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.
View 2 RepliesI have a web service that I'd like to include as a project reference inside a windows forms application. (The application will be running on non-networked hardware.) I could simply copy the *.vb files I need into my forms project, but I'd rather not fork the code base.It wasn't hard to include the ASP project in the windows forms solution. However, I can't figure out how to reference it in my forms code.
View 2 RepliesCan a list class in vb.net contain Data Structures ?
View 1 RepliesI 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.
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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
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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 ".
what the results I need in a Windows Form Application.
Requirement:
(1) I need to create class objects with all various methods and properties, etc.
(2) I will create only one instance of the each class
(3) I need to be able to call the methods and properties of the created class objects (1) from any form I create.
(4) I use the class objects to store data so that separate threads can access them..
Question: how I would code this into a WFA? (I have console application code that works but need to convert it into a GUI).
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I'm trying to write a method that is called from a variety of forms at load. So with a Form1 load event I would call the following:
Dim testpoint As New Point(10, 20)
DrawVerticalStringFromBottomUp("Hello", testpoint, Me)
The DrawVerticalSTringFromBottomUp Method is as follows:
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When I call the code at a form's load event, nothing happens. When I call it from a button click after the form has loaded it works! I know this should be called from the paint method, but that doesn't suit my purposes.
way to make this work from the form load event?
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
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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
I am upgrading my application from vb6 to vb.net.I used to populate my data in datalist control in vb6 forms. I am not finding it in vb.net windows form application. Which one control is the equivalent to it?
How can i list my data in that control?
just like: I had a table with data like id, name
I want the name should be the displayed column and id the bound column? how can i do that
what is the best way to add, delete elements from arrays of structures structure
vb
Structure Proxy
Dim Server As String
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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.
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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.
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?
View 1 Repliesi 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
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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)
View 1 RepliesI 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...
View 3 RepliesI have been assigned a program for homework in which I need to take in information about songs from a text file and then be able to sort the list alphabetically, by genre and by length. I also need to be able to filter it by genre. The user can then move songs they choose from the master list to a playlist where again the list can be sorted by either genre or play order.My book only covered sorting array when they are one dimensional however I need to be able to sort a multidimensional array by different columns. I asked my teacher but she had so much going on that we didn't really have time to get into it, so I decided to ask here.
I'm not looking for code, just to get pointed in the right direction. For instance rather than using a multidimensional array would it be better to pull the values in and then put them into an array of song objects with properties for each value? And if I choose to go that route is an array the best structure to use? I have to use an array of some type, but the problem says nothing about whether or not it can be a list or other array type structure.
I declare my 2D lists:
Dim _invoiceitems As New List(Of List(Of String))
Dim _dbitems As New List(Of List(Of String))
Each List is filled like this: Example Code To fill:
_invoiceitems.Add(New List(Of String))
_invoiceitems(0).Add("Code #")
_invoiceitems(0).Add("Quantity")
Well, now i need a third list called (_changesitems) Note that this result with the differences: be the result of subtraction of quantities if this is found (dbitems - invoiceitems).
I've had experience with using hashvalues from String objects. E.g., if I have StringA and StringB both equal to "foo", they'll both compute out the same hashvalue, because they're set to equal values. Now what if I have a List, with T being a native data type. If I tried to compute the hashvalue of ListA and ListB, assuming that they'd both be the same size and contain the same information, wouldn't they have equal hashvalues as well?
Assuming as sample dataset of 'byte' with a length of 5
{5,2,0,1,3}
I have a pipe delimited file with 3 values on each line, something like this:
0001|234587|Bracket, 3 x 3 x 0.125, Steel
0001|254378|Bracket, 4 x 4 x 0.125, Steel
0003|234587|Hinge, 4 x 4 x 0.125, Brass
The first Value can be duplicated in the file, the second value also can be duplicated. There are no instances of BOTH values duplicated on 2 or more lines. I need to read another file and get the first 2 values, then look up those two on one line to get the proper 3rd value. The "other" file looks a bit like this:
0E0522070001EF54ED7823458700FF00FFA5A5A5A5
-----------XXXX-----------XXXXXX--------------------- (X's are the data, the rest is filler to comply with some code unknown to me)
Right now I have code to read all into an array (split on vbcrlf), then split each line on "|" and populate three arrays, I then go thru every element of the first column that matches the value I am looking for and test that the second column also matches the second value and if so, return the third array contents at the same index. This seems crude and inefficient. Cannot use a hashtable (I don't think) as it only supports 2 values. A List(Of) doesn't seem to work either and I don't want to use a database.
I have written a ActiveX DLL in VB 6 which is like -
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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.
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Find common values in multiple arrays with PHP Pretty much does what I need, but in PHP, I need VB. My situation is I am trying to create an intelligent stock pick system based on multiple stock locations. At the point of invoicing, we loop through the items invoiced and check the stock database for available stock.
If all items on the invoice are available to pick from stock location 1, then all should be picked from stock location 1... etc. If all most items are available from stock location 1 except one or two, then pick all stock from stock location 1 except for the exceptions which should be picked from the location with the highest available stock. Finding highest available stock is simple, but I can't work out how to analyse the stock availability from multiple locations and finding the common stock locations.
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I was wondering how you create a form with three lists. Each list representing a different array.
I guess the question is how do you take an array and make it into a list so it shows up on a list box?
my binary search isnt working, i think it has to do with the fact that im using a list and its searching thru an array
List
Option Strict On
Public Class Form1
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Basically what I'm having to do is create a program that takes a list of CaseIDs and compares them to a table on a remote SQL server. However, the table holding the CaseIDs on the remote server has nearly 120,000 records.
Currently my plan is to query all records on the remote server, save the query and the current list to tables in an Access DB file and then run an outer join to see which CaseIDs have no matching records on the remote server.
I believe this will be a much slower process than I would like. If I could load both queries into arrays or lists in VB and then compare them (therefore, not having to write 120,000 records to a DB file), it would be much faster.
Ever since I started using VB.Net I have been using the Generic List collection List(Of <Type>). Arrays, I haven't used so much. I used them a lot more when I wrote C code years ago.
1.) Are arrays considered a type of collection like Lists, Dictionary, Queue etc are? Or are they in their own category.
2.) Can I iterate over an array with a For Each loop like I can with other collections or do I stick with the normal For loop for arrays?
3.) There are certain methods that return arrays. Can I set a list object to hold this return value instead of an array?
So, I run a select statement in SQL and then it has something like " where clientName = 'John Doe' " I can generate a datagrid or dataset off the SQL statement, but it will only be good fro one client...... I would like to be able to populate a dataset/grid using the select satement and then having something like a combo box of names the USER can choose. Then the user selects the name and the datagrid is populated with that clients info or w/e........
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I am having some trouble with some data I want to display on a form. The data is in a 2-D array, call it myarray(x,y). My attempts to display it have so far not worked. Similarly, I also need to read this data from the form back into an array for further calculations.
View 3 RepliesI have a basic three form application. It doesn't seem to close after navigating through forms. If I were to open the application, and the main form is displayed. If I press the X button, the application closes fine(Goes from processes) If I were to open the application, and then navigate from the main form to another form using me.hide & form1.show, and press the red X on Form1, the application again, closes fine.
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