We use cookies to give you the best experience on our website. If you continue to browse, then you agree to our privacy policy and cookie policy.
Unfortunately, activation email could not send to your email. Please try again.

Showing a hidden floating form with DockManager

Thread ID:





90902 Oct 23,2009 10:46 AM Nov 3,2009 05:07 AM Windows Forms 4
Tags: Tools
Mike Mann
Asked On October 23, 2009 10:46 AM

I have run into a problem when attempting to show a floating form that has been hidden. I was under the impression that SetDockVisibility() was responsible for setting the visibility of floating controls as well as docked controls, however I am getting a NullReferenceException when calling SetDockVisibility() on a control that has been floated.

When the control is hidden by clicking the Close button in the upper right corner of the floating form and then I try to make the form visible again using SetDockVisibility(), the following exception is thrown:
System.NullReferenceException: Object reference not set to an instance of an object.
at Syncfusion.Windows.Forms.Tools.FloatingForm.UpdateFormBorderStyle()
at Syncfusion.Windows.Forms.Tools.FloatingForm.OnVisibleChanged(EventArgs e)
at System.Windows.Forms.Control.WmShowWindow(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at System.Windows.Forms.ContainerControl.WndProc(Message& m)
at System.Windows.Forms.Form.WmShowWindow(Message& m)
at System.Windows.Forms.Form.WndProc(Message& m)
at Syncfusion.Windows.Forms.Tools.FloatingForm.WndProc(Message& msg)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Is there a solution or work around for this? Is this even the proper way of making a floating form visible again after closing it?

I am using Syncfusion v7.3.0.20.
I have been using sample code provided by Syncfusion from an old forum post:

Mike Mann
Replied On October 23, 2009 10:49 AM

Sorry, I forgot to include steps to reproduce in my first post.

1.) Start the sample
2.) Click the "Visiblity=true" button to make the panel visible.
3.) Drag the panel out of the form to make it float.
4.) Close the floating form by clicking the "X" in the upper right corner.
5.) Click the "Visiblity=true" button again to make the floating form visible again.

At this point the application should throw the exception and crash.

Mano J [Syncfusion]
Replied On October 27, 2009 05:42 AM

Hi Mike,

It is a known issue in We have fixed this issue and this fix will be available in volume 4 release, scheduled to be released on first week of November.


Mike Mann
Replied On October 27, 2009 10:02 AM

Would it be possible for you to provide us with a patch for this issue prior to the release of the next build?

Nandakumar R [Syncfusion]
Replied On November 3, 2009 05:07 AM


Can you please create a DirectTrac incident under your account in DirectTrac and we will post a patch in the incident?

Thanks for your interest in Syncfusion Essential Studio.



This post will be permanently deleted. Are you sure you want to continue?

Sorry, An error occured while processing your request. Please try again later.

You are using an outdated version of Internet Explorer that may not display all features of this and other websites. Upgrade to Internet Explorer 8 or newer for a better experience.