BackgroundI am trying to display two tables in an UltraTree control: Location and Machine. The Location table is the hierarchy; the Machine table references the Location table.The tables have the following columns (the relevant ones):Location--------LocationPKNameParentLocationPKMachine-------MachineIDNameLocationPK(lots of other columns)Each node in the tree will have one of two types of children - any number of locations *or* exactly 1 machine.I want the tree to display the Location heirarchy using just the name column, and if they expand a name and it is referenced by a machine, show the machine details (quite a few columns of information).
ProblemCurrently whenever a Location node is expanded, it shows two child nodes - "Location" and "Machine". The user then has to expand the "Location" and "Machine" columns to see the next layer of details.Is there a way to hide the "Location" and "Machine" nodes from appearing, and instead show their children, when only one of those bands has children?
Edited to add: From the documentation on the UltraTreeColumnSettings.ShowBandNodes, it says: "Regardless of the setting of ShowBandNode, band nodes will always be created to separate siblling bands. In a case where a child band has no siblings, a band node will be created for it if ShowBandNodes is set to ShowBandNodes.Always"
Is there a way to hide a band from appearing when there are no child nodes for that band?
ExampleI am seeing this:- RootLocation - Location - ThisIsALocationName - AndAnother - Location - YetAnotherLocation - Location - Machine - AMachine | All | Columns | Appear | Here... - Machine - Machinebut want to see this instead:- RootLocation - ThisIsALocationName - AndAnother - YetAnotherLocation - AMachine | All | Columns | Appear | Here...Further DetailsI have created a DataSet and populated it with two tables, Location and Machine. I have added two relationships to the DataSet like so:
dataSet.Relations.Add("Location", rv.Tables["Location"].Columns["LocationPK"], rv.Tables["Location"].Columns["ParentLocationPK"], false);
dataSet.Relations.Add("Machine", rv.Tables["Location"].Columns["LocationPK"], rv.Tables["MachineColumns["LocationPK"], false);
I have looked through the examples in the WinTree folder in the Samples directory. I have not been able to find an example that uses two tables in one tree via a bound DataSet.
We have also considered styling the screen after the sample in folder "DataBinding (Navigation) CS"; however we'd like to see if this specific problem can be overcome as we will most likely encounter this situation again in the future.
Hi Gavin,
There's no way the tree can handle this for you automatically, but it's probably possible to do what you want with a little extra effort.
I am assuming that you are probably just leaving the tree with the default setting for AutoGenerateColumnSets and so the tree is creating two ColumnSets - one for the Location table and one for the Machine table. The Location table will have five columns. Three of these are the fields of the data. The other two are chaptered columns that represent the child bands - one for Location and one for Machine.
As long as both of these columns exist in the column set and they both have IsChaptered set to true, the tree has to show the two Band Nodes to separate the sibling bands. The IsChaptered property on the column is settable, but you don't really want to set it because that will affect every node in the tree, not just the ones where there are no child Locations.
So what you should be able to do is create a new ColumnSet which is an exact copy of the Locations ColumnSet but does not include the Locations column. Then you would need to examine each node in code and determine if it has no child locations and if it does not, you can assign this ColumnSet to that node - thus eliminating the Locations under that node.
There are a couple of caveats to this. First, you probably don't want to loop through every node in the tree. So I would recommend using the InitializeDataNode event.
Second, getting child rows for a particular node through the DotNet binding model can be an expensive operation. So if, in InitializeDataNode, you check for the existance of child nodes under the Location Band node, it might slow things down. It would probably be better for you to use the DataSource itself to determine if the parent row has any child rows rather than trying to get this information through the tree. You can use the node.ListObject to get the underlying data row for a partilcluar node in the tree.
Hi Mike,
excellent topic, as I am facing exactly the same problem as the other developer.
I could reach to not to show both (as of only one child table can have data (or none of them), and never both for the same parent row - ensured by the business logic).I did it analyzing in the AfterDataNodesCollectionPopulated the given node, and if necessary, I set the node.Visible=false;Only one problem remained: there is a node visible between the parent row and the child table. How can I remove it, so the child1 or child2 table would directly connect to the parent row, and will not be a useless node between?
Have a look at the attached image, to see what I would like to remove.
Thank you, Zoltan
Hi Zoltan,
The tree has to separate sibling bands using Band Nodes. So even if there are no rows in one of the siblings, there's no way to remove that node using a single ColumnSet.
However, what you could do is use two different ColumnSets for the parent nodes. These two ColumnSets would be exactly the same, except you hide (or remove) the column in the parent ColumnSet that represents one the child band or the other.then you have to assign the appropriate ColumnSet to each node.
So, for example, if my data structure looks like this:
Parent
Child Band 0
Child Band 1
For each node in the tree in the Parent band, I would examine the node and see which child band of that node has child nodes, then assign a ColumnSet to that individual node which does not have a column for the other child band.
Hi Mike,thanks the idea! Could you please help me a little bit how/where to do these?Let's see.My ColumnSet is generated automatically when I set tree.DataSource/DataMember. (it's quite a complex data model, with lot's of tables, relations)What I have to do, when that node is expanded, then it's ColumnSet is generated on-demand, I have to make 2 copy of it, removing the not necessary columns (Band), and based on the parent data, have to assign the correct one to the Node.What is the best place to make this ColumnSet copy? In ColumnSetGenerated()?And how to make a copy of a ColumnSet? Is there any simple one-call way?How can I change the ColumnSet of a Node? Silly, but I cannot find, it has a DataColumnSetResolved, but it's read-only.And where / when is the best place to change it to my local DataSouce copy?Thank you very much
pxclient said:What is the best place to make this ColumnSet copy? In ColumnSetGenerated()?
That seems like a good place to do it. In a simple case where you have two child bands and you want to show one of the other, you really only need to make one copy and then just hide one of the child bands in the auto-generated column set. This way, the child band will always be hidden unless you apply the copied columnset to a node.
pxclient said:And how to make a copy of a ColumnSet? Is there any simple one-call way?
I'm not sure off the top of my head. See if there's a Clone method. If not, then what you could do is, instead of making a copy, you could auto-generate a second ColumnSet from the same data and modify it to remove the child band. There's a static method that allows you to pass in a DataSource and DataMember and auto-generates a column set for you.
UltraTreeColumnSet.FromDataSource(dataSource, dataMember)
pxclient said:How can I change the ColumnSet of a Node? Silly, but I cannot find, it has a DataColumnSetResolved, but it's read-only.
It's on the Override:
node.Override.ColumnSet
pxclient said:And where / when is the best place to change it to my local DataSouce copy?
I'd use the InitializeDataNode event to start with and see if that works.