I have BIG trouble trying to understand the decleration and creation of an instance with respect to arrays of objects. Basically I struggle with with this error:
Object reference not set to an instance of an object.
complete the test code I made below, so that I can try to understand it..? Been figthing with this for hours..
Code:
Public Class Point
Public x
Public y
[Code].....
I made a browser and its awesome but i want to reference the browser name so that i can add script to it, I am calling the new browser window "wb" cause that's what it gets named in the script. here is my code. (it labels the tab, the window, and changes the URL text field)
Private Sub wb_Navigated(ByVal sender As Object, ByVal e As System.Windows.Forms.WebBrowserNavigatedEventArgs) Handles wb.Navigated
TextBox1.Text = wb.Url.ToString()
Me.Text = CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).DocumentTitle & " - My Browser"
[code]....
It says "Browse.Name = "wb"" so thats why im trying to call it "wb". I inserted a WebBrowser on the form named wb and then tried to run it and it worked, it labeled the window, tab, and changed the URL field. So i know that the script works. Please help me, I know you guys can solve this, I'm really new at this.So my final question is... What should I call the browser instead of "wb" when I am referring to it in the first script I posted above? I am so confused. How do you refer to an object that gets created dynamically?
Here is my Code snippet
'decleare variables
Dim vmcount As Integer
Dim tabcount As Integer[code].....
The trouble I'm having is working out a way to be able to call the objects in the dynamically created usercontrols. I thought a list maybe an option but I am struggling to get the syntax/get it working. Wondering if anyone has some ideas or different approaches..
I have to ask my first question at some point, so here she goes.I am trying to create a dynamic list of objects. The objects will have several types (String, Integer) associated with them. Currently I am forming a Collection as I instantiate new objects.Is there a prefered to map this collection to, say, a Datagridview? Will I have to Iterate through the collection and add the rows at each iteration?Would I be better served using an ArrayList or something else over a Collection?
View 8 RepliesI am trying to create a form where depending on what the user selects, they are shown a collection of images from the web. Depending on what they select there will be a different amount of images so each picture will need to be added dynamically.
I am able to create PictureBoxes dynamically however I'm stumped how to create event handling in order for each control to give a unique response.This is what I originally tried but I got an error..
Private Sub Form1_Load
For i=0 To 10
Dim picBox As PictureBox
[code]....
The error I got was
'AddressOf' operand must be the name of a method (without parentheses)
How ridiculous that you can't include arguments in your AddressOf! Can anyone shed some light on my situation (or knows a better way of carrying out my goal)?
I have a tools strip menu item with dropdown items that are created dynamically.
For Each file In files
Dim newMenu As New ToolStripMenuItem(FileNameOnly(file))
tsmMachType.DropDownItems.Add(newMenu)
Next
So how would I go about setting up or creating events for these items? I need to have a check event and click event for each of the items.
I am relatively new to C# and winforms, although I have been using Java for years, so forgive me if im asking something relatively straightforward!I have a DataGridView, it needs to update regularly so I wish to provide a Collection of objects as its DataSource and NOT a database table.So far I have a List<MyObject> which will be constantly updated via a BackgroundWorker thread. I want my DataGridView to update when a change has been made to the List i.e. if the objects are resorted, added to or deleted from etc.Currently my DataGridView only displays the first object I add to the List, if I add more the DataGridView doesn't update to display the new objects added.This is a basic overview of how im coding it:
private List<MyObject> myList= new List<MyObject>();
myDataGridView.DataSource = myList;
Then my BackgroundWorker thread updates the list, e.g.
[code].....
I've come up with the following and it's partly working.
Public serial1, serial2, serial3, serial4, serial5 As SerialPort
Public serialports() As Object = New Object() {serial1, serial2, serial3, serial4, serial5}
dComPort = "COM4"[code]....
The above code works fine! But im having trouble trying to now retreive whats stored in the array.In the above example, an entry will be stored in serialports(4), all other array elements will be blank.If I do this it works.
MsgBox(serialports(4).PortName) ' this retuns the value COM4
But I'd like to loop though all array elements and print out ALL the PortNames, The below code doesnt work, I get an error Object variable or With block variable not set.
For i = 0 To serialports.Length - 1
MsgBox(serialports(i).portname)
Next
I have a nested class, let's call it class1 and it has class2 inside it; VB.Net eg:[code]
1) How can I define X number of Class2 objects[let's call it: Node(x) array]** with NEW() subroutine called?' this raises error: dim cls2(n) as new class2 end sub.
2) How can I return actual number of Node() array? [code]Outside my class in main project I define cls1 object:[code]Now an array of class2 is created inside cls1.
3) Now,How can I access All of them[node(x) array which is created inside cls1] with all properties and methods available?
I remember I wrote a ProcessManager class with this functionality in .net 2003, nearly 4 years age, I don't have the code now.
ok first off my over all goal is to create a simple database program. I need to have an index file that i can search and then load the item data from a path refferenced from the index file. So i was thinking that if I have a IndexClass object, that has the following varribles: name as string, Desc as sting, and ImagePath as String.
[Code]...
I am having trouble conceptualizing how to create and load my 3d Array. The Project does the following:
View 6 RepliesI want to build an array with info from an XML file.
The number of columns is static, but the rows will be increased once in awhile and I want one column to populate in a combobox while corrosponding selectedindex appears in a textbox. I think I can figure that part out, but currently stuck at the array building.[code...
I am creating a game which include guns and bullets and I created everything. I want to have a shorter code which I am going to create a array of objects which are the bullets. Can someone help me? In VB6 it's possible to create an array of objects but I am having a hard time for VB 2008.
View 4 RepliesThis is getting on my nerves. All the examples I keep finding deal with Consoles, all I'm trying to do is put data into an array of objects and output them into a Text box, but I don't know the syntax to do that.Here's my class
Public Class Student
Private SID As Integer
Private firstName As String
[code]......
Reverse an array of objects?
View 8 RepliesI have two methods in a class for placing and rotating an array of objects(Pieces) on a Board.pieces have a bounding rectangle and a property called center that is the center point of the rectangle(piece).what i want is to rotate all the pieces in clockwise or counterclockwise direction ,depending on the mouse direction,when the mousebutton is down on any of the pieces other than the center piece and the mouse moves.can anyone modify my code below to achieve this or post some new code that does this. using the rotatepiece() method below in a timerevent with a buttondown event to start the timerrotates all the pieces in clockwise or counterclockwise direction.
Shared PosArray(18) As PointF
Shared Increment As Double
'place pieces in rows [order 3-4-5-4-3]
[code]....
I'm struggling with this Serializing of Data. and I've checked out the MSDN, and saw the Serializing an Array will make the out put like this:
[Code]...
I'd like to create an array of objects with events. Where do I need to put the "WithEvents"? Should it be placed in the ReDim line or the next one?I'm trying to use a "global" event, like objects of people that recieve a time-event to get older.
[Code]...
I'm working on a program that has to get a set of images and then scan them to find pixels that match colors in an color array. Anyway I think I got everything working but how to load the images in as bitmaps. See the images are dynamic, they change there filenames so I can't call them with a static call like Dim bmp2 As New Bitmap("c:button.gif").
So I am using a loop to feed the images into an array for bitmap but thats not working, anyway that I can do this as, right now the program gets all the filenames for the images from a text file that is sent in to us. All I need to do is have the program check each image for pixels that match our color list. But I cant get the images into the bitmap array.
[URL]..And put into a dynamic array where each month represents a record in the array with 3 given with C/P, Strike and Settle
The criterion is for every month grab all C/P that have matching strikes thus returning the following for every month. See data below and what I would like to return below. Want to use excel VBA to return the values from array into a sheet in excel. See data below
[Code]...
I created a code that will prompt someone to enter a name and if the name is in the array it should print out the correct integer, but it keeps printing out not valid.
Private Sub btnDisplay_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnDisplay.Click
Dim strSub() As String = {"Jasmine", "Sean", "Devon", "Jontae", "Whitney"}
Dim intNumb() As Integer = {15, 10, 11, 12, 5}
Dim strSearchFor As String
[Code] .....
A project requires to allocate a varying number of byte arrays (buffers).
It would be ideal if the following definition would be possible:
Dim ArrayOfBuffers() as buffer(10000) as Byte
The byte arrays must be ordered sequentially because they have to be written to a file by efficient procedures destinationFile.Write(ArrayOfBuffer(3),1000,1000)
The number of buffers will change during program execution sometimes. Therefore it would be nice to be able to do a ReDim on the data structure when needed.
I've been programming in VB.net for a while off and on, but never really had a need to use custom classes till now.I built a function in a module to populate a class, The class how ever is supposed to refer to one instance.I need to create an array of this class but the amount of instances needed is not always known.Works fine till the class goes to populate the class array.[code]It's probably something simple, I've just starred at it to long. Keep gettitng "Object reference not set to an instance of an object."
View 1 RepliesDoes this create a dynamic byte array?
Code:
Private m_renderedReport As Byte()()
Or this actually creates a structure?
I'm trying to find the sum of all the digits that make up the number 2^1000, which you may have guessed is from Project Eula. I think it's good so far except I'm just learning about arrays and dynamic arrays, so how will I know what the size of the index will be so I can specify when the Do loop should stop so I don't get an indexoutofrange exception?
vb.net
Dim BigNumber As Double = 2 ^ 1000
Dim DigitArray() As Char = BigNumber.ToString.ToCharArray
Dim Index As Integer = 0
Dim SumOfDigits As Integer = 0
[Code] .....
I m trying to manipulate some excel sheet data in visual basic but for tht i hv converted the excel file into text tab delimited file. now i m able access each column n row value as i want but the prob is the text file has to b input n the no of columns in it could be varied so i need a method to count the number of elements in th tab delimited array wen first time the text file line is read.
View 8 RepliesBasically im having problems programming an array as double. I have it as ' public arrytotal() as double ', however I keep getting the error messages
1. Error 5 Operator '+' is not defined for types '2-dimensional array of Double' and '2-dimensional array of Double'. C:UsersAlexDocumentsCafe AssignmentCafe AssignmentconverthomeBackupWindowsApplication2Form2.vb 115 22 WindowsApplication2
and
2. Error 1 Value of type 'Double' cannot be converted to '2-dimensional array of Double'. C:UsersAlexDocumentsCafe AssignmentCafe AssignmentconverthomeBackupWindowsApplication2Form2.vb 84 19 WindowsApplication2
Is it possible to program an dynamic array as a double? i have seen examples of this online, but cannot seem to do it.
Private Sub LoadButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles LoadButton.Click
Dim lin(8) As String, filRead As StreamReader, i, x, t, d As Integer
[Code].....
I am getting a run time error it is not saving to textfile
I am attempting to figure out the best way to place values into an array using dynamic data that is continuously streaming in from a ComPort. I want the array to hold 5 values at a time, with the newest incoming data point taking the place of the oldest data point. Each set of values in the array will be used in finding a trendline, which is then used in a later portion of the code.
View 1 RepliesI need a way to delete the last element in an array when I don't know how big the array is.Basically I need the VB version of php array_pop, but nothing relevant seems to be appearing in search results.
View 2 Replies