C# Tutorial 5.4: Enumerations

 Enumerations, or enums, in C# are a powerful feature that allows you to define a named set of named constants representing integral values. Enumerations make your code more readable and maintainable by providing a way to give friendly names to numeric values. Here's a tutorial on how to use enumerations in C#.

1. Creating Enumerations:

To create an enumeration, use the enum keyword followed by the name of the enumeration. Here's a simple example:

public enum DaysOfWeek

{

    Sunday,

    Monday,

    Tuesday,

    Wednesday,

    Thursday,

    Friday,

    Saturday

}

In this example, DaysOfWeek is an enumeration representing the days of the week. By default, the values of the enum start at 0 and increment by 1.

2. Using Enumerations:

You can use enumerations in your code just like any other data type. Here's an example of how to declare a variable with an enumeration type:

DaysOfWeek today = DaysOfWeek.Wednesday;

3. Underlying Type:

By default, enums are of type int, but you can explicitly specify another integral type if needed:

public enum Status : byte

{

    Inactive,

    Active,

    Suspended

}

In this example, Status is an enumeration with an underlying type of byte.

4. Accessing Enum Values:

You can access the underlying numeric value of an enum using casting:

int dayValue = (int)DaysOfWeek.Monday;

5. Looping Through Enum Values:

You can iterate through all values of an enumeration using the Enum.GetValues method:

foreach (DaysOfWeek day in Enum.GetValues(typeof(DaysOfWeek)))
{
    Console.WriteLine(day);
}

6. Parsing Enum Values:

You can convert a string to an enum using the Enum.Parse method:

string dayString = "Wednesday";
DaysOfWeek day = (DaysOfWeek)Enum.Parse(typeof(DaysOfWeek), dayString);

7. Checking if a Value is Defined:

You can check if a value is defined in an enumeration using the Enum.IsDefined method:

bool isDefined = Enum.IsDefined(typeof(DaysOfWeek), "Sunday");

8. Flags Attribute:

If you need to combine multiple enum values, you can use the Flags attribute:

[Flags]
public enum Permissions
{
    Read = 1,
    Write = 2,
    Execute = 4
}

With the Flags attribute, you can use bitwise operations to combine enum values:

Permissions myPermissions = Permissions.Read | Permissions.Write;

This is a basic overview of using enums in C#. Enumerations are a simple yet powerful tool for improving code readability and maintainability by giving meaningful names to numeric values.