I have a simple class that I trying to populate from an XML document. The XML file has an attribute called TrackingID in the root node which I would like to get as a property. For some reason, when I deseralize the class, the TrackingID is null. Everything else populates fine. I have tried various attributes on the TrackingID property with no luck.
I am trying to make an Image wrapper class or something. The reason for this is that I need to output a bunch of images only, without pictureboxes. I don't want an imagelist, because I need the images along with their associated image properties which an imagelist cannot provide. I ended up with this :
I am trying to display my data in datagridview. I created a class with different property and used its list as the datasource. it worked fine. but I got confused how to do that in case we have nested class.My Classes are as follows:
class Category property UIN as integer property Name as string
I want to display (DataGridView's) selected row contents (each cell value on appropriate text box) on text boxes on the form. This should be fairly simple task for experienced i am sure.So far i haven't been able to find a single working solution to accomplish that as most of the articles are written for VB / VB 2005/ VB 2008 and not VB 2010.
Here is what i have already tried. (I tried putting an image but i can't due to my privileges over flow) TextBox1.Text =DoctorsDataGridView.CurrentRow.Cells(0).Value.ToString It strangely works for first 4 selected rows and populate text boxes but fails for the rest of the DataGridView.
I have a DataGridView which contains a hidden column. On the BindNavigator SaveItem_Click event i need to populate the hidden column cell with the current date. I tried using the DefaultValuesNeeded event but it did not work out.
I was wondering if someone could explain to me the differences between these 2 ways of accessing a class property.Access Way : 1 (To me this looks like im declaring the property of the class as a Global variable which can be changed anywhere
I am trying to work out a method to reset the image property of my picturebox on the fly.
I am able to load the original image from a file. But i want to save a clean copy of it before i draw on it. Between drawings i want to be able to reload it.
Here is what i have tried
Dim img as image Using OpenFileDialog1 As New OpenFileDialog With OpenFileDialog1
[Code]....
the code does not seem to work it just freezes. Im not sure exactly whats going on with it.
just because you can do something, it doesn't mean it's good programming practice. To that end, I have a question about calling a public property from inside the class in which the said property resides. It seems that I can call it, similar to a sub, using me.property, but is this good programming practice?
Having an issue with my data gridview. I've set the visible property of the ID column to false, and in the designer the column is hidden, yet it still shows up when i run it. Now if i set it to True it shows the column twice.
I have a very simple class that holds a few public properties - ID, Text, Colour, etc. and a Boolean called 'SelectedItem'. Just like the Checked property on RadioButtons, only one item can have its SelectedItem property set to True within a particular group. Note: there will be several separate groups (lists), each allowed to have only one item with SelectedItem = True.
My first thought was that I would probably just have to handle everything outside of the class, setting SelectedItem to False for every other item in a particular list when another item was selected. But that seems rather inelegant to me. So I've been trying to think of how this might be done within the class. For example: could I perhaps have a private string property called say "GroupName" - set in the New sub when adding a new instance of the class - and then use a private shared method to set every item's SelectedItem property to False, provided the item has the same GroupName as the newly selected item? I would have a go at doing this but I have no idea how to enumerate every instance of a class from within that class, or whether that's even possible. Is it? Or is there another (better) way to achieve my goal? Here is a cut-down version of what I've got so far:
Public Class ResourceItem Public ID As Integer Public Text As String[code]....
As can be seen: instead of instantiating a new ResourceItem and passing that as an argument to the manager's Add procedure, I'm simply passing the details of the new item and the procedure is creating the item from those. I don't know whether this is a good or bad idea - please advise - but I've done it because I couldn't figure out how to make the SelectedItem property only writeable by the manager, so I wanted to avoid having directly accessible objects that could have their SelectedItem property set to True without it deselecting all the other items in the same group. Of course that still leaves the possibility of setting a variable to one of the manager's list items and setting it from there, so I would still like to know how I could prevent that, if possible.
UPDATE: I didn't use the code above in the end, deciding instead to go with Cyborgx37's solution - which seems to work perfectly well for me despite the warnings about best practice. I also realised I would need to use the same class in another scenario where multiple items could be selected, so it was easy to add a Boolean property to the manager to enable that.
I need to click an image in a webbrowser from a Windows Form in VS 2010.I can click ordinary links using code such as this one:
Private Sub Button14_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button14.Click Dim lnk As HtmlElement For Each lnk In Form2.WebBrowser1.Document.Links If lnk.InnerText = "the_text_of_the_link" Then
[code]....
When it comes to the second variation of the code I often get the following error message (exception):NullReferenceException was unhandled Object reference not set to an instance of an object.
Basically - how do I tell it to click on it only if there are two separate and unique strings of html code in a html tag?
Public Class MyColorsClass 'Constructors Public Sub New() 'Empty Constructor
[code]....
However, if the empty constructor was called to instatiate this class then the colortype is not yet set. Therefore, if one accesses the 'IsColorCool' property it will always return 'False'. Now for the sake of this example, I must keep the empty constructor as part of the class.Now I could add some code in the 'IsPropertyCool' to check and see if a ColorType has been defined, and throw an exception if it has not been set, but I don't really want to do that.I also could always move the logic OUT of the property and into a method on the class called 'DefineIfColorIsCool' or something, and make the owness on the caller to make sure the method was called if they want to use the property 'IsColorCool'?
Public Class airplane Private var_num_seats As Integer Private var_num_engines As Integer
[code]....
Obviously, I don't wish that the class Glider has the method "start_engines" neither the property "num_engines". Otherwise, other child classes may have. How can I supress these property and method in child class, not just ignoring (if I can)?
I have procedure (Import) that calls a for a new instance of frmImportData. I also have a class name clsBatch that has a data table property called prpParametersTable.For some reason, I get an error (indicated below with ERROR>>>) when trying to assign prpParameterTable to cv_dtImport2. The error states "Object reference not set to an instance of an object.". Why does this error not happen when I assign dtBP to cv_dtImport1? Both cv_dtImport1 and cv_dtImport2 are equal to Nothing and in my Import procedure dtBP = prpParametersTable.
Public Sub Import(ByVal clsB As clsBatch) Try Me.cv_clsB = clsB
I have three class files, accounts.vb and transactions.vb in addition to my form.vb. I am unable to retrieve a member variable from on class from inside the other. When the combobox index changes, the program loads the correct account (checking or saving) from two different sequential files. I don't think I have the calcBalance procedure in the correct class file. And that is what I am having trouble with. Accessing it to display it. [Code]
I'm trying to make a visual map editor, and figured that a DataGridView would be the best way to go. I would like to make it so that you can click one of many buttons to set which new image the grid cell will be set to when you click it. I've set up pretty much everything except that I can't figure out how to set the background image of the cell that I clicked.
i am creating a table in vb.net code (htmltable) with htmltablerows and htmltablecell. I gave on image control but thatr control cant have the .imageurl property, which i need cause i have a handler image.ashx which brings image from the database. heres' the code -
TD = New HtmlTableCell Dim img As New HtmlImage() img.ID = "image_" & rd("ID")
[code]....
on the last line, "img.ImageUrl" i get this error -'ImageUrl' is not a member of 'System.Web.UI.HtmlControls.HtmlImage'how do i fix this?
This is a bit of a continuation from a previous post for which AtmaWeapon was very informative.
Problem: A parent class has a sub class with various properties. A property of the parent class is a List(of T) with T = the sub class The issue is how to store data in the sub class of the instantiated parent
Some example code (hopefully formatted correctly):
Code: '=========== Class Definitions ============= Public Class courseClass Public Class timeTableClass
I'm looking for a tutorial on how to Adding a list(of Class) or Collection as another Class's Property.What I am after is something like the Columns Collection for the DatagridView control.I would like to add Items in the graphics screen. Where the item list is displayed in the left panel and the selected Item properties are displayed in the right panel.
I'm rewriting a VB6 application in VB.Net. So far I have 2 forms, frmLocations (frm1) and frmLocationInfo (frm2). frmLocations has a combobox, cboLocations, from which a selection is made and an "Ok" button is clicked, which then loads frmLocationInfo. frmLocationInfo has a series of textboxes to display info corresponding to the location that was selected - Location, Location Number, Phone, Fax, Email. There are also 3 comboboxes on frmLocationInfo - cboDepot, cboFreight, and cboDispatcher. I need their text property along with items to be populated, also with data corresponding to the initial selection made on frmLocations. I'll spare you all the difficulties I'm having w/the other comboboxes, and instead focus on cboDepot. I have gotten it to populate its text property to display the corresponding Depot, however, the items are not populating and all you see now when you click on the dropdown arrow is only the depot that shows up in the text property.
Here is the code for this portion.
frmLocationInfo Private Sub FillDepotCombo() Dim sql As String = "Select distinct depot.depot_name, depot.depot_refnbr, locations.site from depot inner join locations on depot.depot_refnbr =
I have a class that has the following property that is generated by the methods in the constructor.
Public Class clsLoadTables Private _ds As New DataSet Public Property ds() As DataSet Get
[CODE]........................
My problem is that I do not want to inherit this class, but I have other classes that need to access the ds DataSet property. If at all possible I would like to not use inheritance and not load my datatable more than once in the program.
Here is my failed attempt to access the property inside another class that is not inheriting clsLoadTables:
[CODE].........................
How I can access this dataset that I want to load only once in the program from many classes without using class inheritance or a global module?
I know that an interface can contain another interface within it.But;can a class contain another class within it?Can an interface contain another interface within it?
I have a datagridview which is bound to a local databse table through a Linq to SQL class.
Everything works as I would expect, when the application runs, up to a point.
If, in the datagridview tasks pane I enable Adding, Editing and Deleting all work as expected.
If I disable Adding & Deleting, leaving Editing enabled, Editing works as expected.
If I disable Deleting & Editing, but leave Adding enabled, Adding does not work, despite the row for new records being displayed. I can move around the row but not enter data.
I suspect somehow its the datasource as opposed to the datagridview that is the cause of my problem but as I say, I can add rows if the Enable Editing option is selected.
Changing the relevant properties programatically makes no difference.
I've been searching for the reason for a couple of days without success.
I have a workaround, by leaving Enable Editing set and programatically setting each row during the RowPostPaint event to be readonly except the row for new records. I would just like to understand what is going on.