I have a MyButton class that inherits from Button. On this class I have placed several other controls (Labels, Progessbar). The problem with this is that the controls on the Button make it impossible to fire the Button.Click or Button.MouseHover event. How can I achieve it that the controls on the Button are only displayed but are "event transparent": A click/hover on the label and progessbar is the same as if I clicked/hover directly on the Button (including sender and everything). Something like "inheriting the events from the parent".
class MyButton : Button
{
Label foo = new Label();
ProgressBar bar = new ProgessBar();
}
You should derive from UserControl then have the button as a child control, and bubble up the button child's on click event.
This link is probably more than what you need, but it's a good starting point.
UPDATE
As pointed out, you may not be using ASP.NET. So here is another post that talks about different custom user controls, specifically what you're after is a Composite Control. This is for Windows Forms.
Write Click event handlers for the label and PB, have them call PerformClick().
Making controls transparent to the mouse is possible but is ugly to do. You'd have to override WndProc() to catch WM_NCHITTEST and return HTTRANSPARENT. The all-around better solution is to not use controls. A Label is just TextRenderer.DrawText() in the button's Paint event. ProgressBar isn't hard either, e.Graphics.FillRectangle().
Having the child controls be real controls in front of the button (either in a class inheriting from Button or from UserControl) may make it hard to get button-specific events working properly, as you have found. (Edit: Although it's hard, it's not impossible -- see Hans Passant's answer)
As a workaround, instead of using child controls, you could custom-paint them onto the button surface, since you don't need most of the functionality of the controls (events, focusing, etc.), just their display.
You can do the additional painting in the OnPaint method of your class. Something like:
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
e.Graphics.DrawString("My fake label", Font,
SystemBrushes.ControlText, new Point(10, 10))
// draw progressbar
}
To update the display, you would need to trigger a repaint of the Button using Invalidate().
Take a look at Custom Bitmap Button Using C# on CodeProject for a more complete example.
This answer was here a moment ago, but got deleted:
Can you inherit from UserControl instead? This will allow you to place other controls on the control surface, including your button and subscribe to their events.
If you're using WPF, I guess what you're looking for would be something called Bubbled Events. It's a feature in WPF by which events are bubbled from a control to its parent (in your case, it would be from your ProgressBar and Label to your button). I found this article on the matter which I think would be of help to you.
Hope this helps :)
Related
I have a little problem with winforms and mousewheel events.
I have a custom user control representing a slider. Now, I have a couple groups of sliders in which each group is wrapped inside a panel. All the groups are then wrapped in another panel (which has AutoScroll set to true) and this is wrapped in a form. The slider logic is implemented such that the mousewheel can be used to change its value. For this, the slider user control gets focus when the mouse is over the slider. However, when I scroll, also the AutoScroll parent panel scrolls with it.
I've already lost a lot of time on this issue. Anybody knows what is happening here and how I can solve it? I thought the event was bubbling to the parent panel but I don't find a Handled property on the event when handling it in the Slider control (as is possible with WPF).
many thanks
We implemented the Slider as a complete custom user control (inheriting the UserControl class) with own look-and-feel.
You might have noticed that a UserControl doesn't show the MouseWheel event in the Properties window. Hint of trouble there. The WM_MOUSEWHEEL message bubbles. If the control that has the focus doesn't handle it then Windows passes it on to its Parent. Repeatedly, until it finds a parent window that wants to handle it. The Panel in your case.
You'll need to invoke a bit of black magic in your slider control. The actual event args object that get passed to the MouseWheel event is not of the MouseEventArgs type as the event signature suggests, it is HandledMouseEventArgs. Which lets you stop the bubbling. Like this:
protected override void OnMouseWheel(MouseEventArgs e) {
base.OnMouseWheel(e);
// do the slider scrolling
//..
((HandledMouseEventArgs)e).Handled = true;
}
If you are creating event dynamically like
object.event += new EventHandler<EventArgs>(eventfunction);
try un-registering the event after the eventfunction is called like this
object.event -= new EventHandler<EventArgs>(eventfunction);
My app needs to be able to dynamically create new form elements and work with them. Right now I have a panel with buttons and labels in it. I need to be able to make a duplicate of this and show it in my app and then work with it.
For example, I have panel1. Inside are label1, button1, and button2.
Label 1 just counts up by seconds.
When you click button1, label1 starts counting up. When you click button2, the timer stops.
My problem is that I need to be able to duplicate panel1 many times and still have the new buttons correspond to the correct labels.
On button_click
private void button1_Click(object sender, EventArgs e)
{
Button theSender = (Button)sender;
Panel parentPanel = (Panel)theSender.Parent;
}
From here, I can't target any of the child control . I'm used to targeting and handles in jQuery, so I don't even know the correct C# terminology for how to explain myself.
If understand your problem correctly, I recommend you to make a Usercontrol with a Panel and fill it with your Label, Button and whatever. Write the events for your buttons in the usercontrol. Then introduce this usercontrol in your form and it should work. You can introduce any number of usercontrols in your form and each button will behave/work for the label in that usercontrol only.
As you mentioned you are new in winforms and you are not sure what I am saying, let me know and I will help if I get enough time.
Hope it helps.
Children of a control can be accessed using Control.Contrtols collection, e.g. to access button on a form:
Button btn = this.Controls["button1"];
But that is only true if button1 is placed directly on your form and button1.Name property is set to "button1" (designer does that automattically, if you are creating your controls dynamically, you have to take care of naming your controls yourself.)
You can also enumerate child controls of any control, e.g. child controls of panel1:
foreach(Control c in panel1.Controls)
{
// do something, e.g.
if(c is Label){//do sth...}
if(c.Name.Equals("label1") && c is Label)
{
Label l = c as Label;
}
}
and as #rapsalands said, UserControl may be an answer for you.
I would create a user control (UserControl) for this.
Check this article for more explanation about the difference between Control and UserControl.
Controls and UserControls are easy to duplicate and the full functionality is there.
You can create new UI Controls in code as you would any other object: Button b = new Button();
Then you can add them to the form using form.Controls.Add(b). You'll need to position and size the controls as well (there are properties available for doing this) and hook up your event handlers using b.Clicked += form.button_click;.
To see an example of this, you can try having a look at the designer.cs file that is generated in Visual Studio (don't make changes to it, just have a look). It will look quite complex at first but might go some way to helping demystify Windows Forms, and you will be able to find all of the properties you need to set in there.
Whenever you update something in the designer, Visual Studio generates new code and puts it in the designer.cs file. The entire form is set up in the InitializeComponent() method, which is called from the constructor of your form. You should be able to copy some of that code and with a couple of modifications use it for creating your own dynamic UI elements.
As rapsalands says, it sounds like a user control would be useful in this situation, as it will help encapsulate the functionality you're after. However that may take a bit of time to get your head round and you may find it simpler for now to do everything in your form without creating a new control.
So you are a beginner and need some time to understand Usercontrol as I mentioned in my previous answer. Use a for loop in the Constructor or Load event of your form to dynamically generate controls.
Panel panel;
Label label;
Button button1;
Button button2;
for(int i = 0; i > count; i++)
{
panel = new Panel();
button1 = new Button();
button2 = new Button();
label = new Label();
panel.Controls.Add(button1);
panel.Controls.Add(button2);
panel.Controls.Add(label);
Controls.Add(panel);
button1.Click += Event1;
button2.Click += Event2;
}
private void Event1()
{
label.Text = "Button 1 Clicked."
}
private void Event2()
{
label.Text = "Button 2 Clicked."
}
This way certainly you can create as many controls you want and will also serve your purpose. Use some variables to locate the panel controls appropriately. Set any properties you wish to add in the for loop for the controls.
This is just an alternative for my previous answer. I still recommend the previous answer given by me. This code is dummy and not tested.
Hope it helps.
I added a Panel inside a UserControl i design time.
Then, I added this control to a form.
I want to show a focus dashed border when the control has the focus.
Unfortunately, the Enter event from the panel never fires. I only get a fire when I click on the user control itself.
To extend this question. How can I forward events from controls inside a user control to the base user control? A comment from Hans Passant in this question says that by default events are forwarded to their direct parent. I didn't change any of the control's properties. What am I doing wrong? Is there an obvious property I need to change on each control i order to force it to forward unhandled events?
I am using DevExpress controls but this behavior is same in windows WinForms controls.
edit: I understand that panel might not be able to get focus. If this is true, how do I forward each mouse event to the parent control?
Based on your comment, from inside your UserControl, handle the panel's MouseDown event and set the focus to the parent control:
public UserControl1() {
InitializeComponent();
panel1.MouseDown += new MouseEventHandler(panel1_MouseDown);
}
void panel1_MouseDown(object sender, MouseEventArgs e) {
if (!this.Focused)
this.Focus();
}
Use panel1.Select() on MouseClick event of the panel and you will be able to trigger panel1.Enter and panel1.Leave
How do you get all clicks to go through the event? I noticed if you click too fast it thinks you are double clicking and doesn't send the clicks to the event handler. Is there a way to get all the clicks?
Not that sure why this question got a bounty, the accepted answer ought to be already pretty close to a solution. Except that you ought to use MouseUp instead of MouseDown, your user typically expects a click action to take effect when he releases the button. Which provides the back-out "oops, didn't mean to click it, move the mouse so it gets ignored" option.
Nevertheless, for the built-in Winforms controls, like PictureBox, this is configurable with the Control.SetStyle() method. Add a new class to your project and paste the code shown below. Compile. Drop the new control from the top of the toolbox:
using System;
using System.Windows.Forms;
class MyPictureBox : PictureBox {
public MyPictureBox() {
this.SetStyle(ControlStyles.StandardDoubleClick, false);
}
}
Do beware however that this won't work for the .NET classes that wrap an existing native Windows control. Like TextBox, ListBox, TreeView, etc. The underlying configuration for that is the WNDCLASSEX.style member, CS_DBLCLKS style flag. The code that sets that style flag is baked into Windows and cannot be changed. You'd need different kind of surgery to turn a double-click back into a single click. You can do so by overriding the WndProc() method, I'll give an example for TextBox:
using System;
using System.Windows.Forms;
class MyTextBox : TextBox {
protected override void WndProc(ref Message m) {
// Change WM_LBUTTONDBLCLK to WM_LBUTTONCLICK
if (m.Msg == 0x203) m.Msg = 0x201;
base.WndProc(ref m);
}
}
Just change the class name if you want to do it for other controls. Commandeering Winforms to make it work the way you want never takes much code, just Petzold :)
You want to use the controls MouseDown event instead of the Click event. MouseDown will be called every single time the mouse is "pressed" on that control. Click may not get called if the system thinks it was a double click. A DoubleClick event would be raised instead.
I think you want to count all click.
If you want to count click then set one counter variable and increase it in click event.
May be this help to you....
By Using reflector you can see that WPF UserControl is overriding AdjustBranchSource.
internal override void AdjustBranchSource(RoutedEventArgs e)
{
e.Source = this;
}
My very own problem regards inconsistency caused by that issue.
When an element is based inside a user control or outside. The Source parameter behaves differently. Which surprises me the source should always be the element in target by the RoutedEvent.
The question is why was it implemented like that?
This kinda makes sense. If you treat the UserControl as a black box then you shouldn't know what controls are on it, and thus the source of an event.
If you need to distinguish between different buttons on the UserControl then the UserControl should have it's own events which the buttons trigger. That way from the outside it looks like the right event and the user of the UserControl doesn't need to know which button did which event.
To give an example, on a listbox, do you need to know that the down-scroll button was the button that sent the original event? Or do you just need to know that a scroll-down event was triggered.
The source of a routed event can change throughout the routing of the event. I'm not entirely sure why UserControl changes it, but can you not just use the OriginalSource property on RoutedEventArgs instead?