.NET API Reference

.NET API Reference

String Class
public sealed class String
Represents text as a sequence of code points.
Summary

The String class represents a string of characters. Strings are immutable, meaning that once a String object is created, its value cannot be changed. However, because String objects are immutable, operations that appear to modify them actually create new String objects that contain the modified versions.

Constructors
String(Char[], Int32, Int32)
public String(char[] value, int startIndex, int count)
Initializes a new instance of the String class by concatenating elements of a character array.
Parameters
  • value: char[]
    A character array containing the characters to be converted to a string.
  • startIndex: int
    The starting position of the substring to use.
  • count: int
    The number of characters to use.
    • Methods
    IsNullOrEmpty(String)
    public static bool IsNullOrEmpty(string value)
    Indicates whether the specified string is null or an empty string ("").
    Parameters
  • value: string
    The string to test.
    • Return Value
  • bool
    true if the value parameter is null or an empty string (""); otherwise, false.
    • Example
    string myString = "";
if (String.IsNullOrEmpty(myString))
{
    Console.WriteLine("The string is null or empty.");
}
    Replace(Char, Char)
    public string Replace(char oldChar, char newChar)
    Returns a new string in which all occurrences of a specified Unicode character in this instance are replaced with another specified Unicode character.
    Parameters
  • oldChar: char
    The character to replace.
  • newChar: char
    The character that replaces oldChar.
    • Return Value
  • string
    A new string that is equivalent to this string but with all instances of oldChar replaced by newChar.
    • Example
    string original = "hello world";
string replaced = original.Replace('l', 'X');
Console.WriteLine(replaced); // Output: heXXo worXd
    List<T> Class
    public class List<T>
    Represents a strongly typed list of objects that can be accessed by index. Provides methods for creating, searching and manipulating lists.
    Summary

    The List(T) generic type is a user-defined collection that allows for fast insertion and retrieval of elements. It is a generic type, meaning that it can store any type of data. The List(T) class is a part of the System.Collections.Generic namespace.

    Methods
    Add(T)
    public void Add(T item)
    Appends the given element to the end of the List(T).
    Parameters
  • item: T
    The object to be added to the end of the List(T). The value can be null for reference types.
    • File Class
    public static class File
    Provides static methods for the creation, copying, deletion, moving, and opening of files, and aids in the creation of FileStream objects.
    Methods
    ReadAllText(String)
    public static string ReadAllText(string path)
    Opens a text file, reads all lines of the file, and then closes the file.
    Parameters
  • path: string
    The file to open. The file must exist.
    • Return Value
  • string
    A string containing all of the lines of the file.
    • ControllerBase Class
    public abstract class ControllerBase
    A base class for controllers that handle incoming requests.
    Properties
    ControllerContext
    public ControllerContext ControllerContext { get; }
    Gets or sets the controller context.
    ModelState
    public ModelStateDictionary ModelState { get; }
    Gets a dictionary that contains the model state.