如何从字符串输入中获取显示枚举值

Question

How do I get the value of an enum through input?

enum Planets
{
   Mercury = 0,
   Venus,
   Earth
}

I want something like when a user inputs a string for example I get the Enum integer Value of that input.

UserInput: Mercury

Value: 0

I did something like this:

Console.WriteLine("Value: "+(Planets)UserInput);

and as you can guess it won't compile.

Answer 1

var planet = (Planets)Enum.Parse(typeof(Planets), UserInput);
int planetNumber = (int)planet;

Answer 2

First, you have to cast your input string into an enum of your choice. That can be done with Enum.Parse(Type, String) :

Planets planet = Enum.Parse(typeof(Planets), "Mercury")

Then you need to get the numerical value from the enum, which is a simple cast to integer:

int value = (int)planet;

Be careful with the first step: if the user inputs a string that is not valid, you'll get an exception which you'll have to handle. To avoid that you can use the Enum.TryParse() method which return a bool indicating the success of the action and pass the resulting enum as an out parameter.

Planets result;
bool success = Enum.TryParse<Planets>("Mars", true, out result);
if(success){
    Console.Write((int)result);
} else {
    Console.Write("no match");
}