Use The MyBase And MyClass Keywords?
May 17, 2010In what scenarios would one use the MyBase and MyClass keywords in VB.NET?
View 5 RepliesIn what scenarios would one use the MyBase and MyClass keywords in VB.NET?
View 5 RepliesI have a list of properties and values that i'd like to use to dynamically build an Expression(Of Func(Of MyClass,MyClass))
I can run through the list and create each Expression by itself, but the only way I know how to combine them would be to use Expression.And or Expression.AndAlso, but that returns a BinaryExpression rather than my original Expression(Of Func(Of MyClass,MyClass)).
In C# .NET 3.5, is there a way to instantiate an object given its string name? For example, suppose I have a DLL (e.g., MyClass.DLL) which contains type MyClass. Is possible to write something like... Object myClass = SomeMethodToInstantiate("MyClass"); // ? Is it possible to do this in VB .NET 3.5?
View 2 RepliesI created a module to add some Extension Methods to a Class. This Class inherits from another parent Class. In the code of my Extension Methods, I would like to refer to the base Class using MyBase. This doesn't seems to be allowed (Error message : "'MyBase' is not valid within a Module.")
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I have a class that inherits from a base class (this contains a lot of common db related stuff amongst other things and is marked as MustInherit). I want to write a shared method in which I call a base class method, however the compiler gives me the message 'MyBase is only valid within an instance method'. This shared method is a logging method and will be used a lot within the app, I'm trying to avoid having to instantiate an object each time I want to call it.
Is it possible to access the base class methods from a shared method?
It's a simple concept, but one I've never been taught
View 1 Replieshow do we access MyBase from an extension method?
i'm trying to extend a Sub called PassDown that would call the form's Base's OnPaint method
<Runtime.CompilerServices.Extension()> Public Sub PassDown(ByVal form_instance As Windows.Forms.Form, ByVal e As EventArgs)
MyBase.OnPaint(e)
but of course, mybase couldn't be accessed this way so is there an alternative?
It all works fine it looks like this:Now thats enough for me but as many other users we have a problem of lack of knowledge when it comes to this:Windows is shutting down, the confirmation box appears and stops the windows from shutting down...This is unnaceptable imho and im trying to find a easy way to detect if windows is shuting down, or in other words if its NOT.So i put a: if windows isnot Shutting down then'all the other code in mybase.closingEnd ifIs such thing doable? all ive found was pages and pages of codes (something to do with api) and some outdated vb6 code...
View 3 RepliesIs there any ways to hide/shadow MyBase's properties?
Such as MyBase.Location, MyBase.Font?
When I try to declare a local "Height" properly, VS prompts me warning to use "Overloads" instead. But when in form designer/control test run, I still see this property, or any other properties (BorderStyle) which I tried to hide.
The MyClass keyword behaves like an object variable referring to the current instance of a class as originally implemented. MyClass is similar to Me, but all method calls on it are treated as if the method were NotOverridable. I can see how that could kind of be useful, in some specific scenarios. What I can't think of is, how would you obtain the same behavior in C# - that is, to ensure that a call to a virtual method myMethod is actually invoked against myMethod in the current class, and not a derived myMethod (a.k.a in the IL, invoking call rather than callvirt)?
View 3 RepliesI am getting the following Exception when calling MyBase.Dispose ()ObjectDisposedException was unhandled.I tried adding a Try Catch around the call but it doesn't catch the exception.
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
[code]....
FYI: The value of disposing is False
I'm having a silly problem. Upon loading a form, I'm trying to change the value of a NumericUpDown. The form is being declared as following as a class-level private variable:
[Code]....
i have a code like this
'bug_message is a public shared property
Public Shared Sub bug(ByVal bug_message As String)
msgbox(XX_format(MyClass.bug_message, bug_message))
End Sub
however i get this error: MyClass is valid only within an instance method. I do not wish to use the actual name of my class, and if i could i would prefer to keep the name of the argument as bug_message as well.
I'm using VS 2010 so I have auto-implemented properties.I have a class and I want to access the properties by a string.[code]But, I also want to be able to access the variables something like this way.[code]How can I setup MyClass to work both ways?
View 7 RepliesIs there a simple way to remove Objects from a List by using a specified value?I add 2 persons to a List, how can now I remove a person by a name without using any Loops? (if possible)
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I have a picturebox set to move when the arrow keys are pressed. How do I prevent it from continously moving if the arrow key is HELD DOWN. I want to make it so the user has to press the key each time manually to move the picturebox.
View 14 RepliesI am trying to use myclass.cs from aspx.vb but receive error "myclass not declared" when I give command:
Imports myclass
I'm getting a: mypage.aspx.vb(390,0): error BC30002:Type 'MyNamespace.MyClass' is not defined when I try to compile, run, etc. my website. What's really odd is that I don't have anything in my Error List before or after I do this. I wouldn't have an idea of what was wrong, except I have my compile verbosity turned way up. The line it's failing on looks like:
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Traditionally, class/type name is literally spelled inside its definition.
Public Class MyCustomClass
Public child As MyCustomClass
Public Shared Function Clone(ByVal original As MyCustomClass) As MyCustomClass
End Class
This is not a problem most of the time; C-languages even use class name as constructor methods' name. But consider a generic declaration:
Public Class MyListOfIntegers
Inherits MyCustomList(Of Integer)
End Class
[code]....
This scenario has 2 issues. The first one is that constructors are not inherited, and you have to provide pass-through wrappers in every derived class, — this is quiet dumb, but tolerable. The second issue is more severe: derived class inherits CloneMe() method which returns MyCustomList(Of Integer) , not MyListOfIntegers ! Every returned value must be manually DirectCast 'ed for further use with methods that expect MyListOfIntegers . This issue, together with the first one, renders inheritance of generic class almost useless.
So I need a "MyClass" alternative for static type-binding inside type definition. In case of generic type that is referencing other compound types, task could be accomplished by adding second parameter to type section:
Public Class MyCustomList(Of T, TList)
...
Public Function CloneMe() As TList
[code]....
But since we must reference our own type, it would create an infinite recursive loop of additional typeparamlist arguments. How can this be resolved, aside of creating separate classes without generics?
I have a UserControl that has a ProgressBar on it. The purpose of the UserControl is to be able to show the progress % on the ProgressBar as text. To do this it uses the MyBase.Paint event. To make it work the ProgressBar is made invisible and the UserControl is 'painted' with an image of the ProgressBar and then the text is painted on top. The UserControl has a Value property that is passed through to the ProgressBar.Value property.
I use this UserControl in two places, on a Splash form (not a standard Splash Screen) and also on the main form of the application. It works on the Splash form but not on the main form - by work I mean that changes to the ProgressBar.Value property cause the ProgressBar to show its progress. The cause appears to be that in the Splash form case the MyBase.Paint event is called as a consequence of calling Me.Refresh in the Set procedure of the UserControl.Value property, in the main form case it isn't,
i.e. Me.Refresh isn't causing MyBase.Paint to run.
The main form has two BackgroundWorker components. The first gets called (RunWorkerAsync) from Form_Load after the Splash form has been shown. The BackgroundWorker.ProgressChanged event updates the Value property of the UserControl and it works exactly as intended. The second gets called as a result of a user starting an operation and again the BackgroundWorker.ProgressChanged event updates the Value property of the UserControl but MyBase.Paint doesn't run so the ProgressBar remains resolutely static.
Any ideas why it won't respond to Me.Refresh in one case but does in the other? Happy to make any of the code avaialble but didn't want to fllod the first post with reams of it. Here's what I think are the most relevant code sections. First the UserControl
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Private Sub LMouseDown(ByVal sender As Object, ByVal e As MouseEventArgs) Handles MyBase.MouseDown
If allowMouseCoordinate = False Then Exit Sub
Dim xPos As Integer
Dim yPos As Integer
If e.Button = MouseButtons.Left Then
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But this only works if I press on form. But I have a tile based map covering the entire screen.How can I make it so, that It would check if I clicked on a picture box (or simply anything)?
I can't seem to find the correct words to search for an answer. I'm using VS 2010 so I have auto-implemented properties.I have a class and I want to access the properties by a string.
Public Class MyClass
Property Prop1 As String
Property Prop2 As String[code].....
But, I also want to be able to access the variables something like this way....
Dim MyVar = New MyClass
MyVar.Items("Prop1") = "Prop1 Value"
MyVar.Items("Prop2") = "Prop2 Vaule"
How can I setup MyClass to work both ways?
dim oXT As New Generic.SortedDictionary(Of String, MyClass)
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In VB.NET, you can surround a variable name with brackets and use keywords as variable names, like this:
Dim [goto] As String = ""
Is there a C# equivlent to doing this?
Why does VB have more LINQ keywords than C#?
View 4 RepliesGet web sites keywords
View 6 RepliesI have a question here. I'd like to develop a vb.net program to run thru all source code in a folder to look for certain strings.my initial thought is to create an .ini file then program will read the strings then start searching in the source code for the strings entered.
the final output will be an excel sheet, stating the filename and the line number.
is this a good way to do it? if yes, can i ask for a skeleton program?if no, any other way?
What im trying to get is when a button is pressed, it looks through a textbox and highlights the keywords. I found this:
Dim srch As String = "1"
Dim a As Integer = TextBox1.Text.IndexOf(srch)
TextBox1.Select() 'set focus to control
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Im just wondering how i can achieve the following, this is for my own learning. Im going to be passing an XML file to VB.net and im hoping to pick out keywords from within the XML file is that possible?
So say the XML file had words such as "hello" "Today" "Next Week"
how can i possibly pick these out and store them in a varible?
I can do the first bit i.e passing the XML file in reading it etc, but im curious on the second part?
Can any one help me or if any one knows any good tutorials and locations please do let me know.
I wanted to make a that searches a web page(ex: wikipedia.com) for certain keywords from textbox?
View 2 Replies