I have a button which opens FormTest. When FormTest opens, it creates an instance of ClassTest and that class instance takes the form instance that called it (FormTest) so that it can perform operations on FormTest from the ClassTest class instance. So i have a form which owns an instance of a class which has a reference to the form.
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I'm implementing some custom serialization (to byte array), and have run into a problem handling circular references.Example:
Class A
public MyBs as new List(of B)
End class
Class B
public MyParent as A
public MiscInt1 as integer[code]....
If I know that an instance of B will only ever be serialized through the serialization of an instance of A, then I can handle the setup of the MyParent reference from the instance of A and not even record that information inside the byte buffer for the instance of B.This doesn't feel quite right, but it might be the best solution.
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 2 classess. Role and User like this
Role
Public Class Role
Public Property RoleID As Integer
Public Property CreatedBy As User
[code]....
The situation is like when we create roles, we will save who created this role. So i have a CreatedBy Property of type User. Similarly when we create a User, we will mention what role the new user belongs to .So i have a property called "Role" of type "Role". This circular reference giving me StackOverflow exception as its recursive when i create an object of User class.How do i handle this ? should i restucture my entties ? how ?
I have a theory that the CLR garbage collection mechanism means that I can get away with circular references in my object hierarchy without creating deadlocks for teardown and garbage collection. Is this a safe assumption to make? (Target language VB.NET)
View 2 RepliesOur application uses a custom DataAccessLayer class almost exclusively, and within that we do use Data Access Application Block (currently version 2). We are getting the infamous "GetOrdinal" error sporadically. We are not using out-of-method connections. We are using DAAB version 2. Below is a typical example of our DAL methods:
Public Function MyDALMethod(ByVal Param1 As Integer, ByVal Param2 As Integer) As System.Data.IDataReader
Dim db As Database = DatabaseFactory.CreateDatabase()
[Code].....
My main question is should these DAL references be disposed somehow? It's a custom class written in VB.NET, so it doesn't implement IDisposable so I'm not sure if there's anything to be done or not, but we do have errors and issues (like the GetOrdinal problem) which seem to be load-related, and I'm wondering if this is part of the problem.
I misidentified the problem. It is actually like this:[code...]
Code analysis complains about this because ms can be disposed twice. That will only be true if zStrm, which takes the memory stream as an argument to its constructor, disposes of the memory stream when it cleans up. That seems like a totally nutty thing for the disposer to be doing. Does it really do that? Would a class that takes another class as an argument, be so uncivil as to dispose of that argument?
I suppose it would, since the alternative would be that the memory stream might not be disposed at all if it was created in the constructor like this:[code...]
I guess the only real question is whether or not I have to worry about this?
I can't believe I'm still confused about this but, any way, lets finally nail it:I have a class that overrides OnPaint to do some drawing. To speed things up, I create the pens, brushes etc before hand, in the constructor, so that OnPaint does not need to keep creating and disposing them.
Now, I make sure that I always dispose of such objects, but I have the feeling I don't need to because, despite the fact they implement IDisposable, they're managed objects. I've been vigilant in always using 'using' so that I don't need to go through all my code checking. I just wanted to be clear that I wasn't being a pointless user.As an aside, I did have a strange situation, recently, where I had to replace a using block and manually call dispose! I'll dig that out and create a new question.
I tried to put the mso and msg objects into USING clauses - but they don't have idisposable methods so that doesn't work.
Dim mso As New Outlook.Application
Dim msg As Outlook.MailItem = Nothing
Dim body As String
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So I've created a series of objects that interact with a piece of hardware over a serial port. There is a thread running monitoring the serial port, and if the state of the hardware changes it updates properties in my objects. I'm using observable collections, and INotifyPropertyChanged.
I've built a UI in WPF and it works great, showing me real time updating when the hardware changes and allows me to send changes to the hardware as well by changing these properties using bindings.
What I'm hoping is that I can run the UI on a different machine than what the hardware is hooked up to without a lot of wiring up of events. Possibly even allow multiple UI's to connect to the same service and interact with this hardware.
So far I understand I'm going to need to create a WCF service. I'm trying to figure out if I'll be able to pass a reference to an object created at the service to the client leaving events intact. So that the UI will really just be bound to a remote object.
Am I moving the right direction with WCF?
Also I see tons of examples for WCF in C#, are there any good practical use examples in VB that might be along the lines of what I'm trying to do?
I used the tool about 3 years ago to create the classes for a webservice client to send or recieve arrays as complex data. Now i have to update these classes, since there are additional informations, that have to be exchanged. When i use the tool now with the new wsdl-files, it does'nt create the classes for complex data (structur, IGCTMObjectFactory), but only one class for simple data. In addition i have to establish a new client, that sends an array of complex data and receives another array of complex data. I tried to build the classes manually combining the client that sends an array with the client, that receives an array, but I failed.
View 3 RepliesI am having problem with Visual Studio 2008.... When i add the Microsoft ActiveX Data Objects 2.5 Library from COM References, and just run the blank form, it runs perfectly.... But whenever i declare anything related to ADODB like dim con as new ADODB.Connection, then after that it gives me error and doesnt run the project. A first chance exception of type 'System.IO.FileNotFoundException' occurred in mscorlib.dll. After that if i comment that like (declaration), then error goes........ I tried uninstalling each and every component and VS as well but the error doesnt goes....i am using Windows 7 x64. The same is working in Windows XP x86 in my virtual machine..... as i am not able to start my project
View 2 RepliesI have Crystal Reports 2008 installed on my win7 laptop but when i go to insert references from my application settings the CrystalDecisions references are missing and im not able to find them. Note: they do exist in my "c:windowsassembly" folder.
View 3 RepliesI have to make a learning object program for a school project and i am doing it about circular motion and satellite orbits.how i can get a object to orbit around another object in visual basic, allowing the orbit radius to vary as the user inputs values?
View 2 RepliesAssuming an architecture as such.MODEL > BLL > DLL
Trying to implement lazy loading in my MODEL I have run into a circular dependency between my MODEL and BLL..Basically imagine a property in my model that I want to implement as follows
Public Readonly Property ProjectCategory As ProjectCategory
Get
If Me._ProjectCategory Is Nothing Then
Me._ProjectCategory = ProjectCategoryBLL.GetProjectCategoryByID(Me._ProjectCategoryID)
End If
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I have my MODEL, BLL and DLL in separate projects and because of the fact that my BLL references my model I can not reference my BLL from my model as this would create a circular dependency.
How do I draw a circular gradient like this in vb.net?
View 1 Repliesmy team is working on an application where we have to have one image which is acting as the base of all the elements on the screen.. and this same image has a transparency in the center. now this centre transparency is supposed to display a picture which will be captured from a web cam.currently everything working fine but the only problem which we are facing is that the picture is not proportionate to what is the actual resolution that it was shot at. it has been stretched from the top and bottom. the reason is that the imagebox which has been used to call this webcam display is a aquare.now it seems that the team is not being able to use the exact proportions of the image to call it in the picturebox for a reason that the final image needs to be cropped to fit in a circle.in simple words, i have a rectangular image and i want to draw a circle over this image. whatever is within the circle should be visible, whatever is outside the circle should be transparent. (a mask needs to be created...)but the only thing is that this circle will first display the image/video from the web camera and only once the picture is clicked, it should show the same picture within this circular area.
View 3 RepliesI have been asked to improve the memory efficiency of an application that is used for high speed data acquisition. After running the VS memory profiler several times and scanning the projects for obvious issues I came to the following conclusion: despite using a fixed size circular buffer for storing acquired sample points, the RAM usage increases relative to the polling period. For example: polling data for one signal at 2 microseconds can use 5 times more memory (private bytes) than when running at 50 microseconds ... even though the buffer size is the same.
The circular buffer is an array of SamplePoint objects. Each of these objects contains an array of Shorts (16 bit) for corresponding data per signal and one date object (8 bytes) for the time stamp. For efficiency, the circular buffer is Redimmed only once every time it begins polling and filled with empty sample points which are then "assigned".
Also, it seems that when we stop and run the application it hogs even more memory each time as though the Redim is not releasing the previous array. My questions boil down to the following: What is most memory efficient way of implementing a circular buffer containing managed objects which have arrays?Also, how and why is memory usage increasing with a fixed size array with different polling speeds? Does the garbage collector not have time? Do local variables get disposed of IMMEDIATELY when a sub or function exits?These are some of the doubts and concerns that I would like to rule out before proceeding.
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I have created a TextBox array where certain cells are assigned a number which I do not want the operator to change either intentionally or inadvertantly.The relevant TextBox cells are identified by their BackColor, (in this case LightBlue)If the cell is changed the original content is immediately assigned to the cell and a relevant message is displayed.My problem is that by changing the value back to its original value I create another TextChanged event and the consequence is that the MsgBox is displayed twice, one after the other.I have avoided the problem by not displaying a message box. The outward appearance is that the TextBox is not changed at all, which of course is my aim.However I would prefer to display a message box.An example of the scenario is shown below.
Another bewildering fact, (to me), is that in the example below, if the check is not made of the BackColor but instead the value of the TextBox the problem doesn't occur
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
If TextBox1.BackColor = Color.LightBlue Then[code]...
In the example above, if in the Text_Changed event handler the 'Remark' is changed from one 'If' statement to the other the differences in the result can be seen.
I'm working on creating my own sudoku solver to learn vb.net. I decided to have an element class which represents a single square in the puzzle. That element then has references to three lists which can be validated (no duplicate numbers). The three lists then would be its corresponding row/column/subGrid. Each list then holds a reference to 9 elements. Thus in my design an element has a reference to a list, which then holds a reference to that same element. Now vb.net will allow me to do this so I don't think it is the same issue that I saw when searching for solutions to circular referencing. However, I still wonder whether or not this is bad design.
View 2 RepliesHow can I create a circular buffer on the heap in VB.NET ? This would be used for audio playback via P/Invoke to winmm.dll waveoutopen and waveoutwrite to support development of a software synth. I currently use the marshall class to build a regular array of bytes in the heap.
View 1 RepliesIs it possible to create a circular visual basic form. I see plenty of tutorials on how to do this for VB6 but none on Visual Basic Express.
View 7 RepliesThere is a question that I have from YEARS after working with DotNetBar Components that How do you set the Marquee style of a normal progress bar on the circular one? The circular progress bar from DotNetBar, i want to be clear.There is no "Style" Property and now I really need to know it for a project I'm doing now
View 3 RepliesI've got a requirement where I need to calculate a value, however also refer to this value when calculating it. So I've got for example[code]...
I can see how this can be achieved in excel using Circular Reference, however I'm not sure how I go about it when using VB.Net. Is there a similar method to create a Circular Reference as in excel or any other way I can possibly work out the TotalValue?
If I were to draw a rectangle with e.Graphics.FillRectangle(), how would I make a circular portion of the rectangle transparent?
View 1 RepliesI use the following code (with Imports Microsoft.DirectX.DirectSound and Microsoft.DirectX) to play sound using an 8 second static buffer:
Dim SD As Device = New Device
SD.SetCooperativeLevel(Me.Handle, CooperativeLevel.Priority)
Dim MS As New IO.MemoryStream(Gbuffer) ' Gbuffer is byte array with properly formatted WAV data
Dim waveFormat As New WaveFormat
waveFormat.SamplesPerSecond = 44100
[Code] .....
What I would like to do next is to change to a "circular" or "streaming" buffer so that I can write new data "on the fly". I've done a lot of Googling but can't quite see how to adapt my present code to use a circular buffer. I can get the current write and play positions using Msb.GetCurrentPosition(iPlayPos, iWritePos) but how do I actually insert new data into the buffer? I have tried "manually" writing new data into my Gbuffer byte array but that doesn't work - I guess once a sound has been played through once, the data is cached somewhere and the contents of Gbuffer are not used again.
I have a class that is in an assembly due to being required for other projects that I'm currently working on. One class lets call it Class Factory, creates a group of controls which require click event handlers to be attached, I have algorithms which determine polymorphic behavior based on certain features but that is relatively irrelevant.
Due to the event handler having to open up a specific form that isn't part of my assembly, and that form requiring this "Factory" class. Without creating circular reference is there any way I can essentially "delegate" the handler event for the form to define? As a simple work around I have had to maintain two separate classes, one in the project with the form and one in the assembly.
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.Width = 1500
Dim panel As New Panel
panel.Location = New Point(0, 0)
panel.Size = New Size(1000, 200)
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I'm a newbie in visual basic. We have a project in our school in implementing queue using circular array.
View 5 RepliesI have three forms (form1-3). my startup form is form3. This form calls form1.show. then form1 does form1.visible=false and also calls form2.showat the end form1 shows again.
View 4 RepliesI have created the following code block for use in my app (With the help of You, my online friends), it works ok.
The problem I now have is that I need to Despose of the Array from time to time an then later recreate it.
The "Despose" comand dont seem to work, How should I go about this?
Dim HoofGeregte As DataTable
HoofGeregte = HoofGeregteTableAdapter.GetData
Dim IngredientLabelLocationX As Integer = 42
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