performance. In typical usage strings are fast. But they are sometimes used in an inefficient way. Often reducing string allocations is helpful.

Memory UsageEquals PerformanceToString CacheToString FormatsIsUpper, IsLower

Custom methods. Many string algorithms are composed from the built-in methods. With Substring calls we can Truncate strings. With ToCharArray we can change characters.

TruncateRightUppercase First LettersChange Characters

Explanations. I explain concepts of strings. How do we append strings when there is no append method? We also learn to increment strings.

String AppendString IncrementString Property

StringBuilder. This is not a string, but it is used to build up or change strings. For appending strings in a loop, we likely want to use StringBuilder.


A string is immutable. It can be used in many methods, and none of them have to worry about data changes. It never becomes invalid. This reduces copies and makes programs more robust.