LINQ : Dynamic select

Question

Consider we have this class :

    public  class Data
{
    public string Field1 { get; set; }
    public string Field2 { get; set; }
    public string Field         


        

Answer 1

Using ExpandoObject you can build a dynamic objects or return the full object from the example below.

public object CreateShappedObject(object obj, List lstFields)
{
    if (!lstFields.Any())
    {
        return obj;
    }
    else
    {
        ExpandoObject objectToReturn = new ExpandoObject();
        foreach (var field in lstFields)
        {
            var fieldValue = obj.GetType()
                .GetProperty(field, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance)
                .GetValue(obj, null);

            ((IDictionary)objectToReturn).Add(field, fieldValue);
        }

        return objectToReturn;
    }
}

The following is an example of how to use this from your controller.

http://localhost:12345/api/yourapi?fields=field1,field2

public IHttpActionResult Get(string fields = null)
{
    try
    {
        List lstFields = new List();
        if (fields != null)
        {
            lstFields = fields.ToLower().Split(',').ToList();
        }
   
        // Custom query
        var result = db.data.Select(i => CreateShappedObject(new Data()
        , lstFields)).ToList();

        return Ok(result);

    }
    catch(Exception)
    {
        return InternalServerError();
    }
}