As we all know that Enums are very commonly used in the C# program. While using the Enums, we should also be aware of how the values are parsed into the Enums. In my earlier article, I have talked about the How to Use Enum in C#.In this article, I will specifically talk about the mistake we can make while using the Enum.TryParse() method.
\nAs we know Enum.Tryparse() method will give us the parsed Enum. Like in the below example
public enum IdentityProtocols\n{\n SAML,\n OAuth,\n OpenID\n}\nvar isEnumParsed=Enum.TryParse("0", true, out IdentityProtocols parsedEnumValue);\nConsole.WriteLine(isEnumParsed?parsedEnumValue.ToString():"Not Parsed");The above code will print the SAML because the enum is started by default with the value 0.
What happens if we run the below code with the same Enum declaration?
\nvar isEnumParsed=Enum.TryParse("-1", true, out IdentityProtocols parsedEnumValue);\nConsole.WriteLine(isEnumParsed?parsedEnumValue.ToString():"Not Parsed");As per our understanding isEnumParsed variable should be false, and the above code should print Not Parsed as the value which we are passing in the method is not in the Enum declaration, right?
But here is a catch, isEnumParsed variable have the true value, and the code will print -1.
The default type of Enum in C# is int. That's why any valid integer values are parsed by the Enum.TryParse() method irrespective of those integer values are defined in the Enum or not.
We can define the Enum with types like byte, sbyte, etc. Then the Enum.TryParse() will parse those values which will fall in that defined Enum type.
\nTo overcome this behavior of Enum.TryParse() we can follow the below approaches.
\nvar isValidEnum = Enum.TryParse("-1", true, out IdentityProtocols parsedEnumValue) && Enum.IsDefined(typeof(IdentityProtocols), parsedEnumValue);\nConsole.WriteLine(isValidEnum ? parsedEnumValue.ToString(): "Not Parsed");In the above code Enum.IsDefined() will check that the value which we are getting from the Enum.TryParse() method is defined in the Enum declaration or not.
\nThat will give us the proper result, and the above code will print Not Parsed
var value = "-1";\nvar identityProtocolsList = Enum.GetNames(typeof(IdentityProtocols)).ToList();\nConsole.WriteLine(identityProtocolsList.Contains(value) ? value : "Not Parsed");In this code, checking that value is present or not by getting all the Names from the enum declaration by using Enum.GetNames() method.
\nThis code will print Not Parsed
Note: Here, we will not be able to parse any of the integer values. It will only check the values which are defined in the Enum declaration.
\nIn this article, We have discussed the mistake we can make using the Enum.TryParse() method. This mistake can hurt and can abnormally terminate our program/application. We can use the ways I have mentioned in this article to overcome so that our program/application can run smoothly.
Enum is a typed constant that is specified for the new data form of Enumeration. An effective way to describe a set of named integral constants assigned to a variable is to include a Typesafe enumeration. Enums make the code more readable and less vulnerable to mistakes. If you have a set of functionally important and unchanged values, Enums are useful for developers.
\nEnums' key benefit is to make it possible in the future to adjust values. Enums are a robust alternative to the short String or Int constants used to describe sets of similar objects in far older APIs.
\nSometimes we must use the constant variable in our application to not be changed throughout the application. One of the methods to declare the continuous variables are Enum. Let's discuss it.
Enum is the short form of Enumeration. Enum consumes less memory and space because they are value types, which means they store memory value. Also, Enums are strongly typed named constants.
\nEnums written by developers are used in the .NET system to develop numeric constants. A numeric value must be allocated to all the members of an enum. Here are the main points about Enums:
\nEnums are of two types in C#
\nSimple Enum - The members of this enum contain a single value.
\nFlags Enum - The members of this enum contain multiple values or multiple values combined using a bitwise OR operator. These enums are often used for bitwise operators.
\nHere we will talk about the Simple Enum only.
\nEnum is declared by the enum keyword followed by the enum name and then its enum members. Like an example below
\npublic enum Vehicle\n{\n Car,\n Bike=3,\n Truck,\n Taxi,\n}In the above code, an enum for the Vehicle is created. The enum values are started from 0 by default if we do not assign them the values and incremented by 1 for the next enum member.
That means the Car enum has the value 0 and the Bike enum assigned the value 3 that means the Bike enum now has the value 3 and the next enums are incremented by 1 means Truck and Taxi enum have the value 4 and 5 respectively.
By default, the type for enum elements is int. We can set different type by adding a colon like an example below.
\npublic enum Vehicle: byte\n{\n Car,\n Bike=3,\n Truck,\n Taxi,\n}The different types which can be set are sbyte, byte, short, ushort, uint, ulong, and long.
\nTo get the value of enum we can simply typecast it to its type. In the first example, the default type is int so we have to typecast it to int. Also, we can get the string value of that enum by using the ToString() method as below.
Console.WriteLine((int)VehicleEnum.Car);\nstring vehicle = Vehicle.Bike.ToString();\nConsole.WriteLine(vehicle);Output:
\n0\nBikeFor parsing the string value into enum we have 2 methods
\nConsole.WriteLine(Enum.Parse(typeof(Vehicle),"Car"));Output:
\nCarout variable. If the string value is not parsed, then the result will be false.Enum.TryParse("0",out Vehicle value);\nConsole.WriteLine(value);Output:
\nCarNote - Both the methods also have overload methods.
\nWe can check if a given integral value, or its name as a string, exists in a specified enum.
\nConsole.WriteLine(Enum.IsDefined(typeof(Vehicle), 0));OR
\nConsole.WriteLine(Enum.IsDefined(typeof(Vehicle), "car"));Output:
\nTrueFor looping through the enums you can write the below code -
\nforeach (var data in Enum.GetNames(typeof(Vehicle)))\n{\n Console.WriteLine(data+" - "+ (int)Enum.Parse(typeof(Vehicle), data));\n}Here Enum.GetNames(Type enumType) method is used, which retrieves an array of the names from the specified enum.
\nOutput:
\nCar - 0\nBike - 3\nTruck - 4\nTaxi - 5We can call the enum member by its integral value. If there is no corresponding value related to that integral value, then it will print that integral value.
\n Console.WriteLine((Vehicle)3);Output
\nBikeThe advantages of using enums are that they are very easy to use and represented as strings but processed as integers. Enums are easy to maintain and improve code readability because they provide symbolic named constants, which means you need to remember the names, not the integer values.
\nIf you want to learn more about C programming, here is another article written on C# Exceptions and Exception Handling in C# I hope you learn something new today and will going to try it out, if you have any questions feel free to drop a comment below.
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