How do I set a click event for a form?

Question

I have a c# form (let\'s call it MainForm) with a number of custom controls on it. I\'d like to have the MainForm.OnClick() method fire anytime someone clicks on the form re

Answer 1

This is a common pattern in development, its called the Observer pattern. There are lots of examples of Observer patterns and c# here is 1 example http://msdn.microsoft.com/en-us/library/ms954621.aspx but have a good google around.

Answer 2

I recommend creating a base form for the other forms in your application to inherit. Add this code to your base form to create a new event called GlobalMouseClickEventHandler:

namespace Temp
{
    public delegate void GlobalMouseClickEventHander(object sender, MouseEventArgs e);

    public partial class TestForm : Form
    {
        [Category("Action")]
        [Description("Fires when any control on the form is clicked.")]
        public event GlobalMouseClickEventHander GlobalMouseClick;

        public TestForm()
        {
            InitializeComponent();
            BindControlMouseClicks(this);
        }

        private void BindControlMouseClicks(Control con)
        {
            con.MouseClick += delegate(object sender, MouseEventArgs e)
            {
                TriggerMouseClicked(sender, e);
            };
            // bind to controls already added
            foreach (Control i in con.Controls)
            {
                BindControlMouseClicks(i);
            }
            // bind to controls added in the future
            con.ControlAdded += delegate(object sender, ControlEventArgs e)
            {
                BindControlMouseClicks(e.Control);
            };            
        }

        private void TriggerMouseClicked(object sender, MouseEventArgs e)
        {
            if (GlobalMouseClick != null)
            {
                GlobalMouseClick(sender, e);
            }
        }
    }
}

This solution will work not only for top-level controls, but also nested controls such as controls placed inside of panels.

Answer 3

You can hook all the control's events, if you like, and then monitor that way. I assume there is some uber fancy Win32 api way to trap them all, but that is beyond me at the moment.

    public Form1()
    {
        InitializeComponent();
        HookEvents();
    }

    private void HookEvents() {
        foreach (Control ctl in this.Controls) {
            ctl.MouseClick += new MouseEventHandler(Form1_MouseClick);
        }
    }  

    void Form1_MouseClick(object sender, MouseEventArgs e)
    {
        LogEvent(sender, "MouseClick");
    }

    // and then this just logs to a multiline textbox you have somwhere on the form
    private void LogEvent(object sender, string msg) {
        this.textBox1.Text = string.Format("{0} {1} ({2}) \n {3}",
            DateTime.Now.TimeOfDay.ToString(),
            msg,
            sender.GetType().Name,
            textBox1.Text
            );
    }

The output is something like this, showing all the events and who "sent" them up:

14:51:42.3381985 MouseClick (Form1) 
14:51:40.6194485 MouseClick (RichTextBox) 
14:51:40.0100735 MouseClick (TextBox) 
14:51:39.6194485 MouseClick (Form1) 
14:51:39.2131985 MouseClick (RichTextBox) 
14:51:38.8694485 MouseClick (Button) 

HTH.

Answer 4

Catching a click on an open space on the form is easy, but to get a click that's actually on a control, you'll need the cooperation of that control to send it to the form.

One possibility is to place a transparent control over the entire form, and accept clicks onto that, deal with them, and then pass them onto the proper control underneath.

Answer 5

In the form's ControlAdded event, add a MouseClick handler to the control, with the Address of the form's click event. I haven't tested this, but it might work.

Private Sub Example_ControlAdded(ByVal sender As Object, ByVal e As System.Windows.Forms.ControlEventArgs) Handles Me.ControlAdded

    AddHandler e.Control.MouseClick, AddressOf Example_MouseClick
End Sub

Private Sub Example_MouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseClick
    MessageBox.Show("Click")
End Sub

Answer 6

The only way I've ever managed to do this is to handle the [c]Click[/c] event of every control. I don't believe the event is raised before the control processes it.

In WPF, there are "tunneling" preview events that provide this functionality, but that doesn't really help you in WinForms.