error CS0150:A constant value is expected //error in switch statement

Question

I have a problem with my switch statement. I don't know how to use it properly in c#. It gives me the error CS0150 and I don't know how to care with that. I appreciate any help. Thank you. The code is cut. If you see less brackets than normal, please don't remind me.

int e = 0;
string caseslol;
string multi = "multi";

Console.WriteLine("Hi there!");
Console.WriteLine("Do you want to write a number so I can do cool things with it ??");
Console.WriteLine("Write yes to say YES and no to say NO");
string str1 = Console.ReadLine();
if (str1.Contains("yes") == true)
{
    Console.WriteLine("Enter it please");
    e = Convert.ToInt32(Console.ReadLine());
    Console.WriteLine("lol, we got it!");
    Console.WriteLine("you wrote this : {0}", e);
    Console.WriteLine("Now that we got it, we can do cool stuff!");
    Console.WriteLine("Do you want to know what is this stuff ???");
    string yesorno = Console.ReadLine();
    if (yesorno.Contains("yes") == true)
    {
        Console.WriteLine("OK");
        Console.WriteLine("We can do calculating stuff with your number");
        Console.WriteLine("Soo much cool, right ???");
        string yesorno2 = Console.ReadLine();
        if (yesorno2.Contains("yes"))
        {
            Console.WriteLine("Choose first another number and write it");
            int b = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("So let's start with what ???");
            switch (caseslol) 
            {
                case multi:
                    Console.WriteLine(e * b);
            }
        }
    }

//this is the output :

error CS0150:A constant value is expected
Compilation failed: 1 error(s), 0 warnings
compiler exit status 1

If you want to use a string in a `switch` it have to be a constant string, i.e., `const string multi = "multi"` or use `"multi"` directly at the `switch's case` statement. — dcg, Jun 13 '19 at 21:10

score 1 · Answer 1 · answered Jun 13 '19 at 21:06

1

You can't use a variable like that for the case, and instead must use a constant.

So instead of putting the variable multi in your case statement, you could use the string "multi" (which is the value you've assigned the variable anyway).

answered Jun 13 '19 at 21:06

Owen Pauling

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okay now i understand thank you but now it gives me this error : error CS8070:Control cannot fall out of switch statement through final case label `case "multi":' – minus101 Jun 13 '19 at 21:08
@HamzaTout you need to add a break; to the end of the case. – Owen Pauling Jun 13 '19 at 21:12

score 0 · Accepted Answer · answered Jun 13 '19 at 21:29

case can only be used with a constant. It should either be

private const string multi = "multi";

switch (caseslol)
{
    case multi:
        Console.WriteLine(e * b);

        // you also need this
        break;
}

or you do directly

switch (caseslol)
{
    case "multi":
        Console.WriteLine(e * b);

        // you also need this
        break;
}

or you simply use

if(string.Equals(caseslol, multi))
{
    Console.WriteLine(e * b);
}

in general I don't see where caseslol ever gets set ...

error CS0150:A constant value is expected //error in switch statement

2 Answers2