Never Once Ever Come Across A Time To Use A Write Only Property
Jan 7, 2010
I am just curious about this, but in all my years writing code, I have never once ever come across a time to use a write only property. Of course readonly is pretty common in class development, and while I may have had classes where I don't specifically need to expose a property for reading, generally you end up with a method like SetValue or something like that, which is more or less the same idea as a writeonly property.
I don't recall ever seeing a writeonly property in a .NET framework class. So can anyone provide an example where it actually made good sense to use a writeonly property over either a read/write property, or a method?
I have a listbox binded to a list of objects. For each list item I wanted to have a rectangle whose fill color is determined by a few properties of the binded object. So I did the following:
Made sure INotifyPropertyChanged was implemented on my object.Created a class to expose the properties I am interested in as attached properties.Binded the properties of the object to the attached properties of the rectangle Created a style that uses triggers to set the rectangle fill based on attached properties.
This works, but only the first time the property of the object changes. After that, the attached properties do not seem to be receiving notification when the data object's property changes. I have double checked and my data object is raising the INotifyPropertyChanged event.
I inherits textbox Control and I added some new properties to it .one of these properties value i want it to change it's value in desgin time when i change Name property of the new textbox
Public Class NewTextBox Inherits TextBox Private _txtSubName As String = String.Empty
That is the property for set or get SubstringName of Textbox
Public Property SubName() As String Get Return _txtSubName[code].....
that's the property i want to change it's value when i change Name property of the control.i tried to overrides Name property but it's not overridable also i trieds to overloads it but it doesn't work in desgin time.Here is something i tried but it's wronge.
Private _txtName As String = "" Public Overloads Property Name() As String Get[code]......
i would like to be able to double click on a label for a text box and write a value into the .tag property and then change the color surrounding the label.for example.. if the user double click the default label..(which looks like the stardard label) then I would write a "1" to the tag property for that label, and at the same time, change the line color surrounding the label to red(maybe even changing the thinkness of the line).
when the user would double click the label again.. I was see that it was already selected and change the setting back to the default.
Can any one tell me how to read or write the control property values that has been saved as ocx state value in the XML? I have some controls. I am assigning a property values for that controls and it is saving as binary64 format. I need to automatically assign property values in the binary64 format in xml.
I want to give the user the ability to modify the font characteristics of a textbox on a form, using buttons. In the button click_event, I can successfully have the user change the font color to red directly:
Here's a problem: I've made an ActiveX control with VB.net (VS 2005) to use in a web application. The control has some properties and methods. The control loads fine in IE, calling methods works, but asking for a property with javascript is a problem.
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The first time objTest.SomeProp returns 'Test' as it should. The second time is gives an error: 'Object doesn't support this property or method. After that, all methods and properties are 'unsupported'. Somehow this problem started after I implemented IObjectSafety interface in the control, but I have no idea how it affects the property and how to solve this problem.
I'm trying to write a file in chunks in a loop but the filestream.write just causes the sub to end the second time round but the first chunk it written and the savefiledialog remains?
edit: I was using an offset which I shouldn't have so now it writes the file just fine but the savefiledialog doesn't close itself?
I have a form where I have created a custom property, DataEntryRole, and set its Browsable attribute to True, as shown:
<Browsable(True)> _ Public Property DataEntryRole() As UserRole.PossibleRoles Get Return mDataEntryRole End Get
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When I view the designer for my form, DataEntryRole doesn't appear in the property box. I assume that it should appear if I were to create another form that inherited from this base form, but that's not what I want. I want this property to show up in my current form.
I have a class where it's problematic to relay on the properties being serialized in alphabetical order at design time.In other words, property Z must be serialized before property A.The problem arises because property property Z clears property A whenever it changes - which happens in InitializeComponent.I work around this problem by setting a FirstTime flag, but that seems messy.
[code] i get an app error when running the app, because i didn't set the ID.I was wondering if there's a way to make sure the programmer assigns all properties in the class,and fail at COMPILE TIME rather than have to catch the error at runtime...
A component I'm making has a public property that represents a percentage. How I can give it a % symbol in the Properties Window at design time in Visual Studio? I mean, like the Opacity property of a Windows Form.
I have been making a control and have added a property for a list(of CustomClass). The custom class contains a string, an image and a list of another custom class which contains a string and an image. I have added this property to the designer by adding the browsable attributes and all appears to work correctly with this.
My problem comes when running the program. I can set all of the values within the property and I can go back to them and they are saved, however, as soon as I run the program, the values are wiped out as the property is set to Nothing.In order to allow my property to be edited and saved, I realize that I must initialize the list and have done so in the accessor method of the property (if the property's value is nothing).
I have modified the values in the designer and placed a breakpoint on all of the items which use the property and it's underlying field, as well as on the property's methods itself. The first breakpoint hit is of it being accessed and the value is always nothing.
I'm not sure where the values are supposed to be stored as I have checked the designer code where it would normally store types such as strings and I have checked the resources to see if they have been saved there (like an image would be). After running the code, the values in the designer are wiped out also.
I have a Picturebox, where the .Tag property is holding a path to a file. But I would also like to have something like a .Tag2 property that could hold another file... I'm guessing this is possible to achive, but I have been struggling with this for quite some time now, and I really don't how I to do this... I can't seem to any useful information on the net either...
In my never ending search for more knowledge, I have come across Partial Classes. I was wondering if some of the kind people who actually understand the uses could explain some of them to me. Now I know that when we create a form that we actually create a partial class which the generator rewrites when we add a control or change a property at design-time, and this allows us not to have to worry about setting up the controls ourselves.
I have included a Date and Time Picker Control in oen of my MS Access Forms and want to set its value on the form open event. However, when I try to set the Value property I get the following error message :
I have a class that has a readonly collection property - Its a list of extender providers that have been applied to the control.I've implemented a simple property descriptor for the collection so that the property can be expanded in the property grid to examine each entry.
When I select an extender provider and set it to false, I remove it from the collection. The GetProperties method of the type converter is requeried and the property grid refreshes.However, when I set an extender provider to true, and thus add it to the collection, GetProperties is not requeried.
Somehow, the property grid is making a distinction between adding to and removing from the collection. Or alternativly, its refreshing when an extender provider is added, but not when one is removed.
I am creating a User Control where I have a property called Items. Items is of type LibraryPanelBarItem Collection (custom class) which contains a collection of LibraryPanelBarItem objects. I would like to be able to add these at design time by using the Collection editor that VS uses for adding things such as treenodes/listviewitems. Ideally I would also be able to declaratively add them to the html syntax. I can get the Items property to show up but I get no intellisense to add the items between the opening and closing tags. [Code]
(I've answered the question below with a hack. I'm fairly confident in it unless MS change the way that codedom serializers the designer code.)ETA2:I've worked out what is going on. I wondered why sometimes it would work and not others. It boils down to the name that I give to the internal property and the collection.If I rename the property 'Annoyance' to 'WTF', it will serialize correctly because 'WTF' is, alphabetically, after the name of the collection - 'InternalAnger'.It looks like the serializer is creating instances of objects alphabetically and needs my internal property to be created by the time it comes to create the collection.I can fix this with a rename, but that's a hack and I fear that writing a custom serializer is a big job - which I've never done before.ETA: Jesus, I'm sick of this. This problem was specifically about persisting an interface collection but now on further testing it doesn't work for a normal collection. Here's some even simpler code:
Public Class Anger End Class Public Class MyButton
This is my first post on this forum, so please excuse me if I'm posting wrong. Anyway, I've been having an issue that I've never seen before and is driving me nut, I have a windows form on which I have placed many textboxes that display information from a MS SQL database. The user can then change these values and hit a "save" button which writes the changes to the database. I also have certain textboxes that with the "on leave" event (after a user enters a possible new value) trigger a method that recalculates some of the other fields based on the new information. Hopefully that all makes sense.
So the problem is, when I run through this "recalc" method the first time around, it doesn't update those textboxes that it's supposed to. However, when I put a breakpoint in and debug through it, the debugger shows it putting in the correct values into the textboxes. It's just as soon as the method is done, it puts them back to blank, or whatever they were before
'Rebind stuff here lblCabinets.Text = curMfg.ToString("c") txtCabinets.Text = curMfg.ToString("c")
I have a usercontrol which overrides the property Text. But this property is not shown at design time.If I rename it to caption or value it is shown in properties at design time but Text is not shown.
public Class SomeControl Inherits System.Windows.Forms.UserControl Public Overrides Property Text() As String
I'm currently in VB class at my highschool and we just got chapter 6.1 to read on this online textbook that we follow. Anyway, we are doing loops now and the problem reads "Write a program to request positive numbers one at a time from the user in an input dialog box. The user should be instructed to enter -1 after all the positive numbers have been supplied. At that time, the program should display the sum of the numbers." So far I know this much
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Now I know this isn't right But I can't find out how I'd pull out the numbers the user entered to get the sum of them and not include -1 because as it stands, when I hit ENTER with -1 the label just shows -1.
What is the best way to make a class property "Write Once, Read Many" such that you can only set the property once?
I know that I could pass all the properties in the constructor and make them ReadOnly, but in cases with a lot of properties I don't want a constructor that has 20+ arguments.
Also, I realize I can "roll my own" setters, but having to do that for every property seems like a bunch of redundant coding.
Is there a clean way to do this in VB 2008 .NET 3.5?
