Linq to DataSet - Handling Null Values

Question

I have a requirement to convert LINQ to DataTable.

I stole the following Extension Method from StackOverflow:

public static DataTable ToDataTable<T>(this IEnumerable<T> items)
        {
            var tb = new DataTable(typeof(T).Name);
            PropertyInfo[] props = 
            typeof(T).GetProperties(BindingFlags.Public
                                  | BindingFlags.Instance);

            foreach (var prop in props)
            {
                tb.Columns.Add(prop.Name, prop.PropertyType);
            }

            foreach (var item in items)
            {
                var values = new object[props.Length];
                for (var i = 0; i < props.Length; i++)
                {
                    values[i] = props[i].GetValue(item, null);
                }

                tb.Rows.Add(values);
            }
            return tb;
  } 

When the table contains null values it throws exception. (i.e)

DataSet does not support System.Nullable<> 

Comission (Decimal type) column contains null value)

at

tb.Columns.Add(prop.Name, prop.PropertyType);

How to fix it?

Answer 1

Here's a pimped version:

public static DataTable ToDataTable<T>(this IEnumerable<T> items) { 
    DataTable table = new DataTable(typeof(T).Name);
    PropertyInfo[] props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance); 

    foreach (var prop in props) {
        Type propType = prop.PropertyType;

        // Is it a nullable type? Get the underlying type
        if (propType.IsGenericType && propType.GetGenericTypeDefinition().Equals(typeof(Nullable<>)))
            propType = new NullableConverter(propType).UnderlyingType; 

        table.Columns.Add(prop.Name, propType);
    } 

    foreach (var item in items) { 
        var values = new object[props.Length]; 
        for (var i = 0; i < props.Length; i++)
            values[i] = props[i].GetValue(item, null);  

        table.Rows.Add(values); 
    }

    return table;
}

Edit: Modified my code a bit, tested it, it works! :)