[RESOLVED] How to raise event trapping mouse wheel scroll?

I cant seem to figure out how to raise an event that will pass the delta value for mouse scroll from a user control to main form.

I see that MouseEventArgs has delta as one of its properties. With that in mind I have defined

publiceventMouseEventHandler OnMouseActivity;

in my user control, and raise the event

Code:

---


privatevoid KeystrokesDetails_MouseMove(object sender, MouseEventArgs e)
{
OnMouseActivity(this, e);
}

---

as well.......


In my main program, immediately after I create an instance of the user control(the user control is added to a split container panel2 controls collection), I set up the event like this ..........

newDetails.OnMouseActivity += newMouseEventHandler(MouseMoved);

and have a method programmed to handle the event....

Code:

---


privatevoid MouseMoved(object sender, MouseEventArgs e)
{
if (e.Delta == 120)
{
splitContainer2.Panel2.VerticalScroll.Value += splitContainer2.Panel2.VerticalScroll.SmallChange;
}
else if (e.Delta == -120)
{
splitContainer2.Panel2.VerticalScroll.Value += splitContainer2.Panel2.VerticalScroll.SmallChange;
}
}

---

This doesnt work. Delta is always 0. How can I isolate the Delta value?

override OnMouseWheel method in your user control to catch the delta value, this delta value will not be filled in MouseMove event.

Code:

---

    public partial class UserControl1 : UserControl
    {
        public event MouseEventHandler MouseWheel;
        public UserControl1()
        {
            InitializeComponent();
        }

        protected override void OnMouseWheel(MouseEventArgs e)
        {
            if (MouseWheel != null)
                MouseWheel(this, e);//this e will contain delta value
        }
    }

---

Thank you I'll give this a shot.


If you want, I have another question. Its a stupid one, and a brief response is all I'm looking for.

What does protected and override do?

protected means that the method is accessible by the current class and all class that inherit from it.

while override means that you want to provide a new implementation to a predefined method that is mark as virtual in the base class (phew that was a mouthfull).

Code:

---

public class1{
    protected void SomeMethod(){...}

    protected virtual void SomeOverridableMethod(){...}
}

public class2 : class1 //<-- class2 is inherited from class1
{
    private void Class2OwnMethod(){
        //call class1 method
        SomeMethod();
    }


    protected override void SomeOverridableMethod(){
        //I want to change the behaviour of this method
        //do some cool stuff here
    }
}

---

btw, you're proggressing nicely since the last time, I'll bet in the next couple of months you'll be answering people questions :D

LOL, thanks. My program is coming along great. Just adding some bells and whistles before I get back into the grind of more serious code.

BTW....Not sure what I did wrong. I created the new event, and did the overriding of OnMouseWheel, in my user control, however when I try to scroll OnMouseWheel in user control is never touched.

My code in user control


publiceventMouseEventHandler MouseWheel;

Code:

---


protectedoverridevoid OnMouseWheel(MouseEventArgs e)

{

if (MouseWheel != null)

MouseWheel(this, e);//this e will contain delta value

}



---

The user control needs to have focus before the mousewheel message is processed. Try clicking in the usercontrol to set the focus to it, and set the break point on if (Mousewheel != null) line

My user control is nothing more then some labels and a text box. I tried clicking on the control itself(rather then the labels or textbox, and no event fired.

Just so you know. My user control has no scrollbars. I create multiple instances of this control in my main program and add them to a panel which does have a scroll bar. Its the scroll bar of the panel i'm trying to control.

I assume that in you placed these labels and text in your user control right? If that's the case then the usercontrol will never gain focus since it will always give focus to it's child control. That's why the mouse wheel event never fired.

I don't know any easy solution to this one though

Thats a bummer. Looks like i'd have to use a mouse hook. Because i'm lazy I probably wont do that.

Side note though. I did pass a mouse move event from the user control........ So that when my mouse moved over the control itself, not the child controls, I could manipulate the scroll bar.

What about this. Is it possible to pass wheel scroll from the text box on the user control up the chain of command to my main program?

also, looking at the list of available events in the development environment (you know, in the properties window) I dont see any OnMouseWheel event.

Why would the MouseMove event have a delta value in the arguments? If you cant access delta why is it there?


http://msdn2.microsoft.com/en-us/lib...s_members.aspx

I've just remember one thing, you can use ScrollableControl class to support mousewheel, and it already has Mousewheel event built in

Code:

---

    public partial class UserControl1 : ScrollableControl
    {
        //public event MouseEventHandler MouseWheel;
        public UserControl1()
        {
            InitializeComponent();
            this.TabStop = true;
           
        }

        protected override void OnMouseWheel(MouseEventArgs e)
        {
            Debug.WriteLine(e.Delta);
            base.OnMouseWheel(e);
        }
    }

---

Oh crap, I just did something bad.!!!!!!!

I get this error when trying to go to the user control design



One or more errors encountered while loading the designer. The errors are listed below. Some errors can be fixed by rebuilding your project, while others may require code changes.
The service System.ComponentModel.Design.IInheritanceService already exists in the service container. Parameter name: serviceType
Hide

at System.ComponentModel.Design.ServiceContainer.AddService(Type serviceType, Object serviceInstance, Boolean promote)
at System.ComponentModel.Design.ServiceContainer.AddService(Type serviceType, Object serviceInstance)
at System.ComponentModel.Design.DesignerHost.System.ComponentModel.Design.IServiceContainer.AddService(Type serviceType, Object serviceInstance)
at System.Windows.Forms.Design.ComponentDocumentDesigner.Initialize(IComponent component)
at System.ComponentModel.Design.DesignerHost.AddToContainerPostProcess(IComponent component, String name, IContainer containerToAddTo)
at System.ComponentModel.Design.DesignerHost.Add(IComponent component, String name)
at System.ComponentModel.Design.DesignerHost.System.ComponentModel.Design.IDesignerHost.CreateComponent(Type componentType, String name)
at System.ComponentModel.Design.Serialization.DesignerSerializationManager.CreateInstance(Type type, ICollection arguments, String name, Boolean addToContainer)
at System.ComponentModel.Design.Serialization.DesignerSerializationManager.System.ComponentModel.Design.Serialization.IDesignerSerializationManager.CreateInstance(Type type, ICollection arguments, String name, Boolean addToContainer)
at System.ComponentModel.Design.Serialization.TypeCodeDomSerializer.Deserialize(IDesignerSerializationManager manager, CodeTypeDeclaration declaration)
at System.ComponentModel.Design.Serialization.CodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager manager)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager serializationManager)
at System.ComponentModel.Design.Serialization.BasicDesignerLoader.BeginLoad(IDesignerLoaderHost host)

lmao!!!!!!!!! WHEW I think I fixed it.

This looks hard

Quote:

---

You do not typically use the ScrollableControl class directly. The ContainerControl and Panel classes inherit from this class.

The ScrollableControl class acts as a base class for controls that require the ability to scroll. To enable a control to display scroll bars as needed, set the AutoScroll property to true and set the AutoScrollMinSize property to the desired size. When the control is sized smaller than the specified minimum size, or a child control is located outside the bounds of the control, the appropriate scroll bars are displayed.

---

So instead of using the panel on my main form to scroll, I would drop a panel on the scrollable control, add my labels and text box, and then in code, position them, and have method for adding instances. I think thats how I understand it. Or do I even need a panel for this control? I dont know. I've made alot of progress tonight, in so that I'm happy with the visual layout of my program now. I'll work on the scrolling tomorrow.

Thank you again for your help. :thumb:

Looks like only way is to perform a hook. I dont want to use WH_MOUSE_LL, so how about instead overriding wndProc in my user control to trap WM_MOUSEWHEEL, then just raise a custom event with the delta value? Is this possible. Is this how I should do it?

Ok here's my override of wndProc. If I left click on my user control white space(where I dont have any child controls) I get my messagebox for left mouse click. If I scroll the wheel in same area, It doesnt see it. I assume its because when you click the user control has focus for a moment. Ok, I'll live with not being able to scroll when mouse is over the user control white space. So I commented out this statement if (msg.HWnd != this.Handle) so that all messages will be received. But the problem persists. Even if I click on the child object to bring focus like a text box, it still doesnt see the WM_MOUSEWHEEL, or WM_LBUTTONDOWN

Code:

---

protected override void WndProc(ref Message msg)
 
{
 
base.WndProc(ref msg);
 
if (msg.HWnd != this.Handle)
 
return;
 
switch (msg.Msg)
 
{
 
case WM_LBUTTONDOWN:
 
MessageBox.Show("Left Button Down");
 
break;
 
case WM_MOUSEWHEEL:
 
MessageBox.Show("Scroll!!!!!");
 
try
 
{
 
int zDelta = HiWord((int)msg.WParam);
 
int y = HiWord((int)msg.LParam);
 
int x = LoWord((int)msg.LParam);
 
System.Windows.Forms.MouseButtons butt;
 
switch (LoWord((int)msg.WParam))
 
{
 
case MK_LBUTTON:
 
butt = System.Windows.Forms.MouseButtons.Left;
 
break;
 
case MK_MBUTTON:
 
butt = System.Windows.Forms.MouseButtons.Middle;
 
break;
 
case MK_RBUTTON:
 
butt = System.Windows.Forms.MouseButtons.Right;
 
break;
 
case MK_XBUTTON1:
 
butt = System.Windows.Forms.MouseButtons.XButton1;
 
break;
 
case MK_XBUTTON2:
 
butt = System.Windows.Forms.MouseButtons.XButton2;
 
break;
 
default:
 
butt = System.Windows.Forms.MouseButtons.None;
 
break;
 
}
 
System.Windows.Forms.MouseEventArgs arg0 = new System.Windows.Forms.MouseEventArgs(butt, 1, x, y, zDelta);
 
this.ScrollMouseWheel(this, arg0);
 
}
 
catch (Exception) { }
 
break;
 
 
 
default:
 
break;
 
}
 
}

---

Ok, i'm getting close(I ditched the wndProc idea). In order to use the mousewheel to scroll the panel of user controls, the panel needs to have focus. So now I need to raise events from my user control that tell me when the mouse has entered visability of the labels. Then in my main form, I can trap those events, and set focus to the panel. Sounds pretty easy. Well for me and my NOOBNESS, its not. I am getting an error when trying to pass the mouse enter event for a label control. Here is my code.

Code:

---


publicevent System.EventHandler NoFocus;
 

privatevoid label2_MouseEnter(object sender, EventArgs e)
{
        NoFocus(sender,e); // Object reference not set to an instance of an object.
}


---

and I get this error

Quote:

---

Object reference not set to an instance of an object.

---

the arg sender shows the label control that generated the event, and e is empty. NoFocus = null. I think this is the problem. How do I fix it?

Please help....... This has got to be an easy one for you guys.

I tried adding this statement

newDetails.NoFocus += newEventArgs(NoFocus);

when I create an instance of my user control(named newDetails) and I get a compile error.

Quote:

---

Error 3 No overload for method 'EventArgs' takes '1' arguments

---

I have defined NoFocus as this.....

Code:

---

privatevoid NoFocus(object sender, EventArgs e)
{
        splitContainer2.Panel2.Focus();
}

---

I'm stupid. I knew it was something easy.

newDetails.NoFocus += newEventArgs(NoFocus);

Needed to be........

newDetails.NoFocus += newEventHandler(NoFocus);

Works great now. Got my panel scrolling the user controls.