var query = from table in datacontext.GetTable(tableType).Cast<object>() select table;
foreach(PropertyInfo pi in this.GetType().GetProperties())
{
    // I know this is not the right way of doing it
    query = query.Where( x => x.GetType().GetProperty(pi.Name) == value;
}

var query = from table in datacontext.GetTable(tableType).Cast<object>()
            where table.#somefield# == value1 && table.#someotherfield# == value2
            select table;