VS 2008 : Inheritance And Copy/use Of Member Instances?
Jul 31, 2010If I declare and instantiate an instance of class B within class A, how do I make instances of class A member objects/variables accessible from class B?
View 11 Replies
ADVERTISEMENT
Does The Assignment Operator In 1.1 Do A Member-by-member Copy Of The ObjOriginal To ObjClone
Nov 18, 2009I'm "cloning" objects in my code. For instance: objClone = objOriginal My question is: Does the assignment operator in VB.NET 1.1 do a member-by-member copy of the objOriginal to objClone or does objClone simply point as a reference to memory referenced by objOriginal?
View 3 RepliesVS 2010 Sorting A Listbox (after Trying To Copy Class Instances Properties To A Temp List)
Jan 25, 2012I'm trying to figure out a way to sort the entries of a listbox... but in a different way instead of the obvious one (sorted property). First of all, I need to explain how the items are populated at first:
[Code]...
Access Of Shared Member, Constant Member, Enum Member Or Nested Type Through An Instance; Qualifying Expression Will Not Be Evaluated
Jun 2, 2011how do I overcome it? I have created a class and compiled into .dll This code
[Code]...
Access Of Shared Member - Constant Member - Enum Member Or Nested Type Through An Insta
Aug 13, 2009In Visual Studio 2008, if I do this:
[Code]....
Does anyone here know how to get the above to work WITHOUT warnings being generated?
Warning 1: Access Of Shared Member, Constant Member, Enum Member Or Nested Type Through An Instance; Qualifying Expression Will Not Be Evaluated
May 31, 2010In the following code i get a warning at line 59:Warning 1: Access of shared member, constant member, enum member or nested type through an instance; qualifying expression will not be evaluated.and.. At line 78 I get this Warning:
Warning 2 Property 'SelectedCustomer' doesn't return a value on all code paths. A null reference exception could occur at run time when the result is used.
The program compiles and runs well, but i cant' undesrtand the reason for these warnings. Any Idea ?
1: Public Class Form1
2:
3: 'Form level members
4: Private objCustomers As New ArrayList
[code]....
VS 2005 Access Of Shared Member, Constant Member, Enum Member?
Apr 28, 2011Cannot appear to be able to get this function to not have the above error.Private Function GetIncidentActions(ByVal FromAgentID As Integer, ByVal ToAgentID As Integer, ByVal incidentAction As Integer, ByVal ActionDate As Date) As String
[Code]...
VS 2008 Inheritance And Events
Jul 8, 2009I have a base object, with a event that can be triggered by multiple methods.Then I created a child object that inherits that base object. I want to be able to trigger that event in the new object; but I can't use RaiseEvent to raise a base-object's event.To get around this, I created a small method in the base object that takes the argument for the event and I just use it to trigger the event. Is this the proper way to handle this situation? Similarly, I could Shadow the event with a duplicate one in the child object.Is there a standard way to handle events across inheritance?
View 2 RepliesVS 2008 Inheritance Question (or Maybe Not)?
Dec 15, 2009I've not played with inheritance myself much as I've never really had a need to, but now I have a situation which to me seems the ideal time to learn. I'll explain:
This is a WPF application but that shouldnt make any difference to this question. Basically, I have asearch window that retrieves data from a database - I want this one search window to be able to retrieve any item (business object might be a better word than item) from the database and display the relevant data, rather than having a separate window for each 'type' of item in my program. So I have got 3 classes at the moment, ComputerAudit, ConnectionAudit, and SoftwareAudit and I want my one search window to be able to display any of these items in the listbox. Obviously there would only be one type of item displayed at once, so there wouldnt be a computeraudit item and a connectionaudit item displayed in the list at the same time, but there could be several computeraudit items displayed.
So I thought I could create a base class just named Audit and have those 3 classes I mentioned inherit from that, then I can specify the arguments to methods I am using as just being of type Audit (rather than using a specific type like ComputerAudit or SoftwareAudit) because then I should be able to pass around any of these items which inherit from Audit right? Well that doesnt seem to be the case so I'm wondering if I have misunderstood inheritance.
The problem I'm having specifically is that I have some methods which need to be able to accept any of my Audit subclasses but if I specify a generic List(Of Audit) then it wont let me pass in a List(Of ComputerAudit) for example. Is this because I'm using a List or am I just doing something fundamentally wrong?
EDIT: Found this page which confirms my suspicions that this is more to do with the List than general inheritance:[URL]...
Inheritance And Entity Classes In VB 2008?
Jun 27, 2011I am having trouble getting inheritance to work with the VB 2008 Express entity classes. I am a beginner with VB.Net and self-taught in VB6.0.I am able to pull data from an SQL Server data base into my application using the O/R designer. The data can be successfully queried using LINQ to SQL, either returning a single record, or multiple records or an entire table as a collection of the enty class type (so the problem is not with LINQ queries).
View 2 RepliesVS 2008 Object Inheritance And Casting
Mar 23, 2011I have two custom objects.On of them inherits the other one, appends few more properties and methods, ovverides some other.When I try to cast the Parnet Object to Child I receive an error that it could`nt be done.
View 1 RepliesVS 2008 DGV Inheritance - Create The Control In Another Project To Build The Dll
Nov 26, 2009In my application i will use a customized datagridview for all the application, so instead of adding the normal datagridview and changing the properties, i created an user control and changed the inherited to datagridview... This have a problem i can't use the drag and drop...
[Code]...
VS 2008 Instances With Tcp Clients
Oct 4, 2009I am programming a chat like application using Tcp. Now I have a probem. I am going to have loads and loads of data being transferred so I will have to use 4 seperate ports.[code...]
My problem is for me to use a maximum of 4 ports all together transferring data from the client(s) to the server(s) I will need 4 clients and 4 servers. I need to open 4 instances of 4 clients. I was going to put a client in a form and then when the client is running it creates 4 instances of that form but than there would be too much confusion going on. I think there my be a way to use Classes instead of forms.
[code...]
VS 2008 X86, X64, PID, Multiple Instances?
Feb 6, 2010My ultimate goal is to get a list of PIDs and have a user select 1 of them.For example: the process image name is program.exe. The application name varies for each instance the program.exe is run, and therefor each application name has its own PID associated with it. By application name I mean the Task name under the Applications tab of Windows Task Manager. Another issue I face is that some systems run x64, so the name is no longer program.exe but program.exe*32
So my issue is, how do I search for program.exe, or on x64 platforms program.exe*32, and if there are multiple instances of program.exe/program.exe*32 running, how can I get a list of PIDs for each and associated them with the application name as the Task name under the Applications tab of Windows Task Manager.that might sound a bit confusing! So if it is, please let me know and I will try to explain more. Any reference guides or example code would be greatly appriciated as I have only used the "System.Diagnostics" but once.
VS 2008 : Prevent Opening Of Two Instances?
Aug 18, 2009What's the best way to prevent opening of two instances (or more) of the application?
View 6 RepliesVS 2008 Count Instances In Application?
Dec 7, 2011i have a small prog to test the instances when i run another instance then i want to count it, ex. i open sample.exe this should be 1 in label and i open another instance of sample.exe this should be 2 in label how can i do this
i try this code but the instances count are not working
Dim count As Integer = My.Application.OpenForms.Count()
Label1.Text = count
VS 2008 - Creating Instances Of Controls On Form?
Sep 14, 2010Is it possible to create instances of controls on a form ? Of course I mean visually , not just by code. After all, these languages define themselves as "Visual" so they should provide that possibility. It is important for the instances to be visible during design time because otherwise we could only guess where those controls might "land". Nevertheless , I have the feeling this is not possible in VB .NET but still I thought I should ask first ...
View 11 RepliesVS 2008 Close Multiple Instances Of Form?
Aug 30, 2011I have 30 instances of the same form running. Video array with different video on each. Each form is named "oneForm". I'm looking for a way to close all forms with one click. I have found that I can hide the forms no problem like this.
for each killfrm as form in my.application.openforms
if killfrm.name = "oneForm" then
killfrm.hide()
[code].....
VS 2008 Multithreading Or Creating Project Instances
Feb 15, 2011I have been trying to create good multithreading programs and it is not working well considering the use of global variables, local variables etc and thread safe controls. I have not found a good way of doing it since it seemed to be not as efficient as just running it on a single thread.
The program accesses facebook and twitter api, parses etc. and I am wondering if I can just create new tasks and map the program project file and fire new instances of the project. Someone this using the taskfactory in 2010 but I thought this was just the same as the threadpool. on this: create windows services and set them to run on task scheduler??
VS 2008 Opening Up New Form Instances With Different Datasets?
Mar 24, 2009I�m fetching data from an access db, filtered by date and an ID. The data is then charted on a form (form1).
I want to be able to "duplicate" the form so that the data that is shown on form1 is shown on a different form. That forms data is not supposed to change when I change the data on the first form.
So far I�ve put som code in a contextmenustrip that opens another form1, but the chart is not showing on that form at all.
I'm thinking that I'm going about this the wrong way so I thought I'd ask you guys what you think I should do?
A little info: When Form1 opens up, it loops through selected dates in a listbox, querying each date. This takes a little time, so I decided to put the data in a dataset on form_load, and then do the drawing from the dataset on form_paint, thus not having to query the database each time the form needs repainting. why the second (or third, fourth etc) form1 doesn�t display the chart?
VS 2008 Resize Multiple Instances Of Same Form?
Jan 15, 2009Within the subroutine, I am counting the number of open Forms and dividing the bounds of the screen by the number of open forms everytime a button is clicked.his gives me a way to Size each video box perfectly according to the number of forms open.This is where I have found a problem. The size of the new window only sizes the newly opened on and will not resize the ones that are already open. I will give an example of my subroutine.Note: Because of the nature of my program, I am not allowed to take any code out of the work zone and so I will be summarizing what I am doing rather than showing the actual code.
Private videoShow (byval videoName, byval videoIp)
dim videoForm as new form
videoForm.size = New Drawing.Size
[code]......
Migrating SqlServer (2008) Named Instances To Schemas?
Mar 11, 2011I currently have a sofware with 80 customers.All share the same database structure, when data are differents.We got 5 database for each customer.Today, we have named instances, so the program is accessing to Bdd with something like :
Connect to 127.0.0.1/CUSTOMER1
select * from base1..table1
Now, we need to change, we got many instances.The idea is to have unique SQLSERVER instance, obviously i want to avoid changing the code (VB.NET).Just tried to play with schemas and users, seems to be an option, but since the schema is under the database, in can't make it works :
Connect to 127.0.0.1/GLOBAL_INSTANCE as specific user (customer1)
select * from base1..table1 -> error @ this point
When THIS works :
Connect to 127.0.0.1/GLOBAL_INSTANCE as specific user (customer1)
Use Base1
select * from base1..table1 / or select * from table1
I can easily script some user or schema creation, and change connection strings for all customers, but i can't really change All requests: huge number.
VS 2008 Controlling Events From Multiple Program Instances?
Mar 20, 2010I'm having a lot of trouble finding a solution to my problem, and its probably because I don't know exactly how to ask the right question - can anyone here point me in the right direction?
View 3 RepliesAccess Of Shared Member, Constant Member, Enum Memberor Nested Type Through An Instance; Qualifying Expression Will Not Be Evaluated?
Jun 23, 2009i changed a class variable to shared so i can access it in all instances of the class, but it caused an error. what is causing this, and how can i fix it?
Private
Shared img As Bitmap
Me
.img = bgImage
VS 2005 Configuring A Datasource Value Member & Display Member
Jan 6, 2011I have 2 tables Table A & Table B Table A has the table values that I want to be populated in a datagridview control.The challenge is that column 1 in table A contains an ID(foreign key) to a name field that is a located in table B. I need the datagrid to have the first column be a combobox that displays the names(from Table B) that are already in table A via the ID's, but reference the populating values from Table B. So that when you bring down the combobox you would be choosing from Table B data but populating table A with the ID and you would see a name there instead of an ID.[code] How do I populate my DS dataset with Table B? And how can I create a link to these two tables using a bound datagridview control?
View 1 RepliesVS 2008 Awckward Behavior From Multiple Form Instances Loaded Into A Dictionary?
Jul 27, 2009Ok I have a project which has a MDI parent. Inside the parent I have multiple isntances of a form load(frmLine1t5). When my program loads it will load a different form(frmSelect) and if I manually load a different form(frmRetests) I can put frmSelect on top of frmRetests and bring one another to the front if it's clicked on(without using the bringtofront method)However as soon as I load a single instance of frmLine1t5 I immediately can no longer bring ANY form loaded into the MDI parent(before or after frmLine1t5 has loaded) to the front. I can only bring them to print IF I use .bringtofront method
View 1 Replies.net - The Member 'X' Was Changed To Be Inconsistent With The Association Member 'Y'?
Jan 3, 2011I get this error if I follow these steps: Change property Y of an object (an associated entity property)
Attempt to submit changes At this point the value of Y and the value of X (the underlying key) are not in agreement -- LINQ to SQL apparently doesn't synchronize these until GetChangeSet is called.An expected error occurs due to some business logic or database level constraint during the update operation.At this point the value of Y is in agreement with X because GetChangeSet was called.Change the value of Y to Nothing (aka null).Call GetChangeSet.
The error occurs on the last step because the value of X and the original value of X (returned by GetOriginalEntityState) are different, and the new value does not agree with Y? Is that why? Is this a bug in LINQ to SQL. Must be because I don't see the same behavior if I change Y to another (non-null) value instead during step 5. What's the right way around this? I can see a few ways:
Discard the DataContext when an error occurs and leave the UI as-is. I don't like this because then optimistic cocurrency change conflicts cannot be detected. The new context doesn't have the original values in it that were populated at the same time the UI was populated, so if the UI has any stale values in it, they will cause data in the database to revert.Refresh the datacontext (OverwriteCurrent) and leave the UI as-is. I don't like this for the same reason as #1.Refresh the datacontext (OverwriteCurrent) and re-populate the UI. I don't like this because then the error message just presented to the user does not show the user the error they made and allow them to correct it. It also discards all the other changes the user may have made.When the error occurs, explicitly retrieve the key for Y that corresponds to the original value of X and reset Y, then call GetChangeSet to re-synchronize X (X is read-only or private so I can't reset it directly). This seems to work, but seems like a hack, and may require lots of code for other similar errors.
ComboBox / Binding / Display Member & Value Member
Aug 31, 2011I know I have done this before and as I remember it should be really easy. But for some strange reason I can't do it now and I am about to jump off the building.I will make it simple:Two tables, one is just a list of products and their code.The other table: "details" has a field named product. I want to store only the code there.In the second table's entry form, I am putting a combobox. This combo box should display the list of products, their names, but depending on which one is selected, the code is what is passed to the table "details". Currently If I set the display member to product and the value member to code it still pases the product to the binded data source.
View 3 RepliesShow Display Member Based On Value Member?
Dec 6, 2010I have a database that holds information about a particular job. One of those things is a customerID. CustomerID links to another table containing customer details. I have a combo box attached to a custom object that holds customerID as the valuemember and CustomerName as the displaymember.The JobDetails holds the customerID info. How do I set the default selection in the combobox based on the ValueMember of the combo box?
View 2 RepliesIn C#, Implement An Interface Member Using A Member With A Different Name?
Apr 4, 2011in VB.NET you implement an interface like this...
Sub SomeInterfaceMember()
Implements ISomeInterface.SomeInterfaceMember
End Sub
while in C# you do it explicitly like this (which can only be called via the interface)...
void ISomeInterface.SomeInterfaceMember(){}
or more simply, implicitly like this...void SomeInterfaceMember(){} // Note the name matches the interface member However, regarding VB, I can also do this...
Sub SomeRandomMemberName()
Implements ISomeInterface.SomeInterfaceMember
End Sub
In other words, the method that handles the implementation can have a completely different name than the interface's member name.I'm just wondering if there's something similar to this in C#. (Yes, I know I can simply do an explicit interface, then access it via another 'wrapper' member with a different name that simply delegates to it, but in VB.NET?