This may sound like a really silly question but I've noticed that the Click behaviour of my custom buttons differ when I inherit my class from a Button or UserControl.
I'm developing some controls with a customized look, among others, a button. The default user control class declaration is like this:
public partial class cButton : UserControl
After I added all of the GUI stuff, I added it to my form and tested the click-behaviour.
When I click the button in rapid succession, it only registers ever other click, not even every other click. I thought there is something wrong with the test code, but when I copied the exact code to a normal Winforms button, it registered every click no matter how fast.
Edit: the user control registers every click if I don't click to fast i.e. I wait a few seconds between every click.
I changed my custom control's decleration to inherit from the button class and made absolutely no other changes to any code:
public partial class cButton : Button
When I did my click-test the custom button behaved well, like a winforms button, not missing a click.
Just to test things, I added a list box to my form and added the same test code to its click event and it acted like a non-button, only registering a click every now and then.
I thought a click is supposed to be handled consistently, but apparently it's not that simple.
The question I have arising from this:
What does a button do differently and what could I do to ensure proper
click-behaviour when it is not possible to inherit from a Button?
Your custom UserControl is differentiating between single clicks and double clicks.
To make it operate like a button, you need to set the StandardDoubleClick control style so that when the user clicks twice in rapid succession, the control registers two single clicks and raises two click events, and not a double click event.
Within the constructor add the following statement:
this.SetStyle(ControlStyles.StandardDoubleClick, false);
I think the issue you're experiencing is that if you click the button too fast it registers as a double-click instead of a click. You can check this by writing to your output on double-click so that if your codes doesn't fire, check to see if double-click event did.
Related
I am new to Visual Studio and C#. I have created my first project -- an inventory application using MySql -- and everything works. But I needed to add a new button to the form for deleting records, so I dragged it in from the toolbox, changed the text ("Delete Product") and changed the design name ("DelBtn"). Adding the tool did not create the event handler, so I added the following with the MessageBox for testing:
private void DelBtn_Click(object sender, EventArgs e)
{
MessageBox.Show("Delete button clicked");
}
Clicking the button, however, has no effect, no MessageBox or anything else. Can someone help, please?
Go to your form designer, right-click your button, and select "Properties". In the properties window, there will be an "Events" button (it looks like a lightning bolt). Click that, and look for the Click event of your button. Make sure that DelBtn_Click is listed there. At that point, the button should respond with your code.
Hope this helps!
You need to make sure you've wired up the handler correctly. Look for the designer file that gets generated along with your form (I'm making the assumption that this is winforms).
Then you'll need a line like this in your InitializeComponent method:
this.button1.Click += new System.EventHandler(this.DelBtn_Click);
You don't have to do this in your designer file, you can do it anywhere you want that runs before your form is shown, e.g. the constructor. But it seems to me like something you did -- maybe by manually-renaming your event handler method -- has mangled the automatically-generated designer code that I mentioned above, and you probably just need to fix what's there already.
You need to delegate the event in your designer.cs if you wish:
DelBtn.Click += new System.EventHandler(this.DelBtn_Click);
Just adding a method with the same name as VS would have made for you won't bind the event to that method. Open the properties for the button and at the top of the resulting panel you'll see a lightning bolt. Click that and find the event you want and type in your method name there.
You need to go on the form, click on the button, on the properties menu you need to click on event,find onclick and double click the blank space.
It will automatically create the onclick method for you.
I have a button, contained in a panel, with a click event, that works fine. However when a users presses another button, I need to move this button into another panel (this is actually a panel with a modalpopupextender), so I this code to do so:
newPanel.Controls.Add(buttonPanel)
It all get's moved and looks fine. However now when the button is clicked it doesn't fire the associated event. I have tried re-adding the event in the page_init, with this code
((Button)this.FindControl("serverModalSave")).Command += new CommandEventHandler(modalSave_Click);
But with no luck. How can I get this button to fire it's click event when moved, and why does it stop working when it's moved?
EDIT:
This Button needs to be added to a panel specified by the user at run time, so there is not a way to determine where the button will go in advance.
I could instead of moving this button, create a new one, but because this button is not created in the page_init I am having issues getting that to fire an event either.
Instead of moving the button, have another button on the other panel set to hidden.
Hide the button you wanted to move and show the hidden one when needed.
Moving the control changes the naming hierarchy and now the button can't be found and the click event can't fire.
This is due to how the page life cycle works. Here is a good (if somewhat dated) article about how view state works - if you understand this, you will understand what went wrong.
If you are creating the button in the new panel, when this button is then clicked do you re-create it in the postback ?
You must re-create all controls on each postback see here
.NET newbie alert
Using Visual C# 2008 Express Edition I have accidentally created a click event for a button. I then deleted the automatically-created method code, which resulted in an error saying that the function, which had now been referenced in the form loading code, could no longer be found.
Deleting the following line from the Form1.Designer.cs file's InitializeComponent() function...
this.btnCopy.Click += new System.EventHandler(this.btnCopy_Click);
... seems to do the trick, however, it makes me feel very dirty because of the following warning at the beginning of the #region:
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
I haven't been able to find a way to do this using the form designer, which I assume is the means implied by this warning. What is the correct way to do this?
You do have to be careful when working in the designer.cs files but you don't have to feel dirty about it (when I make the same mistake it is just easier to fix it the designer.cs file). You can do it visually like this:
Open the form in the form designer.
In the form designer, click the button of interest.
Press F4 (or right click the button and then click properties). The properties pane should show up.
At the top of the properties pane, click the lightning bolt. This shows the events for the button.
Find the click event and clear its handler.
Okay, I am usually the one advocating the use of notepad2 or some other text editor to perform coding tasks.
But, since you ask how to do so in the Designer...
Open the form where the erroneous event was added to a control.
Select the control.
Right-click, select "Properties".
Change to "Events" by selecting the button with the lighting-bolt icon.
Select the event you need to remove.
After placing the mouse in the box which is showing the event handler method name, delete all of the text in that box and press enter. This will remove the event handler and the delegate assignment for this event on your control.
The only caveat being: if you wish to preserve your event handler method (i.e. it is not auto-generated by Visual Studio) - you probably want to avoid deleting the assignment in this manner. Because when I say that it removes the event handler - I should say that the declaration of the event handler method in "Form1.cs" (for example) will be deleted as well.
On my main form, there is another (floatable) window. This floatable window works sort of like a popupwindow in that it will close when the user clicks somewhere else outside of this window. This is handled by the Deactivate event. But what I want to do is, if the user clicks on a different control (say a button), I want to both close this float window and then activate that button with just one click. Currently, the user has to click twice (one to deactivate the window and once more to activate the desired button). Is there a way to do this with just one click?
foreach(Control c in parentForm.Controls)
{
c.Click += delegate(object sender, EventArgs e)
{
if(floatyWindow != null && floatyWindow.IsFloating)
{
floatyWindow.Close();
}
};
}
And then add your handlers as normal. This additional handler can close the floaty window.
Make sure you floaty window isn't a dialog too as this will not allow your parent form's controls to be clicked.
I had a slightly hacky solution. In your Deactivate event, fire another custom event to your main form. Then when you main form is handling the custom event, enumerate through your control(this.Controls) and locate the control under the mouse by checking all their bound then call Focus(). You might need to sort by the one with the smallest surface area, or you can have a separate list of "focus-able" control like button just for this purpose.
Another way might be to switch focus to your main form immediately after OnMouseLeave of the floatable window, or OnMouseHover of your main window, but keep the floatable windows on top, just no focus. Handle the global mouse down of your main form, and close the floatable window by then.
These are just theories, not tested.
I had an issue like this once too, when a customer wanted "floaty" windows all over there application. I used used an approach similar to the one described in this article:
http://www.vbaccelerator.com/home/NET/Code/Controls/Popup_Windows/Popup_Windows/article.asp
Code sample available here:
http://www.vbaccelerator.com/home/NET/Code/Controls/Popup_Windows/Popup_Windows/Popup_Form_Demonstration.asp
By extending this a bit we created "floaty" windows similar to the ones VS uses when you get a runtime error while debugging code.
At the very least reading the code may give you some insight, however, quarrelsome's response may be the more simple solution.
Rep steps:
create example .NET form application
put a TextBox on the form
wire a function up to the TextBox's Enter event
When you run this application, the Control.Enter event fires when focus first goes to the TextBox. However, if you click away into another application and then click back into the test application, the event will not fire again.
So moving between applications does not trigger Enter/Leave.
Is there another alternative Control-level event that I can use, which will fire in this scenario?
Ordinarily, I would use Form.Activated. Unfortunately, that is troublesome here because my component is hosted by a docking system that can undock my component into a new Form without notifying me.
What are you trying to do in the Enter event?
I can't find another control-level event that fires in your example program but when my test app does regain focus, the control that last had focus still has it.
Interesting question but it needs a little more context.
If I try your example and click outside the control on another window, desktop, etc, I can get the Got and Lost Focus events to fire, but if you're only trying to click within a form or a control with only 1 control, these event will never be fired because it is the only thing to focus on. Neither will Entered or left, unless you change the dynamics or overload the controls, you cannot get this to happen
In your example, I think you need another control. The reason being is that the first control (tabIndex 0) is the one with focus. With no other control to switch focus to, this control will always be focused, and therefore can never be entered. Switching to another application or form will not change the focus or active control in this form so when you return you will still not get the event fired.
With added controls control.entered should work fine. If this is your only control, why not call the event on formLoad, or TextChanged, when the form gets focus?
Thanks, I'll give some background.
My control is a UserControl that contains a grid and a toolbar. A user will typically launch several of these controls to view different slices of the system's data.
There are several keyboards shortcuts that can launch actions from the selected row in the current grid. However, it is a requirement that these keyboard shortcuts should apply not only to the currently focused grid. If the user is currently focused on one of the many other areas of the application, then this keyboard shortcut should still work, and it should be routed to the last focused grid.
So I wired a function to the Control.Enter event of my UserControl to basically say LastFocusedGrid = this.
And it would work, except for the docking and undocking...
See, these controls are hosted inside an application with docking features, somewhat similar to visual studio.
By default, the control launches as a tab within the main working area of the application, similar to the way a source file opens in visual studio.
However, the user can "rip out" a tab by grabbing the tab header and dragging it out of the main application. At this point, the application creates a new "float form" to host the control. Switching between the main application and this float form is the same as switching between apps, for the purposes of the Control.Enter and Form.Activated events.
At that point we have the "one control within a form" scenario simulated with the example application described in the original post.
Now, there are some ways around this. I could leverage the Form.Activated event, which DOES fire when switching between forms. If you add an event in the test application to the Form's Activated event, you will see that it works great.
The problem is that my UserControl's relationship with its parent Form is fluid, making the solution somewhat complicated. I tried wiring up to "this.ParentForm.Activated" which worked okay. The problem is when do you call this? What happens when you are undocked/redocked? I ended up with a nasty bunch of code with things like "previousParentForm" so that I could unhook from the old form, and then I was still facing the problem that the docking system doesn't notify me when my parent Form is being changed, so I was going to have to make a bunch of changes there, too.
These problems are not unsolvable, but if there is a simpler control-level "parent form was activated" event, then that would be a lot more elegant.
That's rather long, but I hope it clarifies the situation.
So when creating your grid, can you not set the KeyPressed, or KeyUp, etc. event? If so, all the grids can make use of the same event handler. Just make sure that when you get into the event handler to do something like:
Grid currentGrid = (Grid)sender;
Then you should be able to apply that block of code to any grid that gets sent in without having to worry about keeping track.
Since all the event handler really is, it's location is a mute point really as long as everything you need to execute it is accessible.
Frye, the problem is that the keyboard shortcuts should work no matter where the user is in the application. They are gloabl commands, handled at the top level, and then routed to the "last focused grid."
So handling the keystrokes at the grid level will not help.
To be more specific, assume user launches grids A, B, and C. But he also launches other controls X, Y, and Z that have nothing to do with my code.
User clicks on A, then on C. Then he clicks on Y, then on Z. With focus on Z, he hits my keyboard shortcut. In this case, grid C should respond since it was the last grid the user was focused in.
It sounds like the issue that you're having is not directly related to the Enter event and more to the point, if you have controls "that have nothing to do with your code" then you really aren't looking at a control level event.
Guess I wasn't clear.
My control lives in a container application. So do other unrelated controls by other teams. Think of it like visual studio -- my control is the code editing tab, but there is also the pending changes list and the properties window, which cohabitate with the source files but aren't directly related.
The keyboard shortcut is handled by the container application. Then it should be routed to the last one of my controls that the user was focused on.
Maintaing this "LastFocusedGrid" reference is what I do in the Enter event.
If you want to see similar functionality at work in visual studio, try this:
open a few source files
navigate to the "Start Page" tab.
Hit Ctrl-F and search "current document" for some string
Notice that the serach feature auto-navigates to the LAST FOCUSED source file to perform the search.
So even though you weren't focused in the source file, the ctrl-F command was processed by visual studio and routed to the last focused source file tab.
Now try the same thing with Ctrl-G. It doesn't work unless you are focused directly in the source file.
My keyboard commands need to work like Ctrl-F here, not like Ctrl-G. That is why I don't just capture the keyboard events directly in my control.
Does that clarify or make things worse?
Have you tried just a simple Control.GotFocus?
in this example if you toggle between clicking the textboxes neither the enter or got focus will do as expected, however if you click the child forms instead both will behave as expected.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
namespace EnterBrokenExample
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Form Form1 = new Form();
Form c1 = new Form();
Form c2 = new Form();
Form1.IsMdiContainer = true;
c1.MdiParent = Form1;
c2.MdiParent = Form1;
c1.Show();
c2.Show();
TextBox tb1 = new TextBox();
c1.Controls.Add(tb1);
tb1.Enter += ontbenter;
tb1.Text = "Some Text";
tb1.GotFocus += ongotfocus;
TextBox tb2 = new TextBox();
c2.Controls.Add(tb2);
tb2.Enter += ontbenter;
tb2.Text = "some other text";
tb2.GotFocus += ongotfocus;
Application.Run(Form1);
}
static void ontbenter(object sender, EventArgs args)
{
if (!(sender is TextBox))
return;
TextBox s = (TextBox)sender;
s.SelectAll();
}
static void ongotfocus(object sender, EventArgs args)
{
if (!(sender is TextBox))
return;
TextBox s = (TextBox)sender;
s.SelectAll();
}
}
}