Invalid token 'while' in class, struct, or interface member declaration in very simple code

问题

I am not sure what the problem is but I keep receiving this error when I try to use a while statement in my code.

Invalid token 'while' in class, struct, or interface member declaration

I want to use a while loop to have something continuously update while a statement is true.

The rest of my code is rather long but whenever I type in the syntax:

while(a<b)
{
//do whatever i want it to do here
}

It gives me that compiler error right off the bat. Not quite sure what the problem is. I am doing this in a C# windows application under the Form1.cs file with all the other event handlers (for buttons and such). Thanks!

I was unaware that loops had to be placed within a method (fairly new to c#), but I tried it and no errors were returned. Thanks for your help everybody!

Previously, I just had the loop within the main class of the program.

回答1:

Based on the error, it sounds like the compiler thinks this code is typed directly in the body of a class/struct/interface declaration. Statements while/if/for/etc ... must appear with in a method.

Try moving this code into a method to fix the problem. If it's in a method, you likely have a mismatched brace problem.

回答2:

There's nothing wrong with the while, it's something above it that's the problem. Check for mismatched braces and semicolons in a comment or something like that.

回答3:

C# is not allowed to write code directly into the classes; it is allowed to write only data members and function members directly into the classes.

回答4:

You can also get this if you have punctuation issues, I got it today when I missing a simple parentheses:

public static string GetPasswordForEnvironment)

should have been:

public static string GetPasswordForEnvironment()

But the error showed up on the first "if" statement later in the function.

回答5:

C# does not provide writing the for, while or foreach kind of looping statement directly inside the class. These statements should be within a user defined method, main method or constructors.

  class Array
{
    public static void main(string[] args)
    {
        int[] n = new int[10]; /* n is an array of 10 integers */

        /* initialize elements of array n */
        for (int i = 0; i < 10; i++)
        {
            n[i] = i + 100;
        }

        /* output each array element's value */
        foreach (int j in n)
        {
            int i = j - 100;
            Console.WriteLine("Element[{0}] = {1}", i, j);
        }
    }


}

来源：https://stackoverflow.com/questions/397019/invalid-token-while-in-class-struct-or-interface-member-declaration-in-very

标签

loops

while-loop