Develop Reference

WinForms tooltips not showing up

I have a WinForms application. Each form and user control sets up its tooltips as follows:
// in the control constructor
var toolTip = new ToolTip();
this.Disposed += (o, e) => toolTip.Dispose();
toolTip.SetToolTip(this.someButton, "...");
toolTip.SetToolTip(this.someCheckBox, "...");
...
However, the tooltips don't appear when I hover over the controls. Is this an appropriate way to use tooltips? Is there something that could be happening in another part of the application (e. g. listening to some event) that would stop tooltips from working?
Note that tooltips on my outer form's toolstrip buttons (which are configured via the button's tooltip property) do work as expected.
EDIT:
I've observed this more and I've noticed that sometimes the tooltip does show up, it is just extremely "flaky". Basically, sometimes when I mouse over a control it will show up very briefly and then flicker away. I can get it to show manually with .Show() and a long AutoPopDelay, but then it never disappears!

Your code seems ok to me. I couldnt find anything wrong in your code. But, it could be failed only when control is disabled. BTW, you can try another method like this. but, i would not like to suggest you to show the tooltip like this.
private void someButton_MouseEnter(...)
{
toolTip.Show("Tooltip text goes here", (Button)sender);
}
You can also assign the location where tooltip should be displayed in .Show() method. there are some overloaded function that you can use. Read the msdn for more information about ToolTip.Show() method.

I faced similar issue when my tooltip was not showing up over the RichTextBox once in about 3-5 times it normally should. Even forcing it to show explicitly with toolTip.Show didn't help. Until I changed to the way mentioned by Shell - you have to tell where you want your tooltip to appear:
'Dim pnt As Point
pnt = control.PointToClient(Cursor.Position)
pnt.X += 10 ' Give a little offset
pnt.Y += 10 ' so tooltip will look neat
toolTip.Show(text, control, pnt)
This way my tooltip always appears when and where expected.
Good luck!

I wrote the following method to "propagate" ToolTips from parent controls (that have a tool tip set) to its child controls (unless they have their own overriding ToolTip).
It's designed to be dropped into the form or control you're starting with, but it could also just be turned into a static method where the "parent" argument is required.
/// <summary>Setting a toolTip on a custom control unfortunately doesn't set it on child
/// controls within its drawing area. This is a workaround for that.</summary>
private void PropagateToolTips(Control parent = null)
{
parent = parent ?? this;
string toolTip = toolTip1.GetToolTip(parent);
if (toolTip == "")
toolTip = null;
foreach (Control child in parent.Controls)
{
// If the parent has a toolTip, and the child control does not
// have its own toolTip set - set it to match the parent toolTip.
if (toolTip != null && String.IsNullOrEmpty(toolTip1.GetToolTip(child)))
toolTip1.SetToolTip(child, toolTip);
// Recurse on the child control
PropagateToolTips(child);
}
}
Note that the behaviour is undefined if you're using more than one ToolTip instance to manage parent and child control toolTips.

Hide Tab Header on C# TabControl

I am developing a Windows Form Application with several pages. I am using a TabControl to implement this. Instead of using the header to switch between tabs, I want my application to control this e.g. the next tab should open after the user has filled in a text box and clicked the next button.

Add a new class to your project and paste the code shown below. Compile. Drop the new control from the top of the toolbox onto your form. It shows the tabs at design time so you can easily switch between them while designing. They are hidden at runtime, use the SelectedTab or SelectedIndex property in your code to switch the page.
using System;
using System.Windows.Forms;
public class TablessControl : TabControl {
protected override void WndProc(ref Message m) {
// Hide tabs by trapping the TCM_ADJUSTRECT message
if (m.Msg == 0x1328 && !DesignMode) m.Result = (IntPtr)1;
else base.WndProc(ref m);
}
}

tabControl1.Appearance = TabAppearance.FlatButtons;
tabControl1.ItemSize = new Size(0, 1);
tabControl1.SizeMode = TabSizeMode.Fixed;

Create new UserControl, name it for example TabControlWithoutHeader and change inherited UserControl to TabControl and add some code. Result code should look like:
public partial class TabControlWithoutHeader: TabControl
{
public TabControlWithoutHeader()
{
InitializeComponent();
}
protected override void WndProc(ref Message m)
{
if (m.Msg == 0x1328 && !DesignMode)
m.Result = (IntPtr)1;
else
base.WndProc(ref m);
}
}
After compile you will have TabControlWithoutHeader control in ToolBox. Drop it on form, in designer you will see headers, but at runtime they'll be hidden. If you want to hide them in designer too, then remove && !DesignMode.
Hope that helps.
http://social.msdn.microsoft.com/Forums/windows/en-US/c290832f-3b84-4200-aa4a-7a5dc4b8b5bb/tabs-in-winform?forum=winforms

You can replace tabcontrol with a hand made panel that mimic like you want:
class MultiPagePanel : Panel
{
private int _currentPageIndex;
public int CurrentPageIndex
{
get { return _currentPageIndex; }
set
{
if (value >= 0 && value < Controls.Count)
{
Controls[value].BringToFront();
_currentPageIndex = value;
}
}
}
public void AddPage(Control page)
{
Controls.Add(page);
page.Dock = DockStyle.Fill;
}
}
And then add pages and set current visible page:
MultiPagePanel p;
// MyTabPage is a Control derived class that represents one page on your form.
MyTabPage page = new MyTabPage();
p.AddPage(page);
p.CurrentPageIndex = 0;

I was needing this code but in VB.net so I converted it. If someone needs this code in VB.Net there it is
Imports System
Imports System.Windows.Forms
Public Class TablessControl
Inherits System.Windows.Forms.TabControl
Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
' Hide tabs by trapping the TCM_ADJUSTRECT message
If (m.Msg = Convert.ToInt32("0x1328", 16) And Not DesignMode) Then
m.Result = CType(1, IntPtr)
Else
MyBase.WndProc(m)
End If
End Sub
End Class
and thanks to #Hans Passant for the answer in C#

To complement Hans Passant's existing answer, I've found four ways to hide the arrows from the user when the numbers of tabs exceeds the width of the TablessControl. No single solution is necessarily perfect for everyone, but may be for you (or at least a combination of them).
Solution 1:
Simply enable Multiline. This will prevent the arrows from appearing in the first place. However, bear in mind, you may lose WYSIWYG in the designer because the vertical space will be adjusted downwards vertically, and controls within the TablessControl may even be 'chopped off' at the bottom (again, only in developer mode though).
Solution 2:
A more advanced solution which solves the WYSIWYG problem above is to only enable Multiline once the program gets running. Simply add this constructor to the TablessControl class:
public TablessControl()
{
bool designMode = (LicenseManager.UsageMode == LicenseUsageMode.Designtime);
if (!designMode) Multiline = true;
}
To the developer, they will still appear as a single line of tabs.
Solution 3:
Decrease the font size of the TablessControl. Each tab should shrink accordingly. Since the user never gets to see the tabs, it shouldn't matter much if you set the font sizes to even 4pt.
However be careful, because the TablessControl's contents may also be resized. If this happens, re-edit the font size for each widget inside, and at that point, they'll thankfully stay at that size even if you then decide to re-change the main TablessControl's font size again.
This approach also has the advantage of more closely showing the true WYSIWYG vertical real-estate to the developer (which can look fine for the user, but may be cut off slightly at the bottom in the designer due to the height of the tabs).
This solution can be combined with Solution 1 and 2 for accumulated advantages.
Solution 4:
This solution isn't necessarily so great if any of the tabs have text which are long. Thanks to Hans for suggesting it.
First set the TablessControl's SizeMode to 'Fixed', and then reduce the TablessControl's ItemSize Width property to a smaller number to reduce each tab's width. Feel free also to adjust the ItemSize Height property to help address the aforementioned WYSIWYG issue, though Solution 3 may be more helpful for that problem.
This solution can be combined with the above solutions to further accumulate advantages.

If you really want to do this, yo can do something like this
tcActionControls.Region = new Region(new RectangleF(
tbPageToShow.Left,
tbPageToShow.Top,
tbPageToShow.Width,
tbPageToShow.Height)
);
Where tcActionControls is your TabControl and tbPageToShow is a TabPage to show in this precise moment.
Should work for you.
Regards.

This solution appears to work well -
How to hide tabs in the tab control?
Insert Tabcontrol into a form, the default name being tabcontrol1.
Ensure that tabcontrol1 is selected in the Properties pane in visual studio and change the following properties:
a. Set Appearance to Buttons
b. Set ItemSize 0 for Width and 1 for Height
c. Set Multiline to True
d. Set SizeMode to Fixed
This is best done after your have finished your design time tasks as it hides them in the designer as well - making it difficult to navigate!

You can try removing the TabPage from the TabPageCollection :
TabControl.TabPageCollection tabCol = tabControl1.TabPages;
foreach (TabPage tp in tabCol)
{
if(condition)
{
tabCol.Remove(tp);
}
}

In my WinForms app, I was able to work around this by positioning the TabControl's y-coordinate outside the visible range of the form, so the tabs were effectively hidden. This example only works if the tabControl is near the top of the form, but you get the idea.
private void frmOptions_Load(object sender, EventArgs e)
{
tabControl1.Top = -23; //Only tabPage contents visible
}

C# windows form 2 gridviews with synced scroll

I am developing an application in which two datagridviews are being populated from different data sources. I would like to have a single vertical scroll-bar that will make both gridviews work at the same time (scroll up and down together)
can anyone tell me how or direct me to a good tutorial.

If you have dgv1 and dgv2, you can create something like
dgv1.Scroll += new System.Windows.Forms.ScrollEventHandler(dgv1_Scroll);
Then, in dgv1_Scroll method, you can use FirstDisplayedScrollingRowIndex property:
dgv2.FirstDisplayedScrollingRowIndex = dgv1.FirstDisplayedScrollingRowIndex
Of course, if dgv's have different ammount of rows, you need to avoid IndexOutOfRange exception by checking each dgv rows count.

Use HorizontalScrollingOffset (or VerticalScrollingOffset).
this.dataGridViewDataSample.HorizontalScrollingOffset

I believe you can set up an event-like scenario, where whenever scrollbar A's "value" changes, change scrollbar B to the appropriate value as well.
(Note that value is a property of a scroll bar, I do not mean the value of the data inside the container.)
Please see the following msdn article regarding that property of a scroll bar for better reference:
http://msdn.microsoft.com/en-us/library/system.windows.forms.scrollbar.value.aspx
And the class itself --
http://msdn.microsoft.com/en-us/library/system.windows.forms.scrollbar.aspx

You could put the DataGridViews in Panels and use this:
public Form1()
{
InitializeComponent();
panel1.Scroll += new ScrollEventHandler(panel1_Scroll);
}
void panel1_Scroll(object sender, ScrollEventArgs e)
{
panel2.AutoScrollPosition = new Point(0,e.NewValue);
}
Unfortunately it does not seem that DataGridView has this property.

http://www.xs4all.nl/~wrb/Articles_2010/Article_DataGridViewScroll_01.htm
This link shows exactly what I needed and worked fine for me. The only problem I have now is that the datagrids does not have same rows in it. So even when one finishes (no more to scroll) the other must be able to continue.
Any suggestions?

take a look at this. i wanted to sync two listviews when i scroll any of them. u can achieve this using custom controls. code works like a charm.

_dataGridViewInput.Scroll += new ScrollEventHandler(_dataGridViewInput_Scroll);
_dataGridViewOutput.Scroll += new ScrollEventHandler(_dataGridViewOutput_Scroll);
void _dataGridViewInput_Scroll(object sender, ScrollEventArgs e)
{
this._dataGridViewOutput.FirstDisplayedScrollingRowIndex = this._dataGridViewInput.FirstDisplayedScrollingRowIndex;
}
void _dataGridViewOutput_Scroll(object sender, ScrollEventArgs e)
{
this._dataGridViewInput.FirstDisplayedScrollingRowIndex = this._dataGridViewOutput.FirstDisplayedScrollingRowIndex;
}

Why is my ListBox throwing an exception?

Okay, I was able to create a simple Windows Forms project that reproduces some strange behavior I found. In the designer, make a form with a ListBox (named lbx) anchored Top, Left, Right, and Bottom, and a button (button1). Now, the Form's code is here:
using System;
using System.Windows.Forms;
namespace ListBoxKaboom
{
public partial class Form1 : Form
{
private bool _initFinished = false;
public Form1()
{
InitializeComponent();
this._initFinished = true;
this.Height += 100;
this.Height -= 50;
this.Height += 50;
}
private void lbx_SelectedIndexChanged(object sender, EventArgs e)
{
this.button1.Enabled = (this.lbx.SelectedItem != null);
}
protected override void OnLayout(LayoutEventArgs e)
{
if (_initFinished)
{
int lines = (this.lbx.Height - 4) / this.lbx.ItemHeight;
this.SuspendLayout();
while (lines < this.lbx.Items.Count)
{
this.lbx.Items.RemoveAt(this.lbx.Items.Count - 1);
}
while (lines > this.lbx.Items.Count)
{
this.lbx.Items.Add("Item " + (this.lbx.Items.Count + 1).ToString());
}
this.ResumeLayout();
}
base.OnLayout(e);
}
}
}
PLEASE NOTE THE FOLLOWING INSTRUCTIONS:
Run this, click any of the items in the list box, and use the arrow keys to move down far enough to cause the list box to scroll. Kaboom.
Exception (sometimes NullReferenceException and sometimes IndexOutOfBoundsException). Any ideas why? Also, I would think that the items would be in order, but they're not. Is this just a goofy corner case that didn't get handled properly by Windows Forms, or am I doing something wrong?
Stack trace:
at System.Windows.Forms.ListBox.NativeUpdateSelection()
at System.Windows.Forms.ListBox.SelectedObjectCollection.EnsureUpToDate()
at System.Windows.Forms.ListBox.SelectedObjectCollection.get_InnerArray()
at System.Windows.Forms.ListBox.SelectedObjectCollection.get_Item(Int32 index)
at System.Windows.Forms.ListBox.get_SelectedItem()

I Copy/Pasted it to an empty Form and get a StackOverflow exception. Looking at it, with manipulation of the Items inside a Layout event I would say you deserve little better.
I realize this may be a simplification of something else, but there simply are limits to what you can do in a EDS.
My best guess: The ResumeLayout triggers a recursive layout operation. You could try to stem it with a sibling to _initFinished but I would suggest rethinking tour design here.
I copy/pasted wrong, my bad (used layout event).
Second try:
based on the two while-loops I would expect the Item strings to be in order, and no vertical scrollbar. It is clear that the listbox is confused, showing vertical scroll range and with the items out-of-order. So some 'error' is already present in the internals of the Listbox, waiting for a Scroll. I can also reproduce it with the mouse.
A workaround: You should be able to get the desired effect using the Resize event.
Attempt to an explanation: The (unmanaged part of the) Listbox gets confused by (multiple) Add/RemoveAt operations with suspended Layout. The last items are drawn at the wrong place, and the Listbox can't compute pixel-to-item.

You should not manipulate any GUI elements in the
constructor, e.g. this.Height += 100; in your example.
Strange things can happen. I have been bitten by this
several times in legacy code.
Wait until form load time - handle the base.Load event and do the
height manipulation there.
From "When does Form.Load event get raised?":
Q: "... I need to find out basically
what the difference is between
putting code in Load event's handler,
versus putting code in the Form's
constructor after the
InitializeComponents() line ..."
A: "The Load event is fired once the
control/form has been fully
initialized and has a window handle
created. Therefore once this event
has fired it is a fully usable user
interface control. Remember that
inside the constructor the actual
window handle for the control/form has
not yet been created, you are only
creating C# objects here and inside
the InitializeComponent call."

Windows Forms ToolTip will not re-appear after first use

I have a Windows Forms C# application where I would like to use a tooltip on one of the text boxes. I initialize the tool-tip in the constructor of the Form class, and it works the first time. So when I hover over the text box with my mouse it works, but once the toolTip times out and it goes away, it does not re-appear when I move my mouse away and back onto the control. I would expect it to come back. What am I doing wrong?
Here is how I initialize the tooltip:
myTip = new ToolTip();
myTip.ToolTipIcon = ToolTipIcon.Info;
myTip.IsBalloon = true;
myTip.ShowAlways = true;
myTip.SetToolTip(txtMyTextBox,"My Tooltip Text");

I had a similar problem today. Sometimes, the tooltip would not show. I had one ToolTip control for all the controls in my form.
I also had a MouseEnter event on all the controls added automatically, so I modified the MouseEnter event to do:
_tooltip.Active = false;
_tooltip.Active = true;
It fixed the bug, but I don't know why.
Also, the bug always happened on Windows XP machines, but not on Windows Vista.

I guess you'll be happy to know that Microsoft knows about it...since about 5 years...
2/21/2005 Bug acknowledged as reproducable
3/29/2005 Hum we might fix it, but later...
11/15/2005 Well actually it's not a big bug, and it doesn't happen much, so we won't fix it.
Damn I love it when I stumble on bugs Microsoft doesn't want to solve! This time it's called a corner case, last time it was simply too difficult to resolve...
http://connect.microsoft.com/VisualStudio/feedback/details/115385/tooltip-stop-showing-after-autopopdelay
I'm off to tell my client that the bugs in my program are just corner cases and too difficult to resolve...

I had a similar problem today. VS 2010 SP1 .Net 3.5
After AutoPopDelay-Time the ToolTip do not show the Controls ToolTipText.
Kevins solution is the only way to solve the problem.
I encapsulate this in my own ToolTip class:
public class ToolTip : System.Windows.Forms.ToolTip
{
public ToolTip() : base() { }
public ToolTip(System.ComponentModel.IContainer components) : base(components) { }
public new void SetToolTip(System.Windows.Forms.Control ctl, string caption)
{
ctl.MouseEnter -= new System.EventHandler(toolTip_MouseEnter);
base.SetToolTip(ctl, caption);
if(caption != string.Empty)
ctl.MouseEnter += new System.EventHandler(toolTip_MouseEnter);
}
private void toolTip_MouseEnter(object sender, EventArgs e)
{
this.Active = false;
this.Active = true;
}
}

I had this issue in VB.NET. What I did was drop a TooTip control on the form, and then on the target control's MouseHover event, I set the properties of the ToolTip. I did this because I used one ToolTip control for five different Label controls. It worked great. (Really, I wanted the ToolTip to show immediately, so I used the MouseEnter event instead.) I can post my exact code tomorrow when I get to work.

I solved this problem by this
if (t == null)
{
t = new ToolTip();
}
t.IsBalloon = true;
t.ToolTipTitle = "Stop";
t.ToolTipIcon = ToolTipIcon.Error;
t.Show("", yourControlonWhichToApplyToolTip, 0);
t.Show("PDescription", yourControlonWhichToApplyToolTip, 1000);
Note i have added an empty tooltip.

For what it's worth, I was having this problem on my Windows XP system until I noticed that if I placed at least one tooltip control on my form manually (from the toolbox) I could create as many tooltips as needed within my code, and they would all work.
If, however, I tried to create all tooltips in code (say for instance in the formload event) the tips would only show once and never to be seen again. I can't give you the exact "why this happens" story, but I have duplicated this issue several times always with the same effect. It might have something to do with the object scope, but I'm not sure.
So now just as a habit, I always include at least one Visual Studio tooltip control and then the rest within my code.

I just had the the problem on Windows 7 so I found this thread.
In my case this did not work in tooltip_MouseEnter:
tooltip.Active = false;
tooltip.Active = true;
So I tried the following:
this.toolTip.SetToolTip(this.txtbx1, "tooltip-text");
This worked fine for me.

In my case after setting the tooltip text with the SetToolTip method, I used the Show overload with duration parameter, i.e.
toolTip.Show(text, textEdit, 1000);
After that tooltip did not reappear on mouse hover, and resetting tooltip.Active didn't work..
A workaround that worked for me was to use Show overload without the duration, and hide it manually afterwards:
toolTip.Show(text, textEdit);
new Task(() =>
{
Thread.Sleep(750);
textEdit.Invoke(new Action(() => toolTip.Hide(textEdit)));
}).Start();
With this code I have the desired behaviour, i.e.
The tooltip is shown at once for 750 millisec. after the tooltip text has changed
The tooltip does appear for the specified time when the mouse is over the control

System.Windows.Forms.ToolTip ToolTip1 = new System.Windows.Forms.ToolTip();
private void textBox_MouseHover(object sender, EventArgs e)
{
ToolTip1.Show("YOUR TEXT", textBox);
}
private void textBox_MouseLeave(object sender, EventArgs e)
{
ToolTip1.Active = false;
ToolTip1.Active = true;
}