CODEWITHSUNDEEP
c#winformsmodal-dialog
johnc
johnc

Reputation: 40223

C# Delay Modal Dialog showing on Load, whilst allowing execution to continue

I have a form being displayed by a static method.

This static method calls ShowDialog on the form:

//Static method on LockWaitForm
public static LockDetails Lock(string lockedMessage, object[] params parameters)
{
        using (LockWaitForm form = new LockWaitForm(parameters))
        {
            form._lockedMessage.Text = lockedMessage;

            DialogResult result = form.ShowDialog();

            return new LockDetails (form._lockStatus, form._lock);
        }
 }

What I want is the OnLoad method of the dialog to wait up to one second before it shows, so it will only display if a lock on a record cannot be achieved after 1 second. It will happily drop out before one second if a lock is obtained before 1 second, setting its DialogResult to OK.

All functionality works fine except the hiding of the Dialog box for 1 second. All 'Visible = false' calls are ignored, and I can kind of understand why they would do that. The problem with this is that a false 'record is locked' will flash up for a sub second every time the form is used and a lock can be obtained without an issue.

I can figure out a few hacky ways to delay the visibility of the dialog box

Is it possible to limit the display of a Modal Dialog called through ShowDialog? I am reluctantly happy to PInvoke at this point (though I do want to limit non-64bit code for future requirements)

EDIT

By moving my acquire lock code to the form's constructor instead of Load, I can keep the locking code in one place, and just wait while the form's lock status is in a Waiting state before calling ShowDialog. Still feels dirty, but the cleanest method so far

Upvotes: 3

Views: 2699

Answers (3)

rice
rice

Reputation: 1063

What sort of lock? Just a normal thread lock? Can you just use Monitor.TryEnter?

If it returns false, the lock is busy and you can pop some sort of retry/cancel lock-waiting window.

If it's true though, just proceed with life as normal.

As a general comment, I really agree with Eric J that you should not be displaying the form until the lock has failed. It seems awkward to be using the error dialog to perform the ordinary workflow, and trying to secretly hide it in the non-error case.

Instead, you should have a proper workflow doing the lock entirely outside the error dialog, and pop the dialog only on the error workflow.

Upvotes: 1

MusiGenesis
MusiGenesis

Reputation: 75386

Not sure this would work, but: in your LockWaitForm, override ShowDialog() with your own version that calls the code to acquire a lock (or whatever it's doing), and then if more than 1 second passes, call this.ShowDialog() (the real one). This should allow you to only change the code in LockWaitForm, and not anywhere else.

Sorry, my laptop with Visual Studio is in a friend's trunk right now, so I can't check if this is possible.

Upvotes: 2

Eric J.
Eric J.

Reputation: 150198

I would refactor the application to not even display the modal dialog until the lock process has failed to achieve a lock for one second.

Upvotes: 3

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