I will explain my Problem
so Firstly, I use Predicates Linq for Build Where clause dynamically.
I have to build dynamically because I don't know how many parameters will come. Let me give an example. For the A column can be one parameters however, for the B column can be 2 parameters like either value 'Gas' or 'Oil' which select but that's big problem I can not combine for these 2 column correctly.
So as a result, this code work but It return 0 Items. But there are I know.
public List<CarEntity> GetSearchByKCriteria(int cityId, List<string> fuelType, List<string> gearType, List<string> budget,
List<string> caroser, List<string> enginePower)
{
Expression<Func<Car, bool>> query = null;
Expression<Func<Car, bool>> combine = null;
foreach (var bud in budget)
{
if (budget.Count >= 1)
{
if (bud == "1")
{
if (budget.Count > 1)
{
query = car => car.Budget >= 20000 && car.Budget <= 34999;
}
else
{
query = car => car.Budget >= 20000 && car.Budget <= 34999;
}
}
else if (bud == "2")
{
if (query != null)
{
combine = car => (car.Budget >= 35000 && car.Budget <= 49999);
query = query.Or(combine);
}
else
{
query = car => car.Budget >= 35000 && car.Budget <= 49999;
}
}
}
}
foreach (var caros in caroser)
{
if (caros != "-1" && !string.IsNullOrEmpty(caros))
{
if (query != null)
{
if (query.Expand().ToString().ToLower().Contains("karoser"))
{
combine = car => (car.Karoser == caros);
query = query.And(combine);
}
else
{
combine = car => car.Karoser == caros;
query = query.And(combine);
}
}
else
{
query = car => car.Karoser == caros;
}
}
}
foreach (var fuel in fuelType)
{
if (fuel != "-1" && !string.IsNullOrEmpty(fuel))
{
if (query != null)
{
if (query.Expand().ToString().ToLower().Contains("yakituru"))
{
combine = car => (car.YakitTuru==fuel);
query = query.Or(combine);
}
else
{
combine = car => car.YakitTuru == fuel;
query = query.And(combine);
}
}
else
{
query = car => car.YakitTuru == fuel;
}
}
}
foreach (var gear in gearType)
{
if (gear!="-1"&& !string.IsNullOrEmpty(gear))
{
if (query != null)
{
if (query.Expand().ToString().ToLower().Contains("sanzimantipi"))
{
combine = car => (car.SanzimanTipi == gear);
query = query.Or(combine);
}
else
{
combine = car => car.SanzimanTipi == gear;
query = query.And(combine);
}
}
else
{
query = car => car.SanzimanTipi == gear;
}
}
}
foreach (var engine in enginePower)
{
if (enginePower.Count >= 1)
{
if (engine == "1")
{
if (query != null)
{
if (query.Expand().ToString().ToLower().Contains("silindirhacmi"))
{
combine = car => (car.SilindirHacmi >= 0 && car.SilindirHacmi <= 1600);
query = query.Or(combine);
}
else
{
combine = car => (car.SilindirHacmi >= 0 && car.SilindirHacmi <= 1600);
query = query.And(combine);
}
}
else
{
query = car => car.SilindirHacmi >= 0 && car.SilindirHacmi <= 1600;
}
}
if (engine == "3")
{
if (query != null)
{
if (query.Expand().ToString().ToLower().Contains("silindirhacmi"))
{
combine = car => (car.SilindirHacmi >= 1601 && car.SilindirHacmi <= 1800);
query = query.Or(combine);
}
else
{
combine = car => (car.SilindirHacmi >= 1601 && car.SilindirHacmi <= 1800);
query = query.And(combine);
}
}
else
{
query = car => car.SilindirHacmi >= 1601 && car.SilindirHacmi <= 1800;
}
}
}
using (var context = DataContextFactory.CreateContext())
{
var result = (from fkCar in context.Car.Where(query)
join pkCarBrand in context.CarBrand on fkCar.Marka equals pkCarBrand.ID
where fkCar.IsActive == true
select new
{
entity = fkCar,
joinEntity = pkCarBrand
});
List<CarEntity> theCarList = new List<CarEntity>();
foreach (var item in result)
{
CarEntity theEntity = Mapper.Map(item.entity);
theEntity.CarBrand = Mapper.Map(item.joinEntity);
theCarList.Add(theEntity);
}
return theCarList;
}
}
So thanks for reply,
I faced a similar challenge a while back, where I wanted to have a list of allowed values for an attribute where, if matched, the associated instance would pass the filter. I came up with the following extension method:
static public Expression<Func<TElement, bool>> BuildContainsExpression<TElement, TValue>(Expression<Func<TElement, TValue>> valueSelector, IEnumerable<TValue> values)
{
if (null == valueSelector)
{
throw new ArgumentNullException("valueSelector");
}
if (null == values) { throw new ArgumentNullException("values"); }
ParameterExpression p = valueSelector.Parameters.Single();
if (!values.Any())
{
return e => false;
}
var equals = values.Select(value => (Expression)Expression.Equal(valueSelector.Body, Expression.Constant(value, typeof(TValue))));
var body = equals.Aggregate<Expression>((accumulate, equal) => Expression.Or(accumulate, equal));
return Expression.Lambda<Func<TElement, bool>>(body, p);
}
This is based on the discussion and code posted at http://www.velocityreviews.com/forums/t645784-linq-where-clause.html
Related
I have to two function which is used to find tags inside the tags like, there is a tag A=B(C(D(E))) so i have to find all the tags inside B then all the tags inside C and so on. I write two function but getting the error System.StackOverflowException. In the first function i am providing the tag ID and against that tag id i am getting getNestesCalTagsId and then calling the getNestedCalTagsIngredients() function. But when there are lot of recursion calls i get the error System.StackOverflowException. Below is my whole code.
public List<int?> getNestedCalTags(int? calTagId)
{
var getNestesCalTagsId = db.Dependencies_Metrix.Where(x => x.Cal_Tag_P_Id == calTagId && x.Status == true && x.Cal_Tag_Id_FK!=null).Select(x => x.Cal_Tag_Id_FK).ToList();
if (getNestesCalTagsId.Count > 0)
{
nestedCalFTags.AddRange(getNestesCalTagsId);
foreach (var item in getNestesCalTagsId)
{
if (item != null)
{
getNestedCalTagsIngredients(item.Value);
}
}
}
if (nestedCalFTags.Count > 0)
{
int countedTags = nestedCalFTags.Count;
List<int?> tags = new List<int?>(nestedCalFTags);
for (int i = 0; i < tags.Count; i++)
{
if (tags[i] != null)
{
getNestedCalTagsIngredients(tags[i].Value);
}
}
}
return nestedRawTags;
}
public bool getNestedCalTagsIngredients(int nestCalTagId)
{
var getCalTags = db.Dependencies_Metrix.Where(x => x.Cal_Tag_P_Id == nestCalTagId && x.Status == true).ToList();
if (getCalTags.Count > 0)
{
foreach (var item in getCalTags)
{
if (item.Cal_Tag_Id_FK != null)
{
var getNestedCalTagParent = db.Dependencies_Metrix.Where(x => x.Cal_Tag_P_Id == item.Cal_Tag_Id_FK && x.Status == true && x.Cal_Tag_Id_FK!=null).Select(x => x.Cal_Tag_Id_FK).ToList();
if (getNestedCalTagParent != null)
{
nestedCalFTags.AddRange(getNestedCalTagParent);
getNestedCalTags(item.Cal_Tag_Id_FK);
}
}
else
{
var rawTagId = db.Dependencies_Metrix.Where(x => x.Cal_Tag_P_Id == item.Cal_Tag_P_Id && x.Real_Tag_Id_FK!=null).Select(x => x.Real_Tag_Id_FK).ToList();
if (rawTagId != null)
{
foreach (var rawItem in rawTagId)
{
if (rawItem!=null)
{
if (nestedRawTags.IndexOf(rawItem.Value) == -1)
{
nestedRawTags.Add(rawItem.Value);
}
}
}
}
nestedCalFTags.Remove(nestCalTagId);
}
}
}
return true;
}
i started with this! and i would like to avoid this
private IQueryable<Customer> FilterResult(string search, List<Customer> dtResult, List<string> columnFilters)
{
IQueryable<Customer> results = dtResult.AsQueryable();
results = results.Where(p => (search == null || (p.Name != null && p.Name.ToLower().Contains(search.ToLower()) || p.City != null && p.City.ToLower().Contains(search.ToLower())
&& (columnFilters[0] == null || (p.Name != null && p.Name.ToLower().Contains(columnFilters[0].ToLower())))
&& (columnFilters[1] == null || (p.City != null && p.City.ToLower().Contains(columnFilters[1].ToLower())))
);
return results;
}
by using reflection maybe.... because imagine i have 100 properties it would be easy to mess up ...so i tried this way i would like to use reflection to loop on all properties instead of making references to each of them(properties)
public IQueryable<Aangifte> FilterColumn<T>()
{
try
{
List<Aangifte> v = AangifteGetData.GetData(StartDate, EndDate);
List<Aangifte> v2 = new List<Aangifte>();
Aangifte Foo = new Aangifte();
List<string> propertEntity = new List<string>();
var search = Request.Form.GetValues("search[value]").FirstOrDefault();
int count = -1;
var results = v.AsQueryable();
List<string> columnName = new List<string>();
foreach (var prop in Foo.GetType().GetProperties())
{
var t = "";
if (!prop.Name.Contains("FORMAT"))
{
TVALUE = prop.GetValue(Foo, null);
t= prop.Name;
propertEntity.Add(t);
count++;
}
if (count < propertEntity.Count())
{
var newt = t;
var Z = Request.Form.GetValues("columns[" + count + "][search][value]").FirstOrDefault();
results = results.Where
(
p => (search == null || (t != null && t.ToLower().Contains(search.ToLower())))
&& (Request.Form.GetValues("columns[" + count + "][search][value]").FirstOrDefault() == null || (t != null && t.ToLower().Contains(Request.Form.GetValues("columns[" + count + "][search][value]").FirstOrDefault().ToLower())))
);
}
}
return results;
}
catch (Exception EX)
{
throw EX;
}
}
public bool UpdateLevelDetailsList(List<LevelDetailsDALDTO> LevelDetailsObjToUpdate)
{
bool result = false;
//List<LevelDetail> editLevelDetails = DBContext.LevelDetails.Where(g => g.LevelID == a.LevelID).ToList();
List<LevelDetail> levelDetails = DBContext.LevelDetails.ToList();
List<VisioShapeData> VisioData = DBContext.VisioShapeDatas.ToList();
foreach (LevelDetailsDALDTO a in LevelDetailsObjToUpdate)
{
//List<LevelDetail> editLevelDetails = DBContext.LevelDetails.Where(g => g.LevelID == a.LevelID).ToList();
List<LevelDetail> editLevelDetails = levelDetails.Where(x => x.LevelID == a.LevelID).ToList();
List<VisioShapeData> updatevisiodata = VisioData.Where(x => x.ID == a.ID).ToList();
if (a.CreatedDate == DateTime.MinValue)
a.CreatedDate = DateTime.Now;
if (a.ModifiedDate == DateTime.MinValue)
a.ModifiedDate = DateTime.Now;
if (editLevelDetails != null)
{
foreach (LevelDetail b in editLevelDetails)
{
b.Cost += a.Cost;
b.Time += a.Time;
b.Responsible = b.Responsible + "," + a.Responsible;
b.ModifiedBy = a.ModifiedBy;
b.ModifiedDate = a.ModifiedDate;
}
if (updatevisiodata != null)
{
foreach (VisioShapeData c in updatevisiodata)
{
c.Level4Id = a.LevelID;
}
}
if (DBContext.SaveChanges() > 0)
result = true;
}
}
return result;
}
want to combine these two statement in
List<LevelDetail> editLevelDetails = levelDetails.Where(x => x.LevelID == a.LevelID).ToList();
List<VisioShapeData> updatevisiodata = VisioData.Where(x => x.ID == a.ID).ToList();
and
I am developing an Asp.Net MVC Application and i am new to Linq and CodeFirst. In my controller this is the action that i have written:
public ActionResult Filter(int? PaperType , int? PaperGram , int? Brand)
{
var FilteredResult ;
if (PaperType.HasValue && PaperGram.HasValue && Brand.HasValue) {
FilteredResult = db.Stocks.where(m => m.PaperType == PaperType && m.PaperGram == PaperGram && m.Brand == Brand);
}
else if (PaperType.HasValue && PaperGram.HasValue) {
FilteredResult = db.Stocks.where(m => m.PaperType == PaperType && m.PaperGram == PaperGram);
}
else if (PaperType.HasValue && Brand.HasValue) {
FilteredResult = db.Stocks.where(m => m.PaperType == PaperType && m.Brand == Brand);
}
// and ifs continue to last
/*
.
.
.
.
*/
else {
FilteredResult = db.Stocks;
}
return View(FilteredResult);
}
But i know that this is not the best way to do in Linq and Codefirst. So, can you give a better solution to this problem?
You can do this:
FilteredResult = db.Stocks.where(m => (m.PaperType == PaperType || !PaperType.HasValue)
&& (m.PaperGram == PaperGram || !PaperGram.HasValue)
&& (m.Brand == Brand || !Brand.HasValue));
What you want to avoid is code duplication.
Create your original IQueriable and then add your where clauses when necessary
public ActionResult Filter(int? PaperType, int? PaperGram, int? Brand)
{
var FilteredResult FilteredResult = db.Stocks.AsQueryable();
if(PaperType.HasValue)
{
FilteredResult = FilteredResult.where(m => m.PaperType == PaperType);
if(PaperGram.HasValue)
FilteredResult = FilteredResult.where(m => m.PaperGram == PaperGram );
if ( Brand.HasValue)
FilteredResult = FilteredResult.where(m => m.Brand == Brand);
}
return View(FilteredResult);
}
You can just assign all elements to list and then filter every element in each if condition
IEnumerable<Stock> filteredResult = db.Stocks.AsQueryable();
if (PaperType.HasValue)
{
filteredResult = filteredResult.Where(m => m.PaperType == PaperType);
}
if (PaperGram.HasValue)
{
filteredResult = filteredResult.Where(m => m.PaperGram== PaperGram);
}
if (Brand.HasValue)
{
filteredResult= filteredResult.Where(m => m.Brand== Brand);
}
return View(FilteredResult.ToList());
Just trying to get a cleaner code on a delete method. I need to delete records from a database if a certain column value matches one of two columns in another table.
Is there a better way to delete multiple records, with a "OR"-like expression, so that I can have only one for each loop instead of the following two?
public static void DeleteStageById(int StageId, int ApplicationId)
{
using (IPEntities ip = IPEntities.New())
{
var stage = ip.mkStages;
var stageCultures = ip.appObjectCultures;
var stageStates = ip.mkStatesInStages;
foreach (var stageCulture in stageCultures.Where(sC => sC.ObjectCultureId == stage.Where(s => s.StageId == StageId && s.ApplicationId == ApplicationId).FirstOrDefault().OCId_Name))
{
stageCultures.DeleteObject(stageCulture);
}
foreach (var stageCulture in stageCultures.Where(sC => sC.ObjectCultureId == stage.Where(s => s.StageId == StageId && s.ApplicationId == ApplicationId).FirstOrDefault().OCId_Description))
{
stageCultures.DeleteObject(stageCulture);
}
...
ip.SaveChanges();
}
}
my linq would look like this one
var stage = ip.mkStages;
var stageCultures = ip.appObjectCultures;
var stageStates = ip.mkStatesInStages;
//store this result into a temp variable so it only needs to run once
var temp = stage.Where(s => s.StageId == StageId && s.ApplicationId == ApplicationId).FirstOrDefault();
if (temp != null)
{
foreach (var stageCulture in stageCultures.Where(sC => sC.ObjectCultureId == temp.OCId_Name || sC.ObjectCultureId == temp.OCId_Description))
{
stageCultures.DeleteObject(stageCulture);
}
...
ip.SaveChanges();
}
I recommend avoiding confusing expressions, but here you go:
foreach (var stageCulture in stageCultures.Where(sC => {
var v = stage.Where(s => s.StageId == StageId && s.ApplicationId == ApplicationId).FirstOrDefault();
return sC.ObjectCultureId == v.OCId_Name || sC.ObjectCultureId == v.OCId_Description;
})
{
stageCultures.DeleteObject(stageCulture);
}