We Keep Coding

Windows Forms click event not fired when clicking on label?

I have Windows Form TestForm, and in my Form I have several labels that are only used to display some text.
I need to display a MessageBox.Show anytime the Form is clicked. So I have an event handler for the click, which looks like this:
private void TestForm_Click(object sender, EventArgs e)
{
MessageBox.Show("The form has been clicked");
}
Unfortunately, the click event doesn't fire when I click over a label in the Form. Is there a way to fix this, besides consuming the click event for the labels?
Thanks.

To use the same click event for all labels:
In the properties for each label, go to the Events (lightning bolt tab).
You will see (probably near the top) a label for Click, click the dropdown for this event, and you will be shown a list of handlers that you could use for that label.
Here's the Properties > Events > Click handler (bottom right):
Because all of your labels are of the same type, and produce the same EventArgs, you are able to use the same handler for all of them.
Then, when you are adding more Labels, just choose the event handler from the Click event dropdown:
Hope this helps!

To flesh out LarsTech's comment, I have used something like this in the past when I was having problems with labels overlapping each other and lack of true transparency in WinForms. What I did was make the labels invisible on the Form, then iterate through them in the Form's paint event, pull the information out of them and then use Graphics.DrawString to draw the text. That way you you will still be able see them in design mode.
This is a quick example of what I mean.
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Paint(object sender, PaintEventArgs e)
{
foreach (var temp in this.Controls)
{
if (temp is Label) //Verify that control is a label
{
Label lbl =(Label)temp;
e.Graphics.DrawString(lbl.Text, lbl.Font, new SolidBrush(lbl.ForeColor), new Rectangle(lbl.Location, lbl.Size));
}
}
}
private void Form1_Click(object sender, EventArgs e)
{
MessageBox.Show("The Form has been clicked");
}
}

How to get all KeyPress events as a UserControl in C#?

I've read quite some articles now about key press events but I can't figure out how to get them. I know that only the current control with keyboard focus gets the press events. But how can i ensure that my user control has it?
Tried this without luck:
public partial class Editor : UserControl
this.SetStyle(ControlStyles.Selectable, true);
this.TabStop = true;
...
//take focus on click
protected override void OnMouseDown(MouseEventArgs e)
{
this.Focus();
base.OnMouseDown(e);
}
...
protected override bool IsInputKey(Keys keyData)
{
return true;
}
And also this:
//register global keyboard event handlers
private void Editor_ParentChanged(object sender, EventArgs e)
{
if (TopLevelControl is Form)
{
(TopLevelControl as Form).KeyPreview = true;
TopLevelControl.KeyDown += FCanvas_KeyDown;
TopLevelControl.KeyUp += FCanvas_KeyUp;
TopLevelControl.KeyPress += FCanvas_KeyPress;
}
}
The latter gave me the key down and up events, but still no key press. Is there any other method i can use to just get every down/up/press events when my control inherits from UserControl?
Edit:
As there was a comment linking another SO question: It's important that I also get the KeyPress event, since it sends the correct character on every keyboard no matter which language. This is important for text writing. If you only get the individual keys you have to process them into the correct character on your own. But maybe there is a convenience method to transform the pressed keys into a localized character?

Set your parent form's (contains the usercontrol) KeyPreview property to true
Add a new KeyPress event to your parent form
Set the parent form keypress event to forward the event to your usercontrol:
private void parentForm_KeyPress(object sender, KeyPressEventArgs e)
{
// Forward the sender and arguments to your usercontrol's method
this.yourUserControl.yourUserControl_KeyPress(sender, e);
}
Replace the yourUserControl1_KeyPress method with your own method, which you want to run each time the user presses a button (the button is pressed down and then released).
You can also create a new KeyPress handler to your usercontrol, and forward the sender and KeyPressEventArgs objects there, as in this example.

Can you attach to form event.
Private Sub MyControl_Load(sender As Object, e As EventArgs) Handles Me.Load
Dim f = Me.FindForm
If Not f.KeyPreview Then Throw New Exception("Form requires has Keypreview enabled")
AddHandler f.KeyUp, Sub(sender2 As Object, e2 As KeyEventArgs)
End Sub
End Sub

How do I make buttons do the same thing?

I just started programming, and I want to use WinForms to make multiple buttons that you can click on to change from white to lime-green and back to white. I have done this for one button:
private void button1_Click(object sender, EventArgs e)
{
if (button1.BackColor != Color.Lime)
{
button1.BackColor = Color.Lime;
}
else
{
button1.BackColor = Color.White;
}
}
Now I could copy and paste that for all of the buttons, but I know that is inefficient; and if I use winforms to reference button1 on button2, it will just change the color of button1 (obviously).
So, do I need to use a helper method, new class, or something else? What would that look like?

There are a couple of approaches. One might be to create a common function which the different buttons call:
private void button1_Click(object sender, EventArgs e)
{
ChangeColor(button1);
}
private void ChangeColor(Button button)
{
if (button.BackColor != Color.Lime)
button.BackColor = Color.Lime;
else
button.BackColor = Color.White;
}
Then each button handler can use that same function call.
Or, if all of these buttons will always ever do exactly the same thing, then you can use one click handler function for all of them. In this case what you'd need to do is determine which button invoked the handler (whereas you're currently referencing button1 directly) so that you know which one to change. The sender object passed into the handler function is actually a reference to the form element which invoked the handler. All you need to do is cast it:
private void button_Click(object sender, EventArgs e)
{
var button = (Button)sender;
if (button.BackColor != Color.Lime)
button.BackColor = Color.Lime;
else
button.BackColor = Color.White;
}
So first the handler grabs a reference to the button which invoked it, then runs the logic on that button. Note also how I made the name of the handler function slightly more generic. Now you'd go to the form designer and set button_Click as the click handler for all of the buttons which should invoke this.

You do this the exact same way you'd do it for any C# class. You derive your own class and customize the base class behavior. Every event has a corresponding OnXxxx() method that you can override.
Add a new class to your project and paste this code:
using System;
using System.Windows.Forms;
class MyButton : Button {
protected override void OnClick(EventArgs e) {
// Your code here
//...
base.OnClick(e);
}
}
Change the code in OnClick() to do what you want to do. Compile. You'll now have your own button control on the top of the toolbox. And can drop as many copies of it as you want on a form. They'll all behave the same without having to add any code in the form.

Probably the easiest way would be to have each button invoke the same click handler. Then inside of your handler use the Sender instead of hard coding Button1.
private void buttons_Click(object sender, EventArgs e)
{
var theButton = (Button) sender;
if (theButton.BackColor != Color.Lime)
{
theButton.BackColor = Color.Lime;
}
else
{
theButton.BackColor = Color.White;
}
}

You can get the button that raised the Click event by casting sender to Button.
You can then add the same handler to every button.

I'm a VB guy.... in VB.Net you can add multiple handlers for events and connect multiple events to the same handler.
This sub hooks all clicks to color the buttons.
Private Sub ColorButtons(sender As System.Object, e As System.EventArgs) _
Handles Button1.Click, Button2.Click, ..
I do this all the time accidentally because I drag/copy a control to make a new one and the new button gets added to the original's events.
Other Subs can handle the same events to do other work - both will execute.
No idea how to do this in C#.

The proper way to do this really is to associate each button's click event to the function you have coded for that purpose (you want the function to run when the button is clicked, right?), so add the following (or similar) to an appropriate section of your code:
MyButton1.Click += new RoutedEventHandler(buttons_Click);
MyButton2.Click += new RoutedEventHandler(buttons_Click);
etc...
You can associate as many controls to the event handler as you like.

What I usually do before is this:
private void button2_Click(object sender, EventArgs e)
{
button1.PerformClick();
}
This code will just simply run the codes under button1_Click.
But try not to practice as such and just simply put it in a function/method just like what David suggested.

How to sync up to different events in Winforms

If I have a button which does something and also a double-click event on a data grid which I want to do the same thing, what is the best way to ensure that only one function has to be maintained?
Apart from doing the following, is there any fancy C# way to indicate that two events are to do the same thing?
void button1_Click(...) { MyFunction(); }
void dataGrid1_DoubleClick(...) { MyFunction(); }
void MyFunction() { // do stuff }

I suppose that you are talking about a DataGridView (WinForms) so the signature of the event DoubleClick in the DataGridView and the signature of Click event on a button control is the same.
(An EventHadler). In this case you can simply set the same method using the form designer or manually bind the event
dataGridView1.DoubleClick += new EventHandler(MyFunction);
button1.Click += new EventHandler(MyFunction);
Of course the MyFunction method should match the expected signature of an EventHandler
private void MyFunction(object sender, EventArgs e)
{
// do your work
}
Reviewing my answer after a few minutes I wish to add:
If you find yourself in a situation in which you need to differentiate between the controls using the sender object (like Control c = sender as Control; if (c.Name == "someName") ) I really suggest you to return to the first idea. Call a common method but keep the EventHandler separated for each control involved.

Using VS, in the form's designer view You can set the procedure You want to call to each control's each event in the control's properties window.
image

Just to add to what Steve said, you will want to bind these events to your function manually in the Load event of your form, instead of using the events under the lightning bolt in the properties window in the designer, like so:
private void Form1_Load(object sender, EventArgs e)
{
button1.Click += MyMethod;
dataGridView1.DoubleClick += MyMethod;
}
void MyMethod(object sender, EventArgs e)
{
//Do Stuff
}
Also, declaring a new instance of the EventHandler class has been redundant since Anonymous methods were introduced to C#, you can just point the event directly at the method as shown above.

Which control has been clicked?

I have a problem with MouseEvents on my WinForm C# application. I want to get ALL mouse clicks on my application.
How to determine which control has been clicked ?(I'm beginner C#)

Try this:
private void Control_Clicks(object sender, EventArgs e)
{
Control control = (Control)sender; // Sender gives you which control is clicked.
MessageBox.Show(control.Name.ToString());
}
This, this or this may help.
Hope it helps.

private void Form1_Load(object sender, EventArgs e)
{
SetupClickEvents(this);
}
/// <summary>
/// This will loop through each control within the container and add a click handler to it
/// </summary>
/// <param name="container">The container whose children to handle clicks for</param>
private void SetupClickEvents(Control container)
{
foreach(Control control in container.Controls)
{
control.Click += HandleClicks;
}
}
private void HandleClicks(object sender, EventArgs e)
{
Control control = (Control)sender;
MessageBox.Show(string.Format("{0} was clicked!", control.Name));
}

If you're doing Windows Forms, you have several options :
Hook mouse event, and after figure out if the clicked component actually makes part of your application
You can declare a base class MyComponent : Control. That component overrides MousClick event and raise a special event notifying about a fact. Every control in your app derive from that control, so every control will notify about click happened on it. It's enough to subcribe
to thier events and process them as requested.
Just a couple of ideas...

You'd have to wire them all up to the same event handler. This can be done in the properties window for the controls in question. You could also write your own function to traverse the control tree and tie the function to each of their event handlers.
You can recursively traverse the Form.Controls collection with a foreach loop.
void attachGlobalHandler(Control aToParse, EventHandler aGlobalHandler)
{
foreach(Control lControl in aToParse.Controls)
{
attachGlobalHandler(lControl, aGlobalHandler);
lControl.Click += aGlobalHandler;
}
}
And then you call that on your form, with the name of the function you want to call:
attachGlobalHandler( Form1, myClickHandler );
And that should tie it to EVERY clickable control on the form. The sender argument of the handler should then always refer to the control that fired the event. That being said, I'd probably just attach individual event handlers, unless you need to treat multiple controls as a group.
WARNING: The code above is untested.

For the second question asked "How to determine which control has been clicked?" each control has events which may be handled in code.
The easiest way to know when a control has been clicked is to attached to the clicked event of a control which is done from the properties for the control. You may have to click the lightning bolt icon to see the events. Double-clicking beside the even will create an empty handler.
For example if you had a simple form with a single button attaching click events to the form and to the button will tell you when there is a click anywhere. In most cases the button click would be the most useful to handle.
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Click(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
}
}

It's really simple!
On your click event in your Win-Form, You add
// Here is a modified version of your code:
private void Form1_Click(object sender, EventArgs e)
{
var control = Form1.ActiveControl;
}