Is this possible to do or are you only allowed to .focus one textbox on each form? I'm looking to highlight more than one textbox at one time if data is empty.
Only one control can have the focus every time (and thus what you request is not possible). In any case, note that the focus is meant for actions (not for visuals) and that only one control can perform actions every time in the GUI thread (e.g., text written in a TextBox or Button being clicked). On the other hand, you might provoke situations similar-enough to various controls getting the focus simultaneously (e.g., text written in various textboxes, coordinated via TextChanged Events: the actions are not performed simultaneously but the user will not realise about it).
If your intention is just highlighting the given control, you shouldn't rely on the focus. The focused control does get somehow highlighted, although this visual effect is not too relevant and, some times, not even perceptible. The best thing you can do is provoking the highlighting effect "manually". For example: Panel surrounding the TextBox, whose dimensions/visibility are affected; or just simply changing the BackColor property of the TextBox.
Related
I'm working on a fairly complex Access Database, trying to build forms with custom buttons for working with records. I'm using list boxes to display and navigate through records and all fields for existing records are disabled unless the user presses an edit button. The problem I'm having is that if I press the Edit or Add New button, enabling all of the fields, and then try to change the selection in a combo box, it does not update on the first try.
If I edit a text box first then the combo boxes work fine.
I've determined that the control's beforeUpdate and afterUpdate events are not firing on the first try but the action triggers the form_Dirty event and then it works as expected. I tried setting Me.Dirty = True with the Edit button and that solved the problem but it causes problems with some of my other code and it seems like an unnecessary workaround if only I understood the actual cause of the problem. It also works as expected if I leave the Combo Box unbound, but I am trying to build a template that doesn't require too much work to build new forms off of and I would rather not go that route.
It must have something to do with some bit of code I'm using because I can start a basic form and the combo boxes work fine.
I've started a basic test form and am adding code from my template form bit by bit until the problem arises, but it's a tedious process. Any help would be appreciated.
What am I missing? Is there some way of getting the Combo Box events to fire before the form is dirty?
UPDATE:
I have templates for a basic form, a form with a single subform, and a form with multiple subs in a tab control.
After some more testing I discovered that this problem does not apply to the basic form which has no subforms. This template uses similar code to the others for new, edit, cancel, save and delete buttons and for preventing accidental changes, preventing Form_unload during an edit and so on. The main difference I can think of off the top of my head is that the templates with subforms use class modules and collections to hold various data and pass it between the main form and subforms. Not sure if or how this might relate to combo box functionality.
I built most of this last winter then got too busy over the summer to work on it. Just now picking it up again and I'm having to re-learn a lot of the details of how my code works.
you can try to use Me.CboName.Requery in your After Update event.
I figured it out. I was calling a procedure with a form refresh in it from the Form_Dirty event and for whatever reason the refresh at exactly the wrong time was causing the combo box Before_Update and After_Update events to be skipped and the combo box value to not change. It was also causing text entered into a textbox to overwrite existing text on the first keystroke.
MSAccess VBA:
Assume, in an arbitrary form, the focus is set to MyControl on that form.
How to "unset" the focus without giving the focus to another control?
I'm lokking for a code like
MyControl.UnsetFocus
In your circumstance, you probably want to just set focus back to the parent form. This meets the conditions of unsetting focus without giving another control focus, and tabbing or clicking will activate the focus / tab-navigation again from that form.
Here's an example:
Forms![MyForm].SetFocus
Note that per the documentation for SetFocus, if you attempt to SetFocus to a Form with child controls that have Enabled set, this will cause focus to automatically bounce to the first eligible child control per the documentation.
Form.SetFocus method (Access) # Microsoft Docs
The option to give focus to the parent form does work as proposed by meklarian
Alternatively, I recently had to do something similar but I wanted to update a textbox value and simply go back to whatever had focus before. This is another case where something like an "unsetfocus" would be awesome, but unfortunately doesn't exist.
Should you need to do something like this, the following works well
Screen.PreviousControl.SetFocus
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.
All controls offer some kind of event to indicate that the value has been modified. For example, when you enter a textbox and begin typing with each keystroke there is a TextChanged event. When opening a combobox and selecting a new item in the dropdown, you get a SelectedIndexChanged event.
The trouble is that in many cases the change events signal a series of changes that represent some interim, unfinished state. e.g. When a user is typing his zipcode there's no reason to lookup the city and state or even attempt to validate it until the user finishes typing. When the user has focus on the shipping method combo and presses the up/down keys to navigate through the combo values as he attempts to find the one he wants there is no reason to assume the shipping method has been specified and thus apply it to the invoice. It may make sense to wait until he exits the combobox after paging through the values to signal that a shipping method has been selected. We don't want to be bothered by a series of interim states.
In our shop, we implemented a Finalized event that is only triggered when the user starts making some manual change (as opposed to programmatic changes like setting the zipcode from the DB) and then later finishes up. This Finalized event had to be handled differently for different controls; I'm not aware of any .NET features that would make providing this easier.
The only idea I now have is to try to use something like Rx (Functional Reactive Programming) to accommodate this. Any idea for a simple .NET approach that would facilitate this?
For the zip code textbox, you can use the leave event(occurs when the textbox loses focus), or in the textchanged event you can use an if statement:
if ziptextbox.text.length = 5 then
'Hooray! do stuff here
end if
And you can also just use the leave event for the combobox
The Validating and Validated events work just fine; however, the names were misleading and so it never occurred to me that these were appropriate.
All credit to Hans Passant for his comment that solved this for me. (Hans, will redirect credit to you if you answer.)
All,
I have a TabControl in an application that started behaving strangely. Some background...
This program was converted from VB6 to VB .NET 2008, and used to refer to forms using their class names. In other words, I might have a form class called frmFoo. In the code for the program you might see:
frmFoo.Show()
or
frmFoo.UserDefinedProperty = True
During some recent changes, I created variables to represent instances of my forms much like these:
Public MyForm as frmFoo
MyForm = New frmFoo
MyForm.Show()
In doing so, I also removed code from the form's Load event handler and put it in the form's constructor.
When the form loads, or when a document is loaded and should influence the TabControl's selected index, something like the following will not necessarily fire the SelectedIndexChanged event.
MyForm.tbsForm.SelectedIndex = ValueReadFromFile
...or...
MyForm.tbsForm.Tabs(ValueReadFromFile).Select
Sorry to be so wordy, but there's more. If I open the form and look at the TabControl to verify that it's been set properly, everything works like it's supposed to. The misbehaving TabControl is contained within another TabControl, so I have to click the parent TabControl to see it. If I can see it, and run a test, the test always works. If I can't see it, and run a test, the first test I run will not fire the event. ...paging Dr. Heisenberg...
It's almost as if the control has to be initialized first by changing the value or making it visible onscreen...I'm totally lost on this one. It's the most unusual behavior I've ever seen. And everything worked perfectly before I began using variables to represent forms and placed the Load event code into the form constructors.
Can anyone help, or at least put me out of my misery?
SH
-------------------------------------------------------------- Edit #2
I just performed a test after having attempted to eliminate some of the variability in the behavior. But I wanted to confirm the previously-stated behavior.
I opened the program and read a file. This file contained a value that should have triggered the event handler. Without making the control visible, I can change the SelectedIndex property of the tab control without the event firing.
I closed the program down again, and reopened it. This time, selected the parent tab that allowed the child tab (the one whose event I'm concerned with) to become visible. I then selected a different tab in the parent control, meaning that the child control was no longer visible. When I opened the same file as before, it fired the event.
I'm tempted to implement a flag that confirms that the control has been repainted or whether the parent tab has been displayed. I may have to fire the event in code if the flag isn't set.
I want to reiterate that everything worked when the program referred to the forms by their class names and much of the arrangement of controls on the forms was done in the load event. Now the program creates variables and the arrangement of the controls is done in the form's constructor. I'm sure this has something to do with the problem I'm having, but I can't understand how. Any wisdom to share?
MyForm.tbsForm.SelectedIndexChanged = ValueReadFromFile
doesn't make a lot of sense. Is tha trying to assign a handler to the SelectedIndexChanged event? or is ValueReadFromFile the name of the tab?
What you're saying is that you have two tab controls, say, A and B. Tab control B is contained within a tab of A, and unless A has the tab page selected that contains the tab control B, the SelectedIndexChanged event of B will not fire if you change its tab programatically?
In which different ways have you tried to select a tab within the child tab control, and when is this code being executed?