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.
Related
I have about 20 MS-Access databases with about 400 Forms and wish to perform an action whenever any form is loaded.
I would need, perhaps, an event at database or application level that would trigger at any form being opened/loaded. Then I might need only to add code once to each of the 20 databases, but not to each of the 400 forms.
And: it has to be in VBA (Access >= 2010)!
My Question: Is this even possible? And if so, does someone have a hint?
Thanks,
Pete
There are multiple ways to go about this, I think.
What I'd probably do is the following:
Create a hidden form that opens whenever your database opens (using an autoexec macro) with a timer.
When loading the hidden form, initialize a collection/multi-level array of all available forms in the database, and set their status to closed (somewhat difficult, probably would go with multilevel array or a collection inside a collection to be able to store form name + boolean open or closed).
Periodically iterate the collection, check for changes, so you can see whenever a form closes and trigger your event.
You could also use VBA to iterate through all the forms, add a module to them if there is none, and then add your desired Form_Load code to that module. (Would probably be wise to simultaneously create code to undo that action, so you can actually maintain the code). While refining that, you could check if the form already has a Form_Load action, and append code to that if it exists.
Alltogether, possible, but difficult. If you want pointers on some of the steps, I can give them, but for major issues on the implementation, I'd ask a separate question.
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.
I have a form that is re-used. That is, instead of creating a new instance of the form each time, the form is kept hidden, and is made visible when needed. (A design I inherited; I presume this was a performance optimization.)
The problem: The second time that the form is used, the focus is on the OK or Cancel button, from the first use of the form.
The user wants the focus to start the way it did the first time the form appears - on the control with lowest tab index.
If there were just one such form, I would hack it: add a line of code hardwired to the desired control.
But there are many such forms, and the visibility logic is in a common base class.
So it would make more sense to do this right, and tell the form to focus on its first (lowest tabindex) control.
Is there an easy way to do so?
(I could iterate through all the controls, but then I have to correctly handle nested controls. Since the GUI has to do this the first time it shows a form, I am hoping there is some method I can call that does it for me.)
(Coded in VB.net, but a C# answer would be fine.)
It is a one-liner, the logic to find the next control is exposed as a method, SelectNextControl(). You should start at the Form object, the one that can never get the focus, and ask it to find the next one in the tabbing order. Which is the child with the lowest TabIndex, whatever value it might have.
So something like this:
public void ShowAgain() {
this.Show();
this.SelectNextControl(this, true, true, true, true);
}
And do consider that a Form object that isn't visible is a rather major resource hog, using up lots of operating system resources for a small convenience. Surely you can also Close/Dispose it and recreate it when needed. YMMV.
You can try to set ActiveControl property before making form visible:
_frm.ActiveControl = null;
This should clear the active control for the form and remove focus from its controls.
I am writing a Windows Forms application in VB.NET. I have three forms: the main form, which shows a list of accounts, the account form which allows the user to view/edit the information for a specific account, and the policy form which allows the user to view/edit the information on a specific policy for that account. I want the forms to appear as if they are all the same window. Example: when the application starts, the user clicks an account name in the list box on the main form and clicks "edit". What I want to happen is that the window stays in the exact same place and stays the same exact size, only the content of the main form appears to be replaced with the content of the account form. Same thing if the user then chooses to edit a policy from the account form. When the user finishes and clicks "save", the main form comes back up. Through this entire use case, it would appear to the user as if they were viewing the same window the entire time, with the content of that window changing.
How can I do this? I have tried something like:
Dim newForm as New AcctForm
newForm.Location = Me.Location
newForm.Show()
Me.Close()
The problem is that if the user moves the original window, the new window appears where the parent form originally appeared, not where it ended up.
I see this is already in the comments, but what I have done in this case in the past is build each "form" in the application as a custom control. Then I have one actual form, and navigation works by changing which custom control is currently loaded on the parent form. To move from one screen/view to another, you remove the current custom control from the form's controls collection and add the new custom control.
I believe this is superior to manually setting the startup position and size, because you can use the form's .SuspendLayout()/.ResumeLayout() methods to hide the interim state, where there is no control loaded, from the user. This is harder to do when you want one form to be completely replaced by another.
This also makes it easy to set certain form properties in one place and have them be consistent for the application. You can even have an area on the form with controls that will now show in every view.
When using this pattern, I typically have each of my custom controls inherit from a common base. You may not have anything specific you will do with that base at the outset, but it almost always comes in handy later.
Finally, switching to use this scheme is easier than you think. Just go to the code for the each of your current forms, and you will find that each class currently inherits from System.Windows.Forms.Form. Most of the time, all you really need to do is change them to inherit from System.Windows.Forms.Panel and you're most of the way there.
As others have said, it may be better to redesign your application using custom controls or panels etc.
However, to answer your question regarding the seemingly random location of your forms, the first thing to check is that each form has it's StartPosition property set to Manual.
If your main form is resizable, then I would also add code to adjust newForm to the same size too.
I hope that helps with your immediate issues; so that you can move on to redesigning the application!
good morning there is another way . set property for second form to (top most) and use also
from2.show();
that make you switch between forms and keep form2 top other
Thanks
try using ShowDialog()
Dim newForm as New AcctForm
newForm.Location = Me.Location
newForm.ShowDialog()
Me.Close() <-- removed this
I am trying to hide specific columns in an Access 2007 split form through code. I need the form to check certain conditions to see whether it needs to display a column or not. I have code in the form's 'Activate' event to hide the column like this:
txtControl.ColumnHidden = True
This code works in the "Open" event, but if I hide the column on Activate, it won't display these changes until I close the form and open it again. I have tried calling the form's refresh, repaint, and requery methods, but this doesn't work. Please help!
Edit: Ideally, I need this event to occur whenever the focus switches to this form.That's why I'm using the Activate event rather than the Open event.
Try setting it in either the form's Current or Load events. You will also probably need to requery the control after setting that property: Me.TextControl.Requery Current is called every time a form's record is changed, the form is repainted or requeried. Load, as its name suggests, is called once, after the form has opened when the form loads its records. These have always been more reliable for me than using Activate, which really has to do with more the focus of the form, not really what you want.
I've had a problem like this before working in Access 2002. I was able to solve the problem with a subform by setting the subform source object equal to itself and then running the requery.
Me.SubForm.SourceObject = Me.SubForm.SourceObject
Me.SubForm.Requery
See if this technique works for your particular situation.