DevForce Community Forum : Duplicate ViewId's

Duplicate ViewId's : Works great. Tx.

Thu, 11 Oct 2007 07:27:05 -700

Author: orcities
Subject: 486
Posted: 11-Oct-2007 at 7:27am

Works great. Tx.

Duplicate ViewId's : Congratulations--you've found...

Wed, 10 Oct 2007 16:46:09 -700

Author: Bill Jensen
Subject: 486
Posted: 10-Oct-2007 at 4:46pm

Congratulations--you've found a genuine "undocumented feature" in CAB. It took Ward and myself quite a while to figure it out.

It turns out that when a view is being built (a consequence of ViewFactory.AddNew<>(), the object builder traverses the view's control hierarchy and adds certain controls to the Items collection of the workitem. These are:

SmartParts (doesn't happen often because we rarely add SmartParts statically to a view),

Workspaces,

and

SmartPartPlacehoders.

These are added to the workitem Items collection using a key value composed of

1. The value of the control's Name property

and

2. The name of the control's type.

If the control's Name property is null, a GUID is used instead.

When the first ThreePanelView is created, its SmartPartPlaceholders are added to the items collection using the names mLeftSmartPartPlaceholder, etc. When the second ThreePanelView is created, it attempts to add the same three names and throws the exception. This will happen any time we try to add two instances of a view that contains any of the above three control types.

So, the workaround is to give the SmartPartPlaceholders unique (or null) names. This can be done in ThreePanelView in the PresenterReady() method:

///

/// Configure the view once the Presenter declares it is ready.

///

protected override void PresenterReady(EventArgs e)

{

// Set the SmartPartPlaceholder names to null so they will be

// added to the workitem's Items collection with unique (GUID) names

mLeftSmartPartPlaceholder.Name = null;

mMiddleSmartPartPlaceholder.Name = null;

mRightSmartPartPlaceholder.Name = null;

// Assign the view ids to be displayed in the SmartPartPlaceholders

mLeftSmartPartPlaceholder.SmartPartName = ThreePanelViewContext.LeftViewId;

mMiddleSmartPartPlaceholder.SmartPartName = ThreePanelViewContext.MiddleViewId;

mRightSmartPartPlaceholder.SmartPartName = ThreePanelViewContext.RightViewId;

}

Alternatively, we could use:

mLeftSmartPartPlaceholder.Name = ThreePanelViewContext.LeftViewId+"SPH";

mMiddleSmartPartPlaceholder.Name = ThreePanelViewContext.MiddleViewId+"SPH";

mRightSmartPartPlaceholder.Name = ThreePanelViewContext.RightViewId+"SPH";

Note that we can't create unique names (within the workitem) until the instance of the view is created. Also the designer won't allow setting of null control names.

This should get you back on the air.

Bill & Ward

Duplicate ViewId's : As a test I add another tab to...

Wed, 10 Oct 2007 12:56:16 -700

Author: orcities
Subject: 486
Posted: 10-Oct-2007 at 12:56pm

As a test I add another tab to the Cabana project that uses the MasterDetailTab.

I added SalesRepCustomers2TabViewController to the go along with the SalesRepCustomersTabViewController tab on the SalesRep page and got the same error.

Duplicate ViewId's : I have verified that the Id that...

Wed, 10 Oct 2007 08:47:51 -700

Author: orcities
Subject: 486
Posted: 10-Oct-2007 at 8:47am

I have verified that the Id that is being set changes. This is done by adding the Guid to the panel id (LeftViewId = readonly string for guid + "_Left").

ViewFactory.AddNew(Constants.ViewNames.ActionView, WorkItem, LeftViewId);

So I do not understand how it is getting only the mLeftSmartPartPlaceholder as the id and causing a duplicate.

Duplicate ViewId's : This error is occuring when the...

Wed, 10 Oct 2007 08:32:27 -700

Author: orcities
Subject: 486
Posted: 10-Oct-2007 at 8:32am

This error is occuring when the base ViewFactory.AddNew method is called in the CreateView() method of the BaseTabController (ThreePanelTabVewController).

In stepping through it I have found that the Guid does change. But for some reason it only uses the last one submitted.

Duplicate ViewId's : I have created a custom view that...

Wed, 10 Oct 2007 08:20:18 -700

Author: orcities
Subject: 486
Posted: 10-Oct-2007 at 8:20am

I have created a custom view that will be used on tabs. Same as the Layout Demo's ThreePanelView. When I have more then one tab with this view, using the same type of TabController, I get an error:

An object with this ID alread exists: mXSmartPartPlaceholder

I have duplicated this error with the LayouDemo example.

I believe this error is created because the ID which contains the Guid is determined at the base TabController, ThreePanelViewTabController, and not at the used TabController, UserRolesTabViewController.

I am looking at ways to fix this. If anyone comes up with something please let me know.

Edited by orcities - 11-Oct-2007 at 7:50am