Dynamic Property Created Class
Dec 26, 2011I am using System.Collections.Generic List.I created new class[code]but i want "UserName" in "ONE" class property created dynamic.
View 1 Replies
ADVERTISEMENT
Dynamic Custom Class Property
Dec 18, 2009I have a For Each block loops through a list of objects, the objects are all instances of a single custom class I have made which has multiple properties.The logic used in this block uses a property of the custom class to do a set action, is it possible to dynamically supply which property it uses in the logic? This will be more efficient and prevent me from having to create this logic over for each property of the custom class.My best guess was that maybe it is possible with reflection, however my searches into reflection have left me more confused.
View 2 RepliesVS 2010 Created New Class And Require Text-box Field Within A Sub In New Class
May 9, 2012can someone please help me with a textbox? I have created a new class and require this textbox field within a sub in the new class but i get Error1 'TextBox1' is not declared. It may be inaccessible due to its protection level.I have tried MyClass.TextBox1 = Form1.TextBox1 but I get declaration expected.
View 23 RepliesReference Dynamic Textboxes Created At Run Time?
Apr 27, 2011I have an ASP project which references a WCF service. Does exactly half of what I need.
A button on the page calls a function from the WCF, which returns a list of objects (variable names). When returned, the vb code dynamically adds textboxes to a panel on the page.[code]...
Use /change Attributes From Dynamic Created Buttons?
Aug 15, 2011how can i select these buttons in the program ?I can change the propertiies inside the click event because i know wicht button i pressed thru the sender of the event but i don't find a way to adress the other buttons outside the event.
please note that i am a beginner in programming in vb.net
For i 0To 1
For y = 5
[code]....
Declaring A Object - Instance Of An Object To Be Created When A Form Loads Or Another Class Is Created
Oct 5, 2009If you want a instance of an object to be created when a form loads or another class is created, you have two options:
Public class example
private IAmAObject As IAmAObject
public sub new()
[CODE]...
Or like this:
public class example
private IAmAObject as new IAmAObject
public sub new()
[CODE]...
I always use the first one. It's more type work but I think it's neater. How about you people and is there any real difference between the two?
C# - ASPX Page (vb.net) With Dynamic Controls Created At Runtime?
Jun 14, 2011I have a nested content page within a master page, upon load the the page retrieves from a SQL a list of controls to create (Field Type, FieldName) i.e. String, Username.The function loops around the list creating the controls on the webform in a Placeholder, this part works perfectly. The problem that I am experiencing is the request to obtain the value entered by the user in the dynamically created control, I need to perform this call following postback/callback.
If I take the Content page and make it a standard aspx page with no master page the application works fine. Unfortunatley taking the page out of the master page is not an option (unfortunatley a restriction by my client)
Class With Dynamic Arrays Inside Another Class Which Also Has Dynamic Arrays?
Nov 15, 2011Below you will find a code sample that I have dummied up to try and demonstrate the issue I am having. However, this is just a dummied up piece of code. The actual program has noting to do with STUDENTS or TEACHERS. Basically, the problem I'm having is trying to have a CLASS within another CLASS each of which contain ARRAYS that need to be dynamic in size. The sample has a CLASS called STUDENTS that can have in theory many students, the number of which are unknown to the CLASS. I need to be able to add STUDENTS to the ARRAY programmatically.
The CLASSROOM Class should also be an Array since each TEACHER will have MANY Students. There will be only 1 Teacher for a given classroom but the SCHOOL will have MANY CLASSROOMS. Again, I need to programmatically add Teachers and Students without having predefined Array sizes. The code I have listed below will NOT work but it demonstrates what I am trying to achieve. I want to be able to reference the CLASS by using something like this ...
School(iTeacherIndex).Student(iStudentIndex) = "Rick Smith"
I feel like I should be able to use ARRAYLIST in both classes but haven't been able to get it to work. I've tried DIM'ing as ARRAY and can't get that to work either.If I can get ARRAYLIST to work then I shouldn't need to worry about expanding the array via UBOUND (if it's even possible).The REAL question is "How do I have a CLASS within a CLASS, each of which has ARRAYS that need to be dynamic in nature so they can be expanded as needed? The size of the array cannot be determined ahead of time".
REMEMBER . . . the actual program has nothing to do with Students and Teachers. This was just my way of demonstrating the issue using an analogy that I thought everyone could understand. The actual Class is much more involved.I have purposely hardcoded some values just to make the sample easier to work with. This is NOT how I normally program but is just here to hopefully make things a little more clear.
Here is the sample code . . .
'***********************************************************************************
'***********************************************************************************
'***********************************************************************************
'Here is the code that is in the form - This obviously doesn't work
Private Sub TeacherTestDemo()
Dim iTeacherIndex As Byte
Dim iStudentIndex As Byte
[code]....
.net - Make A Class Property Behave Like The Checked Property On RadioButton?
Jun 1, 2012I have a very simple class that holds a few public properties - ID, Text, Colour, etc. and a Boolean called 'SelectedItem'. Just like the Checked property on RadioButtons, only one item can have its SelectedItem property set to True within a particular group. Note: there will be several separate groups (lists), each allowed to have only one item with SelectedItem = True.
My first thought was that I would probably just have to handle everything outside of the class, setting SelectedItem to False for every other item in a particular list when another item was selected. But that seems rather inelegant to me. So I've been trying to think of how this might be done within the class. For example: could I perhaps have a private string property called say "GroupName" - set in the New sub when adding a new instance of the class - and then use a private shared method to set every item's SelectedItem property to False, provided the item has the same GroupName as the newly selected item? I would have a go at doing this but I have no idea how to enumerate every instance of a class from within that class, or whether that's even possible. Is it? Or is there another (better) way to achieve my goal? Here is a cut-down version of what I've got so far:
Public Class ResourceItem
Public ID As Integer
Public Text As String[code]....
As can be seen: instead of instantiating a new ResourceItem and passing that as an argument to the manager's Add procedure, I'm simply passing the details of the new item and the procedure is creating the item from those. I don't know whether this is a good or bad idea - please advise - but I've done it because I couldn't figure out how to make the SelectedItem property only writeable by the manager, so I wanted to avoid having directly accessible objects that could have their SelectedItem property set to True without it deselecting all the other items in the same group. Of course that still leaves the possibility of setting a variable to one of the manager's list items and setting it from there, so I would still like to know how I could prevent that, if possible.
UPDATE: I didn't use the code above in the end, deciding instead to go with Cyborgx37's solution - which seems to work perfectly well for me despite the warnings about best practice. I also realised I would need to use the same class in another scenario where multiple items could be selected, so it was easy to add a Boolean property to the manager to enable that.
Having A Class Property Dependent On Another Property Opinion?
Aug 13, 2009I have the following code:
Public Class MyColorsClass
'Constructors
Public Sub New()
'Empty Constructor
[code]....
However, if the empty constructor was called to instatiate this class then the colortype is not yet set. Therefore, if one accesses the 'IsColorCool' property it will always return 'False'. Now for the sake of this example, I must keep the empty constructor as part of the class.Now I could add some code in the 'IsPropertyCool' to check and see if a ColorType has been defined, and throw an exception if it has not been set, but I don't really want to do that.I also could always move the logic OUT of the property and into a method on the class called 'DefineIfColorIsCool' or something, and make the owness on the caller to make sure the method was called if they want to use the property 'IsColorCool'?
.net - Suppress A Property Or Method From A Base-class In A Derived Class?
Apr 7, 2011Supose a base class
Public Class airplane
Private var_num_seats As Integer
Private var_num_engines As Integer
[code]....
Obviously, I don't wish that the class Glider has the method "start_engines" neither the property "num_engines". Otherwise, other child classes may have. How can I supress these property and method in child class, not just ignoring (if I can)?
Can't Set DataTable Class Level Variable = Class Table Property?
Sep 29, 2011I have procedure (Import) that calls a for a new instance of frmImportData. I also have a class name clsBatch that has a data table property called prpParametersTable.For some reason, I get an error (indicated below with ERROR>>>) when trying to assign prpParameterTable to cv_dtImport2. The error states "Object reference not set to an instance of an object.". Why does this error not happen when I assign dtBP to cv_dtImport1? Both cv_dtImport1 and cv_dtImport2 are equal to Nothing and in my Import procedure dtBP = prpParametersTable.
Public Sub Import(ByVal clsB As clsBatch)
Try
Me.cv_clsB = clsB
[code]....
Class Property Usage - Unable To Retrieve A Variable From On Class
Nov 14, 2009I have three class files, accounts.vb and transactions.vb in addition to my form.vb. I am unable to retrieve a member variable from on class from inside the other. When the combobox index changes, the program loads the correct account (checking or saving) from two different sequential files. I don't think I have the calcBalance procedure in the correct class file. And that is what I am having trouble with. Accessing it to display it. [Code]
View 1 RepliesVS 02/03 Dynamic Textbox MaxLength Property?
Mar 11, 2011i am struggling with something quite elementary and simple. I am creating 200 dynamic textboxes with the following code :
[Code]...
Now, I need to restrict the user to type a maximum of 5 characters inside. The MaxLength property is supposed to help me with that, but the user is still allowed to type more than five characters!Later on, after I have crossed this bridge, I'll need to allow a minimum of five as well - so that the user will always be able to enter only five characters inside each textbox. Another problem in the future will be to allow only numeric digits. These are product codes, whic are always numeric, and always 5 characters in length
Access Members Of A Sub Class Through A Property Of The Parent Class?
Mar 30, 2010This is a bit of a continuation from a previous post for which AtmaWeapon was very informative.
Problem:
A parent class has a sub class with various properties. A property of the parent class is a List(of T) with T = the sub class The issue is how to store data in the sub class of the instantiated parent
Some example code (hopefully formatted correctly):
Code:
'=========== Class Definitions =============
Public Class courseClass
Public Class timeTableClass
[Code].....
Adding A List (of Class) Or Collection As Another Class's Property
Apr 2, 2010I'm looking for a tutorial on how to Adding a list(of Class) or Collection as another Class's Property.What I am after is something like the Columns Collection for the DatagridView control.I would like to add Items in the graphics screen. Where the item list is displayed in the left panel and the selected Item properties are displayed in the right panel.
View 4 RepliesDynamic Enumerated Property Of User Control?
Mar 27, 2009I am using VB 2008 Express edition.I have created a user control that has an enumerated property like:Public
[Code]...
There are 3 alternatives for this property: Member0, Member1 and Member2.Is it possible to change the alternative values of this property in runtime dynamically?
Dynamic Property Setter With Linq Expressions?
Jan 5, 2011I want to create a simple function that does the following:
Sub SetValue(Of TInstance As Class, TProperty)(
ByVal instance As TInstance,
ByVal [property] As Expression(Of Func(Of TInstance, TProperty)),
[code].....
VS 2008 Change The Property Of A Created Object
Apr 24, 2009how do i change the property of a created object in the timer event? In other words i have a button that creates a panel for me, in a time event i want to change the created panels to a different backcolor, how would i do this?
View 1 Replies.net - Accessing Property Of A Class Without Inherting The Class
Apr 7, 2012I have a class that has the following property that is generated by the methods in the constructor.
Public Class clsLoadTables
Private _ds As New DataSet
Public Property ds() As DataSet
Get
[CODE]........................
My problem is that I do not want to inherit this class, but I have other classes that need to access the ds DataSet property. If at all possible I would like to not use inheritance and not load my datatable more than once in the program.
Here is my failed attempt to access the property inside another class that is not inheriting clsLoadTables:
[CODE].........................
How I can access this dataset that I want to load only once in the program from many classes without using class inheritance or a global module?
VS 2005 Class Contain Another Class Within It - Interface And Property?
Jul 29, 2010I know that an interface can contain another interface within it.But;can a class contain another class within it?Can an interface contain another interface within it?
View 9 RepliesDynamic Way Of Loading The Information From The XML File Into A Specific Object Property?
Aug 11, 2010I currently have a XML file for an application I am developing. I have built a a XMLFile.GetContent function to read my XML File and load the content into a set of specific objects. These objects are then added to a collection and passed back to the main code to be loaded into the memory of the application.I am looking for a dynamic way of loading the information from the XML file into a specific Object Property. I have added comments to the function to show what I want to make dynamic.Content of XML File
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Config>
<IQSDataSources>[code].....
IDE :: Creating A Dynamic Database And Set Field Property Index To Yes (No Duplicates)
Mar 4, 2011I needed to create an Access table programmatically an was able to by using Martin Xie's post but how can I set the Field1 - Field Property Index to Yes (No Duplicates)?
[code]...
Reading 'Checked' Property Of Dynamic CheckBox On Page Postback
Dec 29, 2009How can I check the 'Checked' property of a dynamically-created checkbox during the Page_Load subroutine? Basically, I have a VB.NET page that creates some table rows dynamically, based on a number selected by the user. So, for example, if the user selects "3" from a dropdown list, the page posts back and creates three table rows. Each row contains a couple of textboxes, a dropdown list, and a checkbox (which are all .NET form controls rather than plain HTML controls, I should point out).Typically, the user would enter a few details into the form controls, and click the 'Submit' button, after which the page iterates through each row, and inserts the data into a SQL Server table.But if the user ticks the checkbox for that row, this signifies that the page is to ignore that row, and NOT insert that row of data into the database when the user clicks 'Submit'. This works well, but there is a problem. If the user clicks 'Submit' and some of the values entered into the form controls are invalid (so, for example, the user didn't enter their name) then the page won't submit the data, and instead, shows an error to the user informing them of the values they need to change. But if the user creates three rows, for example, but decides to "ignore" the third row (by ticking the checkbox) then when the page posts back, finds some invalid entries, and re-shows the form to the user to allow them to correct any errors, I'd rather the page didn't render the third row altogether. After all, they chose to create three rows originally, but then decided that they only needed two. So it makes sense that the third row is not recreated.
But what seemed to happen was that objCheckbox.Checked was always returning False, even when the checkbox was ticked. Once the page had loaded, the table rows had rendered again, and the tick was present in the checkbox, so it's not like the value was lost on postback. But at the point I check whether the checkbox is ticked, it always returns False, rendering a table row that the user doesn't need.Does anyone know how to get round this problem? I've read lots of articles about the .NET ViewState, and the page lifecycle, but I've yet to find a solution that works. I simply need to be able to check if a checkbox is ticked before re-creating some dynamic controls. [code] But then I basically found out that you can't override a protected member with a public one.
Accessing The Property Inside Dynamic Control Gives Null Reference Exception?
Jul 13, 2010I have an app with 24 different Forms. They have some security options based on which the 5 different buttons Submit, Approve, 2nd Approve, 3rd Approve, Reject etc get enabled disabled.Now I designed a MainForm that has all the buttons and the security code for them. I have created eachform as a usercontrol and load them dynamically based on which form the user wants. My loading works perfectly fine. I load the control and Add it to the place holder in the Page load event of the main page.
Now when the user selects the Submit button I want to call the Save method inside the usercontrol of the Form as each form will have a separate Save. So when I try this code snippet I get the Null reference error. Do let me know how to resolve it.
Private UCDynamic As UserControl
Then on Page Load event I use this code
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If not Me.IsPostBack
UCDynamic = LoadControl("Controls/BkCode.ascx")
Me.PlaceHolderForm.Controls.Add(UCDynamic)
End if
Then on the ButtonClick Event for Submit I do this
Protected Sub Save_OnClick(ByVal sender As Object, ByVal e As EventArgs)
Save()
End Sub
[code]....
Thats where I get the cast Null reference error. So is it that after post back the control no longer exist on the page.
Have A Dynamic URL In Generic Class?
Apr 22, 2009I need to have a dynamic URL preferably from a Test Classformatting this design pattern to handle dynamic links from tests. instead of a constant HomePageURL.
Namespace TestDesign
Public Class HomePage
Inherits IE
[code].....
VS 2008 Add A Newly Created Textbox To A Dynamic Textbox Array
Aug 30, 2011I wanted to simply on click a button to add those newly created textboxes to an array of textboxes. Starting with those labeled "Address". But I am finding this very difficult. I am able to add those originally on the form into the array very easily. But am unable to add the newly created textboxes into the array.
Here is my code so far below.
Public Class Form1
Dim MyBoxes() As TextBox = {Address, UserName, Password}
Dim Numbox As Integer = 1
[Code]....
Access Dynamic Controls From Class?
Jun 10, 2012Create a web browser with tabs and I want to add a "Open in a new Link" Button with a Custom Menu .
The problem is I'm trying to use a Dynamic Control(Webbrowser) created in a class from a local sub (A picture box) on the event click . But i get this error [code]....
Dynamic Array Of Custom Class
Jun 16, 2009I've been programming in VB.net for a while off and on, but never really had a need to use custom classes till now.I built a function in a module to populate a class, The class how ever is supposed to refer to one instance.I need to create an array of this class but the amount of instances needed is not always known.Works fine till the class goes to populate the class array.[code]It's probably something simple, I've just starred at it to long. Keep gettitng "Object reference not set to an instance of an object."
View 1 RepliesClass Array As Another Class Property?
Jul 28, 2010I have two classes, and for a property in one of the classes I'd like to be able to load it up with an array of the other class. However my attempt at accomplishing this results in a "Object reference not set to an instance of an object" error. I know it's a rookie mistake, but I'm stumpedssist?
My code is as follows:
Namespace Parking
Public Class garage
[code]......
