I need to call this function saveBase from more than one place so i decided to send a number in variable x to know of what type to create the object named Model. however when it's within the if statemet i keep getting the error that model is not declared ![code]...
View 6 RepliesIf 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?
I hope the question makes sense, anyways. I'm looking to know if in VB.NET, when we call an object's constructor, is there some kind of a reference that points back to the caller? I'm interested because of a corner case where I want the object being created to first be able to validate the existence of some data in the caller before it allows itself to be created. If this validation fails, I plan on throwing an exception. This corner case will never happen at runtime unless the object being created is used improperly by a programmer. The object being created is not inheriting the object I want it to validate, so I can't do anything with the MyBase qualifier.
It's bit of a "future-proofing" issue that I have a (bad) habit of doing. Not critical -- I can always leave stern comments behind as a last resort. Wanted to know if this was possible.
I have some variable that when divided I get this symbol: -1.#IND when you look at the variable in debug. This only happens when I put the equation in the Dim statement.
[Code]...
I don't have a problem. Why when I put the equation up in the declaration area it sets it to -1.#IND (I assume this is infinite or NAN or some such). I'm curious as this is the only time I've had difficulty with this.
I am using asp.net with vb for my scripts.I want to use an array of a Structure to store data parsed from an xml file.[code]All appears to work fine until I add the code that is in bold, I then get the Object reference not set to an instance of an object.
View 6 RepliesI am trying to input specific information on a form.I have created an sql statement from a table that will out put 18 rows of data.I have opened a recordset and instituted a do until loop.I need for the program to look at each row and if the Standard Score = the value of a field I have on the form it takes the value of the other three columns in updates it on the form.I have created the code and it works for upto 3 (Do Until loops)records, but when I try to add a 4th in the SQL statement and put in another do loop my computer runs it but it acts as if it freezes up. [code]
View 3 RepliesIs there a way in which a case statement can be constructed to call, activate or triger a button control? If not, is there a way any statement can be created to activate a butt non control?
View 2 RepliesI just started in VB, I have created select...case statement to do some input validation.
Everything apart from the works. Its an extended ASCII character, can this be the cause?
[Code]...
I created an Access Object in vb.net:Dim acApp As Object = CreateObject("Access.Application.11")en I open Access I need to pass a parameter to it though "/cmd".I read that the only way to accomplish this is through a shell - that it is not possible directly using an Access object.
View 5 RepliesI have a dll that create container object. How can dll inform a form that the container (me) has been created. Is it possible in new sub of that class?
View 13 RepliesI'm adding some functionality to an app that was made a few years ago and I need to raise an event when the tabcontrol is clicked. However it would seem because the control was created publicy I can't add a handler to it? I never ran across this before. I stripped the code down to the bare essentials. As you can see in the image, if I Dim the control within the sub I can add the handler. But any handler created for the publicly created control fails.
Is there another way to create the hander in this case?
My
Public Class Form1
Dim x As Integer = 0
[Code]....
As you can see, i can retrieve the tag of the button (which is created at runtime) without any problems, i've made a temporary msgbox to show me the value of the tag, just for testing purposes. What i do have a problem with, is retrieving the tag of the individual web browsers, how should i do this?
Next issue, how would i code for my buttons to show the web browser with the same tag as the button that's just been clicked?
I need to save a object that i programing to be drawed onto apictureboxPictureBox1.CreateGraphics().FillEllipse(Brushes.Blue, ci)how do i save the object as a image or the picturebox? And then be able to open it again?
View 7 RepliesI have written some code to generate 10*10 textboxes during run-time.the problem is; I don't know how to access / change them after they are created. after some googling, I found this code to show the text of ie box42;
MessageBox.Show(Me.Controls.Item("box42").Text)
but it gives an error (nullreference exception was unhandled) hereby the code;
For i = 1 To 10
For j = 1 To 10
Dim tb As New TextBox
tb.Name = String.Format("box{0}{0}", i.ToString, j.ToString)
[code]....
I want to make a lotto bulletin and i created the buttons in the program. I have assigned a handler to it and that is working also but how can i change the background of this button later on in the program ?
'/ teken 10 groupboxen
For i = 0 To 1
For y = 0 To 5
[Code]....
I have a scanned document in my system. It's a tiff file. You will see below the code i have written. The problem is that i get an error message. The message is like this "A Graphics object cannot be created from an image that has an indexed pixel format." [Code]
View 3 Replieshow would I create an event procedure for something not yet on a form?
View 3 RepliesNot sure exactly what I need to do to make this work, so my description may be lacking at first.Essentially I am writing a program launcher that recreates itself each time on load. It pulls the data regarding the tabs and buttons from an SQLite database and builds itself dynamically at run time. I get my problem when I pass the tab name through to the function that creates the buttons. I need the name to pull the right set of buttons from the database and I then tried to use the name to place the buttons on the right tab when I create them, but the debugger calls it a null reference because it doesn't point correctly to the tabpage that I'm trying to make it point to (at least that is what I'm guessing). Any ideas on how to make this work right?
[Code]...
how 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 RepliesSay I have an object that I dynamically create. For example, say I create a button called "MyButton":
[Code]...
Below is some code that I'm using to create objects with Visual Basic:
For indexCounter As Integer = 1 To TotalParticipants Step 1
participantClock = New Label
participantClock.Size = New Size(100, 20)
participantClock.Name = "participantClock" & indexCounter
[code]....
I'm creating a label, a button, Timer, and Stopwatch. (Though I have sinking feeling I don't need BOTH a timer and stopwatch since I'm counting time.)What I would like to do, is create the label and set that label's text to be the value from the stopwatch. The button that will be created will stop THAT stopwatch.
The problem that I'm having is that I cannot call the stopwatch by name since it wasn't created yet and VB throws a hissy fit at me for it. (After all it wasn't really declared.)So the question becomes, how do you call the most recently dynamically created control and assign events using that control. If it's not possible to do, I do not mind dumping the form and starting over creating 30 stopwatches instead (but I'd like to avoid that, if possible).
I'm creating a textbox at runtime, which works fine, but now I need it to have a selection_change. How do I do that?
View 9 RepliesI am trying to create a function that will return a pen(System.Drawing.Pen to be exact) that will have a random color and width. I thought that something like this should do the trick:
Public Function random_pen() As Pen
Dim clr As Color = Color.FromArgb(255, random_rgb_color_gen, random_rgb_color_gen, random_rgb_color_gen)
Dim pn As Pen = Pens.PeachPuff 'just a random color else i get a null exception...
pn.Color = clr ' the error is here
[Code].....
However when the code is run i get an Argument Exception with the error message:"System.ArgumentException was unhandled Message="Changes cannot be made to Pen because permissions are not valid.""
Here is a test program I wrote to explore a facet of object casting ...
Module Module1
Sub Main()
Dim class1 As MyBaseClass = New MyBaseClass()
Dim class2 As MyInheritedClass = New MyInheritedClass()
Dim class3 As MyBaseClass = Nothing
[Code] .....
The problem comes with the TryCast statement on class3. My intention is that class3 remains as a baseclass, but when the TryCast is applied, class3 morphs itself into an Inherited class which is not what I wanted. So is there a gap in my OOP/VB.NET knowledge and this action is legitimate or should class3 still be regarded as a base class?
[code]How would I switch on an object's type but using VB.NET's Select Case?I'm aware that some might suggest using polymorphism but I'm using a hierarchy of small message classes so that really wouldn't work in my csae.
View 6 RepliesI have an editor created invb.net that creates html files. And when i click the button run , the Internet Explorer opens my file that is inside the Richtextbox.
View 3 RepliesI have a select statement and it will go to a datatable object, I would like to do the following
textbox1.text=datatable(first field value)
textbox2.text=datatable(second field value)
textbox3.text=datatable(third field value)
I am creating an Excel Add-In using Visual Studio 2010. My intention was to add a context menu to a cell and perform some action on the selected cell or cells. Here is the code I have got as of now
[Code]...
See
Public Class Form1
Dim sql As String
Dim conn As New OleDb.OleDbConnection
Dim da As New OleDb.OleDbDataAdapter
[CODE]...
The problem, The INSERT statement works fine in the form load but not in the button click event?
I was convinced that If <expression> Then <statement [:statement]> Else [statements] in concrete form of If a = b Then SayHello() Else SayBye() End has sense. I read article on msdn on If-then-else, but I forgot why I was reading, so I concluded, that snippet above means this
If a = b Then HelloIsSaid : IsNotEnded Else ByeIsSaid : IsEnded But I have tested it now, and I see, that Else without statement is nothing more than decoration. It would be pretty good if it had function I described. Do you think its good request? Or do you know any circumstance where this Else has some function?