System.Text.StringBuilder | .NET API Documentation

Overview

The StringBuilder class represents a mutable string of characters. It provides methods for efficiently manipulating strings without creating new immutable string instances.

                    using System.Text;

                    var sb = new StringBuilder();

                    sb.Append("Hello, ");

                    sb.AppendLine("World!");

                    Console.WriteLine(sb.ToString());

Constructors

StringBuilder() – Initializes a new instance of the StringBuilder class.
StringBuilder(string value) – Initializes with the specified string.
StringBuilder(int capacity) – Initializes with a specified capacity.
StringBuilder(string value, int capacity) – Initializes with a string and capacity.

Properties

Property	Type	Description
`Capacity`	int	Gets or sets the current capacity.
`Length`	int	Gets or sets the number of characters.
`MaxCapacity`	int	Gets the maximum capacity.
`Chars[int index]`	char	Gets or sets the character at the specified position.

Methods

Appends the string representation of an object to the end of the current instance.

public StringBuilder Append(object? value)

Inserts a string at the specified index.

public StringBuilder Insert(int index, string value)

Replaces all occurrences of a specified string with another string.

public StringBuilder Replace(string oldValue, string newValue)

Converts the value of this instance to a String.

public override string ToString()

Operators

StringBuilder does not overload any special operators.

Examples

Building a CSV line dynamically:

                    var sb = new StringBuilder();

                    string[] columns = { "Id", "Name", "Email" };

                    foreach (var col in columns)

                    {

                      sb.Append(col).Append(',');

                    }

                    sb.Length--; // Remove trailing comma

                    Console.WriteLine(sb.ToString()); // Output: Id,Name,Email