Develop Reference

Disable all mouse messages on control

I have a graph control that plots data points. The data points are plotted as 1 point per pixel. If the number of data points get larger than a certain amount, or the size of the window is increased the performance of the plotting when you move your mouse over the control suffers. If you move quickly the plotting actually stops during the motion.
Is there a way to disable all the messages when the mouse is over that control except for button clicks?
I have not been able to find anything.

Based on your description, I believe that it should be sufficient to filter out MouseMove messages sent to the control. This can be accomplished by having the Form implement IMessageFilter similar to the example presented below. Returning true from IMessageFilter.PreFilterMessage prevents the message from being sent to the control (a panel in the example). A registered filter is active application wide, so it is added/removed when the form actives/deactivates.
public partial class Form1 : Form, IMessageFilter
{
private Panel pnl;
public Form1()
{
InitializeComponent();
pnl = new Panel { Size = new Size(200, 200), Location = new Point(20, 20), BackColor = Color.Aqua };
Controls.Add(pnl);
pnl.Click += panel_Click;
pnl.MouseMove += panel_MouseMove;
pnl.MouseHover += panel_MouseHover;
}
private void panel_MouseHover(sender As Object, e As EventArgs)
{
// this should not occur
throw new NotImplementedException();
}
private void panel_MouseMove(object sender, MouseEventArgs e)
{
// this should not occur
throw new NotImplementedException();
}
private void panel_Click(object sender, EventArgs e)
{
MessageBox.Show("panel clicked");
}
protected override void OnActivated(EventArgs e)
{
base.OnActivated(e);
// install message filter when form activates
Application.AddMessageFilter(this);
}
protected override void OnDeactivate(EventArgs e)
{
base.OnDeactivate(e);
// remove message filter when form deactivates
Application.RemoveMessageFilter(this);
}
bool IMessageFilter.PreFilterMessage(ref Message m)
{
bool handled = false;
if (m.HWnd == pnl.Handle && (WM) m.Msg == WM.MOUSEMOVE)
{
handled = true;
}
return handled;
}
public enum WM : int
{
#region Mouse Messages
MOUSEFIRST = 0x200,
MOUSEMOVE = 0x200,
LBUTTONDOWN = 0x201,
LBUTTONUP = 0x202,
LBUTTONDBLCLK = 0x203,
RBUTTONDOWN = 0x204,
RBUTTONUP = 0x205,
RBUTTONDBLCLK = 0x206,
MBUTTONDOWN = 0x207,
MBUTTONUP = 0x208,
MBUTTONDBLCLK = 0x209,
MOUSELAST = 0x209
#endregion
}
}

C# - show child control (Listbox) on top of parent control(textbox) in winform

Created a custom intellisense textbox (textbox with listbox a child).
As shown in below image, the listbox pops up when i enter a char which all works fine and good but when i am at the end of textbox the listbox is partially visible, is there anyway i can show the whole listbox content?
Tried this "Show control inside user control outside the boundaries of its parent
But when the popup window opens the text box looses focus and i cannot type anything further, my intellisense textbox keeps giving better results based on what they type but in this situation i am not able to type anymore.
FYI tried to add pParentControl.Focus() into show method defined in other article as shown below, missing something?
public void Show(Control pParentControl)
{
if (pParentControl == null) return;
// position the popup window
var loc = pParentControl.PointToScreen(new Point(0, pParentControl.Height));
pParentControl.Focus();
m_tsdd.Show(loc);
}
Here is the complete code
class TextBox_AutoComplete : TextBox
{
#region Class Members
List<string> dictionary;
ListBox listbox = new ListBox();
#endregion
private PopupHelper m_popup;
#region Extern functions
[DllImport("user32")]
private extern static int GetCaretPos(out Point p);
#endregion
#region Constructors
public TextBox_AutoComplete() : base()
{
this.Margin = new Padding(0, 0, 0, 0);
this.Multiline = true;
this.Dock = DockStyle.Fill;
this.KeyDown += Textbox_KeyDown;
this.KeyUp += Textbox_KeyUp;
listbox.Parent = this;
listbox.KeyUp += List_OnKeyUp;
listbox.Visible = false;
this.dictionary = new List<string>();
}
#endregion
#region Properties
public List<string> Dictionary
{
get { return this.dictionary; }
set { this.dictionary = value; }
}
#endregion
#region Methods
private static string GetLastString(string s)
{
Regex rgx = new Regex("[^a-zA-Z0-9_.\\[\\]]");
s = rgx.Replace(s, " ");
string[] strArray = s.Split(' ');
return strArray[strArray.Length - 1];
}
protected override void OnTextChanged(EventArgs e)
{
base.OnTextChanged(e);
Point cp;
GetCaretPos(out cp);
List<string> lstTemp = new List<string>();
List<string> TempFilteredList = new List<string>();
string LastString = GetLastString(this.Text.Substring(0, SelectionStart));
//MessageBox.Show(LastString);
/*seperated them so that column name matches are found first*/
TempFilteredList.AddRange(dictionary.Where(n => n.Replace("[", "").ToUpper().Substring(n.IndexOf(".") > 0 ? n.IndexOf(".") : 0).StartsWith(LastString.ToUpper())
).Select(r => r)
.ToList());
TempFilteredList.AddRange(dictionary.Where(n => n.Replace("[", "").ToUpper().StartsWith(LastString.ToUpper())
|| n.ToUpper().StartsWith(LastString.ToUpper()))
.Select(r => r)
.ToList());
lstTemp = TempFilteredList.Distinct().Select(r => r).ToList();
/*Getting max width*/
int maxWidth = 0, temp = 0;
foreach (var obj in lstTemp)
{
temp = TextRenderer.MeasureText(obj.ToString(), new Font("Arial", 10, FontStyle.Regular)).Width;
if (temp > maxWidth)
{
maxWidth = temp;
}
}
listbox.SetBounds(cp.X + 20, cp.Y + 20, maxWidth, 60);
if (lstTemp.Count != 0 && LastString != "")
{
listbox.DataSource = lstTemp;
// listbox.Show();
if (m_popup == null)
m_popup = new PopupHelper(listbox);
m_popup.Show(this);
}
else if (m_popup != null)
{
//listbox.Hide();
m_popup.Hide();
}
}
protected void Textbox_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Down)
{
if (listbox.Visible == true)
{
listbox.Focus();
}
e.Handled = true;
}
else if (e.KeyCode == Keys.Escape)
{
listbox.Visible = false;
e.Handled = true;
}
}
protected void Textbox_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Space && listbox.Visible == true)
{
listbox.Focus();
List_OnKeyUp(listbox, new KeyEventArgs(Keys.Space));
e.Handled = true;
}
if (e.KeyCode == Keys.Down && listbox.Visible == true)
{
listbox.Focus();
e.Handled = true;
}
}
private void List_OnKeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Space || e.KeyCode == Keys.Enter)
{
int Selection_Start = this.SelectionStart;
string StrLS = GetLastString(this.Text.Substring(0, Selection_Start));
this.Select(Selection_Start - StrLS.Length, StrLS.Length);
// MessageBox.Show(this.Selection_Start.ToString() + " Last string" + StrLS);
this.SelectedText=((ListBox)sender).SelectedItem.ToString();
listbox.Hide();
this.Focus();
}
}
#endregion
}
public sealed class PopupHelper : IDisposable
{
private readonly Control m_control;
private readonly ToolStripDropDown m_tsdd;
private readonly Panel m_hostPanel; // workarround - some controls don't display correctly if they are hosted directly in ToolStripControlHost
public PopupHelper(Control pControl)
{
m_hostPanel = new Panel();
m_hostPanel.Padding = Padding.Empty;
m_hostPanel.Margin = Padding.Empty;
m_hostPanel.TabStop = false;
m_hostPanel.BorderStyle = BorderStyle.None;
m_hostPanel.BackColor = Color.Transparent;
m_tsdd = new ToolStripDropDown();
m_tsdd.CausesValidation = false;
m_tsdd.Padding = Padding.Empty;
m_tsdd.Margin = Padding.Empty;
m_tsdd.Opacity = 0.9;
m_control = pControl;
m_control.CausesValidation = false;
m_control.Resize += MControlResize;
//m_hostPanel.Controls.Add(m_control);
m_tsdd.Padding = Padding.Empty;
m_tsdd.Margin = Padding.Empty;
m_tsdd.MinimumSize = m_tsdd.MaximumSize = m_tsdd.Size = pControl.Size;
m_tsdd.Items.Add(new ToolStripControlHost(m_control));
}
private void ResizeWindow()
{
m_tsdd.MinimumSize = m_tsdd.MaximumSize = m_tsdd.Size = m_control.Size;
m_hostPanel.MinimumSize = m_hostPanel.MaximumSize = m_hostPanel.Size = m_control.Size;
}
private void MControlResize(object sender, EventArgs e)
{
ResizeWindow();
}
/// <summary>
/// Display the popup and keep the focus
/// </summary>
/// <param name="pParentControl"></param>
public void Show(Control pParentControl)
{
if (pParentControl == null) return;
// position the popup window
var loc = pParentControl.PointToScreen(new Point(0, pParentControl.Height));
pParentControl.Focus();
m_tsdd.Show(loc);
}
public void Hide()
{
m_tsdd.Hide();
}
public void Close()
{
m_tsdd.Close();
}
public void Dispose()
{
m_control.Resize -= MControlResize;
m_tsdd.Dispose();
m_hostPanel.Dispose();
}
}

Firstly, I personally don't see any benefit in having a control inside another. Yes, the child control is locked inside its parent's boundaries automatically for you, but this benefit is negated by the issue that you're facing, and solving that issue requires the same work as when the two controls have no relation. In both cases, you'll have to do the calculations manually to keep the child visible inside its parent. In the second case the parent is the app's window.
Secondly, I don't recommend using hacks like the one mentioned in the comments to show the child outside its parent's boundaries. The hack creates more issues than it solves, as you found out. And what's the point of that hack anyway? If you want to show the child outside the parent, then don't make it a child control in the first place, and you don't need any hack.
The best solution is the one that you find in any well designed app, and in Windows itself. Open any app, let's say Notepad, and right-click near the upper-left corner. You'll see the context menu pulling to lower-right direction. Now right-click near the other three corners and you'll see the context menu pulling in different direction each time, so it will always be visible inside the app. Now if you resize the app window too small and right-click, the context menu will choose the best direction but some of it will be outside the app because the window is too small. That's why you need your list not to be a child, but it's up to you, and it's only about these edge cases. The solution will be similar in both cases.
You're displaying the list in this line:
listbox.SetBounds(cp.X + 20, cp.Y + 20, maxWidth, 60);
The key is cp.X and cp.Y. This is what decides where the list will appear. You need to make this point dynamic and responsive to the boundaries of the parent. You fixed the width to maxWidth and height to 60, so I will use those values in the calculation.
To make sure the list will not go beyond the bottom:
var y = this.Height < cp.Y + 60 ? this.Height - 60 : cp.Y;
To make sure the list will not go beyond the right:
var x = this.Width < cp.X + maxWidth ? this.Width - maxWidth : cp.X;
Now you can show your list at the calculated point:
listbox.SetBounds(x, y, maxWidth, 60);
Notes:
I didn't include the 20 gap that you used. I think it looks better without the gap and I haven't seen any app that has a gap. If you prefer the gap, add it to the calculation of x and y. Don't add it in the SetBounds() or that will screw up the calculation.
The calculation above doesn't take into account when the parent size is too small to show the child inside. If you want to support that edge case, you need to make the child a separate control and add some checks to the calculation.

Custom ComboBox not closing properly

I am trying to make my custom ComboBox inheriting from ContainerControl. I used this article as a base but rewrote it, but I use a ToolStripControlHost, my own custom ListBox & a ToolStripDropDown.
Now the ComboBox is a button where you click on to show the DropDowncontaining my ListBox, works fine with overriding OnMouseClick.
The problems starts when I try to close the DropDown, with the DropDown's 'AutoClose' property to true, the DropDown closes if you click somewhere outside the DropDown (including the button) ...
protected override void OnMouseClick(MouseEventArgs e)
{
base.OnMouseClick(e);
/* listboxControl = ToolStripDropDown */
if (!listboxControl.Visible)
{
listboxControl.Show(this, GetDropLocation(), ToolStripDropDownDirection.BelowRight);
//listbox.Capture = true;
}
}
This is the code for the click on the button .. so what happens if you click it ?
If the DropDown is shown, it first closes the DropDown, then it fires the OnMouseClick event. Meaning: listboxControl.Visible is already false & it will show the DropDown again. All of this causing a quick close-open.
I have been stuck with this problem for some time now and google doesn't seem to know a lot about this subject (that article on CodeProject has the same bug).
What I have tried is disabling AutoClose and capturing the mouse after I show the DropDown, this works partially but it affects the working of my hosted ListBox. The ListBox contains a set of controls (the items), these items have a hover paint effect. Capturing the mouse in the ListBox control prevents the OnMouseEnter to be fired.
All input would be greatly appreciated !

You need a variable to track the cursor position when the DropDown is closing.
Here is a quick and dirty example control:
public class CustomDropBox : Control {
private ListBox box = new ListBox() { IntegralHeight = false };
private ToolStripControlHost host;
private ToolStripDropDown drop;
private bool wasShowing = false;
public CustomDropBox() {
box.MinimumSize = new Size(120, 120);
box.MouseUp += box_MouseUp;
box.KeyPress += box_KeyPress;
box.Items.AddRange(new string[] { "aaa", "bbb", "ccc" });
host = new ToolStripControlHost(box) { Padding = Padding.Empty };
drop = new ToolStripDropDown() { Padding = Padding.Empty };
drop.Closing += drop_Closing;
drop.Items.Add(host);
}
private Rectangle GetDownRectangle() {
return new Rectangle(this.ClientSize.Width - 16, 0, 16, this.ClientSize.Height);
}
void drop_Closing(object sender, ToolStripDropDownClosingEventArgs e) {
if (e.CloseReason == ToolStripDropDownCloseReason.AppClicked) {
wasShowing = GetDownRectangle().Contains(this.PointToClient(Cursor.Position));
} else {
wasShowing = false;
}
}
void box_KeyPress(object sender, KeyPressEventArgs e) {
if (e.KeyChar == (char)Keys.Enter && box.SelectedIndex > -1) {
drop.Close();
}
}
void box_MouseUp(object sender, MouseEventArgs e) {
int index = box.IndexFromPoint(e.Location);
if (index > -1) {
drop.Close();
}
}
protected override void OnMouseDown(MouseEventArgs e) {
if (e.Button == MouseButtons.Left && GetDownRectangle().Contains(e.Location)) {
if (wasShowing) {
wasShowing = false;
} else {
drop.Show(this, new Point(0, this.Height));
}
}
base.OnMouseDown(e);
}
protected override void OnPaint(PaintEventArgs e) {
e.Graphics.Clear(Color.White);
ControlPaint.DrawComboButton(e.Graphics, GetDownRectangle(), ButtonState.Normal);
base.OnPaint(e);
}
}

ToolStripDropDown loses mouse autoclose

Not sure how to explain this, but:
there is a control MyPopup, made out of ToolStripDropDown;
there are many based on MyPopup controls (call them popups);
there are no problems to open popup from the Form;
but there is is a problem to open popup from popup.
Problem is what after child popup is closed, parent popup stays on screen even when its parent Form get focus. The only way to close that stuck parent popup is to get focus to it (with the mouse) and hit Esc.
To have popup able to show another popup I have to trick Closing event:
void Popup_Closing(object sender, ToolStripDropDownClosingEventArgs e)
{
// prevent from closing when stay
if (_stay && e.CloseReason != ToolStripDropDownCloseReason.CloseCalled )
{
e.Cancel = true;
return;
}
}
Before of after closing child popup, parent popup has:
value of _stay is False;
the value of Popup.AutoClose is True;
I tried to "bring" mouse focus back to the parent popup with the following:
TopLevel=true no luck;
Focus(); no luck;
Focused=true; no luck;
AutoClose=true; no luck;
Captured=true; no luck;
Also tried setting above value to False and then to True, still no luck.
And here is some more code, which could be useful or not:
public class MyPopup : UserControl
{
protected bool _stay = false;
private ToolStripDropDown _popup;
private ToolStripControlHost _host;
public MyPopup()
{
// create popup
_popup = new ToolStripDropDown();
_popup.Margin = _popup.Padding = Padding.Empty;
_popup.AutoSize = false;
_popup.Closing += Popup_Closing;
// add host
_host = new ToolStripControlHost(this);
_host.Margin = _host.Padding = Padding.Empty;
_host.AutoSize = false;
_popup.Items.Add(_host);
}
public void Show(Control parent, int x, int y)
{
_popup.Show(parent, x, y);
}
public new void Hide()
{
_popup.Close();
}
private void Popup_Closing(object sender, ToolStripDropDownClosingEventArgs e)
{
// prevent from closing when stay
if (_stay && e.CloseReason != ToolStripDropDownCloseReason.CloseCalled )
{
e.Cancel = true;
return;
}
}
protected void PopupChildClosedDefaultEvent(object sender, EventArgs e)
{
// hide popup if mouse is outside of client region when closing child popup
if (!ClientRectangle.Contains(PointToClient(MousePosition)))
Hide();
else
{
// >> here I am trying different things <<
_popup.AutoClose = false;
_popup.AutoClose = true;
}
}
}
public class PopupParent: MyPopup
{
private void TestChildren()
{
_stay = true;
PopupChild popup = new PopupChild();
popup.Show(button1, 0, 0);
popup.Closed += PopupChildClosedDefaultEvent;
_stay = false;
}
}
public class PopupChild: MyPopup
{
}
Question: Is there any way to fix "broken" popup after it has lost its ability to autoclose on mouse event (clicking somewhere outside of the client area)?

Ok, morning bring some freshness to brains and I managed to solve that issue with following:
_popup.Close();
_popup.Show(_parent, _x, _y);
So I have to reshow popup to have it functioning as before. It flickers, but works.

How to prevent tooltip from flickering in custom control?

I have made a custom control and when a condition is met, I want to show a tooltip:
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
var plannedItem = GetPlannedItemByPosition(e.Location);
if (plannedItem != null)
_tooltip.SetToolTip(this, plannedItem.Description);
else
_tooltip.RemoveAll();
}
This code works fine, excepts for the face that the tooltip flickers.
This custom control, paints all the information in the OnPaint event, maybe this has something to do with it? And if it does, how can I prevent the tooltip from flickering?

Remember last mouse position and set the tooltip only when the mouse position changes.
public partial class Form1 : Form
{
private int lastX;
private int lastY;
private void button1_MouseMove(object sender, MouseEventArgs e)
{
if (e.X != this.lastX || e.Y != this.lastY)
{
toolTip1.SetToolTip(button1, "test");
this.lastX = e.X;
this.lastY = e.Y;
}
}

This will happen when you display the tooltip at the mouse cursor position. As soon as the tip window shows up, Windows notices that the mouse is located in that window and posts a MouseMove message. Which makes the tooltip disappear. Which makes Windows send a MouseMove message to your control, running your OnMouseMove() method. Which makes the tooltip appear again. Etcetera, you'll see the tooltip rapidly flickering.
Solve this by any of the following methods:
show the tooltip well away from the mouse position so it won't overlap the mouse cursor
only update/show the tooltip when it needs to be changed
set the control's Capture property to true so the tooltip won't get a MouseMove message

Since this is a painted custom control, I think it might be easier to just have a variable hold the last shown tip, and instead of always "setting" the tooltip, just show it.
Simple example (using just a form):
public partial class Form1 : Form {
private List<TipRect> _Tips = new List<TipRect>();
private TipRect _LastTip;
private ToolTip _tooltip = new ToolTip();
public Form1() {
InitializeComponent();
_Tips.Add(new TipRect(new Rectangle(32, 32, 32, 32), "Tip #1"));
_Tips.Add(new TipRect(new Rectangle(100, 100, 32, 32), "Tip #2"));
}
private void Form1_Paint(object sender, PaintEventArgs e) {
foreach (TipRect tr in _Tips)
e.Graphics.FillRectangle(Brushes.Red, tr.Rect);
}
private void Form1_MouseMove(object sender, MouseEventArgs e) {
TipRect checkTip = GetTip(e.Location);
if (checkTip == null) {
_LastTip = null;
_tooltip.Hide(this);
} else {
if (checkTip != _LastTip) {
_LastTip = checkTip;
_tooltip.Show(checkTip.Text, this, e.Location.X + 10, e.Location.Y + 10, 1000);
}
}
}
private TipRect GetTip(Point p) {
TipRect value = null;
foreach (TipRect tr in _Tips) {
if (tr.Rect.Contains(p))
value = tr;
}
return value;
}
}
Here is the TipRect class I created to simulate whatever your PlannedItem class is:
public class TipRect {
public Rectangle Rect;
public string Text;
public TipRect(Rectangle r, string text) {
Rect = r;
Text = text;
}
}

I imagine your mouse does move a little when you think it is still. I suggest you do some kind of caching here - only call _tooltip.SetToolTip if the plannedItem has changed.

For the visitors of this thread, here is what I did, following suggestions above (VB.NET):
Dim LastToolTip As String
Private Sub PictureBox1_MouseMove(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseMove
Dim NewToolTip = CalculateTooltipText(e.X, e.Y)
If LastToolTip <> NewToolTip Then
ToolTip1.SetToolTip(PictureBox1, NewToolTip)
LastToolTip = NewToolTip
End If
End Sub
It stopped the flickering.

c# (works on tooltip chart):
Point mem = new Point();
private void xxx_MouseMove(MouseEventArgs e){
// start
Point pos = e.Location;
if (pos == mem) { return; }
// your code here
// end
mem = pos
}