/// <summary>
/// Creates a <see cref="DbOrderByExpression"/> that represents ordering the result set.
/// </summary>
/// <param name="dbSelectQuery">The target <see cref="DbQuery{TQueryExpression}"/>.</param>
/// <param name="expressionSelector">A function used to specify an element in the 'ORDER BY' clause.</param>
/// <param name="orderByExpressionType">Specifies the sort order direction.</param>
/// <returns></returns>
public static DbQuery <DbSelectExpression> OrderBy(this DbQuery <DbSelectExpression> dbSelectQuery, Func <DbExpressionFactory, DbExpression> expressionSelector, DbOrderByExpressionType orderByExpressionType)
{
var dbExpression = (DbExpression)DbExpressionFactory.MakeOrderBy(orderByExpressionType, expressionSelector(DbExpressionFactory));
if (!dbSelectQuery.QueryExpression.OrderByExpression.IsNull())
{
dbExpression = DbExpressionFactory.List(new[] { dbSelectQuery.QueryExpression.OrderByExpression, dbExpression });
}
dbSelectQuery.QueryExpression.OrderByExpression = dbExpression;
return(dbSelectQuery);
}