private Func <T1, TVal[]> CreateExpression(IEnumerable <string> fields)
{
var t1param = EE.Param <T1>("obj");
var elist = fields.Select(f => t1param.Dot(f)).Cast <Expression>();
if (typeof(TVal) == typeof(object))
{
elist = elist.Select(e => EE.Box(e));
}
var resultArr = Expression.NewArrayInit(typeof(TVal), elist);
var l = Expression.Lambda <Func <T1, TVal[]> >(resultArr, t1param);
return(l.Compile());
}
private Func <T1, T2, DifferReturnValueType[]> CreateExpression(IEnumerable <string> fields)
{
var t1param = EE.Param <T1>("left");
var t2param = EE.Param <T2>("right");
var NULL = EE.Val <DifferReturnValueType>(null);
var TupleCreate = EE.Method(() => Tuple.Create <string, object>("", null));
var cmplist2 = fields.Select(f =>
Expression.Condition(t1param.Dot(f).IsEq(t2param.Dot(f)),
NULL,
Expression.Call(TupleCreate, EE.Val(f), EE.Box(t2param.Dot(f)))));
var resultArr = Expression.NewArrayInit(typeof(DifferReturnValueType), cmplist2);
var l = Expression.Lambda <Func <T1, T2, DifferReturnValueType[]> >(resultArr, t1param, t2param);
return(l.Compile());
}
