Control/Object Initialization On Form?
May 27, 2011I am Visual Foxpro Programmer and moved to Vb.Net. In Foxpro for each control I add to the form, there is a method called Init where this is executed only once when the form run.
View 2 RepliesI am Visual Foxpro Programmer and moved to Vb.Net. In Foxpro for each control I add to the form, there is a method called Init where this is executed only once when the form run.
View 2 RepliesI am Visual Foxpro Programmer and moved to Vb.Net.
In Foxpro for each control I add to the form, there is a method called Init where this is executed only once when the form run.
I am doing the code for a control in the Form_Load and things working fine.
I create a form2.vb which have a report viewr and modifier set to public. In reportviewer properties i add the Report1.rdlc Now i want to pass the vlue in the textbox at report1.rdlc i use following steps and code to do it butnot sucessful yet i need ur guidelines first from menu click report ___ report parameter and set the parameter name like conparm. Then i frm2 load event i write following
[Code]...
why is this code not working?
Dim tcplistener As New System.Net.Sockets.TcpListener
This does not compile with the error "Overload resolution failed because no accessible 'New' accepts this number of arguments." The thing is, I have to declare it as New because otherwise I will get a null-reference exception...
The last line in the code below throws the error. Is it because I haven't intialized the size of the byte array?
Public Class Form1
Private toSocket_IPP As Byte()
Public Sub New()
[code].....
Got a question regarding declaring a variable. Basically I have a module that writes to a text file using textwriter which is declared for the whole module to use at the top of the code. But what I want to do is clear the contents of the text file when the program is executed (using file.writealltext). The problem I have is that the file is obviously already in use as a result of the textwriter and the file cannot be modified because of this.
My question is: is there any way of declaring the textWriter object later on (not during the initial initialization of the module) without passing the object between functions? Setting the variable as inactive or something along those lines during initialization would be ideal.
I have a solution with several Projects in it. There is a Windows App project (called ImportClient), and a Class Library (Import.Library). The Import.Library has functions to perform data imports (I have other applications in the solution that also need to call it). But the interactive application, I want to be able to pass in some form controls, and have it update the GUI. No problem. But, I also want to execute a DoEvents() so that the loop execution doesn't hang other interaction to the app.
So, ImportClient has a reference to Import.Library. But I can't add a reference to ImportClient to the Import.Library, because the compiler complains about circular reference, etc. I don't know how else to define the My.Application object of ImportClient as a parameter to the data function in ImportLibrary.
(I realize this is a dumb question - problem is, for this project I have a tight timeline, and haven't learned how to do the BackgroundWorker process. If you think I could pick it up quickly, I'm open to some hints about how to update the progress bar on the GUI, and how to pause / cancel the background task.)
Consider a simple VB.NET form with a couple of radio buttons and a checkbox.
Each of the radio buttons has a CheckedChanged handler setup that performs some action based on the state of the checkbox.
My problem is, when I initialize on the default radiobutton to be checked (from the designer properties window) the CheckedChanged event is fired for that radio button, but the Checkbox hasn't been initialized yet so I either get a null pointer exception or the wrong value is used in the handler. Either way, I don't want that handler code to be run unless the user picks a radio button after the form has been loaded.
I currently get around this by not initializing the radio button, but I need to set that default eventually and the best place is from the designer. I also can add a boolean field that's not set to true until the form is fully loaded and not process the events if that is false, but it's a dirty hack.
What can I do to prevent that handler from running its code?
I am writing this codes on classlibrary to make the changes of the text and I want to control the form as well. I have wrote the last if statement on the bottom of the code that if the form is on the right side, then set the form from righttoleft. I get an object reference which is not set to an instance of an object. Here is the list of the codes that I am writing to make changes of the text on each menu items and control the form. [Code]
View 5 Repliesthink i have 2 form & one module..
form1 (has one button name button1)
form2 (also has one button name button1)
[Code]....
I want to insert a Windows Media Player object in my Form, but I have not the control on my Toolbox.
I have done the steps:
Right-click
the Toolbox -> Choose item -> COM Components -> add Windows Media Player component
(which references to C:WindowsSystem32wmp.dll)
But there is not the control on my Toolbox.
In my project references I see "MediaPlayer" into "Imported namespaces" and it is checked. In the references window it is also present "Windows Media Player". Where is the error?
I have created a custom user control (JCUserControl), and I am using it in the Main Window. And my Main Window has no codebehind. I have this in the JCUserControl codebehind:
Private Sub ImmediateRadioButton_Checked(sender As System.Object, e As System.Windows.RoutedEventArgs) Handles ImmediateRadioButton.Checked
SomeTextBox.IsEnabled = False
End Sub
When I run it, it fails with the NullReferenceException. If I comment out the SomeTextBox.IsEnabled = false, it runs without any problems.
Edit: Found out that I could just check if the radio buttons are loaded before doing whatever I want to do.
Private Sub ImmediateRadioButton_Checked(sender As System.Object, e As System.Windows.RoutedEventArgs) Handles ImmediateRadioButton.Checked
If ImmediateRadioButton.IsLoaded Then
SomeTextBox.IsEnabled = False
End If
End Sub
How to know if a List(Of T) contains any control object without using a loop ?This doesn't work
Dim lstObject As New List(Of Object)
lstObject.Add("STRING")
lstObject.Add(2)
[code].....
I am trying to write a VB .NET (2008) DLL. When the DLL loads, I would like to perform an initialization task. Trouble is, I don't know how to do this. If I were writing this in C++, I would put the necessary code in DllMain, and all would be well. Is there any similar mechanism to DllMain in VB .NET? Or is there another way to do this?
View 4 RepliesI'm having this problem with my code and cannot seem to get past it although it was working fine before. The error is "An error occurred creating the form. See Exception.InnerException for details. The error is: Object reference not set to an instance of an object." The code is:
CODE:
I am trying to get information to be pulled out of a database and show in text boxes on another form (frmviewsdets). The error occurs when it gets to the line frmviewsdets.txtsnumber.Text = rdr("StudentNumber") and even when a breakpoint is applied there it just moves on to the next and so on.
I have tried to show frmviewsdets before I pull the data out of the database beut I get the same message.
I've got 3 forms that have exactly the same functions, so I decided to create an interface.
public Interface IExample
public sub Add()
Public sub Edit()
[code]....
At this point, objfrmExample is now instantiated, even though I've not done a "objfrmExpample = new [what-goes-here?] " and I'm curious as to why.I could possibly guess that because you cannot instantiate an interface variable, then vb.net automatically creates an instance. But thats just a guess. The question is , what is meant by declaring a variable of type Interface, and how does it work?
I am getting this error "Object reference not set to an instance of an object" and I dont know where/how to fix it and it does not tell me where the error in the code occurs, just a pop-up windows saying the error. Here is the code on the "start up" Windows form..
[Code]...
Anyone can suggest what's wrong to the code below as the User Control objects ONLY appear in the first tab and NOT in the balance tabs ?
1) User Control name - usRFQDetail
2) Tab Control name - tcRFQDetail
what's wrong to the code below as the User Control objects ONLY appear in the first tab and NOT in the balance tabs ?
1) User Control name - usRFQDetail
2) Tab Control name - tcRFQDetail
Dim tcPage As New TabPage
[code].....
I need to do a dynamically loaded Header and Footer on Master page where there are two placeholders to store the users controls which will become the Headers and Footers. The reason why I am doing it to make it more customizable and it is the how it is required from my supervisor as well.So I have two key-value in web.config such as <add key="MasterHeader" key="~/Controls/Header.ascx"/> <add key=" Master Footer" key="~/Controls/Footer.ascx"/>So I am wondering which Page event should I load these users controls by saying
[code]...
Where is the best Page event to put the codes above?Do I need to put something in the page directive to make it work?
I have created a project in VB.net and its working fine in my machine.But when I provide the exe to my senior to test it shows the initialization error.I came to know the reason that the error is because the microsoft .net framework is not updated in my seniors machine....So there can be a possibility that the framework might not be updated on the client's machine as well.... when the user clicks on the exe file it should check that the microsoft framework is present and updated if not then the exe file should first prompt the user that the microsoft framework is needed and should be updated and start the installation....
View 10 RepliesIs there a way to add comments to an array initialization? For example:
Dim test As UShort() = { _
1, _
2, _
3, _
4 _
}
I'd like to add a comment on each line, but the obvious syntaxes fail (for obvious reasons)
1, 'test _
1 'test, _
So, am I out of luck?
i want to create an anonymous class in vb.net exactly like this:
[Code]...
I am unable to initialize textbox and combobox in my form when i click on the binding navigator 'New' button. Why is it so? But at the same time the datetimepicker does!ere's the code:
Private Sub BindingNavigatorAddNewItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BindingNavigatorAddNewItem.Click
Me.CreatedbyTextBox.Text = Master.user
[code].....
When I want to run several programs out of visual studio IDE the program couldn't be run and this message appear for me and say ("Unable to find a version of the runtime to to run this application")I am using visual studio 2005 .net My program is made by basic language.What am i do to fix this error??
View 2 RepliesI am experiencing some trouble with the autogenerated initializecomponent function. Visual Studio insists on initializing a variable like the following, when I drag a usercontrol onto a form:
Dim HierarchyTreeNode1 As NewDelfiLib.HierarchyTreeNode = CType(New System.Windows.Forms.TreeNode(""), ND.HierarchyTreeNode)
I'm new to VB and my question is whether all elements of an array will be initially zero per default:
Dim myArray( nx, ny ) As Single (all elements zero ?)
or do i have to loop over the array and set all elements to zero?
(p.s. my background is in Fortran where the standard does not guarantee that all elements will be zero initially and one has to set all elements to zero explicitly if one desires a zero-initialized array. )
I'm looking for a list numeric type initalization identifiers for both C# and VB.Net.[code]
View 3 RepliesI am using visual studio 2008 and i can't seem to rectify this error..it seems simple but i really can't seem to rectify this.What iam trying to do is pass the values of an initialized string array to an uninitialized string array using a loop..here's my code:-
Document ^doc = gcnew Document("Abdul.doc");
String ^yes = doc->GetText();
array<Char>^chars = {' '};
array<String^>^splitx = yes->Split(chars);
[code]....
Whats the difference between these two initialization methods for obj? I've seen both of these, but know know if there is an appropriate time to use one vs the other. I found this post which covers C#, but not sure if the same applies to VB.Net.[code]
View 3 Replies