I have created a custom Textbox using a new class of which inherits. To this custom Textbox I have added two buttons (embedded) inside the control which are both declared inside the class. One button is for Search and the other for Clear.
The purpose behind these buttons is to populate a Listview control when using Search and Clear the results when using clear...pretty straight forward.
However, my issue that I need help with is...
Because I have declared these buttons inside of my custom class, I cannot work out how to pass a 'Click' event outside of the class and back to the form. For example, if I type into the Textbox and hit the search button, I somehow need to execute code on the click event (and same for clear).
I have read a little about not being able to pass event handlers outside of the class it was created, but I'm not really familiar with this.
Is there/and if so what is the best way to achieve my results? Is it possible to handle a click event outside of the class to pass information to other controls?
Any help appreciated. Thanks
Thanks to the comments from Hans Passant for putting me on the right track, I was able to refer to this site Raising Events and solve my issue.
Related
I'm implementing an app w/ Excel-style functionality where I have a ListBox of baskets, each containing a ListBox of Items, each containing a StackPanel-nested Button inside it.
XAML, What the layout looks like
Goal: I want to click on the button, such that the item entry (StackPanel) is highlighted via SelectedIndex(). I try to accomplish this in the GotFocus="ItemGotFocus" event handler, by traversing the visual tree to find the parent ListBox, so I can call SelectedIndex() on it.
However, I am getting errors whenever I call VisualTreeHelper::GetParent() or other functions from the namespapce in general:
Do I need to define a template definition somewhere, so it can figure out the type I want it to return, or is there a better way to go about this?
Thank you, it worked!
Turns out I had included <winrt/Microsoft.UI.Xaml.Media.h> in "pch.h", when what I really needed was <winrt/Windows.UI.Xaml.Media.h>.
Probably simple question but couldn't find any working solution. I have User control on windows form. I would like on button click placed on user control to reload user control. By reload i mean to reset all its variables and show again. How to achieve that?
There is nothing that does that. You could dispose the existing control and create a new one but noone would do that. Basically, it's a manual process. If you want the control's fields reset to defaults then you need to write code to do that. You might declare a Reset method and put all the code in there if that's appropriate and then you can simply call that method from the form.
I have my form with a menu bar and space underneath to display my controls. One of the buttons in my menu bar is suppose to be a print button that prints a graph that's currently in a User Control I display in the form. If the graph was on the form in the print button's eventhandler I could just simply call
graph.printing.print(true)
which isn't going to work in my case since the graph is in the control and not the form.
How do I communicate with a User Control from the containing form and access or pass its variables when needed? I also have a status bar on the bottom of the form which would also need to get updated from the User Control, but I'll be able to deal with that if I got help with just this one part. Please bear in mind, I also have another User Control I'm going to add to the form which will also contain a graph which will need the same treatment as the other graph on the first control when the print button is pressed. I plan on swapping these two out so I have one form displaying one control at a time.
I got this idea from this answer: https://stackoverflow.com/a/18191630/2567273 but after further research I can't find anyone asking about the actual communication process between a form and the control it contains.
I think this answer is close to what I'm looking for, but I think it's leading me down the path to using panels instead of User Controls.
After typing this I noticed the closest answer to my question may be this, but that question has the child raising events and the parent responding while I have the parent raising the event and the parent has to get information from the child.
One way to think about this is Roles. Presumably you built this UserControl to handle the management of the data related to the graphs. As such you can think of them in the Role of a Graphs Specialist . Once you do that, printing them is actually just one more thing it should perhaps do.
The form on the other hand, is not special just because it happens to get receive the command from the user to print. Its role in this might simply to be to know which usercontrol to contact and which method to invoke:
Sub PrintGraphMenuClick....
Select Case something ' determinant as to which UC to contact
Case operation.Foo
ucFoo.PrintGraph
Case operation.Bar
ucBar.PrintGraph
Other menu options like Clear, NewGraph, Save and whatever else there is somewhat the same way. The Form's Role here may be to receive the command from the user and pass it along to the right control, invoking the correct right method and passing the correct parameters - that is not a trivial task.
Of course, rather than a MainMenu, the usercontols could alternatively implement a ContextMenu and even receive those commands directly.
Very often offloading an operation to something else results in so many properties, filenames, streams etc having to be moved from here to there that it becomes burdensome. In this case it is not like the MainForm has some special ability regarding printers that the UserControl cannot handle.
There is only one right solution:
1) Add an event to your user control.
2) Raise the event when the particular "thing" happens in the user control.
3) Attach a handler to the event in Form code.
4) Add code to update the bottom bar in the event handler.
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!
Is there a way to start a Windows Forms in (VB language) application with the main window not visible? Then later on when an external event occurs, I want to display the form.
How can I accomplish this?
Thanks.
Hint: See the 'Visible' property.
Initially you just put:
Load SuperAmazingForm
..then when you want to display the form, simply call its Show method as normal.
Doing it this way allows you to interact with the form's objects without the user being aware of it.
It depends on if you are doing this in Excel/Word or Access. If you are using Excel/Word then the Load MyForm syntax works. However, Access uses it's own variation of the standard UserForm. To load a form hidden you can do:DoCmd.OpenForm "MyAccessForm", WindowMode:=acHidden.