Converts a Generic List to a DataTable.

// Method: 1
// http://www.extensionmethod.net/csharp/datatable-c-list/list-to-datatable

//
// Converts a List to a DataTable.
public static DataTable ToDataTable<T>(this IList<T> data)
{
    PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(T));
    DataTable table = new DataTable();

    foreach (PropertyDescriptor prop in properties)
    {
        table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
    }
    foreach (T item in data)
    {
       DataRow row = table.NewRow();
       foreach (PropertyDescriptor prop in properties)
       {
            row[prop.Name] = prop.GetValue(item) ?? DBNull.Value;
       }
       table.Rows.Add(row);
    }

    return table;
}

//
// Example:
List<string> myList = New String[]{"a","b","c","d"}.ToList();
DataTable dt = new DataTable();
dt = myList.ToDataTable();


/// -------------------------------------------------------------------------

// Method: 2
// http://www.extensionmethod.net/csharp/ienumerable-t/todatatable

public static DataTable ToDataTable<T>(this IEnumerable<T> varlist)
{
    DataTable dtReturn = new DataTable();

    if (varlist == null) return dtReturn;

    // column names
    PropertyInfo[] oProps = null;

    foreach (T rec in varlist)
    {
        // Use reflection to get property names, to create table, Only first time, others will follow
        if (oProps == null)
        {
            oProps = ((Type)rec.GetType()).GetProperties();
            foreach (PropertyInfo pi in oProps)
            {
                Type colType = pi.PropertyType;
                if ((colType.IsGenericType) && (colType.GetGenericTypeDefinition() == typeof(Nullable<>)))
                {
                    colType = colType.GetGenericArguments()[0];
                }

                dtReturn.Columns.Add(new DataColumn(pi.Name, colType));
            }
        }

        DataRow dr = dtReturn.NewRow();

        foreach (PropertyInfo pi in oProps)
        {
            dr[pi.Name] = pi.GetValue(rec, null) == null ? DBNull.Value : pi.GetValue
            (rec, null);
        }

        dtReturn.Rows.Add(dr);
    }
    return dtReturn;
}

//
// Example: It will result an IQueryable (IEnumerable)
var result = from c in db.customer
             where c.id = 26
             select c;

DataTable dtResults = new DataTable();
dtResults = result.ToDataTable();