Only dock control once

[scottw]

How can I ensure that a UserControl that has been docked to an MDIForm doesn't get docked a 2nd time?  That is, I need a control to only be visible once.  I tried making it a singleton class, but calling the DockControl of the RadDock still added a new visual element, though one was an empty shell.

I tried to find a list of controls or some other addressable way but failed.

Thanks,

VSmirk

[Richard Slade]

Hi VSmirk,

Have a look at my replies in this forum post which may help you. If that's not what you mean, then let me know a bit more about what you have and I'll do my best to help.
Thanks
Richard

[Richard Slade]

Hello,

Did this help? If so please remember to mark as answer. If you need further assistance, let me know
thanks
Richard

[Julian Benkov]

Hi Vania,

Like Richard said, you can find and use the solution from the given forum thread. In addition, you can use following code snippet for your scenario:

public partial class DockForm : Form
{
    public DockForm()
    {
        InitializeComponent();
    }

    private void radButton1_Click(object sender, EventArgs e)
    {
        UserControl myControl = new UserControl();
        DockControl(myControl);
    }

    private void DockControl(UserControl myControl)
    {
        foreach (DockWindow dockwindow in this.radDock1.DockWindows)
        {
            if (dockwindow.Controls.Count > 0 && dockwindow.Controls[0] == myControl)
            {
                return;
            }
        }

        this.radDock1.DockControl(myControl, DockPosition.Fill);
    }
}

I hope this was helpful.

Kind regards,
Julian Benkov
the Telerik team

[scottw]

Julian,

Thank you for your post.  Your solution presumes the control is a singleton, and does not work otherwise as the caller of the function instantiates an entirely new instance.  But I think I can make it work.  

While I can make the UC a singleton and avoid the creation of the control the 2nd time, I am not able to delete the static instance of the user control as I cannot find a reliable event in which to do this.

I tried a variation on your code and tested the name rather than the instance, but it appears there is a different problem.  Closing the control does not appear to unload it from the dock window's controls.

private void ShowLibraryMaintenance()

{

    ucLibraryInfoBar _ucLibraryInfoBar = new ucLibraryInfoBar(_logic);

    _ucLibraryInfoBar.Name = "LibraryInfoBar";

    ShowInfoBar(_ucLibraryInfoBar);

 

    FrmLibraryMaintenance _frmLibraryMaintenance = FrmLibraryMaintenance.Instance(_logic, OnSelectedSongChanged);

    _frmLibraryMaintenance.MdiParent = this;

    _frmLibraryMaintenance.Show();

 

    //sets visibility of menu items based on access control

    SetMenuItems();

 

}

 

private void ShowInfoBar(UserControl libraryInfoBar)

{

    foreach (DockWindow dockwindow in this.rdMainDock.DockWindows)

    {

        if (dockwindow.Controls.Count > 0 && dockwindow.Controls[0].Name == "LibraryInfoBar")

        {

            return;

        }

    }

    HostWindow _libHost = rdMainDock.DockControl(libraryInfoBar, DockPosition.Left);

    _libHost.DockTo(_libHost, DockPosition.Fill);

    ((ucLibraryInfoBar) libraryInfoBar).LoadControls();

    _libHost.Text = "Library";

}

When I close the LibraryInfoBar and refire the ShowLibraryMaintenance method, the dockwindow.Controls.Count is still greater than 0. 

Thank you!

[Julian Benkov]

Hi VSmirk,

In this case you can change the close action of created HostWindow:

...

HostWindow _libHost  = rdMainDock.DockControl(libraryInfoBar, DockPosition.Left);
_libHost.CloseAction = DockWindowCloseAction.CloseAndDispose;

...

Kind regards,
Julian Benkov
the Telerik team