C# /code>用if..else if…替换if语句怎么样?这有帮助吗@UweKeim不,事实上我不能,因为可能两个条件都会满足,并且还需要其他条件记录。@canton7您上面提到的这个参考与我的不相关。这是真实的代码吗?每个条件都会导致相同的操作:收集ID
C# /code>用if..else if…替换if语句怎么样?这有帮助吗@UweKeim不,事实上我不能,因为可能两个条件都会满足,并且还需要其他条件记录。@canton7您上面提到的这个参考与我的不相关。这是真实的代码吗?每个条件都会导致相同的操作:收集ID,c#,performance,entity-framework,linq,output-window,C#,Performance,Entity Framework,Linq,Output Window,/code>用if..else if…替换if语句怎么样?这有帮助吗@UweKeim不,事实上我不能,因为可能两个条件都会满足,并且还需要其他条件记录。@canton7您上面提到的这个参考与我的不相关。这是真实的代码吗?每个条件都会导致相同的操作:收集ID。只需将代码简化为单个select查询。 if (queryObj.AgeCategory.Contains((int)AgeList._0to5)) { var list = queryRecord.Where(v => v.B
/code>用
if..else if…
替换if
语句怎么样?这有帮助吗@UweKeim不,事实上我不能,因为可能两个条件都会满足,并且还需要其他条件记录。@canton7您上面提到的这个参考与我的不相关。这是真实的代码吗?每个条件都会导致相同的操作:收集ID。只需将代码简化为单个select查询。
if (queryObj.AgeCategory.Contains((int)AgeList._0to5))
{
var list = queryRecord.Where(v => v.BuildYear <= yearNow && v.BuildYear > year5).Select(s => s.Id);
Ids = Ids.Concat(list);
}
if (queryObj.AgeCategory.Contains((int)AgeList._6to10))
{
var list = queryRecord.Where(v => v.BuildYear <= year5 && v.BuildYear > year10).Select(s => s.Id);
Ids = Ids.Concat(list);
}
if (queryObj.AgeCategory.Contains((int)AgeList._11to15))
{
var list = queryRecord.Where(v => v.BuildYear <= year10 && v.BuildYear > year15).Select(s => s.Id);
Ids = Ids.Concat(list);
}
if (queryObj.AgeCategory.Contains((int)AgeList._16to20))
{
var list = Ids.Concat(queryRecord.Where(v => v.BuildYear <= year15 && v.BuildYear > year20).Select(s => s.Id));
Ids = Ids.Concat(list);
}
if (queryObj.AgeCategory.Contains((int)AgeList._21to25))
{
var list = Ids.Concat(queryRecord.Where(v => v.BuildYear <= year20 && v.BuildYear > year25).Select(s => s.Id));
Ids = Ids.Concat(list);
}
if (queryObj.AgeCategory.Contains((int)AgeList._26to30))
{
var list = Ids.Concat(queryRecord.Where(v => v.BuildYear <= year25 && v.BuildYear > year30).Select(s => s.Id));
Ids = Ids.Concat(list);
}
if (queryObj.AgeCategory.Contains((int)AgeList._31to35))
{
var list = Ids.Concat(queryRecord.Where(v => v.BuildYear <= year30 && v.BuildYear > year35).Select(s => s.Id));
Ids = Ids.Concat(list);
}
if (queryObj.AgeCategory.Contains((int)AgeList._36to40))
{
var list = Ids.Concat(queryRecord.Where(v => v.BuildYear <= year35 && v.BuildYear > year40).Select(s => s.Id));
Ids = Ids.Concat(list);
}
if (queryObj.AgeCategory.Contains((int)AgeList._Over41Years))
{
var list = Ids.Concat(queryRecord.Where(v => v.BuildYear <= year40).Select(s => s.Id));
Ids = Ids.Concat(list);
}
queryRecord = queryRecord.Where(v => Ids.Contains(v.Id));
Ids = queryRecord.Where(st => ((queryObj.AgeCategory.Contains((int)AgeList._11to15)) ? st.BuildYear <= year10 && st.BuildYear > year15 : true) &&
((queryObj.AgeCategory.Contains((int)AgeList._6to10)) ? st.BuildYear <= year5 && st.BuildYear > year10 : true))
.Select(s => s.Id);
public static Expression<Func<T, bool>> OrElse<T>(
this Expression<Func<T, bool>> expr1,
Expression<Func<T, bool>> expr2)
{
var parameter = Expression.Parameter(typeof(T));
var leftVisitor = new ReplaceExpressionVisitor(expr1.Parameters[0], parameter);
var left = leftVisitor.Visit(expr1.Body);
var rightVisitor = new ReplaceExpressionVisitor(expr2.Parameters[0], parameter);
var right = rightVisitor.Visit(expr2.Body);
return Expression.Lambda<Func<T, bool>>(
Expression.OrElse(left, right), parameter);
}
private class ReplaceExpressionVisitor
: ExpressionVisitor
{
private readonly Expression _oldValue;
private readonly Expression _newValue;
public ReplaceExpressionVisitor(Expression oldValue, Expression newValue)
{
_oldValue = oldValue;
_newValue = newValue;
}
public override Expression Visit(Expression node)
{
if (node == _oldValue)
return _newValue;
return base.Visit(node);
}
}
Expression<Func<Whatever, bool>> query = t => false;
if (queryObj.AgeCategory.Contains((int)AgeList._0to5))
{
query = query.OrElse(v => v.BuildYear <= yearNow && v.BuildYear > year5);
}
if (queryObj.AgeCategory.Contains((int)AgeList._6to10))
{
query = query.OrElse(v => v.BuildYear <= year5 && v.BuildYear > year10);
}
... and so on...
queryRecord = whatever.Where(query);
WHERE (BuildYear <= yearNow AND BuildYear > year5) OR (BuildYear < year5 AND BuildYear > year10) etc
public enum AgeList
{
_0to5 = 0,
_6to10 = 1,
_11to15 = 2,
_16to20 = 3,
_21to25 = 4,
_26to30 = 5,
_31to35 = 6,
_36to40 = 7,
}
var yearNow = 2020;
var buildYear = 2019;
var ageGroupNumber = (yearNow - buildYear) / 5; // 0
var ageGroup = (AgeList) ageGroupNumber; // _0to5
Ids = queryObj.AgeCategory
.SelectMany(category => // For every category :
queryRecord.Where(v => // Select the items in this category :
(DateTime.Now.Year - v.BuildYear) / 5 == (int) category
)
.Select(s => s.Id)
);
private void FilterQueryRecord(IEnumerable<Record> queryRecord, ? queryObj)
{
this.Ids = queryRecord
.Where(item => queryObj.AgeCategory.Contains(ConvertBuildYearToAgeCategory(item.BuildYear)))
.Select(item => item.Id)
.ToList();
}
private int ConvertBuildYearToAgeCategory(int buildYear)
{
switch (buildYear)
{
case int value when value <= yearNow && value > year5: return (int) AgeList._0to5;
case int value when value <= year5 && value > year10: return (int) AgeList._6to10;
case int value when value <= year10 && value > year15: return (int) AgeList._11to15;
case int value when value <= year15 && value > year20: return (int) AgeList._16to20;
case int value when value <= year20 && value > year25: return (int) AgeList._21to25;
case int value when value <= year25 && value > year30: return (int) AgeList._26to30;
case int value when value <= year30 && value > year35: return (int) AgeList._31to35;
case int value when value <= year35 && value > year40: return (int) AgeList._36to40;
case int value when value < year40: return (int) AgeList._Over41Years;
default: return (int) AgeList.Undefined
}
}
Ids = queryRecord.Where(st =>
((queryObj.AgeCategory.Contains((int)AgeList._11to15)) ? st.BuildYear <= year10 && st.BuildYear > year15 : false) ||
((queryObj.AgeCategory.Contains((int)AgeList._6to10)) ? st.BuildYear <= year5 && st.BuildYear > year10 : false)
).Select(s => s.Id);