I am new to classes, and I am new to Visual Basic in general, but I am working on a multi class program. The code seems to be correct, but I am trying on instantiate a class oject with the code:
View 3 RepliesI am getting a strange error when I try to build my solution. The error occurs when I am calling the oGetHeaderValue function and passing the parameters.
Dim oGetHeaderValue As New clsGetHeaderValue
Dim returnString As String
returnString = oGetHeaderValue(strInvoiceNumber, strOrderNumber)
The error message is: Class 'clsGetHeaderValue' cannot be indexed because it has no default property.
What i am having trouble doing is set the current parameter to the current row at a specific column like e.row[column index]
For Each trow As TableRow In table.Rows
cmd1.CommandText = "dbo.directway"
cmd1.CommandType = CommandType.StoredProcedure
cmd1.Connection = conn
[code]....
Class 'System.Web.UI.WebControls.TableRow' cannot be indexed because it has no default property.
I am newer in VB NET.
VB code:
Public Class InputBox
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim a, b, S, p
a = InputBox("Enter length")
b = InputBox("Enter width")
S = a * b
p = a + a + b + b
End Sub
End Class
In InputBox lines i get this error:
Class 'LearningVB.InputBox' cannot be indexed because it has no default property.
Am getting: "Structure cannot be indexed because it has no default property". What am I doing wrong?
With grid.Rows(10).Cells
Dim note As New Note With {.ID = "Blah", _
.Date = "1/1/2011", _
.Message = "AAA", _
[code]....
[code]This is my Code the error is Class 'System.data.datatable' cannot be indexed because it has no default property.. When i try this code in oledb it works but here it wont..
View 1 RepliesThis used to work.
<AcceptVerbs(HttpVerbs.Post)> _
Function Widget(ByVal collection As FormCollection) As ActionResult
...
If ... Then
[code]....
I upgraded to ASP.NET MVC 2 Beta and ASP.NET MVC 2 Futures Assembly for Beta and now ToValueProvider() fails with this compile-time error: Interface 'System.Web.Mvc.IValueProvider' cannot be indexed because it has no default property How do I use ModelState.SetModelValue() if not with collection.ToValueProvider()?
I'm having a few problems converting some code into VB.NET from C#. Most of the translating is done, but I am getting errors when I try to run my code, and I can't figure out what is causing them. Here is the Sub I translated.
Public Sub CreateWidget()
Dim blue As LCDColor
blue.Red = 0
blue.Green = 0
[code]....
The error I receive on this line ("vision.Widgets.CreateWidget(wg1)") reads "In order to evaluate an indexed property, the property must be qualified and the arguments must be explicitly supplied by the user."
I am making a new class that requires a lot of input information. Some of the properties need to be set to a default value, however I do not want to hard code them into the class.
What do you think would be the most efficient way to populate these properties?
I've been thinking of making a new class to hold all the default props and pass them as one object into the new class as a single argument but it seems kind of clunky.
Given a simple class like this:
Public Class clsOB
Implements System.ComponentModel.INotifyPropertyChanged
Private _Frequency As Double
Private _Value As Double
Public Event PropertyChanged(ByVal sender As Object, ByVal e As
[Code] .....
And then I'd like to do something like this:
Dim
o As
New
clsOB(50, 30)
o = 31
I receive a System.Data.SqlClient.SqlException in the following code: Specifically Incorrect syntax near ' In order to evaluate an indexed property, the property must be qualified and the arguments must be explicitly supplied by the user. The exception detail in its entirety is shown below the code.
[Code]...
I have a listbox and I want to loop through each of the items to see if the string im looking for is inside. I know I could do .contains but that wouldnt look at substrings. The code im using looks like this:
While tempInt > Listbox.items.count then
if searchString.contains(listbox(tempInt)) then
end if
tempInt+=1
end while
Everything in the loop is fine but VB gives an error on the listbox(tempInt) part. The error is "class windows.forms.listbox cannot be indexed because it has no default value". get around the default value crap? I tried putting in a blank string but no change.
If we say blue is the default colour of the Backcolor property I understand it as if you don't specify a colour for Backcolor blue will be its colour. But I could not make sense of default property of a class in the context of building a custom user control. After calling an instance of a class we have to either call one of its members or assign an other object for it. Therefore why should there be a default property?
View 9 RepliesStructure EmployeeData
Dim EmployeeName As String
Dim JobTitle As String
Dim TaxRate As Single
End Structure
[Code] .....
how do you declare a default indexed property in VB.NET such that it is callable from VBScript?[code]
View 3 RepliesSay I wanna bind to dictionary that TKey is string with XAML:<Label DataContext="{MyDictionary}" Content="{Binding Item("OK")}" />Doesn't work.How should I do it?
View 1 RepliesWhile running the code I've included below I receive the error "EntityCommandExecutionException was unhandled by user code.I'm then told to look at the inner exception for details...and there I see under Data:"In order to evaluate an indexed property, the property must be qualified and the arguments must be explicitly supplied by the user."And under Inner Exception --> Message:"A transport-level error has occurred when receiving results from the server.[code]
View 2 RepliesI am trying to use the right function in VS 2008. I am simply trying to get the right 5 characters of a string.
VendorID = Right(cboVendors.Text, 5)
I am getting an error when I type that:
Error1'Public ReadOnly Property Right() As Integer' has no parameters and its return type cannot be indexed.
Class 'System.Windows.Forms.Label' cannot be indexed because it has no default property Really can't figure out why I'm getting this error... tried to google it but no success. Could anyone point out what I'm doing wrong? I'm sure it's something simple. The code in red is where the error occurs.
[Code]...
I believe that the correct way to give a property a default value is to use the Default Attribute on the Property.[code]In the property window, the value that's displayed in a grid's property bag when it's newly dropped onto a form is False, not True. It does recognise that the default value should be True because it shows the value as bolded and then de-bolds it when we manualy set it to true - but it doesn't respect the default as the initial value. Is there any way of getting the property bag to respect the default value?
View 4 RepliesI 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 have the following code:
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'?
Supose a base class
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
[code]....
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]
View 1 RepliesFor a given class, with a default property of list, you can access an instance object in the list by doing myClass.defProperty("key"). You can also achieve the same results by typing myClass.defProperty!Key.
I have been told that using the parenthesis and quotes is faster for the way the runtime accesses the Property, but I'd like to understand what is the difference and how do each work...
I understand C# has a similar behavior by replacing the parenthesis with square brackets.
Is there anyway to have a class that can return a default type without specifying the property.
If I had a class that had a few properties and one property returned a string value and others returned additional types, could I do the following?
Dim StudentGrade as new StudentGradeClass
'call and get default property
Dim CurrentGrade as string=StudentGrade
'instead of this
Dim CurrentGrade as string=StudentGrade.Current
The reason I am asking this is when I have classes that have other classes as properties and would like to just get a default return value,.
I'm attempting the following:Default Public Property Data(Of dataType)(ByVal key As String) As dataType
Get
Return DirectCast(values.Item(key), dataType)
End Get
Set(ByVal value As dataType)
values.Item(key) = value
End Set
End Property
[Code]...
It made more sense to make it a property, and it would be the default property of the class. The data type can not be specified on instantiation of the class, because it can contain multiple objects of different data types.
I'm attempting the following:
Default Public Property Data(Of dataType)(ByVal key As String) As dataType
Get
Return DirectCast(values.Item(key), dataType)
[code].....
I have a FontFamily property, but I don't know how set the default value:
Public UnitsFontFamilyProperty As DependencyProperty = DependencyProperty.Register("UnitsFontFamily", GetType(FontFamily), GetType(ValueAndUnit), New FrameworkPropertyMetadata(New
[Code]....