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WinForms listbox keydown event won't fire

I am trying to make a WinForm ListBox in which you can loop trough using the arrow keys. I also have two buttons on which you can click to go up and down the list. The buttons do produce the desired effect. The problem is that the ListBox's keyDown event is never triggered
public MainForm()
{
InitializeComponent();
if (this.clipboardHistoryList.Items.Count > 0)
this.clipboardHistoryList.SetSelected(0, true);
clipboardHistoryList.Select();
}
private void goUpButton_Click(object sender, EventArgs e)
{
goUpList();
}
private void goDownButton_Click(object sender, EventArgs e)
{
goDownList();
}
private void goDownList()
{
if (clipboardHistoryList.SelectedIndex == clipboardHistoryList.Items.Count - 1)
{
clipboardHistoryList.SetSelected(0, true);
}
else
{
clipboardHistoryList.SetSelected(clipboardHistoryList.SelectedIndex + 1, true);
}
}
private void goUpList()
{
if (clipboardHistoryList.SelectedIndex == 0)
{
clipboardHistoryList.SetSelected(clipboardHistoryList.Items.Count - 1, true);
}
else
{
int l_currentlySelected = clipboardHistoryList.SelectedIndex;
clipboardHistoryList.SetSelected(l_currentlySelected - 1, true);
}
}
private void clipboardHistoryList_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Up) //Brekpoint is never reached
{
goUpList();
}
else if (e.KeyCode == Keys.Down)
{
goDownList();
}
}
I have put the MainForm's keypreview proprety to true.
The arrow keys do work by default on a listbox but they won't let you go from last to first element if you press the down arrow on the last element --hopes this makes sense.
EDIT
I have seen on Microsoft's documentation that I need to override the ProcessDialogKey method but I am not exactly sure of what I need to do.
Perform special input or navigation handling on a control. For example, you want the use of arrow keys in your list control to change the selected item. Override ProcessDialogKey
Is there already a built-in way to enable this behaviour?
What did I miss?
Thanks!

From looking at the code in your Designer.cs file, it doesn't look like you've actually got your clipboardHistoryList control wired into your clipboardHistoryList_KeyDown event handler. You can do that through the "Events" subtab of the Properties window in your visual studio form designer (look for the little lightning bolt icon) and wire up the event through the designer that way, or alternatively you can do it in code:
public MainForm()
{
InitializeComponent();
if (this.clipboardHistoryList.Items.Count > 0)
this.clipboardHistoryList.SetSelected(0, true);
clipboardHistoryList.Select();
clipboardHistoryList.KeyDown += clipboardHistoryList_KeyDown;
}

How to detect when an MDIClient window has been scrolled

I need to update the position of a child window inside my System.Windows.Forms.MDIClient container when the user scrolls it by dragging the MDIClient's scrollbar thumb.
However I can't find an event that triggers when this happens.
Am I simply missing it, or do I need a workaround, possibly by talking direct to the scrollbar?
I've already tried handling MDIClient.Layout events, but they aren't being triggered by scrolling.
EDIT: I actually only need to know when the scrolling has stopped, in order to change my child window's position.
EDIT2: As a temporary workaround, I'm resetting the child window position on a timer every second, obviously not ideal, but better than nothing. Looks terrible though!

That's possible although a bit awkward. Winforms doesn't make it very easy to find the MdiClient window back and the class itself doesn't expose the Scroll event. That can be worked around, as always in Winforms, you have to sub-class the native MDI client window of your parent window so you can capture the WM_VSCROLL message. This code worked well, paste it into your parent form class:
void MdiClient_Scroll(object sender, ScrollEventArgs e) {
if (e.Type == ScrollEventType.EndScroll) {
// Do your stuff
//...
}
}
private MdiClientWrapper wrapper;
protected override void OnHandleCreated(EventArgs e) {
// Find the MdiClient and sub-class it so we can get the Scroll event
base.OnHandleCreated(e);
if (wrapper != null) wrapper.Scroll -= MdiClient_Scroll;
var client = this.Controls.OfType<MdiClient>().First();
wrapper = new MdiClientWrapper();
wrapper.AssignHandle(client.Handle);
wrapper.Scroll += MdiClient_Scroll;
}
private class MdiClientWrapper : NativeWindow {
public event ScrollEventHandler Scroll;
private int oldPos;
protected override void WndProc(ref Message m) {
if (m.Msg == 0x115) { // Trap WM_VSCROLL
var type = (ScrollEventType)(m.WParam.ToInt32() & 0xffff);
var pos = m.WParam.ToInt32() >> 16;
Scroll(this, new ScrollEventArgs(type, oldPos, pos));
oldPos = pos;
}
base.WndProc(ref m);
}
}

Focus on scroll

I have a user control with a scrollbar (scrollbar appears as a contained user control, which inherits from Panel, is too large). When using the mouse to scroll all is well, but trying to scroll with the mousewheel dont work.
My solution here is to set focus to my child-control in an eventhandler for Scroll. This works. Now the question; Will this result in a lot of unecessary calls to childControl.Focus()? Is there a more neat way of doing this?
Edit: I think I was a bit unclear with my question so Rephrasing the question:
is
private void ChildControl_OnScroll(object sender, ScrollEventArgs scrollEventArgs)
{
this.childControl.Focus();
}
a bad way of setting the focus? I.e. will the focus be set mutliple times each time I scroll? or rather, will this cause (tiny) performance issues.

Here's another approach that gives focus when the scrollbar area of panel1 inside SomeUserControl is clicked. It uses NativeWindow so you don't have to change the panel in your UserControl. This way Focus() will only be called once, when the mouse goes down in the scrollbar area:
public partial class SomeUserControl : UserControl
{
private TrapMouseDownOnScrollArea trapScroll = null;
public SomeUserControl()
{
InitializeComponent();
this.VisibleChanged += new EventHandler(SomeUserControl_VisibleChanged);
}
void SomeUserControl_VisibleChanged(object sender, EventArgs e)
{
if (this.Visible && trapScroll == null)
{
trapScroll = new TrapMouseDownOnScrollArea(this.panel1);
}
}
private class TrapMouseDownOnScrollArea : NativeWindow
{
private Control control = null;
private const int WM_NCLBUTTONDOWN = 0xA1;
public TrapMouseDownOnScrollArea(Control ctl)
{
if (ctl != null && ctl.IsHandleCreated)
{
this.control = ctl;
this.AssignHandle(ctl.Handle);
}
}
protected override void WndProc(ref Message m)
{
switch (m.Msg)
{
case WM_NCLBUTTONDOWN:
if (this.control != null)
{
Rectangle screenBounds = control.RectangleToScreen(new Rectangle(0, 0, control.Width, control.Height));
if (screenBounds.Contains(Cursor.Position))
{
control.Focus();
}
}
break;
}
base.WndProc(ref m);
}
}
}
This might be overkill for your scenario, but it demonstrates one way to trap lower level messages. As said before, you could also derive from Panel to achieve the same affect. You could also trap messages at the application level with IMessageFilter.

The MouseWheel event is an event that "bubbles". Windows sends it to the control that has the focus, regardless of where the mouse cursor is located. The most typical problem is that you have a control that cannot receive the focus. A Panel for example.
This changes when you put a control on the panel. Now that control can get the focus and gets the MouseWheel message. It won't have any use for it so the message passes to its parent. Which does have a use for it, the panel scrolls as expected.
You can get a focusable panel control from this answer. A generic "make it work like a browser or Office program" solution from this question

If childControl has a MouseEnter() event then use that instead:
private void childControl_MouseEnter(object sender, EventArgs e)
{
childControl.Focus();
}
Then the mouse wheel events should be direct to childControl.

Disable focus cues on a SplitContainer

How can I disable the focus cues on a SplitContainer?
I ask because I'd rather draw them myself using OnPaint in order to make it look somewhat smoother.
I tried this:
protected override bool ShowFocusCues
{
get
{
return false;
}
}
And this is my control:
public class cSplitContainer : SplitContainer
{
private bool IsDragging;
protected override void OnMouseDown(MouseEventArgs e)
{
base.OnMouseDown(e);
if (!IsSplitterFixed) IsDragging = true;
Invalidate();
}
protected override void OnMouseUp(MouseEventArgs e)
{
base.OnMouseUp(e);
if (IsDragging)
{
IsDragging = false;
IsSplitterFixed = false;
}
}
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
if (IsDragging)
{
IsSplitterFixed = true;
if (e.Button == MouseButtons.Left)
{
if (Orientation == Orientation.Vertical)
{
if (e.X > 0 && e.X < Width) SplitterDistance = e.X;
}
else
{
if (e.Y > 0 && e.Y < Height) SplitterDistance = e.Y;
}
}
else
{
IsDragging = false;
IsSplitterFixed = false;
}
}
}
protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
{
base.OnPaint(e);
if (IsDragging)
{
e.Graphics.FillRectangle(new SolidBrush(Color.FromArgb(127, 0, 0, 0)), Orientation == Orientation.Horizontal ? new Rectangle(0, SplitterDistance, Width, SplitterWidth) : new Rectangle(SplitterDistance, 0, SplitterWidth, Height));
}
}
}
but it didn't work. I also tried some other methods mentioned before, but I'm still getting focus cues.

I don't think what you are seeing is the FocusCue so much as a floating window that is used to move the slider.
If keyboard access isn't important, you can try making it unselectable:
public class MySplit : SplitContainer {
public MySplit() {
this.SetStyle(ControlStyles.Selectable, false);
}
protected override void OnPaint(PaintEventArgs e) {
e.Graphics.Clear(Color.Red);
}
}
This prevents the SplitContainer from getting focus, but your mouse can still interact with it.

The code of SplitContainer is like:
protected override void OnPaint(PaintEventArgs e) {
base.OnPaint(e);
if (Focused) {
DrawFocus(e.Graphics,SplitterRectangle);
}
}
DrawFocus is not virtual. So you can't override it.
Focused is virtual. Maybe you can set it to false while calling base.OnPaint(...) in your OnPaint override.
So you could add following code (I did not tested if it works):
private bool _painting;
public override bool Focused
{
get { return _painting ? false : base.Focused; }
}
protected override void OnPaint(PaintEventArgs e)
{
_painting = true;
try
{
base.OnPaint(e);
}
finally
{
_painting = false;
}
}
That is more a hack than a clean solution.

I was googling for this issue and this question came up on the top.
There is a solution and interesting discussion on a Microsoft forum regarding the splitter stealing focus for no good reason. The following comment is spot on:
The focus issue you mentioned is by design, however to get the performance you want, you can use the following workaround: ....
It may be "by design", but it is not a very good one. What spitters have you ever seen in any Microsoft production application that even temporarily take the focus from the panes they split? I also added the code you suggest, and it does keep me from permanently losing the focus to the splitter, but I still don't like the fact that my panes hide and show their selections during splitter manipulation.
This distracting selection flash just is not present in most professional applications. It is just good enough that it probably won't be worth my time to fix for a while, but not what most people really want. If you respected the TabStop property or even added a AcceptsFocus property, most people would want this off. I think you should add this option to the design in a future version.
--Brendan

Simple solution: give away focus immediately when receiving it!
Three steps:
Create a GotFocus handler for the SplitContainer
Forward the focus to another control with AnotherControl.Focus().
Set TabStop to False
That's all. The ugly focus cue is never shown.
Now, one subtlety: Which other control to give the focus to? It's up to you. Just take the first control by tab order, or a upper-left focusable control in the right pane of the SplitContainer (TextBox in the ASCII diagram below). The perfect solution would be the previous control which had focus, but sadly this is not easy to find out: Find out the control with last focus, but IMHO the upper-left focusable control is a very good response.
left pane right pane
------------------------------------------------
: :: :
: :: [TextBox] [Button] :
: :: :
: :: [Combobox V] :
: :: :
------------------------------------------------

it is a kind a similar question being asked on stackoveflow one solution is sugested as being used by you also along with overriding showfocuscues property you need to override paint method as well.

in winforms, can i drag a control with a bunch of controls (like listboxes) in it into another control and resize / move them from there?

I'm running into some situations where it has been nice to make a control (Control A) with a bunch of things in it like buttons, listboxes, datagridviews etc so I can drag it into other controls (Control B) whenever I like, so I don't have to write the logic for the stuff within Control A over and over again.
The only annoying thing with this approach has been that I can't seem to find a way in the designer to move/resize the buttons, listboxes, datagridviews etc of Control A around from the designer of Control B. All it seems to let me do is resize the entirety of Control A.
Does anyone know how to make these custom controls containing multiple controls in such a way that they support design time resizing/moving?
Thanks
Isaac

There is no built in way to do this. You would essentially have to implement event handlers in order to handle the resizing of individual components within your control. One alternative for you is to expose the Size and Location properties of each individual component to the control's clients. For example, within the Control class you could do something like this:
public Size Component1Size
{
get { return component1.Size; }
set { component1.Size = value; }
}
public Point Component1Location
{
get { return component1.Location; }
set { component1.Location = value; }
}
and do this for each component of your control. I think this would be your best option, even though the user won't be able to physically click/drag the components to move and resize them.

Yes you can my friend ,you need to create a SizeAble and DragAndDrop pannel where you can Insert Controls and by Moving That Pannel you can reach that .And for the Resizing Issue you can play with Anchor of Control's that you already added .
using System;
using System.Drawing;
using System.Windows.Forms;
public class SizeablePanel : Panel {
private const int cGripSize = 20;
private bool mDragging;
private Point mDragPos;
public SizeablePanel() {
this.DoubleBuffered = true;
this.SetStyle(ControlStyles.ResizeRedraw, true);
this.BackColor = Color.White;
}
protected override void OnPaint(PaintEventArgs e) {
ControlPaint.DrawSizeGrip(e.Graphics, this.BackColor,
new Rectangle(this.ClientSize.Width - cGripSize, this.ClientSize.Height - cGripSize, cGripSize, cGripSize));
base.OnPaint(e);
}
private bool IsOnGrip(Point pos) {
return pos.X >= this.ClientSize.Width - cGripSize &&
pos.Y >= this.ClientSize.Height - cGripSize;
}
protected override void OnMouseDown(MouseEventArgs e) {
mDragging = IsOnGrip(e.Location);
mDragPos = e.Location;
base.OnMouseDown(e);
}
protected override void OnMouseUp(MouseEventArgs e) {
mDragging = false;
base.OnMouseUp(e);
}
protected override void OnMouseMove(MouseEventArgs e) {
if (mDragging) {
this.Size = new Size(this.Width + e.X - mDragPos.X,
this.Height + e.Y - mDragPos.Y);
mDragPos = e.Location;
}
else if (IsOnGrip(e.Location)) this.Cursor = Cursors.SizeNWSE;
else this.Cursor = Cursors.Default;
base.OnMouseMove(e);
}
}