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How do I search a dynamic object IEnumerable<dynamic> using a dynamically built lambda expression?

Previously, I had great help on my previous question, thank you vyrp
,
How do I create and populate a dynamic object using a dynamically built lambda expression
I'm now looking to search the dynamic object, and as before, I don't know the objects properties, and therefore what I'm searching until runtime.
Here's the code that builds the dynamic object:
// Get list of optional fields
var optFieldList = await _tbList_FieldRepository.GetAsync(lf => lf.ListID == listId && lf.DisplayInList == true);
// order list of optional fields
optFieldList.OrderBy(lf => lf.DisplayOrder);
// Get base Data excluding Inactive if applicable
IEnumerable<tbList_Data> primaryData = await _tbList_DataRepository.GetAsync(ld => ld.ListID == listId && (ld.IsActive == includeInactive ? ld.IsActive : true));
// Build IEnumerable<dynamic> from base results plus any optional fields to be displayed in table
var results = primaryData.Select(pd => {
dynamic result = new System.Dynamic.ExpandoObject();
result.Id = pd.ID;
result.PrimaryData = pd.PrimaryData;
result.DisplayOrder = pd.DisplayOrder;
result.IsActive = pd.IsActive;
foreach (var optField in optFieldList)
{
switch (optField.FieldType.ToLower()) {
case "text":
((IDictionary<string, object>)result).Add(optField.FieldName, pd.tbList_DataText.Where(ld => ld.DataRowID == pd.ID && ld.ListColumnID == optField.ID).Select(ld => ld.DataField).DefaultIfEmpty("").First());
break;
}
}
return result;
});
For the purpose of testing, I have 2 dynamic fields, "PhoneNumber" and "FuelType"
I can search the known field(s) i.e. PrimaryData, no problem, as below.
results = results.Where(r => r.PrimaryData.Contains(searchString));
And the following will work if I know the field PhoneNumber at design time
results = results.Where(r => r.PhoneNumber.Contains(searchString));
but what I want to do, is something like:
results = results.Where(r => r.PrimaryData.Contains(searchString)
|| foreach(var optField in optFieldList)
{
r.optField.FieldName.Contains(searchString)
})
ending up with
results = results.Where(r =>
r.PrimaryData.Contains(searchString)
|| r.PhoneNumber.Contains(searchString) ||
r.FuelType.Contains(searchString));
but obviously that code doesn't work. I've tried a bunch of different attempts, none successful, so I'm looking for suggestions. Thanks

Since you know that the dynamic element of your query is actually ExpandoObject, hence IDictionary<string, object>>, you can safely cast it to dictionary interface and use it to access the property values by name, while Enumerable.Any method can be used to simulate dynamic || condition:
results = results.Where(r => r.PrimaryData.Contains(searchString)
|| optFieldList.Any(f =>
{
object value;
return ((IDictionary<string, object>)r).TryGetValue(f.FieldName, out value)
&& value is string && ((string)value).Contains(searchString);
}));

Only do Where condition if a value is passed in

I have the following LINQ statement that does on where on the date and a LabID.
I'm passing in a list of LABS and a date, however they are not required, and I could potentially only pass in a date, and no lab, in which case I'd like to get results for all labs for that particular lab.
here is what I have now:
List<dExp> lstDatExp = (from l in ctx.dExp.Include("datLab")
where values.Contains(l.datL.Lab_ID)
&& l.reportingPeriod == reportingPeriod
select l).ToList<dExp>();
But this breaks if the value getting passed in is not there. How do I change this to make sure both of my where statements are optional?

With IQueryable you can simply add conditions in steps:
int? reportingPeriod = ...;
IQueryable<dExp> resultsQuery = // don't use `var` here.
ctx.dExp.Include("datLab");
if (values != null)
resultsQuery = resultsQuery.Where(exp => values.Contains(exp.datL.Lab_ID));
if (reportingPeriod.Hasvalue)
resultsQuery = resultsQuery.Where(exp => exp.reportingPeriod == reportingPeriod.Value);
// additional .Where(), .OrderBy(), .Take(), .Skip() and .Select()
// The SQL query is made and executed on the line below
// inspect the string value in the debugger
List<dExp> results = resultsQuery.ToList();

Here are two ways to do that.
But first, please don't use a single lowercase l as an identifier. It is way too easy to confuse it with the number 1. More generally, stp using abbrevs in yr cde, it mks it hrdr to rd.
First technique:
var query = from lab in ctx.dExp.Include("datLab")
where values == null || values.Contains(lab.datL.Lab_ID)
where reportingPeriod == null || lab.reportingPeriod == reportingPeriod
select lab;
var list = query.ToList<dExp>();
Second technique:
IEnumerable<dExp> query = ctx.dExp.Include("datLab");
if (values != null)
query = query.Where(lab=>values.Contains(lab.datL.Lab_ID));
if (reportingPeriod != null)
query = query.Where(lab=>lab.reportingPeriod == reportingPeriod);
var list = query.ToList<dExp>();

What we do is something like (l.reportingPeriod == reportingPeriod || reportingPeriod == null) So you check to see if the parameter is its default meaning it hasnt been used or if there is something there check it against the database.

You need to check if your values are null before doing the query, and if they are, don't do the extra condition.
List<dExp> lstDatExp =
(from l in ctx.dExp.Include("datLab")
where
(values == null || values.Contains(l.datL.Lab_ID)) &&
(reportingPeriod == null || l.reportingPeriod == reportingPeriod)
select l).ToList<dExp>();
This way if values or reportingPeriod are null they are essentially optional.

Nullable filters in XRM where clause

I'm using the XRM (early bound) types in a WCF project so I have access to the CRM model and can use LINQ queries. But I've been running into a problem described here, it's the limitations on the where clause specific to XRM LINQ:
where [clause limitations]
The left side of the clause must be an attribute name and the right side of
the clause must be a value. You cannot set the left side to a constant. Both
the sides of the clause cannot be constants.
Supports the String functions Contains, StartsWith, EndsWith, and Equals.
One requirement that keeps popping up is when a parameter is null, all entities should be returned otherwise filter by the parameter. But I can't think of a way to do this without breaking the requirements above, or writing multiple queries to handle the scenario when it's null.
this is an example of one of my queries, the typeFilter == null is the problem here is I've used a constant on the LHS. In my real code there's a guard clause that points typeFilter == null to another query but I now have to add a start/end date filter (both nullable) and I cannot express how much I don't want to write a query for every combination of nullables.
private IQueryable<EventInfo> getAllEvents( DataContext context, EventType? typeFilter )
{
return (
from evt in context.new_eventSet
where
( evt.statecode == new_eventState.Active ) &&
( typeFilter == null || evt.new_EventType.Value == (int) typeFilter.Value )
select new EventInfo()
{
ID = evt.Id,
EventType = (EventType) evt.new_EventType.Value
...
} );
}

How about:
if (typeFilter == null)
{
return (
from evt in context.new_eventSet
where
( evt.statecode == new_eventState.Active )
select new EventInfo()
{
ID = evt.Id,
EventType = (EventType) evt.new_EventType.Value
...
} );
}
else
{
return (
from evt in context.new_eventSet
where
( evt.statecode == new_eventState.Active ) &&
evt.new_EventType.Value == (int) typeFilter.Value )
select new EventInfo()
{
ID = evt.Id,
EventType = (EventType) evt.new_EventType.Value
...
} );
}

I've answered my own question! sometimes you just need a place to vent your problems before you get it.
the trick was to not use LINQ syntax:
private IQueryable<EventInfo> getAllEvents( DataContext context, EventType? typeFilter, DateTime? startDateFilter, DateTime? endDateFilter )
{
var result = context.new_eventSet
// active records
.Where( evt => evt.statecode == new_eventState.Active )
// is publish-able
.Where( ..etc.. );
if ( typeFilter != null )
{
// filter by type
result = result.Where( evt => evt.new_EventType.Value == (int) typeFilter.Value );
}
if( startDateFilter != null)
{
// filter by startDate
result = result.Where(evt => evt.new_StartDate > startDateFilter.Value);
}
if( endDateFilter != null)
{
// filter by endDate
result = result.Where(evt => evt.new_StartDate < endDateFilter.Value);
}
return result.Select( evt => new EventInfo()
{
ID = evt.Id,
EventType = (EventType) evt.new_EventType.Value,
...
} );
}

If you want to use the Linq syntax, it is possible to construct a query dynamically using LinqKit.
I have used it for this purpose on the Dynamics CRM project which I'm currently working on, and it does the job very well.
Please refer to the following answer, which is where I got the idea: https://stackoverflow.com/a/5152946/344988

Linq: how to exclude condition if parameter is null

I have some table and the following condition of query: if parameter A is null take all, if not, use it in the query. I know how to do that in 2 steps:
List<O> list = null;
if (A = null)
{
list = context.Obj.Select(o => o).ToList();
}
else
{
list = context.Obj.Where(o.A == A).ToList();
}
Is it possible to have the same as one query?
Thanks

How about:
list = context.Obj.Where(o => A == null || o.A == A)
.ToList();
You can do it in one query but still using a condition:
IEnumerable<O> query = context.Obj;
if (A != null)
{
query = query.Where(o => o.A == A);
}
var list = query.ToList();
Or you could use a conditional operator to put the query in a single statement:
var query = A is null ? context.Obj : context.Obj.Where(o => o.A == A);
var list = query.ToList();
I would personally suggest either of the latter options, as they don't require that the LINQ provider is able to optimise away the filter in the case where A is null. (I'd expect most good LINQ providers / databases to be able to do that, but I'd generally avoid specifying a filter when it's not needed.)

I opted for
var list = context.Obj.Where(o => A.HasValue ? o.a == A : true);

I would probably write the query like this:
IQueryable<O> query = context.Obj;
if (A != null)
query = query.Where(o => o.A == A);
var list = query.ToList()
It's not one expression, but I think it's quite readable.
Also, this code assumes that context.Obj is IQueryable<O> (e.g. you are using LINQ to SQL). If that's not the case, just use IEnumerable<O>.

FindAll in a c# List, but varying search terms

List<DTOeduevent> newList = new List<DTOeduevent>();
foreach (DTOeduevent e in eduList.FindAll(s =>
s.EventClassID.Equals(cla)
&& s.LocationID.Equals(loc)
&& s.EducatorID.Equals(edu)))
newList.Add(e);
cla, loc, edu can be (null or empty) or supplied with values--
basically how can I simply return the original list (eduList) if cla, loc, edu are all null
or search by loc, search by loc, edu, search by edu, cla -- etc........
my sample code only makes a new list if all 3 vars have values--
is there an elegant way to do this, without brute force if statements?

List<DTOeduevent> newList = eduList.FindAll(s =>
(cla == null || s.EventClassID.Equals(cla))
&& (loc == null || s.LocationID.Equals(loc))
&& (edu == null || s.EducatorID.Equals(edu)));
Assuming the values are Nullable value types or classes. If they're strings, you could replace cla == null with String.IsNullOrEmpty(cla).

IEnumerable<DTOeduevent> newList = eduList;
if (cla != null)
{
newList = newList.Where(s => s.EventClassID == cla);
}
if (loc != null)
{
newList = newList.Where(s => s.LocationID == loc);
}
if (edu != null)
{
newList = newList.Where(s => s.EducatorID == edu);
}
newList = newList.ToList();
Due to deferred execution, the Where statements should all execute at once, when you call ToList; it will only do one loop through the original list.

I would personally lean towards something that encapsulated the logic of what you seem to be doing here: checking that a found id is equal to some search id. The only wrinkle is how to get that check for null or empty in there first.
One way to do that is by using a static extension method:
public static class DtoFilterExtensions
{
public static bool IsIdEqual(this string searchId, string foundId) {
Debug.Assert(!string.IsNullOrEmpty(foundId));
return !string.IsNullOrEmpty(searchId) && foundId.Equals(searchId);
}
}
I would also lean towards using LINQ and IEnumerable<> as Domenic does, even though you could make it work with List.FindAll just as easily. Here would be a sample usage:
public void Filter(string cla, string loc, string edu) {
var startList = new List<DTOeduevent>();
var filteredList = startList
.Where(x => x.classId.IsIdEqual(cla) && x.locationId.IsIdEqual(loc) && x.educatorId.IsIdEqual(edu));
Show(filteredList.ToList());
}
In your own code of course you have got that start list either in a member variable or a parameter, and this assumes you have got some method like Show() where you want to do something with the filtered results. You trigger the deferred execution then, as Domenic explained with the ToList call (which is of course another extension method provided as part of LINQ).
HTH,
Berryl