Csvhelper: The best way to inject parameter into own ClassMap constructor definition

Created on 13 Jun 2017 · 6Comments · Source: JoshClose/CsvHelper

````c#
public sealed class MyClassMapWithParametrizationNeeded : CsvClassMap {
// I am not sure CsvHelper has construcor injection support for class maps
// What is the best way to make class maps parametrizable?
MyClassMapWithParametrizationNeeded (ClassMapDependencyParamter param) {

}
}

````

Source

hellboy81

👍1

Most helpful comment

void Main()
{
    using (var stream = new MemoryStream())
    using (var writer = new StreamWriter(stream))
    using (var reader = new StreamReader(stream))
    using (var csv = new CsvReader(reader))
    {
        writer.WriteLine("Id,Name");
        writer.WriteLine("1,one");
        writer.WriteLine(",");
        writer.WriteLine("2,two");
        writer.Flush();
        stream.Position = 0;

        var map = new TestMap(-1, "n/a");
        csv.Configuration.RegisterClassMap(map);
        csv.GetRecords<Test>().ToList().Dump();
    }
}

public class Test
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public sealed class TestMap : ClassMap<Test>
{
    public TestMap(int id, string name)
    {
        Map(m => m.Id).Default(id);
        Map(m => m.Name).Default(name);
    }
}

JoshClose on 5 Jan 2018

👍6 🎉1

All 6 comments

You should be able to do that. What is the issue?

JoshClose on 14 Jun 2017

hi Josh,
Hope this message finds you well, do you happen to have an example for this question.
I want to know how to tell csv helper to use the constructor of the map class with parameters defined.

Thanks
Lokesh Balu

lokeshkumarbalu on 5 Jan 2018

👍1

void Main()
{
    using (var stream = new MemoryStream())
    using (var writer = new StreamWriter(stream))
    using (var reader = new StreamReader(stream))
    using (var csv = new CsvReader(reader))
    {
        writer.WriteLine("Id,Name");
        writer.WriteLine("1,one");
        writer.WriteLine(",");
        writer.WriteLine("2,two");
        writer.Flush();
        stream.Position = 0;

        var map = new TestMap(-1, "n/a");
        csv.Configuration.RegisterClassMap(map);
        csv.GetRecords<Test>().ToList().Dump();
    }
}

public class Test
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public sealed class TestMap : ClassMap<Test>
{
    public TestMap(int id, string name)
    {
        Map(m => m.Id).Default(id);
        Map(m => m.Name).Default(name);
    }
}

JoshClose on 5 Jan 2018

👍6 🎉1

hi Josh,

Thank you for the quick reply, is there a way to write the constructor parameter to a row and not map it to any of the property and ignore it while reading the CSV file.

Thanks and Regards
Lokesh Balu

lokeshkumarbalu on 6 Jan 2018

No, but you could manually do it I think. Add properties for the parameters and when writing, write those properties out on a commented line or something.

JoshClose on 10 Jan 2018

@JoshClose how to pass constructor params for the references mapping present in testmap