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Entity Framework Core : Include issue when using spatial filters

I a have a method which first creates an IQueryable for a DbSet of my DbContext with all the Include clauses needed.
Then, for each input parameter in that method, I test if it has a value and if yes, I get a new instance of the IQueryable by adding a Where clause.
Everything works great except for one parameter. If that parameter has a value and the where clause is "executed", then one of the Include seems to be ignored. I haven't seen any warning about that Include beeing ignored so I don't know if that's really what happened but after the ToListAsync(), that navigation property of my object is empty (it's a list).
That list is not empty after the ToListAsync() if that specific parameter is null (so the Where is not stepped through).
I've also notice that, in debug mode with a breakpoint after the problematic Where(), if I set a quick watch on my IQueryable and call the method ToList() on it, I can reproduce the problem. Now, on the same quick watch, I call the method First(), the object that I get have all his navigation property correctly populated. Calling the method ToList() again now gives me the first object of the list fully populated but not the others.
I hope that I have explained this well enough because I'm not sure that I have the permission to post some code. (I'll ask, if the answer is positive, I'll come back to illustrate a bit more).
Thanks in advance for those who will take the time read this.

Why can't Json.Decode handle arrays in C#?

Could someone help shed light on what is going on here?
If I do this in a C# program:
dynamic data = Json.Decode("{\"myObjects\": [ { \"id\": 1 }, { \"id\": 2 } ] }");
int id = data.myObjects[0].id;
I am able to access id and it is set to 1... everything is fine up until this point.
What I don't understand is why, when I'm debugging the program, I cannot view the contents of datain the Locals inspector. Instead it tells me this, as if it doesn't know how to process the array.
Error No further information on this object could be discovered

'data' is declared as dynamic type and thats why you cannot mouse over and see the value. You could still see the value if you add 'data' to Watch.

There seems to be a bug/limitation of Visual Studio (at least the 2013 version I use). If you put a watch on data, you can click on Dynamic View and see that it has stuff, but if you click on myObject (that is a DynamicJsonArray) you only get its "dynamic" part, and not its "fixed" properties (like the Length) and if you try to click on its Dynamic View you receive No further information on this object could be discovered... but if you create a watch for data.myObject, then you'll still have the unusable Dynamic View, but you can look at the "fixed" properties of the DynamicJsonArray (like the Length) and if you click on the Result View you can see the items of the array. See image:

The other answers did not work for me, but I found an alternative way to view the array contents in Visual Studio.
I have found that we can see the contents of the DynamicJsonArray in the Watch window (or IntelliSense), by looking inside the Non-Public members of the top level object. Inside that, we see the private _values member and inside that, we see the values. Upon opening the relevant value, we see the Key and Value members inside.
We can then proceed to open the Value node and then, the Results View, which will show the items in the array. We can then finally access the individual items in the collection

Asp.net-MVC Custom Validation - NULL vs Empty

For security and consistency I would like to test on post-back if a field is missing? In Java (servlets in particular) when we perform a request.getParameter(key) the result is either a String value or otherwise NULL if the field is missing. In MVC I've created a custom validation that I call "ThrowOnNull". The behavior I'm trying to capture is: If an intended field is missing (null) I want to throw, otherwise return success.
Consider this Custom Validator (that doesn't work):
public class ThrowOnNull: ValidationAttribute
{
public ThrowOnNull() { }
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
if (value == null)
throw new Exception(validationContext.MemberName + " field expected, but missing."));
return ValidationResult.Success;
}
}
Is it possible to do what I want here? (this validator doesn't work as expected and it's because the framework is assigning NULL to an empty value [oh dear].)
UPDATE: Per #emodendroket, the following code example now works as expected:
public class ThrowOnMissing: ValidationAttribute
{
public ThrowOnMissing() { }
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
if (!HttpContext.Current.Request.Form.AllKeys.Contains(validationContext.MemberName))
throw new Exception(validationContext.MemberName + " field expected, but missing.");
return ValidationResult.Success;
}
}
EDIT: I've cleaned up the question and example code significantly to make it all much clearer, hope it helps.

You're missing one important point - when you submit a form, all fields belonging to that form get submitted. If the user doesn't fill them, they're blank, so the validation for null can't really work like this...
You should probably redefine what "missing value" means.
EDIT:
After some discussion it seems you're not really concerned about null values, but about the security (false forms with missing fields and stuff like that). In that case you should simply use the standard - antiforgery token and maybe check the origin of the request. You should be more than fine this way. Checking for missing fields won't help a bit, because attacker can easily send those fields as well.
Over/Under posting is a real concern. Furthermore, if fields aren't submitted (due to a hack or DOS attack of some kind)
Not really.
Overposting is handled by the action method on the controller. It won't accept more parameters than you've specified.
Underposting will be handled pretty much the same way as if you didn't fill the text fields in the form, again a non-issue if you have validated your model correctly.
DDOS attack can't be prevented a believe me, some checking for missing fields won't help a bit if someone has a network powerful enough to cause DDOS. Just look up latest cases on attacks and you'll understand, that if HUGE servers can't withstand that, you certainly can't prevent it like this.
Your data validation shouldn't be too expensive either. It's a web, people don't like to wait too much.

If you want your own validator you can look at the dictionary HttpContext.Current.Request.Form. You can then do what you've proposed with this code:
if (!HttpContext.Current.Request.Form.AllKeys.Contains("prop"))
{
throw new Exception();
}

I think you're being unreasonably paranoid here about things. Note that I said Unreasonably paranoid, since a little paranoia is a good thing.
First, let us analyze the "threats" and determine the risks. You've presented several arguments:
Over-posting
Under-posting
Validation of empty vs null
The first item is not an issue in MVC if you are using a View Model. You simply can't post information that the view isn't expecting (well, you can, but it's ignored). If you're not using a view model (or not using a properly defined one) then you can use binding attributes to prevent posting of items you don't want bound.
The second, under-posting, if it's truly a concern for your model (99.999% of the time simply treating it as required is more than fine, but ok let's take your argument. The issue here is not the validation attribute, it's the model binder. You simply have to register a custom model binder that looks for missing values in your view model and throws if they are null. This is easily accomplished by reflecting over the bound model and comparing it to the posted values, then throw.
The problem with your RequiredThrowIfNull approach is.. what if it's not required and it's under posted? That's still an error according to your argument.
Finally, validation of empty vs null... you talk about expensive validation... I don't know what kind of expensive validation you could be talking about here, but server side there is noting in attributes that could be considered expensive.
The reason your attribute doesn't work is because validation attributes are called within a try/catch block by the framework already, and if it's null it's the very mechanism that treats it like empty (this mechanism also does things like catching parsing errors when a type is incorrect, such as characters in a datetime field.)
.NET is not Java, even though it largely works similarly... trying to re-implement Java patterns in .NET is going to lead to misery on your part because many basic philosophies are just different.
Even if we accept your argument of wanting to catch errors or be notified of hacking attempts, throwing is the wrong thing to do in most cases. Instead, just log the information from the model binder and continue on as normal. Only throw if you absolutely need to abort the request, and most of the time that simply isn't the case, even if you're being hacked... throwing will just cause the attacker to vary their attack until they no longer get the exception.
Frankly, this is an over-engineered, solution looking for a problem and there are many good .net specific ways of dealing with the REAL issues you are trying to solve.

#ignatandrei from ASP.NET answered the question:
by default MVC transforms empty string to null string.
http://forums.asp.net/t/2006146.aspx?Custom+Validation+and+NULL

Visual Studio Visualizer

To make this clear, I'm using .net 3.5
I'm currently creating an Visual Studio Visualizer in order to be able to see the values of individual rules in a WF RuleSet. Everything is ok, but now I need to do the following.
Let's say I have a rule which is "this.Age > 50" and one then action as MessageBox.Show("Bigger than 50") and one else action as MessageBox.Show("Less than 50")
I need to be able to select the rule "this.Age > 50" and evaluate it as true or false. Or I need to select part of the rule, eg. "this.Age" and evaluate it to let's say 70.
This last bit is working. I'm getting the object in which the RuleSet executes and getting the fileds and try to find one field named Age and if I do find, I get it's value, on the event of not finding the field I then look at properties. This is working.
The problem is evaluating "this.Age > 50". Of course, I could do a parser in this case and evaluate it, but the problem is then I would have to evaluate "this.Age > 50", "this.Age < 50"... I guess you understand the problem. And of course I also want to evaluate for example, "this.GetCurrentAge()", in which GetCurrentAge() is a method in the class represented by the object in which context the RuleSet executes.
I've thought I could try to inject a method at runtime into the object I currently have and which is instantiated. This way, I could create something as simples as
public string EvaluationMethod()
{
return (this.Age > 50).ToString();
}
in this case, I would at runtime build this method and inject it in the current instance of object.
The problem is that I can't seem to find a way to inject code into the current instance of the object. I can only find examples on how to create new classes at runtime, but nothing about only creating a method and inject it.
Can someone please help, or give any other idea?
Thanks

How to debug a WPF application with asynchronous data access and no Call Stack?

I have a large WPF application that uses the MVVM design pattern and asynchronous data access methods. It uses the old style asynchronous code with callback handlers and the IAsyncResult interface... here is a typical example:
function.BeginInvoke(callBackMethod, asyncState);
Then , in the view model, I have the following callback handler:
private void GotData(GetDataOperationResult<Genres> result)
{
UiThreadManager.RunOnUiThread((Action)delegate
{
if (result.IsSuccess) DoSomething(result.ReturnValue);
else FeedbackManager.Add(result);
});
}
The RunOnUiThread method is basically the following:
public object RunOnUiThread(Delegate method)
{
return Dispatcher.Invoke(DispatcherPriority.Normal, method);
}
This problem only affects one view model, the one that enables the users to edit the Release objects. On the related view, certain collections that populate ComboBoxes are requested from the database when it is first loaded. Let's simplify this saying that there is just one collection called Genres. After the data arrives in the view model, it is handled like so:
private void GotGenres(GetDataOperationResult<Genres> result)
{
UiThreadManager.RunOnUiThread((Action)delegate
{
if (result.IsSuccess) Genres.AddEmptyItemBefore(result.ReturnValue);
else FeedbackManager.Add(result);
});
}
When the collection is present and a Release object has been selected in the UI, I have the following code selects the current Release.Genre value from the collection:
if (!Release.Genre.IsEmpty && Genres.ContainsItemWithId(Release.Genre.Id))
Release.Genre = Genres.GetItemWithId(Release.Genre);
At this point, I should note that this all works fine and that this is the only line that references the Release.Genre property from the view model.
My particular problem is that sometimes the Release.Genre property is set to null and I can't work out how or from where. >> Edit >> When I put a break point on the property setter, << Edit << the Call Stack provides no real clues as to what is setting the null value, as there is only a [Native to Managed Transition] line. On selecting the Show External Code option from the Call Stack window, I can see basic asynchronous code calls:
Now I can confirm the following facts that I have discovered while attempting to fix this problem:
The one line that references the Release.Genre property is not setting it to null.
The call to Genres.AddEmptyItemBefore(result.ReturnValue) is not setting it to null... this just adds the result collection into the Genres collection after adding an 'empty' Genre.
The Release.Genre property is sometimes set to null in or after the call to Genres.AddEmptyItemBefore(result.ReturnValue), but not because of it... when stepping through it on a few occasions, execution has jumped (in an unrelated manner) to the break point I set on the Release.Genre property setter where the value input parameter is null, but this does not happen each time.
It generally happens when coming from a related view model to the Release view model, but not every time.
The related view model has no references to the Release.Genre property.
To be clear, I am not asking anyone to debug my problem from the sparse information that I have provided. Neither am I asking for advice on making asynchronous data calls. Instead, I am really trying to find out new ways of proceeding that I have not yet thought of. I understand that some code (almost certainly my code) somewhere is setting the property to null... my question is how can I detect where this code is? It does not appear to be in the Release view model. How can I continue to debug this problem with no more clues?

I usually use Flat File, XML or Database logging for debugging purpose. I created those Log classes for logging purpose, so that I can call it from every applications I develop.
For database logging, you can do it as simple as:
void WriteLog(string log){
// Your database insert here
}
Maybe you need datetime and other supporting information, but it's up to the developer. For simple flat file logging is:
void WriteLog(string log){
using(TextWriter tx = new StreamWriter("./Log/" + DateTime.Now.ToString() + ".txt", false)){
tx.WriteLine(log);
}
}
You can use the logging in your application in both ways:
1: Method call
WriteLog((Release.Genre == null).ToString());
if (!Release.Genre.IsEmpty && Genres.ContainsItemWithId(Release.Genre.Id))
Release.Genre = Genres.GetItemWithId(Release.Genre);
2: Add it in your Release.Genre set (or get) property
public class Release{
private Genre _genre=null;
public Genre Genre{
get{
WriteLog((_genre == null).ToString());
return _genre;
}
set{
WriteLog((_genre == null).ToString());
_genre = value;
}
}
}
With this, you can try to get the call sequence, whether the Release.Genre is being set in other places before, during call, etc.
Please note I just giving the general image of building logging. Please expect errors. However, it is developer's responsibility to develop the Logging acitivities to meet requirement.