Linq Inheritance And Subtypes (filter Out Base Type)
Nov 8, 2010
OK I have a base query that is returning a list (ObjectQuery, actually but I don't think it matters) I have about 5 subtypes based on the main type and I need to filter them. Everything works fine until I want the results to be of the main type (not a subclass) Basically I have a query that includes everything, then I filter out the types that are not checked in a checkedbox list. (asp.net) Lets say I have an Entity named Task, and SubTask1 and SubTask2 that inherit from Task
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Jul 29, 2010
how variables declared with protected access in a base class are used to implement inheritance.
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Aug 8, 2011
Background:I have a base class and several inherited derived classes. The derived classes don't always need to have the same properties. If any properties are shared among the derived classes, those properties would live at the base class level ('Contents', for example).Similarly, GoodDocument below has 'GoodThings' but would not want/need to have 'BadThings'.I want to treat instances of both 'GoodDocument' and 'BadDocument' as type 'Document'
public mustinherit class Document
public property Contents as string
public sub new()...
[code]....
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Jul 7, 2010
I have created a Dictionary class (MyDictionary for the example). I am currently trying to pass MyDictionary into a function, filter it into a new instance of MyDictionary and pass this new instance into another method. When I am attempting to create the second instance from the filtered first instance of MyDictionary via Lambda Expressions and the ToDictionary Method, I am getting the following error:
Unable to cast object of type 'System.Collections.Generic.Dictionary`2[System.Int32,System.String]' to type 'MyDictionary'. I have simplified the example and recreated it in LINQPad and am getting the same error.
Here's the simplified version of my code:
[Code]...
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Aug 20, 2009
I have a number of controls (Device1, Device2, etc.) that all inherit from BaseDeviceControl. In the DragEnter event handler I am trying to test for the correct type by using the BaseDevvceControl like this....
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Nov 23, 2009
I have a copy function that I'd like to override in subclasses to return the type of the subclass. Here are my interfaces:
Public Interface IBase(Of T)
Function Copy() As T
End Interface
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Sep 10, 2009
Example-I have a person class
Public Class Person
Private _fname As String
Public Property Fname() As String
[Code]...
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Mar 30, 2010
1) VB Allows non-type template parameters2) VB supports explicit specialization 3) VB allows the type parameters to be used as the base class for the generic type4) VB allows a generic type parameter itself to to be a generic 5) VB enforces that all codes are valid for all types of parametrs
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Jun 29, 2010
I'm wrestling with this treeview control. I have extended the TreeNode class to attach some extra data to the node. Basically, I added one property:[code]Is there a way to cast from a base type to a derived type?
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Apr 15, 2010
I have put this code in the global form Inherits System.Windows.Forms.Form. And then in the form that will inherit this from the global Inherits MenuStrip. "MenuStrip" is what the global form is called. But keep getting this error: Error1Base class 'MenuStrip' specified for class 'Lesson2' cannot be different from the base class 'System.Windows.Forms.Form' of one of its other partial types.
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Apr 5, 2011
I'm trying to create a list of all my objects from several lists of objects using Union.
Return Chart.AnnotativeNodes.Union( _
Chart.DecisionNodes.Union( _
Chart.EndNodes.Union( _
Chart.StartNodes.Union(Chart.WorkCenterNodes))))
The above line gets an error because I can't union List(of AnnotativeNode) with List(of DecisionNode). Each list defined like List(of EndNode) or List(of StartNode), but each class inherits from the base type Node.Is there a possible way to union these to get a result of IEnumerable(of Node)?
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May 3, 2011
Public Sub adjectAllNormals()
Dim qry As LinkedList(Of CElement) = From elm In Elements
From id In SelectIDs()
Where elm.ID = id
Console.WriteLine(qry.Count)
End Sub
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Jul 12, 2011
I'm trying to filter out the time which is greater than 8:00 am and store it in array . Can anyone give me some suggestion?[code]
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Dec 29, 2011
Is anyone any good with Databases & VB if so could you give me your opinion on the diagram i have drew and my application.ive never used a database before but would like to encorprate one into my app - i have done a diagram - i would like to know if it is possible to do and what type of data base would be esiest to do it with.
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Jun 9, 2009
One thing that always bugged me, is that I do not see the base type in Visual Studio.I just stumbled on this, because I tried to cast a System. Windows.Forms.MenuItem to a System.Windows.Forms.Control..In eclipse the "intellisense" (or whatever it is called) shows me while exploring the members of a class for each member from which base class it is inherited.In Visual Studio I cannot see the base class, even if I use the Object browser or the help.[code]Is there a way to query the base type tree of a class at Design Time?
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Oct 1, 2009
I have a list(of t) and I got a iqueryable(of a)
I want to filter out any item from the iqueryable(of a) where a.id = t.myotherid
I'm not really sure how to write this query[code]...
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Dec 11, 2008
I am trying to grasp using Linq to read and filter xml files. I've been googling and trying all day long but still not successful.[code]
1. Firstly I want to select a contact with a certain node value, my code looks like this:[code]
2. The third level nodes have some same descedants child elements. Is it possible to sort the entries by <contactId>? How can I do that? For example I want to have a result like this:[code]
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Oct 4, 2010
Imagind I have the following in VB:
function doSomething()
From ou In ctxt.Users.Where(Function(p) p.UserName = username)
...
end function
how can I send the filter as parameter (something like below)?
function doSomething(filter as whatTypeHereAndHowToInstantiateInCallingFunction)
From ou In ctxt.Users.Where(filter)
...
end function
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Mar 14, 2012
I've a simple class like this:
Public Class CalculationParameter{
public Long TariffId{get;set;}
}
In a workflow activity, I've an Assign like this:
(From tariffDetail In db.Context.TariffDetails
Where tariffDetial.TariffId = calculationParameter.TariffId).FirstOrDefault()
Dto is passed to Activity as an Input Argument.It raise following error and I'm wondering how to assign Id.LINQ to Entities does not recognize the method 'Int64
GetValue[Int64](System.Activities.LocationReference)' method, and this method cannot be translated into a store expression.
How can I assign the calculationParameter.TariffId to tariffDetial.TariffId?!
UPDATE:Screen shot attached shows that how I'm trying to assign calculationParameter.TariffId to tariffDetail.TariffId (car.Id = Dto.Id) and the query result should assign to CurrentTrafficDetail object.
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Mar 9, 2010
Is there a way to get an enum to explicitly cast to it's base type?If I have something like this:
Code:
Public Enum Packets As Byte
Stuff = &H0
End Enum
I have to do
Code:
Dim test As Byte = CByte(Packets.Stuff)
Rather than
Code:
Dim test As Byte = Packets.Stuff
I don't see why that's the way it works, since you know that the enum will always have values of the base type.
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Nov 26, 2010
How do I get using reflection the most generic type from a shared constructor in the base class :
Public Class Foo()
Shared Sub New()
'Here we have code to get the type[code]....
I expect the result to be Bar type and not the Foo. Is it possible?
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Oct 8, 2010
I have a project that has mainly two objects, both inheriting from a base. Like this:
Public Class Vehicle
Property Model As String
Property Make As String[code].....
The above function doesn't work because myVehicle is a Vehicle, not a Truck.Is there a way I can pass around a Vehicle type and have the IDE know which type to use? Or am I completely missing a better way to do this?
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Nov 2, 2011
I am trying to write a query for an existing database, I am using LINQ on EF3.5 inside VS2008 as that is the only environment available to me.I have a starter query that gives me a list of items so the user can select what they want.
"e.Result =
From c In MLDb.TBL_FeatureInfoSet
Order By c.INSP_ROUTINE_NM
Select c.INSP_ROUTINE_NM
Distinct"
The user can then select from the list one or several items they are intersted in and i want to use these as the filter in a further database call. It's not then difficult to have a where to filter on one string however, I would also like to be able to allow the user to select several items from the list box and the data for all of those to be returned.
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Jan 6, 2011
I`m looking for a way to parse a parameter name like linq does.I want to filter before i download the date from the database.With LINQ the data is already red into a dataset. I only want to select data from the database witch i need. how i can send a property name to a function without using the property name as string and without to use to mutch code inside the function and without creating an instance of the object, etc.
Module
Module1
Dim user
As user =
[code]....
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Feb 6, 2010
I have a LINQ query:[code]How can I pass "MyField" to the Sub and make the LINQ "Where" clause work?
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Sep 1, 2010
I am wondering if it is possible to filter data from a datatable.Sample datatable
Quote:
Sno CatID Nos
1 XYZ 25
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May 10, 2010
I'm trying to find a way to trick the compiler into exposing lines of code where the default "ToString" method of Integers, Longs, Doubles, DateTimes, etc. is being used. These are lines of code that must be reviewd for culture specifics. FxCop does not expose these areas when .ToString is not used explicity in the code.Putting a class in with something like the following freaks it out
Namespace system
Public Class Int32
Public Overrides Function ToSt
[code].....
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Feb 3, 2010
I've got a datacontext and created a binding source using LINQ to sql but cannot filter said bindingsource. The supportsfilter of the bindingsource is set to false ? why ? I can't find any info to say that I cannot filter a binding source based on a linq query.[code]
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May 28, 2012
I've got a custom NumericEditor control that has a nullable Decimal property called Value. When I bind a data field to Value, I'd like to retrieve the underlying Type of the data that's bound, so that I can restrict the use of decimal places if the source field is an integral data type.I figure I'd have to do this in the BindingContextChanged event, but how do I get the Type of the data field from the binding itself? My Google-Fu is failing me at the moment.
In short, I'm looking for something like the GetValueType method mentioned in the following question: Simple databinding - How to handle bound field/property change. Winforms, .Net I imagine this method would also be handy if the Value property was an Object.
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Apr 22, 2010
VB.NET 2008 .NET 3.5 I have two base classes that are MustInherit (partial). Let's call one class OrderBase and the other OrderItemBase. specific type of order and order item would inherit from these classes. Let's call these WebOrder (inherits from OrderBase) and WebOrderItem (inherits from OrderItemBase).
Now, in the grand scheme of things WebOrder is a composite class containing a WebOrderItem, like so:
[Code]...
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