c# Using enum in Switch Case throwing exception

I am working on .NET 6.0 application, I have enum that I am trying to use in switch as to compare with string value but getting exception.

error

private static bool ValidateAlphanumericCase(string text, string fieldName)
    {
        if (!string.IsNullOrWhiteSpace(fieldName))
        {
            var rule = GetRule(fieldName).TxtFieldFormat; // string value

            switch (rule)
            {
                case TextFieldFormat.AlphanumericUpperCase.ToString():
                    break;

                case TextFieldFormat.AlphanumericLowerCase.ToString():
                    break;
            }

        }
        else
        {
            new EmptyFieldNameException();
        }

        return false;
    }

enum

 public enum TextFieldFormat
{
    AlphanumericUpperCase = 0,
    AlphanumericLowerCase = 1,
}

>Solution :

TextFieldFormat.AlphanumericUpperCase.ToString()

This is a method invocation expression and it is not a valid pattern for swith statement.

You can find all valid patterns here: https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/patterns

The closest pattern is type pattern or constant pattern, I guess the compiler recognizes AlphanumericUpperCase as a nested class of TextFieldFormat and fails.

In this case you can use nameof operator.

 switch (rule)
 {
      case nameof(TextFieldFormat.AlphanumericUpperCase):
          break;
      case nameof(TextFieldFormat.AlphanumericLowerCase):
          break;
 }