The child controls of my custom control are obstruction the mouse events in my custom control. I have worked through the accepted answer and the answer at the bottom of this thread...
exposing-events-of-underlying-control
I haven't gotten them to work (the answer at the bottom seemed most straight forward to me). But really I would like to disable the events of them altogether. I have a pictureBox and a label, I don't need to interact with either of the child controls. Is there a way to disable them so they wont interfere with the events of my custom control?
Edit:
I'm using the custom control to gather and process a number of things and make them available as properties. When I click on it, I need to access to the properties. When the event happens at the child control, I don't have access to the propertied of my custom control. The following code is in my form...
public void Form1_MouseDown(object sender, MouseEventArgs e)
{
var myControl = sender as SubstanceViewer;
richTextBox1.Text = myControl.substanceInfo;
}
so I will need to access the properties of the parent control.
If you need the the events that are normally trapped by the child controls to be handled by the custom control itself, then simply wire up those events at run-time in the constructor of the custom control.
For example if you needed the MouseMove() event of the PictureBox and Label to fire the already wired up event of the UserControl:
public partial class SomeUserControl : UserControl
{
public SomeUserControl()
{
InitializeComponent();
this.pictureBox1.MouseMove += SomeUserControl_MouseMove;
this.label1.MouseMove += SomeUserControl_MouseMove;
}
private void SomeUserControl_MouseMove(object sender, MouseEventArgs e)
{
}
}
Be aware, though, that since different controls are firing the same handler you'll need to take that into account. For example, the e.X and e.Y values in the handler above would be relative to the source control.
*You can also wire these events up at design-time using the IDE itself, but I thought code better illustrated the solution.
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);
I'm trying to create a custom control which fires an even on click.
My control is just a panel with a couple of labels and a picturebox inside.
The click works perfectly, the only issue is that I have to click the background of the control and if I press on the picturebox, is not working.
I've added the on click event to the control, but I would like to press in every place of it to trigger the event, not just the background of the panel.
I thought about adding a transparent object that covers entirely the control. I actually don't like this idea, however, I've tried with a picturebox, but i cannot see through it. It's not transparent. I can just see the panel background but It covers the labels and the image.
Thanks for the support.
If you just have a couple of objects in your panel, you can hook the Click event of all objects it contains to the same event handler, there is nothing wrong doing this.
public class MyUserControl : UserControl
{
public event Action<MyUserControl> MyControlClick
public string ID {get; set;}
public MyUserControl()
{
InitializeComponents();
// The same event handler code will be used for the three controls
myPictureBox.Click += global_Click;
myLabel1.Click += global_Click;
myLabel2.Click += global_Click;
this.Click += global_Click;
}
void global_Click(object sender, EventArgs e)
{
if (MyControlClick != null)
MyControlClick(this);
}
}
If you have a more important amount of objects, you can rely on this answer to create a truly transparent panel that handles clicks. The drawback is that you will have to detect which object has been clicked by using HitTest based on the mouse location.
On the form side :
aControl.MyControlClick += aControl_MyControlClick;
// ...
// This code is triggered when a MyUserControl is clicked
void aControl_MyControlClick(MyUserControl ctl)
{
MessageBox.Show(ctl.ID);
}
Actually! You cannot raise any event to the element in the Usercontrol unless you have to apply own method to your usercontrol or you can disable the element in the usercontrol but it will change the color of that element but It will raise the click event when you click your control.
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
I'm creating a custom dropdown box, and I want to register when the mouse is clicked outside the dropdown box, in order to hide it. Is it possible to detect a click outside a control? or should I make some mechanism on the containing form and check for mouseclick when any dropdownbox is open?
So I finally understand that you only want it to close when the user clicks outside of it. In that case, the Leave event should work just fine... For some reason, I got the impression you wanted it to close whenever they moved the mouse outside of your custom dropdown. The Leave event is raised whenever your control loses the focus, and if the user clicks on something else, it will certainly lose focus as the thing they clicked on gains the focus.
The documentation also says that this event cascades up and down the control chain as necessary:
The Enter and Leave events are hierarchical and will cascade up and down the parent chain until the appropriate control is reached. For example, assume you have a Form with two GroupBox controls, and each GroupBox control has one TextBox control. When the caret is moved from one TextBox to the other, the Leave event is raised for the TextBox and GroupBox, and the Enter event is raised for the other GroupBox and TextBox.
Overriding your UserControl's OnLeave method is the best way to handle this:
protected override void OnLeave(EventArgs e)
{
// Call the base class
base.OnLeave(e);
// When this control loses the focus, close it
this.Hide();
}
And then for testing purposes, I created a form that shows the drop-down UserControl on command:
public partial class Form1 : Form
{
private UserControl1 customDropDown;
public Form1()
{
InitializeComponent();
// Create the user control
customDropDown = new UserControl1();
// Add it to the form's Controls collection
Controls.Add(customDropDown);
customDropDown.Hide();
}
private void button1_Click(object sender, EventArgs e)
{
// Display the user control
customDropDown.Show();
customDropDown.BringToFront(); // display in front of other controls
customDropDown.Select(); // make sure it gets the focus
}
}
Everything works perfectly with the above code, except for one thing: if the user clicks on a blank area of the form, the UserControl doesn't close. Hmm, why not? Well, because the form itself doesn't want the focus. Only controls can get the focus, and we didn't click on a control. And because nothing else stole the focus, the Leave event never got raised, meaning that the UserControl didn't know it was supposed to close itself.
If you need the UserControl to close itself when the user clicks on a blank area in the form, you need some special case handling for that. Since you say that you're only concerned about clicks, you can just handle the Click event for the form, and set the focus to a different control:
protected override void OnClick(EventArgs e)
{
// Call the base class
base.OnClick(e);
// See if our custom drop-down is visible
if (customDropDown.Visible)
{
// Set the focus to a different control on the form,
// which will force the drop-down to close
this.SelectNextControl(customDropDown, true, true, true, true);
}
}
Yes, this last part feels like a hack. The better solution, as others have mentioned, is to use the SetCapture function to instruct Windows to capture the mouse over your UserControl's window. The control's Capture property provides an even simpler way to do the same thing.
Technically, you'll need to p/invoke SetCapture() in order to receive click events that happen outside of your control.
But in your case, handling the Leave event, as #Martin suggests, should be sufficient.
EDIT: While looking for an usage example for SetCapture(), I came across the Control.Capture property, of which I was not aware. Using that property means you won't have to p/invoke anything, which is always a good thing in my book.
So, you'll have to set Capture to true when showing the dropdown, then determine if the mouse pointer lies inside the control in your click event handler and, if it doesn't, set Capture to false and close the dropdown.
UPDATE:
You can also use the Control.Focused property to determine if the control has got or lost focus when using a keyboard or mouse instead of using the Capture with the same example provided in the MSDN Capture page.
Handle the Form's MouseDown event, or override the Form's OnMouseDown
method:
enter code here
And then:
protected override void OnMouseDown(MouseEventArgs e)
{
if (!theListBox.Bounds.Contains(e.Location))
{
theListBox.Visible = false;
}
}
The Contains method old System.Drawing.Rectangle can be used to indicate if
a point is contained inside a rectangle. The Bounds property of a Control is
the outer Rectangle defined by the edges of the Control. The Location
property of the MouseEventArgs is the Point relative to the Control which
received the MouseDown event. The Bounds property of a Control in a Form is
relative to the Form.
You are probably looking for the leave event:
http://msdn.microsoft.com/en-us/library/system.windows.forms.control.leave.aspx
Leave occurs when the input focus leaves the control.
I just wanted to share this. It is probably not a good way of doing it that way, but looks like it works for drop down panel that closes on fake "MouseLeave", I tried to hide it on Panel MouseLeave but it does not work because moving from panel to button leaves the panel because the button is not the panel itself. Probably there is better way of doing this but I am sharing this because I used about 7 hours figuring out how to get it to work. Thanks to #FTheGodfather
But it works only if the mouse moves on the form. If there is a panel this will not work.
private void click_to_show_Panel_button_MouseDown(object sender, MouseEventArgs e)
{
item_panel1.Visible = true; //Menu Panel
}
private void Form1_MouseMove(object sender, MouseEventArgs e)
{
if (!item_panel1.Bounds.Contains(e.Location))
{
item_panel1.Visible = false; // Menu panel
}
}
I've done this myself, and this is how I did it.
When the drop down is opened, register a click event on the control's parent form:
this.Form.Click += new EventHandler(CloseDropDown);
But this only takes you half the way. You probably want your drop down to close also when the current window gets deactivated. The most reliable way of detecting this has for me been through a timer that checks which window is currently active:
[System.Runtime.InteropServices.DllImport("user32.dll")]
static extern IntPtr GetForegroundWindow();
and
var timer = new Timer();
timer.Interval = 100;
timer.Tick += (sender, args) =>
{
IntPtr f = GetForegroundWindow();
if (this.Form == null || f != this.Form.Handle)
{
CloseDropDown();
}
};
You should of course only let the timer run when the drop down is visible. Also, there's probably a few other events on the parent form you'd want to register when the drop down is opened:
this.Form.LocationChanged += new EventHandler(CloseDropDown);
this.Form.SizeChanged += new EventHandler(CloseDropDown);
Just don't forget to unregister all these events in the CloseDropDown method :)
EDIT:
I forgot, you should also register the Leave event on you control to see if another control gets activated/clicked:
this.Leave += new EventHandler(CloseDropDown);
I think I've got it now, this should cover all bases. Let me know if I'm missing something.
If you have Form, you can simply use Deactivate event just like this :
protected override void OnDeactivate(EventArgs e)
{
this.Dispose();
}
I tryed to create new components from one base Windows Form, also I found difficulties when I worked with toolstrip components, for example :
how to bind a datagrid.datasource on a child form using events from a button (clicks) on the parent toolstrip?
I have to use some snippets on each child form for doing this, btw why?
// btnSearch
//
this.btnSearch.Click += new System.EventHandler(this.btnExec_Click);
private void btnExec_Click(object sender, EventArgs e)
{
//do stuff
}
Thanks
EDIT: I also know about modifiers issue :
I mean, I have to replace the toolstripbutton with a common button, also have to add more code on designer class (base form) :
grpCommonControls.Height = 20;
dtTScomponent = new ToolStripControlHost(grpCommonControls);
dtTScomponent.Alignment = ToolStripItemAlignment.Right;
toolStrip1.Items.Add(dtTScomponent);
tssbExporta.Alignment = ToolStripItemAlignment.Left;
toolStrip1.Items.Add(tssbExporta);
I was needed to add a simple toolstrip with some toolstrip controls on my base form, but the designer dont allow me to work correctly with those (I cannot route the events from toolstripbutton to my child forms as an example)
When you create a form that inherits another form that contains different controls, there are not event handlers automatically hooked up for you. Instead you need to do that as in your code sample. Another approach is to attach that event handler in your base form, and then have the base form expose events that you can listen to. Example:
In the base form:
public event EventHandler ExecInvoked;
private void btnExec_Click(object sender, EventArgs e)
{
OnExecInvoked(e);
}
protected virtual void OnExecInvoked(EventArgs e)
{
EventHandler evt = ExecInvoked;
if (evt != null)
{
evt(this, e);
}
}
Then, in your inherited form, you can either set up an event handler for the ExecInvoked event (you can probably do this using the events list in the property grid), or you can override the OnExecInvoked method:
protected override void OnExecInvoked(EventArgs e)
{
base.OnExecInvoked(e);
// do what the form should do when Exec is invoked
}
This way you have encapsulated the internals of the base form, so that the child form does not know what kind of control that raises the event (it could even be several different controls leading to the same event being raised), but the base form still provides a clear point where the child form can react on it.
To be able to change properties and subscribe to events of controls inherited from your parent Form (or UserControl), the parent form should set those controls' Modifiers property to protected (or, in general, to any value such that fields generated for controls in parent form are visible to the child form). The default value for Modifiers is private.