FYI if anyone else encounters a similar situation, I was getting this while debugging a form with the control on it.  I thought it was coming from the running application, but it was actually coming from Visual Studio itself when the form is open in the designer when debugging.

I am familiar with the message. It comes from the tree designer.

By default, the tree automatically generates ColumnSets based on the data source. When the data source changes or is reset, the tree gives you a warning before it blows away the existing ColumnSets and creates all new ones. This is so you don't accidentally lose any changes you might have made to the existing ColmunSets.

But this message only displays when something changes that would cause the tree to re-create the ColumnSets - such as setting the DataSource/DataMember or making a structural change to the data source.

If you make changes to the ColumnSets and then change the data source, you have two choices:

1) Let the three regenerate the ColumnSets to match the data source, in which case you will lose any changes you made.

2) Don't let the tree regerentate the ColumnSets, in which case, your ColumnSet changes will remain intact, but the tree's ColumnSet may be out of synch with the changes in the data source. You could, of course, update the ColmunSets manually to match the data source. If you added a column to your data source, you could add the same column to the ColumnSet, for example.

mac_swit said:

My current solution for this is setting the data source at runtime. In this case the event columnssetgenerated will be called as you said.

This is my preferred solution, too. If you set the DataSource of the tree at run-time, you can modify the ColumnSets in code in the ColunSetGenerated event and you get the best of both worlds since the tree will always generate the ColumnSets based on the data source structure and then your modification occur after that.

Hi Mike,

thanks for your answer. As you can see I'm using a project data source object as data source for the tree. The underlaying class is 'OrgBase' (the root class of my composite pattern).

At design time the tree generates always two column sets, one with empty key for the columns (properties) of OrgBase and one with key = "Childs", the Name of a list property.

The message we talking about, seems to be a bug in visual studio or in the tree. Resetting the DataSource of the tree, the generated columns sets remains in the designer. And if I make any changes to my business object 'OrgBas', changes are not reflected in the generated column sets in the designer. I guess that's, however, the reason for the message. I have to remove, save, recompile and playing a little bit around and sometimes visual studio hangs.

My current solution for this is setting the data source at runtime. In this case the event columnssetgenerated will be called as you said.

Maybe I will update to the newest version / newest service release.

Hello Mike,

is this problem solved? I have attached a sample project where I get this message everytime I run my test app.

By the way I wonder why the handler TreeOrganisation_ColumnsetGenerated is not called.

Checking out the column sets properties at designtime I see that two columns sets are generated. One with key of empty string, one with Key "Childs". Why I have these two column sets and how I can access it in code to set the node text column, hide some columns etc.?

At the moment nothing is showed as node text.

My tree is bound to a project data source (class OrgBase). OrgBase is the base class of a composite pattern. 

Regards

Markus