C# Discussion Boards - CodeProject

6-Jul-06 19:53

hi. i am trying to prevent the form from queueing repeat clicks.
i set the cursor to wait, but when the user clicks on a menu button it queues the command still.
i want it to ignore the command.
how do i do this?

i tried the following:

if(cursor.current == cursors.waitcursor)
return;
cursor.current = cursors.waitcursor;

Nader Elshehabi6-Jul-06 20:38

6-Jul-06 20:38

Hello
Check the MouseCapture property. Set it to true in an irrelevant control of your form -eg. the statusbar-, this way it will capture the mouse and no other control will respond to hovering or clicking, until you release the capture again by setting it to false in the same control.

Regards Rose | [Rose]

lushgrass6-Jul-06 21:02

6-Jul-06 21:02

can you please elaborate?
which mouse capture?

Nader Elshehabi6-Jul-06 21:22

6-Jul-06 21:22

Hello
There is a Control.Capture property in all controls. When you set it to true in any control, it will capture the mouse and the mouse click won't work until you click on something else once, then the control will lose its capture and the second click will work -remember: the first won't do anything- This will give you a chance to handle the MouseCaptureChanged event of that control to check if you intentionally released the mouse -you might want to use a boolean here-, or if the user clicked somewhere. If so, it will recapture the mouse. Here is a code snippit:

bool Release;
public void MyMethod()
{
     Release = false;
     UseWaitCursor = true;
     MyControl.Capture = true;
     //Do a lengthy operation...
     UseWaitCursor = false;
     Release = true;
     MyControl.Capture = false;
}

private void MyControl_MouseCaptureChanged(object sender, EventArgs e)
        {
            if(!Release)
               MyControl.Capture = true;
        }

Regards

lushgrass6-Jul-06 22:24

6-Jul-06 22:24

how do i associate the method with my control?

Nader Elshehabi6-Jul-06 22:58

6-Jul-06 22:58

What method?? The MyMethod is your method that does the lengthy operation. you write it from the scratch!! The other one is the event handler. Just select your control, then double click on its MouseCaptureChanged event in the event tab of its property grid.

If you don't already have a control to capture the mouse just make a dummy one:

Control MyControl = new Control();

lushgrass6-Jul-06 23:21

6-Jul-06 23:21

i cant seem to get the MouseCaptureChanged event on my dummy control, myControl.

myClass()
{
busy = false;
Control myControl = new Control();
myControl.Capture = false;
}

myLongMethod()
{
myControl.Capture = true;
busy = true;
Cursor.Current = Cursors.WaitCursor;

// work code

Cursor.Current = Cursors.Default;
busy = false;
myControl.Capture = false;
}

btw, i appreciate the help. it probably seems really simple and basic to you, but for some reason i cant get it to work.

Nader Elshehabi7-Jul-06 2:46

Re: hourglass mouse still clicking [modified]

7-Jul-06 2:46

Hello

Forgive me if I say that your code has some mistakes Blush | :O

. One of them is that you don't really recognize the scope of objects. if you declare an object in one method, it's destroyed & goes out of scope once the method is over -well, there are more details on this subject-.

Also you must add an event handler for your event to be handled by a method -notice the += operator below-

I'll assume that MyClass is your class, & it's driven from System.Windows.From

class MyClass : Form
        {
            Control Dummy;
            bool busy;
            MyClass()
            {
                Dummy = new Control();
                busy = false;
                Dummy.MouseCaptureChanged += new EventHandler(Dummy_MouseCaptureChanged);
            }

            public void MyLongMethod()
            {
                busy = true;
                Dummy.Capture = true;
                UseWaitCursor = true;

                // TODO: Add your code here

                busy = false;
                Dummy.Capture = false;
                UseWaitCursor = false;
            }

            void Dummy_MouseCaptureChanged(object sender, EventArgs e)
            {
                if (busy)
                    Dummy.Capture = true;
            }
        }

Happy programming Rose | [Rose]

lushgrass9-Jul-06 16:59

9-Jul-06 16:59

when i compile this code, i get the following error:
System.Windows.Forms.Control' does not contain a definition for 'MouseCaptureChanged

MS development environment 2003 version 7.1.3088
.net framework 1.1 version 1.1.4322 sp1

edit: turns out this event is only in 2.0

-- modified at 1:41 Monday 10th July, 2006

Nader Elshehabi9-Jul-06 20:49

9-Jul-06 20:49

Hello

lushgrass wrote:
turns out this event is only in 2.0

unfortunately that is true. Yet still the Capture property is present in the Framework 1.1 you are using. So instead of using the MouseCaptureChanged event. You may use the Control.LostFocus like this:

1- Change the event handler declaration to this:

Dummy.LostFocus += new EventHandler(Dummy_LostFocus);

2- And the event handler definition into this:

private void Dummy_LostFocus(object sender, System.EventArgs e)
{
    if(Busy)
        Dummy.Capture = true;
}

Regards

lushgrass9-Jul-06 23:26

9-Jul-06 23:26

so the end code should look like the following:

<br />
public class Form1<br />
{<br />
     private StatusBar status;<br />
     private bool busy;<br />
     private Control control;<br />
<br />
     public Form1()<br />
     {<br />
          status.Capture = true;<br />
          busy = false;<br />
          control = new Control();<br />
          control.Capture = false;<br />
          control.LostFocus += new EventHandler(control_LostFocus);<br />
     }<br />
<br />
     private void control_LostFocus()<br />
     {<br />
          if(busy)<br />
               control.Capture = true;<br />
     }<br />
<br />
     private void Search()<br />
     {<br />
          status.Text = "Searching";<br />
          busy = true;<br />
          control.Capture = true;<br />
<br />
          // search code here<br />
<br />
          control.Capture = false;<br />
          busy = false;<br />
          status.Text = "";<br />
     }<br />
}<br />

Nader Elshehabi9-Jul-06 23:40

9-Jul-06 23:40

Hello

Well, something like that. Yet there are two modifications

public class Form1
{
    private StatusBar status;
    private bool busy;
    private Control control;
    
    public Form1()
    {
        //status.Capture = true;    1)Don't put this or you'll lose capture to the status bar. Whyis that?
        busy = false;
        control = new Control();
        control.Capture = false;
        control.LostFocus += new EventHandler(control_LostFocus);
    }

    private void control_LostFocus()
    {
        if(busy)
            control.Capture = true;
    }

    private void Search()
    {
        status.Text = "Searching";
        busy = true;
        control.Capture = true;
    
        // search code here
    
        busy = false;    //2)This must be before changing the capture to false
        control.Capture = false;
        status.Text = "";
    }
}

NB.
Next time use the "pre" instead of "code" formatting

Regards Rose | [Rose]

lushgrass9-Jul-06 23:48

9-Jul-06 23:48

for some reason this doesnt resolve my issue.
if i click on search really quickly it still searches in series instead of ignoring the extra clicks.

Nader Elshehabi10-Jul-06 1:42

Re: hourglass mouse still clicking [modified]

10-Jul-06 1:42

If this is your problem simply add

if(busy)
    return;

at the beginning of the click event handler (ie. Button1_clicked) or the Search() method

Ragards Rose | [Rose]

lushgrass12-Jul-06 16:22