Sharing Structures Of Arrays In Multiple MDIchilds
Nov 10, 2010
I have the following code... in an MDI application. [code] Various lines of code which put data into the Myinstance and then save the instance into the ArrayList.I have buttons which run procedures and functions in the formchild and also in the Class1. I need it so you can jump between formchild instances, and when you do so and click a button on that form, it will run the Class1 code but using the data in the arraylist and myinstance that was set previously by the selected formchild. Then if you switch to another child it uses data from this form. Can this be done by declaring the arraylist with more dimensions and then refer to the records with the index of the selected form instance, e.g.Selected Child is index(3)
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Nov 6, 2010
I have created an MDIparent form and a MDIchild. There is a button on the parent which makes multiple 'clones' of the child form, each time its clicked.I also want (maybe with a module) a set of variables, and array of a structure but these are available to each copy of the child, but each copy's variables, arraylist etc contain its own data?Therefore if you select child1 the variables and array will have different data to child2, child3...etc...
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Jan 20, 2009
I have a structure called 'Scheme' and in my program I want (ideally) an ArrayList of 'Schemes' (so i can add, remove schemes etc.). However, within the 'Scheme' structure, I want to have an ArrayList of 'Item''Item' is another structure. Are there any solutions out there for iterating through these arrays quite easily?
How can I easily add multiple Items to a Scheme and mutliple Schemes to my Scheme array. Code is below. When I try to add Items to a Scheme, I get the 'Object not set to a reference of an object, try the 'New' keyword', but you cannot declare 'New' keywork within a structure.
[Code]...
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Jun 2, 2010
I read in the Book "Mastering Microsoft Visual Basic 2008" about "User-Defined data types".The example given is creating a Structure as follows.I wanted to check that so I wrote all the code given; I used a TextBox and a Button for this.(I didn't include the "CheckDate" here; that is in the book)
Structure CheckRecord
Dim CheckNumber As Integer
[code]....
The problem is this does work.What I get is "00000". and I found out that the "Checks(4)" Array does hold any value ie: on keeping the cursor over that, it shows "CheckAmount 0.0, CheckNumber 0 , CheckPaidTo Nothing ".
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May 24, 2009
I'm currently doing this project where i have to create a program that let's the administrator manage students (and their tests.) I have decided to use Random Access file in this project.because structures will need fixed lengths...i don't know how will i search through the students (a function of the program) when each student structure has a different length because of the number of tests they've done.* I have created a variable in the aStudent structure so that i can know the number of tests a student has done...but don't know how to use it.
Public Class FormAdmin
Dim currentStudentName As String
Dim currentStudentID As Integer = 0
[code]....
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Jun 18, 2011
I have created a structure as below. I want the structure to be an array...so I can use a call like picks(1).a or picks.a(1) = blah blah. I don't understand how to use an array of a structure..
Public Structure apicks
Dim a As String
Dim b As String
End Structure
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May 22, 2011
what is the best way to add, delete elements from arrays of structures structure
vb
Structure Proxy
Dim Server As String
[Code].....
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Mar 14, 2010
I would be more that happy for someone to tell me I am missing something very simple here I am writing code that - amongst other things - talks to code on other servers using the tcpclient function in .net
What I want to do is - in essense very simply. I want to define a structure which includes an array load it with data and sent it to the other end of the socket.
[Code]...
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Nov 15, 2011
I want to create a relational database in VB2010 and I am attempting to accomplish this goal by creating a structure of records to be stored in a Random Access File.For each record, I want to organize each fixed-length record so that 4-integer sets of data are stored into a a multi-dimensional array.But when I try to write the code below at the module level, I get an error.
Structure PictureDat
'len= needed for Open
of Random Access File [code].....
Since I want to read/write/save the data in this structure to a Random Access File with a fixed record length size, I need to exactly specify the size of the record...which is, of course, determined by the array's dimensions.If I could accomplish this strategy, then I could search this random access file for a match of search criteria consisting of 4-integers with any of the 4-integer sets of data in each record and thus find, edit, delete and search records...therby retrieve information from my database.
Is my program design inefficient? Is there a better way to handle perhaps hundreds of thousands of records? The IDE keeps telling me that I am using a deprecated method of file I/O when I use FileOpen(), FileGet(),FilePut() and should be using MyFile.I am entirely comfortable with my time-tested method of data storage that ensures the security of disk storage while exposing only one record at a time to the PC's volatile RAM, thereby not allowing all my data exposed to possible memory corruption on a PC left on for hours, which would be the case if I loaded the whole file as a monster- sized string or stream. Also, these older file access methods allows my code to run on PC's with modest amounts of memory.
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Jan 29, 2009
I have to make this program to keep track of product description, ID, price, and quantity. I am manually coding some and the user can input products as well. I want to display the product and it's ID in a listbox and put price and quantity in seperate labels. [code] My question is how do i keep the array index numbers sorted so when i click an item in the listbox it will show the price and quantity in the labels for them?
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Feb 16, 2009
i am currently running a program that will allow me to save all data on the form to open and edit at will. It uses a structure of 8 arrays, each with 16 values to save the information.
When i try to save the text into the array, it tells me that its a bad record length and crashes.
Here is the
Public Structure save_weekly
<VBFixedString(8)> Public dates() As String
<VBFixedString(30)> Public description() As String
[Code].....
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Jul 9, 2011
I have a very simple 2D array, it holds a list of song titles, their genre, and their runtime. frmMain loads the array from a text file and allows me to manipulate it and boil it down to a desired (implicitly sized) playlist. i want to THEN pass that playlist array to a second form, frmPlaylist The problem i'm running into....When frmPLaylist calls the Property from frmMain I receive an error that VB cannot convert the string value to a two dimensional array. Simplified...frmPlaylist is all locked and ready to receive a 2D array, but frmMain seems to only be sending a single string variable. on frmMain
Public ReadOnly Property PlaylistOut() As String
Get
Return mstrTimedPlaylist(,)
[code].....
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Sep 29, 2008
I have written a ActiveX DLL in VB 6 which is like -
[Code]...
When I do this everything works fine and I am able to pass value to dll. I am passing two structures arrays and other single values like int and double etc. So far so good. But when I insert this code in another application (created in same vb.net 2005) where I actually intent it to use then i get the following error -
System.Runtime.InteropServices.SafeArrayTypeMismatchException
Specified array was not of the expected type.
I am puzzled as to why is this happening. I checked basic settings and they are same. In short the code works if i create a new project and go on but does not work and gives error if I insert in an existing application's code where i wanna use. To test I created a dll without passing structure arrays and then it worked in that application.
[Code]...
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Jun 27, 2012
I'd like to give a homework assignment to a person learning VB.NET. I'd like it to use basic inheritance and a variety of data structures including queues, lists, arrays, or stacks in a windows forms application. I was thinking of a pizza-ordering application. This would allow them to utilize some basic inheritance and practice using .NET UI elements.
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Jul 7, 2011
I know a little about threading and delegates, as well as socket programming. I'm working with a VB.NET-compatible SDK called TrueVision3D to create a small online game for me and my friends. The problem is that I cannot for the life of me figure out how to pass data from one thread to another. I've created 2 seperate threads on seperate forms.
The first thread is created on a form titled FrmLogin, and it contains all the socket code. I need to be able to update variables in the second thread, which mainly consists of a render loop. The second thread is created on a form titled FrmMain. I'm not quite sure if it matters what forms the threads are created on, I'm just trying to give as much information about the issue as I can. I've tried using delegates and events to pass information from the thread back to the form it was created on, which works fine, but how do I pass data to the second thread from the first?
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Aug 4, 2010
I have an application that needs to perform a series of different actions at specific points in time.To do this I have a timer with various actions that occur in its tick event.One possible action is to send out a few messages via a serial port and then wait (between 1- 300 mins typically) for the next timer tick.Another possible action is to continuously toggle one of the control lines on the serial port until the next tick (again 1-300 mins).
In most instances, i'm happy for everything to run on the main thread, but in the case of toggling the line endlessly, I thought it better to give it its own thread.My problem is that for the new thread to use the Serial Port, it must open the port. Likewise, it must close it before the main thread can have it back.
Here are 2 code snippets
Private Sub activityTimer_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles activityTimer.Tick
Dim some variables here
activityTimer.Stop()
If speedThread.ThreadState = ThreadState.Running Then
[code]....
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Sep 7, 2010
I'm starting to put in a database into my application, however I'm drawing a blank on how to share a database connection among the dozen or so different forms in my MDI application. I'm assuming this has to do with interfaces or something but I can't find any relevant examples anywhere. Can someone help me out? Ideally what I'd like is when the app is loaded up there is a call to a function in the forms loading area which establishes a single connection to the mdb, that I can then call via any form so I don't always have to open/close connections everytime I need to update the db?
Here's a basic example of the mdb database access code I've got working:
Dim dt As DataTable = New DataTable()
Dim OleDbTran As OleDbTransaction = Nothing
Using connJET As OleDbConnection = New OleDbConnection("connection string here...")
[code]....
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Sep 13, 2011
My question is in two parts:
1) I am writing an application for a touchscreen which will have several different Forms - each of which will be full-screen. What is the best way to achieve this? Hide/show each Form as the user navigates between screens? MDI Parent with multiple Child Forms becoming visible 'on top'? Or is there a more elegant solution?
2) I would also like a 'banner' on the top of each Form (or always visible on the top of the MDI Parent, etc) similar to a 'navigation frame' on a website. This banner will display a clock with the current time, and the current GPS location (meaning that a Timer will be used to get/set these values every 1000 milliseconds). I thought of using a UserControl for the banner - but if this is used on multiple Forms then I will end-up with multiple Timers all waiting 1000 milliseconds to update essentially the same information.
Is there a best practice for this type of scenario? - my thoughts so far are using the "Main" Form for Global Timers, etc - but then how do I update all Form clocks each second? (without iterating through all visible Forms... which seems messy).
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Jun 11, 2011
I have a windows forms application with one exe and several dlls(Class libraries) in a single solution. The application uses common data that is used across all the dlls. I would like to load the data when the application is starting up and use the loaded data at various points in the dlls so that I do not have to load the common data again and again. How can I share the data loaded in main EXE across the DLLs?
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Apr 14, 2010
I am using Synclock to prevent multiple threads from logging text messages to the same file at the same time, but this doesn't seem to work:I get frequent sharing errors on the logfile, within the synclock block.The Synclock is using the variable holding the filename, because it exists all the time and because it is always the same object, whatever class instance or thread I'm in.[code]Despite using Synclock and a Using block around the code, I keep getting this error in the sw.WriteLine(Msg) line:System.IO.IOException: The process cannot access the file '(filename)' because it is being used by another process.Should I use some other type of object than a string to synchronize on?I cannot use a user interface object (button or so) because it is a windows service project.It was written and compiled in Visual Studio 2008, but targeting the 2.0 framework because it has to be able to run on some old Win2000 machines.
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Nov 18, 2011
how can i stop other mdiChilds opening up as maximised when the previous one is set to maximised.[code]
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May 7, 2009
I'm new to this, so sorry if my question has been asked before. I have searched but have not been able to find, or perhaps recognise, an answer. I am using visual studio 2008 and creating an app in vb.net.
I have 4 arrays named:- account1 account2 account3 account4. They all have 4 elements.I want to assign values to the elements in the arrays in an efficient manner. I thought two for next loops would do it. [code]....
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Apr 29, 2010
trying to save users names and passwords from input boxes and save it as arrays in text file that in future multiple users will log in with their names and passwords
have this code so far but doesnt realy save the user info to file, dont even create file.
Imports System.IO
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[Code].....
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Mar 13, 2009
I want to go to a class.vb file that has a function from an aspx page and I want to return mutiple arrays. Is that possible? If so, how would I call it from the aspx page and how would I return it?
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Jan 8, 2009
I'm trying to find out a way to search multiple arrays for a specific value. I looked through here, yahoo, google and msdn and couldn't find anything specific to what I'm looking for. Don't have any sample code as I'm not quite sure where to start.
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May 11, 2011
The scenario is:
1)A large 2 dimensional array (400,20)
2)The program needs to access particular chunks(for example (0,20) to (50,20)
3)The program will open multiple files and process each into it's own 2D array (400,20)
What I have right now is code capable of creating the array, but no way to store the array so that I can open a new file and process that data into another large array. Someone mentioned the generics List(of T) might be a good way to store each new array as you could use the Add function. I have done some research on the List(of T) class but I'm not totally convinced that is the way to go. I'm just looking for some direction as I've just started on .net this year.
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Apr 28, 2011
how to take a text file that was provided for my homework assignment, and put the information within it into 3 different arrays.[code]
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Jun 10, 2011
i'm having issues where I can't figure out how to take a text file that was provided for my homework assignment, and put the information within it into 3 different arrays.The .txt file looks like so:tc.Amanda/Ashley have to be in the same array as well as 4/2, 166/20.This is what I've come up with for the snippet of code, and so far, it hasn't really been working right.
Dim namearray(MaxItems), rankarray1990(MaxItems), rankarray2009(MaxItems) As String
Dim Numitems As Integer
Dim sr As System.IO.StreamReader
[code].....
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Apr 9, 2010
if its possible to split an array into multiple smaller arrays?
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Mar 29, 2011
I'm looking to be able to save and load the content from multiple structured arrays and variables into/from an encrypted file, is there any reliable source of information or tutorial that I'd be able to use for this? I've never written a program in visual basic that writes to/reads from a file.
I'm using microsoft visual studio 2008.
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