Using Inheritance-Based Controls - Creating As New Classes (not UserControls) Inheriting From An Existing System Control
Oct 15, 2011
I seem to be having a problem with controls that I am creating as new classes (not UserControls) inheriting from an existing system control. Everything seems ok while I create the control code, through to the compile (which is successful and adds the control to the toolbox) and dragging the control from the toolbox to the GUI surface. However, when I then debug or compile the project, I get a message such
Can a custom control NEW Sub be the only one that executes when Inheriting from an existing control please?I am Inheriting from TabControl and I do not want the base New Sub called, is this possible?In other words, I do not want TabPage1 and TabPage2 to be added.A Form has an Activated Sub which runs once a Form is activated.It is a pity that Microsoft have not got such a method in the baseControl Class otherwise I could have used it within a custom TabControl.
Public Class Form1 Private Sub Form1_Activated(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Activated End Sub
how to write the code for my project.I am to base my new project on an existing one(existing one has code that works 100%)and create an Array of a structure that bascially holds the information from a summary form AND the totals from an AddToOrder_Click event. If you are still with me)... I cant figure out what the code is for my structure and Array so that I STILL have a Summary Form but I have an array that shows when I click my PrintPreview. So an Array is basically a "space" that holds information, like my summary form except it doesnt show until I click PrintPreview right?
If I just wanted to show the table then my code belongs in the PrintDocument1_PrintPage to show the array but the actual structure code belongs in the Click_Event of my AddToOrder? Please Please understand I AM NOT asking for anyone to write my code, basically I am asking for some clarification on what exactly creating an array from a structure is and therefore determing where the structure is to be placed in my code..
Can we make a test if a user control, classs, or procedure is working properly without running the whole program?Im testing a user control behaivor but its parent window located deep in the program, is there any way running a control for testing purposes only? im starting to get annoyed by running my whole program to test a user control just to find out that its not
I 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).
I've been wondering if there is anyway to extend a sub of a base class in a derived class or subclass. To date, the only thing I've been able to find is overrides and overloads functions, but to my understanding these functions just ignore your base class's sub and just allows you to run the new one with the same name.
What I want to be able to do is:
CODE:
I'm not sure whether this is possible, or if I'd simply either make a new sub in my derived class that first ran the base's class sub or whether I'd override the base class and then copy and paste the old code.
In businesslayer, there is a inherited Class Called BaseEdit which contains contractor and base properties. There are about 30 CustomEdit (inheriting classes), all of them has methods "Load","Save" and "Delete". The require for this existing system is to add a readonly user. Possible solutions considering the cost of works:
1) Modify the BaseEdit so all CustomEdit can stay the same. The system will check 'user role' in session by using httpcontext then to accept or reject the user's action.
I want to define a generic interface which will be implemented by an abstract Generic Class. Basically this generic class is a collection class of any class. Interfaces are in a separate project saved as FileReconciliation. Here are the interface definitions
Interfaces Imports System.Collections Public Interface ICollectionCommon(Of T As Class) Inherits IEnumerable Function Exists(ByVal oKey As Object) As Boolean [Code] .....
I have a form with some textboxes on it. The textboxes show values from a table. I have a binding navigator that lets you step through the records in the table and the textboxes update. What I want, is to have a control, say a listbox, that allows you to select a value which will filter the data behind the controls so that you only have one record.
So, for example, say you have a table of contacts. There are textboxes on your form that show name, phone, address etc. You could then have a listbox that showed a list of all the contacts and you could select one, which would in turn the textboxes. The filtering field could be contactID for example.
I need to upgrade my application to a modern style interface component like Dotnetbar or Krypton,these doesn't provide a equivalent control for bindingnavigator so I have to create it with some buttons and textbox.I use bindingnavigator only for navigation as in the image
It is possible to create a user control (with 4 buttons and a textbox) that inherit bindingnavigator and to have new style buttons ?
I'm having some trouble trying to inherit a control that uses an embedded resource. The trouble is - this control uses me.GetType() instead of GetType(ControlName). Now when I try to use the derived control, it looks for the resources in the derived control's assembly, instead of the base control assembly, and obviously - doesn't find them.
At work we have a pretty large web application that works by having a few pages, with lots of user controls which are nested in these pages. This is working fine most of the time but we have a problem at the moment where one of the user controls isnt working. Originally it was referenced from another project in the solution but when this wasnt working I decided to copy the file into the project and try to register it locally. It works on our development system, its only when we move it to deployment that it stops working, and I'm thinking it's something that I'm missing in the build. When you go to the page on Live the control is just missing, and no errors are generated.
The project I'm working on (the same one I'm always asking about) has tabs as the main navigation. I've made some User Controls to sit above the tabs in an attempt to reduce the number of overall controls that are being used (to great success). Now, however, there's one control that overlaps some controls on a tab that are obscured by my newest UControl and I want to make the background transparent.I've seen that AtmaWeapon keeps pointing people to this page detailing how to make the background transparent. That's great and it worked for me. All I did was create the
Code:Protected Overrides ReadOnly Property CreateParams() AsSystem.Windows.Forms.CreateParamsand it worked the way I wanted. Yay. I did write the rest of it too as well as part from a post I saw on the msdn forums, but they weren't needed to get the effect I wanted.However, I've got a number of PictureBoxes on this UControl that should have a BorderStyle of "Fixed3D". However, when this UControl is repainted the borderstyle doesn't reflect this (Note to self: don't .Refresh() a control inside its own .Paint() event ). This doesn't happen the FIRST time they become visible, but only when they've shown up and are made to redraw (like toggling visibility). If the border changes programmatically they look fine
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()...
I am cleaning up some code and I have multiple classes that are 99% exactly the same. So my understanding is that my options are...
1. Create a class and all other classes inherit from it and modify it a bit
2. Create an abstract class and all classes inherit from it and modify a bit ** I took this route
3. Create an interface and all classes Implement that interface.
Here is my 'original' class below (the one that all of them look 99% identical). This class is used in an arraylist so I have a listing of all my images from a folder I have searched.
In runtime I'm programmatically changing the forecolor to all label and radiobutton controls placed in the groupbox.
The only thing missing is to set the groupbox text/caption forecolor, but as soon as I do so programatically all controls in the groupbox inherits the font type and color making the text hard to read on the Button controls placed within the groupbox.
I have created a Scada System in Visual Basic 2010 In this system , its display the radial Gate position of hydro power plant. i have the analog value of particular signal in a textbox which use for gate position. how can i make the radial Gate animation in this VB based scada system. Or i have a gate opening and closing video of gate. Is it possible to control the video from textbox values so that i can show the gate position at the particular analog value..
i have the following function in default.aspx i have webusercontrol which have 10 checkboxes and 1 button i want when i click on button1 of user control then it can access the function of default.aspx page ...if i dragged the usercontrol to default.aspx
I have created a usercontrol that contains two rectangle shapes to create a unique button effect and a rounded-corner rectangle shape serving as a border to provide a look similar to a group box. It also contains two labels, one for use with a Text property of the control and the other to indicate the status of expansion of the control. The control is designed to collapse itself when the "button" is clicked leaving only the "button" visible. Clicking it again toggles this affect. I've dubbed it an ExpansionBar. It is also designed to be a container control so that I can add controls to it and allow these to disappear when the bottom portion collapses. The problem is that the controls contained in this usercontrol cannot be accessed during runtime. In other words, I can add a checkbox to it and it will disappear correctly when the control collapses, but I can't select the checkbox to check it... same thing with any other controls, you can see, but can't touch. I'm a novice developer, so I'm sure I'm missing something obvious.
my project is about creating stock control system to a bookstore which you can get details of books available,slow moving books..etc i just want to know about creating forms for my project what kind of forms you needed for ex: add,edit,delete btns.
is there any reason why we couldn't add/extend an interface to an already existing class?
i believe this would be v useful. it would be like drawing links from my class to already existing classes, and drawing links from already existing classes to already existing classes
I'm creating a hierarcy of folders where we have a standard group that have modify access on root and level 1 that is set to apply on this folder, files and subfolders. When I create a special set of folders in level 2 I don't want the default group to be inherited (only administrators). The new folder wil get new access from a new group in AD.My chalange is to stop inheretage on the new folders on level 2 in VB.NET.
I have a component class that inherits a user control class and i'm trying to inherit from that same class in a new class.public class B inherits class Unfortunately, I get an error pointing to the .g.vb file saying:Base class 'System.Windows.Controls.UserControl' specified for class '...' cannot be different from the base class '...' of one of its other partial types When I swap the "Inherits System.Windows.Controls.UserControl" with inherits from the base class in .vb files the program compiles but when I try to access any of the components I get an error saying "Object reference not set to an instance of an object."Why is it doing this? it's as if the my sub class isn't inheritingUserControl method at all.
When you develop a class library that will be used by others, are there any guidelines on how you decide what namespace to put it under? I often find third party classes just use the company name as the root namespace but I was also wondering if it is frowned upon (or even possible) to add one of your own classes to an existing framework namespace.
I have a custom VB.NET control that I created that is working correctly in one program but not in another.The control has one button and one form. The form displays some data based on the settings in the control.
[Code]...
In TestProject1 - the control is working as expected In TestProject2 - the control is not sending any of the settings I set to the form My control works fine when I debug with the UserControl TestContainer.
I am using VB.NET on VS2005. This is all done on the same machine. Why would this work in one project and not another?
