CsvHelper.WriterException: 'No properties are mapped for type 'IData'

[Ghyath-Serhal]

Describe the bug I have a interface IData and 2 classes that implement this interface. I need to pass a list of IData to the CsvWriter. I am getting the below error CsvHelper.WriterException: 'No properties are mapped for type 'IData'

The function WriteRecordsAsync is considering the IData as the type of the list and not the class that implement the interface.

I am not sure if there is another way to solve this problem or is it possible to have another WriteRecordsAsync function where we can specify the type.

To Reproduce

interface IData { }

class Person : IData
{
    public DateTime DOB { get; set; }
    public string? Name { get; set; }
}

class Student : IData
{
    public int Id { get; set; }
    public string? Name { get; set; }
}


List<IData> list = new List<IData>();

for (int i = 0; i < 100; i++)
{
    Person pe = new Person();
    pe.DOB = DateTime.Now;
    pe.Name = "Ghyath";

    list.Add(pe);
}

var result = await WriteToCsv(list);

async Task<string> WriteToCsv<T>(List<T> list) where T : IData
{
    string fileContent = string.Empty;
    if (list.Count > 0)
    {
	    using var swriter = new StringWriter();
	    using var csv = new CsvWriter(swriter, CultureInfo.InvariantCulture);
	    await csv.WriteRecordsAsync<T>(list);
	    fileContent = swriter.ToString();
	    csv.Flush();
    }

    return fileContent;
}

[Rob-Hague]

The function WriteRecordsAsync is considering the IData as the type of the list and not the class that implement the interface.

That's because it is. Using csv.WriteRecords((IEnumerable)list) might work for you.