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So I have looked through existing answers tagged with and have not found what I am looking for (as I type this, it is also not appearing in the Similar Questions area). For starters, note that I am NOT asking about saving and restoring the entire Workspace.

So here is the scenario. I have a graphical window (we will call it "Timeline") that is added upon user request. When it is added, it is automatically docked to the bottom-most area of the main form. The user then takes the Timeline window and redocks it somewhere else (could be docked to an edge, or within another docking pane) and changes its docking behavior (floating, auto-hide, tab, etc.).

A demonstrable example is in Visual Studio. If you have the Solution Explorer on a tab within an docked pane on the right and close Solution Explorer, you can go to View -> Solution Explorer and bring it back up again, and it restores to the correct location.

Now the user closes the Timeline window entirely by hitting the [x] on its pane, and in the future, they request to add it to the application again. I want to bring it back in the last dock state and position it was in when it was last closed.

Now, I appear to be able to catch the closing of the pane with the ContentRemoved event, but in there e.Content.DockHandler.Pane, e.Content.DockHandler.PanelPane and e.Content.DockHandler.FloatPane are all null so I have no obvious way to get the previous dock geometry. e.Content.DockHandler.DockPanel is valid, but it is the parent/root docking panel, and calling SaveAsXml(...) does nothing for me because it would get the entire workspace.

Even if I were able to capture it here, information I need. However, I do not appear to be able to simply call LoadFromXml(...) on anything either.

If I try to do it before the DockContent object is added to the DockPanel, DockHandler.DockPanel member is null, so I appear to have no place to restore the XML into, even if I was able to get it.

There are no other events hanging off of DockPanel that seem to be able to help me here.

So - is there a way to do this, and what is the correct way to do it? I want to make sure I am not barking up the wrong tree with trying to capture the dock information as XML when closed and restore it later.

I have toyed with the idea of not actually closing the window but just undocking and hiding it, but have not explored that very far yet. Same with hooking the DockChanged event, but it does not seem to fire on the DockContent objects being docked/floated/etc. and I am not sure why.

Also the solution needs to be robust enough so that I can correctly handle scenarios such as if the last docking parent no longer exists. For example, if it was docked as a tab somewhere, but now that parent window (containing the tabs) has also been closed. I do not know if LoadFromXml, presuming it is the right way to do, is robust enough to handle this scenario, as I have not been able to test it yet.

James R. Twine
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  • The request goes far beyond what DPS can offer. You will have to hack on your own I think. One hint is that your data cannot be persisted by the default XML. You should use your own file to store them. – Lex Li Oct 07 '15 at 14:49

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If I understand the question, what I do is to trap the Closing or FormClosing event, .Hide() the form and set e.Cancel = true. If you are using DockContent, then there is a HideOnClose() that does the work for you. Then when you want to "re-open" the window, you simply use an empty .Show(), and it will Show right where it was when you "closed" it. As far as saving if the last docking parent no longer exists, I agree with Lex Li, that will take a hack.

OldDog
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