How to Pivot IEnumerable<T>

Question

I needed to "pivot" or "rotate" a collection of objects. The example will clear up what I needed to do:

var people = new List<Person>(new[] {
                new Person{ Name="Ronnie",Age=25, HairColor="Brown",EyeColor="Blue"},
                new Person{ Name="Tina",Age=25, HairColor="Brown",EyeColor="Green"},
                new Person{ Name="Lukus",Age=4, HairColor="Blonde",EyeColor="Blue"}    
            });

DataTable rotatedData = people.Pivot("Name", "Property");                

/* Results In:
* ___________________________________________
* Property  |  Ronnie  |   Tina    |   Lukus
* ___________________________________________
* Age       |  25      |   25      |   4
* HairColor |  Brown   |   Brown   |   Blonde
* EyeColor  |  Blue    |   Green   |   Blue
* ____________________________________________
*/

Here is the code that I wrote accomplish this:

/// <summary>Converts an IEnumerable into a pivoted DataTable object.</summary>
/// <param name="collection">The IEnumerable object to pivot and convert.</param>
/// <param name="headingMember">The name of a public field or property member of type T to be used as column name's in the pivoted DataTable object.</param>
/// <param name="membersHeading">The name of the column that lists the public fields and properties of type T.</param>        
static DataTable Pivot<T>(this IEnumerable<T> collection, string headingMember, string membersHeading)
{
    // get object information
    var type = typeof(T);
    var members = new List<MemberInfo>();
    members.AddRange(type.GetProperties(BindingFlags.Public | BindingFlags.Instance));
    members.AddRange(type.GetFields(BindingFlags.Public | BindingFlags.Instance));

    // create dataTable and establish schema
    var dt = new DataTable();
    dt.Columns.Add(membersHeading);
    foreach (var item in collection)
    {
        var member = members.Single(x => x.Name == headingMember);
        if (member is FieldInfo)                        
        {
            FieldInfo fieldInfo = (FieldInfo)member;
            dt.Columns.Add(fieldInfo.GetValue(item).ToString(), fieldInfo.FieldType);
        }

        if (member is PropertyInfo)
        {
            PropertyInfo propInfo = (PropertyInfo)member;
            dt.Columns.Add(propInfo.GetValue(item, null).ToString(), propInfo.PropertyType);
        }
    }

    // add rows to table
    foreach (MemberInfo member in members.Where(x => x.Name != headingMember))
    {
        var row = dt.NewRow();
        row[0] = member.Name;
        int i = 1;

        foreach (var item in collection)
        {
            if (member is FieldInfo)
                row[i++] = ((FieldInfo)member).GetValue(item);

            if (member is PropertyInfo)
                row[i++] = ((PropertyInfo)member).GetValue(item, null);
        }

        dt.Rows.Add(row);
    }

    return dt;
}

Is there What would be a better way to do this?

Answer 1

You could Pivot an IEnumerable simply by using Group on the name. Assuming the name is distinct. Once you've pivoted the data, you can Convert IEnumerable to DataTable.