CODEWITHSUNDEEP
c#csvhelper
Franky
Franky

Reputation: 1574

CsvHelper dynamic column mapping

I am following this example to map custom column names to my class model:

CsvHelper Mapping by Name

In this particular part:

public FooMap()
{
    Map(m => m.Id).Name("ColumnA");
    Map(m => m.Name).Name("ColumnB");
}

Is it possible to use string as column name instead of hard-code it? Something like this --

public FooMap()
{
    Map("Col1").Name("ColumnA");
    Map("Col2").Name("ColumnB");
}

"Col1" and "Col2" are the property of my class model. I've tried to use reflection but it didn't work:

Map(x => typeof(MyClassModel).GetProperty("Col1")).Name("ColumnA");

Please let me know if what I am trying to achieve is possible. Some additional info -- the column mapping (source and destination) are both stored in a table.

Thanks!

Upvotes: 1

Views: 7650

Answers (2)

David Specht
David Specht

Reputation: 9074

This should allow you to use a string to map both the property name and the header name.

void Main()
{
    var mapping = new Dictionary<string, string>
    {
        {"Id","FooId"},
        {"Name","FooName"}
    };
    
    using (var reader = new StringReader("FooId,FooName\n1,Jordan"))
    using (var csv = new CsvReader(reader, CultureInfo.InvariantCulture))
    {
        var fooMap = new DefaultClassMap<Foo>();

        fooMap.Map(mapping);
        
        csv.Context.RegisterClassMap(fooMap);
        
        var records = csv.GetRecords<Foo>().ToList();
    }   
}

public static class CsvHelperExtensions
{
    public static void Map<T>(this ClassMap<T> classMap, IDictionary<string, string> csvMappings)
    {
        foreach (var mapping in csvMappings)
        {
            var property = typeof(T).GetProperty(mapping.Key);

            if (property == null)
            {
                throw new ArgumentException($"Class {typeof(T).Name} does not have a property named {mapping.Key}");
            }

            classMap.Map(typeof(T), property).Name(mapping.Value);
        }
    }
}

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

Upvotes: 9

praskulkarni88
praskulkarni88

Reputation: 65

As an another approach, define an XML/JSON config file where you can define the columns you want to map. Write a parser that could parse your XML/JSON config and return the columns to be mapped dynamically. This approach allows you to map any no of columns on fly, without having to recompile your code.

Upvotes: 1

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