CsvHelper: modify a string before loading it into a ClassMap?-CodePudding

Using CsvHelper v29, when creating a ClassMap, is it possible to modify a string before it is loaded into the map?

For example, in the code below, m.EmployeeNumber is of type string? and it may have a value of "001234":

    public sealed class CsvMap : ClassMap<Employee>
    {
        public CsvMap()
        {
            _ = Map(m => m.EmployeeNumber);
            ...
        }
    }

I'm trying to convert its value using Map() to "=001234".

I have tried: _ = Map(m => m.EmployeeNumber?.Prepend('='));

But this will not work because an expression tree lambda cannot have the null propagating operator.

CodePudding user response：

The bigger issue is that Map is expecting the expression to return a class member, for example EmployeeNumber. You would need to use Convert to actually change the output.

_ = Map(m => m.EmployeeNumber).Convert(args => "="   args.Value.EmployeeNumber);