I am finding that this may not be possible, but am trying to see if anybody has a solution.
I have four classes, two are core classes and two are those core classes extended[code]...
This fails because es is of type, extSecurity and the base class expects a type of coreSecurity. I've not found anyway to cast this to allow for me to override this base class in C#. In VB it works just fine.
I have designed a small component I need to derive. The problem is one property from base class doesn't make sense in derived class, but won't hurts too (just it's ugly in property editor)
Now there is a solution to make that property non-derivable or hidden in derived objects?
We use a custom collection derived from CollectionBase to store our Business objects
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I do have a customized treeView which inherits from treeview and uses customized treenodes which inherit from treenode. It works, but each inherited method of the treeview using a treenode as a parameter forces me to do an explizit cast from treenode to my customized treenode to access the additional functionalitiy of my treenode class.
Is there a general way to avoid explizit casting all day long? E.g. telling my customized treeview that all it's properties, mehthods, etc. from now on are working with my customized treenodes instead the general treenode as default?
Turning off option strict is not an option because I want to keep this. Overriding each method, etc. is to cumbersome.
I'm trying to pass a list of objects to my WCF service, but it doesn't seem I can pass an object list from my console test application. I have an error that states:
Value of type
'System.Collections.Generic.List(Of
ConsoleTestingApp.ServiceReference1.LetterVariables)'
[code]....
I have an object of type Dictionary(Of Int16, Polygon) and which contains sometimes up to 15 or so Polygons that i am creating bitmap files with the Polygon. This can take like 20 seconds sometimes so i was trying to pass the full Dictionary to background worker as an argument but i get an issue when trying to access each individual Polygon inside of the Dictionary because the Polygons still belong to the UI thread. How can I access the Polygons inside the Dictionary with the backgroundworker?
Dim worker As New BackgroundWorker
AddHandler worker.DoWork, AddressOf MeasurePolygons
AddHandler worker.RunWorkerCompleted, AddressOf WorkerCompleted
worker.RunWorkerAsync(PolygonCollection)
that is how im calling the thread. PolygonCollection is the Dictionary(Of Int16, Polygon) that contains all the polygons that i will be creating a bitmap file out of.
I'm redesigning an old VB6 application into VB.net and there is one thing I'm not sure on the best way to do. In the VB6 application whenever we created a new instance of a component, we would pass in the user details (user name and the like) so we new who was performing the tasks. However, no that I'm redesigning I've created some nice class designs, but I'm having to add in user details into every class and it just looks wrong.
Is there a VB.net way of doing this so my classes can just have class specific details? Some way so that if my classes need to know who is performing a task, they can get the information themselves, rather than having it passed in whenever the objects are created?
I have created a COM Object via VB .NET and exposed some functions that I wish to call in Excel using VBA. I am currently trying to pass an array of objects as a result to VBA but Excel is complaining the following:
'Function or interface marked as restricted, or the function uses an automation type not supported in Visual Basic.'
I have looked around on the internet and have seen similar issues but not to one I am trying to do.My VB .NET function, which I wish to call in Excel is declared as follows:
Public Function CallArray(ByVal serviceName As String, _
ByVal effectiveDate As String,
ByVal serviceParams() As System.Object,
ByRef ArrayRes() As System.Object) As System.Boolean
VBA is complaining about the System.Objects my question is how the heck are you supposed to pass and return arrays from .NET to VBA. Also the data that will be in the ArrayRes() is mixed type, its not just strings etc, its an array of arrays that can contain strings, integers doubles etc.I chose VB .NET because I assumed it would be possible to map to VBA easier.if System. Object and Arrays in VB .NET is not the way, ie maybe theres another way via collections or lists, then Im open to that. I just need to get this data into VBA.Also I could move over to C# if needs be.
What is the best way to pass objects between threads? I would like to create a new thread that creates a new object : Dim myobject as newobject = new newoject Then in my main thread, I would like to use myobject. Ideally I would like to just assign to a global variable but I don't think that is possible. I think I may have to use some form of delegate function (but I think the child thread would need to complete to use a callback). The new thread will not actually end before I need the object reference in the main thread. How should I go about this?
View 2 RepliesI want to make an numerical integration method with takes in an analytic function and integrate it over a specific interval. For the numerical integration procedure I want to use some procedures in nr.com. The problem is that these are programmed in C++ and they uses functors to pass a function to the integration method. How can I do this in VB 2010?
I want to initialize the function (i.e. set a=1,b=0 for function y(x)=a*x+b) and then pass the function to the integration method. Then when the integration method call the function it only calls the function with one parameter (i.e. x since a,b is already set)
What is the best way to do this in VB2010?I want to make a general integration method where I can pass any single valued function and integration limits.
I have just started using VB, and from what I have found so far it seems like the tools you have is
- to us a delegate for the function
- to use a lambda expression for the function
- send a pointer/adressOf
- to create a function class/structure and submit this to the function
As for now I am most inclined to create a function-class. But I am not really sure how.F.ex. I make different classes for each "uniqe function" I want to integrate, but how can I pass them to the integration function when I need to specify the argument type in the integration-function-call?This seems like a basic problem which applies to many Math operations, so I think it would be very useful to clarify this.
I use to set WithEvents variables to Nothing in Destuctor, because this will "Remove" all the Handlers associated with Handles keyword. Will this have the same effect for derivated classes?
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I have a base class where amongst other code I have declared 2 properties. In my derived class, I get data from the DB and assign the results to the base class properties. This is so when I go back to the base class code, I can access the property values. It allows me to set the values in the derived class but once I go back to the Base class, the values don't exist.
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make objects from the ToolBox using code instead of changing existing objects invisible then visible later?
View 7 RepliesI am getting this error, Not sure why it is happening "Error The SqlParameterCollection only accepts non-null SqlParameter type objects, not Int32 objects."I have tried with all sorts of possibilties, now try to enter default data as dummy data,
Using connection As New SqlConnection
connection.ConnectionString = ConfigurationManager.ConnectionStrings("DentalDeviceConnectionString").ConnectionString
connection.Open()[code].....
I have a program like this.
Module Module1
Public Class Mstr
Public Property Prop1 As String
Public Property Prop2 As String[code]....
But it is not working as I expect it to. You can see it from.The DtlsB properties of all three DtlsA objects are having values from last iteration.
I want to let the user input objects to a richtextbox 1 object on each line, and somehow use Random.Next to select pseudorandomly a few objects, the number 'few' inputted in a textbox.
View 9 RepliesPrivate Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Using conn As New SqlConnection("Database=Clinic_Management_System;Data Source=.SQLExpress;Integrated Security=True;AttachDBFilename=|DataDirectory|Clinic Management System.mdf")
Dim cmdRecord As SqlCommand
[code]....
I have a user control that inherits the FW ListView and I need to dispose of two objects when the form's disposing of it's objects. Here's what I've concluded already, am I on the right track?
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I have a derived DataTable[code]...
Overload resolution failed because no accessible LoadDataRow' can be called with these arguments.
I am developing a program in VB.NET. I have an enum called PriceType that is declared in a super class ItemPriceBase. There are 3 classes that derive from ItemPriceBase - ItemPriceMeasured, ItemPriceNDI and ItemPriceExtraCost. The subset of PriceTypes for these classes are totally unique from each - Measured prices are 1 to 6, NDI prices are 7 to 15 and ExtraCost prices are 16 to 22.
Is there a way declare the enum in the super class and then extend the enum in each of the derived classes so that they only have access to those options, yet I can still access a property in the super class that returns an enum of PriceType?
I have a function that 2 derived classes use, but the third doesn't, would it make sense to just leave it in the base class, even though one of the 3 derived classes doesn't use it?The only way I could think of disallowing the third class is to basically create an intermediate class that is derived of the base, then the 2 that use the common function are derived off the second class.
Is it possible to prevent the 3rd class from using the function, while letting the two that are supposed to use it, use it?Does that just seem to go overboard, I mean as long as I don't "try" to call the function from the 3rd class, it shouldn't be a problem, I just was interested if there was a way to prevent it all together without a lot of hassle.
Trying to implement some sort of commit/rollback functionality in my base objects. I have it working with some help from google. However, I have a question My Base Class has a BeginEdit as shown below -
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Now, what I'm confused about is if I create another class, Class1, that inherits the base class. I add some properties such as Name, Age, Location, etc. to Class1.When I do Class1.BeginEdit, wouldn't "Me.memberwiseclone" make a copy of Class1, then CType try to cast it from Class1 to the BaseObject class? How does that work if Class1 has additional properties like the Name, Age..blah blah? Where do those gets stored in the Base class? I'm having a hard time wrapping my head around the concept...
long story short, I have created a ListView type control, using UserControls for the parent control and the ListViewItems. Most the of the control is written and works fine, right up to the point where I tried to replicate the 'Control.SelectedItems(0).Index' property and the 'SelectedIndexChanged' event.
Each child object knows its index value, and could pass this value via the SelectedIndexChanged event (assuming this is how it works in a normal ListView control -- user clicks on an item, and that item fires an event updating the selected index value in the parent object).
How does the child object raise an event in the parent object? I have a feeling this could be done with Delegates, but I'm still learning about their usage.
I have created an ASP.NET class derived from the standard WebControls.TextBox, with the intention of adding extra properties that will persist between post-backs. However, I cannot figure how to get the values in these properties to persist. I have tried setting the value of the properties into the controls ViewState as part of the PreRender handler, but the value is then not accessible in the Init handler on the post-back, because the ViewState has not yet been setup.
I could look for the ViewState value in the Load handler of the control, but if the page/usercontrol that is using the control asks for the properties value during its Load handler, the control hasn't yet reached it's Load handler, and it therefore not there.
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In the end, the way I managed to get it to work was to use a <asp:PlaceHolder> control within the repeater, create an instance of my control within the ItemDataBound handler of the repeater, and then add the control to the <asp:PlaceHolder>... all done within the Init section (which fortunately I'm able to do).
As Andrew found out in this previous question you can end up in a chicken/egg situation, where you need to create the controls in the Init, but you won't know what controls you need until the Load.
The test is base on Visual Basic inheritance, need to create a derived class, and identify the inheritance.
View 5 RepliesI would like to inherit from the Data.DataColumn in order to produce a DataTextColumn. That means that in the derived class, I dont want to see the non-applicable AutoIncrement property and the like - all I want to see are properties that apply to string types.[code]...
View 5 RepliesI want to have a single table that represents a person and have a number of other tables (such as Student/Teacher) use the Person table to store information related to a person. Unfortunately the entity framework doesn't seem to like it when I try to add an association between the Student or Teacher class and I don't understand why. The Person table contains a column called ParentEntityID, which equals either a StudentEntityID or a TeacherEntityID. In an ideal world I would like to be able to reference the Person table by going Student.Person.FirstName instead of Student.Entity.Person1.FirstName. The error .Net returns when trying to connect the Student/Teacher table to the Person table is:
Error 3007: Problem in Mapping Fragments starting at lines 265, 289: Non-Primary-Key column(s) [ParentEntityID] are being mapped in both fragments to different conceptual side properties - data inconsistency is possible because the corresponding conceptual side properties can be independently modified.
The actual database I am working with is a bit more complicated and has a number of tables connected to the Entity table, which makes my object model pretty ambiguous and was hoping to be able to clean it up a bit by using the entity framework.I am using VB.Net 3.5 in a web application.
Update...In an attempt to internalize the different types of relationships I can form, I have been playing with this simple example and have come up with the following possibilities:And the reason why I cannot make an association between the Student and Address table is because that relationship is not enforced in the database. If I wanted an association between these two tables I would need to re-think the design of my database. Is that correct?
I have an interface (called IPersistentBusinessObject) with a required function that looks like this:
Function GetFields(ByVal fromDatabase As clsODBCDatabase) As enumSuccessFailure
In a class, I try to satify the requirement with the following:
Public Function GetFields(ByVal fromDatabase As clsDatabase) As enumSuccessFailure Implements IPersistentBusinessObject.GetFields
In this example, clsDatabase inherits from clsODBCDatabase. So I'd expect this to work since clsDatabase does everything clsODBCDatabase does and more. However, it does not work. The compiler complains that I haven't properly satisifed the interface requirements for GetFields. Can anyone tell me why this does not work?In slightly different but related example, I have an interface that requires a function called 'AddItem' as in:
Sub AddItem(ByVal objObject As IPersistentBusinessObject)
In my 'building' class, I attempt to satisfy this requirement using:
Public Sub AddItem(ByVal building As clsBuilding) Implements IPersistentBusinessCollection.AddItem
In this example, clsBuilding implements the interface IPersistentBusinessObject. So I'd expect this to work since clsBuilding satisfies the interface contract. However, it does not work. The compiler complains that I haven't properly satisifed the interface requirements for AddItem. why this does not work?
I'm struggling here.. I know I can disable the warning manually. However I'm not sure if this would be the right way to go about this.
Here's my interface..vbnet Public Interface IPopulatingClassBase Property Identity() As Int64 ReadOnly Property Dirty() As Boolean Sub Populate_Class(ByVal RecordID As Int64) Sub Save_Class() Sub Reset_Class()End Interface
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PS In my example think of it as classes that populate with data from a database. The parent class would be an organization, and the derived class a location. Both populate and have similar functionality. The only difference is locations are an entity of an organization(the data record for a location constraints it to an organization) upon loading location data I also populate the organization class. This is a real example of what my project does.. so having said I just want to know how I can get around this warning, and if not would it have any consequences if I left it as-is.
I have two tables:
table1
case_no flow result
tc_1 001 pass
tc_1 002 pass
tc_1 003 pass
tc_2 001 pass
tc_2 002 fail
tc_2 003 pass
table2"
case_no result
tc_1 pass
tc_2 fail
Table2 should be updates from table based on the results... If all results is PASS then the table2 should be updated as pass... if any result is FAIL then the entire case_no should be updates a s fail..
