I am making an usercontrol with only one textbox so basically I expect that properties of textbox have to be applied to whole usercontrol.
That means (for example) that I would like from outside of usercontrol (in main program which contain those usercontrol) to get value of those (intern) textbox's selectionstart property.
But I can't find a way to do this except in creating a new public property of my UC.
I suppose that here should be some better way because textbox have many properties which may be needed to read (or maybe write) from main program and making another public property in UC for every internal property of textbox don't seems like "way to go" for me.
Any advice on how to get properties of internal control in UC from main program?
you may inherit your usercontrol from textbox control,liKe:
Class MyTextbox
inherits TextBox
End class
and then try to override, overload and access the events and properties you want.
you can check the following links,
1- For textbox inheritance example
2- Answered Question in Satckoverflow
Will not a regular FindControl check solve this?
Related
and thanks in advance.
I have created a class that is derived from TextBox and I want to add a DateTimePicker object to its right (ie outside of the dimensions of the control, on the owner control)
.
That means that I need to find the Controls collection that contains the derived Textbox class.
I don't want to use a UserControl because I have a chain of inherited/derived Textbox classes that have required validation etc.
At what point is Parent established in a control's creation?
I thought that I could access the Textbox's Parent in the New constructor, but it is Nothing. I thought I could use the OnPaint handler but that doesn't fire.
I have created a forms which are derived from another form thus:-
Public Class MyForm
' ...etc
End Class
Public Class MyDerivedForm
Inherits MyBaseForm
' ...etc
End Class
Public Class MyOtherDerivedForm
Inherits MyBaseForm
' ...etc
End Class
This works quite nicely and I can add controls to the derived form using the form designer. But I'd like to move some of the inherited controls around a bit on MyDerivedForm without disturbing MyBaseForm or MyOtherDerivedForm. I can't see any way of doing this on the forms designer.
Is it possible to do this (preferably with the designer but with code if necessary)?
This is not a typical VB.NET problem so not so sure what's going on here. You'll get the lock icon on the inherited controls and a grayed-out Properties window for an inherited control when the Modifiers property of the control in the base class is Private. The Winforms designer observes the accessibility of the base class member. Private members can't be messed with. The default value for Modifiers is Friend in VB.NET, Private in C#.
Make it Friend to allow the derived form class to modify the control properties. If the base form class lives in another assembly then Friend isn't good enough, you'll need Public.
The Anchor property can be an issue, but only if you anchor to the right or bottom. The control has a knack for ending up in the wrong spot when the derived form has a different size from the base form if the control is anchored that way. Simply avoided by not anchoring at the right/bottom in the base class and changing the anchor in the derived class.
In my VB.NET WinForms application I have inherited forms and I can just grab the inherited controls in the designer and move them about as I would with non-inherited controls on the form.
However I have noticed two things in the past that stop this. If you change the position of the controls on the base form, or change some of the positioning properties (such as anchor or docking), then this can (but not always) move your inherited controls. Also I couldn't move some of my inherited controls in an earlier version of .NET (2.0 I believe), but I never figured out the cause for that so I had to resort to changing the locations via the property grid.
I have two Forms, which have similar Functionality (i.e. an amount of similar Controls) but complete different Layout. So the normal inheritedForm (which VS2010 provides) wont work here.
I have tried following:
Public Class BaseForm
Inherits System.Windows.Forms.Form
Friend WithEvents Button1 As System.Windows.Forms.Button
End Class
And in Form1.Designer.vb:
Partial Class Form1
Inherits BaseForm
...
<all Designer generated Code>
...
' Friend WithEvents Button1 As System.Windows.Forms.Button <- remove this Line
End Class
If i compile/execute this, the test form works as expected; But now I am unable to design the form any longer.
If I switch to Design-Mode, it says:
The variable 'Button1' is either undeclared or was never assigned.
So it looks like, the Designer only tries to guess how the Form looks like by inspecting the top-most Class, without compiling the full inheritance-Tree...
Does anyone know a workaround for this?
Thx,
Daniel
I have a feeling you have some existing controls on the base form which you want to bring to the inherited form and then add more functionality of your own. Remember one thing, inheritance in VB.NET is by default set to shadowing, so you can redefine code in your inherited page for the same button to do a different function.
However, I think you forgot the Overridable keyword when declaring the form elements in the parent form. This will help the compiler know that the form can be overridden and allow you to define custom functionality.
Remember, all controls and pages in VB.NET are classes and whatever we learned during OOP classes in college apply here.
The idea is that I would have a set of forms, users would click through a "forward" and "back" button, and the current form would change to a different one. My issue is that I can write code that just pops up a new form, but im not sure how to do a "replacement" of my current form. How is this usually done?
What I did recently was to create a form with buttons already in place and a large panel to contain each step. The dialog would accept an initial step in the form of a IWizStep instance, and the things would roll from there.
Each step was a class exposing a UserControl responsible for the visual aspect of the step, while the logic itself was handled by the class (it was a little more complicated that that, but that was the general idea).
The IWizStep interface, implemented by the step and accepted by the dialog, was on the lines of:
Interface IWizStep
Event StateChanged As EventHandler
ReadOnly Property Control As Control
ReadOnly Property Title As String
ReadOnly Property CanMovePrevious As Boolean
ReadOnly Property CanMoveNext As Boolean
Function MovePrevious As IWizStep
Function MoveNext As IWizStep
End Interface
To put everything together, a controller class would know how to compose the steps necessary for each given action. Therefore I had a controller for, say, "Emit Order", which needed some 10 steps, and a controller for "Emit Orders in Batch", which needed only a couple of steps.
Create a set of UserControls, and add and remove them from a Panel in a single form. (and set Dock to Fill)
You could define a user control which acts as a "wizard". It just needs the buttons you have and an array of content panels, just have it switch through the panels when the buttons are pressed assuming a certain condition is met within the controls on the panel. There's no real definitive "wizard" maker, since it's pretty easy to roll your own wizard.
You don't need to do a "replacement" of your current form really, you could just add a new one to the project. If you do need to for whatever reason, just grab the control collection with Me.Controls, copy that somewhere, and put the new controls up. When you don't need the wizard, swap them out again. It's generally best practice to make a new form however!
I am looking for some information on how to properly implement data binding on a user created control.
My UserControl contains a Textbox, a Button, and a MonthCalendar. I am able to databind to the Textbox inside of my user control, however, I want to implement the databinding on the UserControl itself, and not reference to textbox inside the control.
I have attempted to set a Property as follows:
<System.ComponentModel.Bindable(True)> _
Public Property BoundDate() As DateTime
Get
Return _currentSelectedDate
End Get
Set(ByVal value As DateTime)
SetDateTime(value, True)
End Set
End Property
However, when I add a binding source to the control, the field does not populate with the data, it remains blank. Do I need to do something to make the data appear afterwards?
Can anyone direct me to a good tutorial, or if possible, explain it here.
The project is written in VB.NET.
EDIT: I am implementing the DefaultBindingPropertyAttribute
What is the textbox bound to at this point? I'd suggest the following:
In the user control load event, declaratively bind the text box to a private member variable, e.g. private _boundDate as DateTime
Have you setter in your boundDate property update _boundDate
This looks like a pretty good read, although I haven't looked at it myself