Using Nested Structures - Barking Up The Wrong Tree?
Mar 8, 2010
I am building a custom OCR program to grab data from the screen. I am a self taught programmer and have learned things as I needed them but I believe I'm struggling with properly using Object-Oriented principles in my code.
I have been able to build a solution using separate single column arrays to hold my data and they are linked by the index number but I keep thinking that if can get classes/structures nailed down, the code will be much neater.
[Code]...
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Mar 8, 2010
I have been trying to read the cd toc in one go from the API, I can read it OK with a single byte array, but I can't find a way to fill the formatted arrays
Code:
'ORIGINAL STRUCTS
'MAXIMUM_NUMBER_TRACKS = 99
'typedef struct _CDROM_TOC {
' UCHAR Length[2];
[code].....
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Nov 15, 2011
I have two Structures, one of them is nested.
Public Structure RetailRpt
Public FromDate As Date
Public ToDate As Date
[Code]....
I've added the DSRPT structure from the datasource of the datagridview. but unfortunately I can't manage to show the nested structure data with [+] in the datagridview row.
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Jul 11, 2011
I have a List Table (lstTable) that is on the same form that I am trying to fill in with information from a public structure (ELEM_DATA). I understand nested with statements will work if it is within the same scope but how can I do this with example 2 below:
Example 1:
With me.lstTable.Items(RECORD)
.SubItems(1).text = ELEM_DATA(RECORD).name
.SubItems(2).text = ELEM_DATA(RECORD).number
end with
[code]....
I didnt know if it is possible or if it would be as simple as changing (.name) to something else.
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Jun 12, 2011
I am not the original author of this software project and the code is poorly documented. I am mainly a Java/C++ developer.The program displays the tree structure and allows files and folder to be selected. The program is getting errors with FileSystemTreeView when trying to return nodes on a system with a reserved partition.Here is what is happening: tree.SelectedNode = tree.Nodes(0) 'returns error with system reserved partition.calling, GetDriveList() will properly return all the drive letters - and not throw an error. Only when trying to get a tree.Node() or tree.load() is the error occurring.
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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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Jan 12, 2010
I've got a DataGridview I want to remove columns from as it greatly increases performance when I format the DGV. The first time I remove columns in a loop (using the removeat) property, everythings fine. But when I try to remove more columns in another loop, it appears to remove the wrong columns and displays the wrong data. In other words, it displays the wrong data and headers; and the columns it does show has headers and cells that don't match.
[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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Sep 24, 2010
so far i got
code
For Each item As Reflection.FieldInfo In GetType(NameSpace.ClassWithNestedClasses).GetFields
rtfAppend(item.Name & ":" & Tab & item.GetValue(Me))
Next
For Each item As Reflection.PropertyInfo In GetType(NameSpace.ClassWithNestedClasses).GetProperties()
[code]...
which gets me the simple string vars and properties of my top class, but how can i apply this to loop through all sub classes and get there vars and props?
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Jul 20, 2009
I'm attempting to create a list of structures that contains a list of structures. I can't seem to figure out how to properly allocate the object for the inner list of structures. I expect the outer list of structures to have a couple thousand entries and the inner list of structures to be fairly small at 2 to 10. Both lists will grow over time but the number of elements within the inner list will be constant for an instance of the outer list. Meaning, if an instance of the outer list has 2000 entries each of those will have the same number of elements on the inner list, say 4 entries.
Here is a simplified code fragment. This fragment makes no attempt to create the instance of the inner list "StructBlist" since I can't figure out where to put it. Tried "New List(Of StructB)" in the declaration as well as "Alist(0).StructBlist = New List(Of StructB)" but neither works.
Public Class Form1
Structure StructA
Dim FieldA1 As Integer
[Code]....
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Oct 20, 2010
drag and drop nodes within the same tree (not between trees) when users drag and drop nodes within the tree, give them the option to move the original node to a new location within the tree OR to just copy the original node in a new location (seems complex but I have a month to figure this out). change the system default blue highlight for selected nodes to another color change the system default cursors for invalid and valid drops (instead of the circle with slash indicating invalid target, i want a red minus) and (instead of the little plus sign with little box indicating a valid target, i want just a big green plus sign) add a red insert line to indicate where the node would be dropped within a tree also drag and drop the text of a node from the tree to a textbox add a "folder" image next to parent nodes and a "document" image next to children nodes
I have looked through the internet but I am having difficulty sorting through all the information available (I see a lot of information for Visual Basic 5 and 6, and those codes don't work for me in visual studio 2008). I can email anyone my code I have so far.
Public Class Form1
Private MouseIsDown As Boolean = False
Public Sub TreeView_ItemDrag(ByVal sender As Object, ByVal e As ItemDragEventArgs)Handles TreeView1.ItemDrag
[Code]....
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Mar 28, 2010
What is the different between these 2 structures?
Structure INPUT
Public dwType As InputType
Public mi As MOUSEINPUT
Public ki As KEYBDINPUT
End Structure
[Code]...
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May 14, 2011
Structure TextureStruct
Dim unk1 As ULong 'always 0x70007
Dim unk2 As ULong 'always 0x70007
Dim unk3 As ULong 'always 0x70007
Dim unk4 As ULong 'always 0x70007
Dim unk5 As ULong 'always 0x70007
Dim unk6 As ULong 'always 0x70007
[Code]...
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Jun 5, 2010
Is it possible to declare a new list inside a structure.
I'm trying to get a list of structures that each contain a list of points,
but when i try to declare a new list inside the structure VB says "keyword not valid as an identifier"
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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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Jan 21, 2010
I am currently working on a project for myself which looks through employee's information to find their availability to work. I've tried making a structure which holds the employee's information but I can't think of a good way to create different instances of it and store information in it at runtime. I'd prefer to load the information in at startup and not have to declare each employee and information. I am very new to Visual Basic 2008 but I have a good grasp of arrays from C and C++.
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Oct 23, 2010
I know that Structures are value types and classes are reference type, i know that since structures are stored in stack they are faster to use i also understands that structures can not use the Inheritance concept but still in most examples i see i always see that the authors use classes when building something like BBL library, if structures is light-weight compare to classes and i don't need it to be inherited should i use structure instead of class?is there a rule of when to use class and when to use structure ?
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May 1, 2012
lets say its something like[code]...
i want to add a function like this inside the structure
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Nov 7, 2009
I have a Structure, and I am having trouble initialising it. Specifically when I try to populate the Vector3 variables, it tells me that they are Nothing, so I need to make them New when the array of this structure is declared.[code]Structures cannot declare a non-shared 'Sub New' with no parameters.I have no parameter to supply, and this will be an array so I'm not even sure how I would supply it.The second option to fix the error is to make the Sub New shared, but then I get other errors: Cannot refer to an instance member of a class from within a shared method or shared member initializer without an explicit instance of the class.Does anyone know how I can resolve this. My end goal is to have an array of this structure type with the Vector3s ready to use.
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Mar 10, 2009
I have created a collection of structures. Each structure, of course, contains fields.
Lets say something like:
Public Structure clientStructure
Public ID As String
Public firstName As String
[Code]....
How can I access a field of a particular structure using for.... each?
That is, how can I retrieve out of the collection (lets say item 5's) firstName, using for...each?
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Sep 1, 2009
Can a list class in vb.net contain Data Structures ?
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Jul 26, 2009
Just a little frustrated with a simple error in a listbox result on a mobile application.Here is a sample of the results I should be getting:
The inputs are 50mph & 4.5 hours
Hour distance
1 50
[code].....
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Feb 21, 2012
I need to have an Array of UDTs(Structures). Elements have to be added (at end) and removed (from anywhere). The different values of the elements need to be changeable.
I know how to implement it as an oldstyle array, but wouldn't it be better to implement as a List ( of T)? and if yes is such a procedure possible?[code...]
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Mar 16, 2011
It says that I can't have structures as optional arguments.That's really annoying for my program. Isn't there any way to circumvent this?
Sub fa(Optional ByVal colz As System.Drawing.Color = Color.AliceBlue)
End Sub
This example cannot compile
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Aug 4, 2011
I have an interface IDigitalState defined as
Public Interface IDigitalState
ReadOnly Property Code As Integer
ReadOnly Property Name As String
End Interface
[Code]....
What I wanted to do was declare a variable as a nullable type of IDigitalState. I understand why I cant do this because the interface may be implemented by a class which is not allowed to be nullable. Is there a way to define the interface so that it can only be implemented by a structure.
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May 31, 2011
I have 2 Structures
Public Structure One
Public ItemOne As String
Public ItemTwo As Integer
End Structure
[Code]...
Results In an Unhandled exception. Bad Record Length. and then If I close it and reopen it I get an 'Unable to read beyond end of stream' error. So what is the best way to save an array of structures? Binary Reader/Writer? and why does this way not work (Even if its derived from VB6)
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Jan 29, 2011
The following is a mini version of a data structure that I need to be able to write & save to disk. Can someone give me a sample of code needed to do this
Public CardType
Card(0 to 52) as Integer
Suit(0 to 52) as Integer
[code]....
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Nov 17, 2009
I have an array of structures:
Structure stCar
Dim Name As String
[code].....
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