Flatten Input List

Replies to This Discussion

Permalink Reply by Damien Alomar on August 31, 2010 at 7:39pm

I would say the "simplest" way would be to flatten the data yourself, as this would be pretty quick and simple. See below.

'replace object with your specific type....
Dim myInputDataTree as New DataTree(of Object)
Dim myFlattenedList as New List(of Object)

DA.GetDataTree(someIndex, myInputDataTree)

myFlattenedList = myInputDataTree.AllData()

Permalink Reply by kermin chok on August 31, 2010 at 8:40pm

Damien,
Ok that sounds like a way. Thus when we use a "list" as an input, we will "trick" the component by using "GetDataTree"? This will ensure that the component will not run multiple times. Is this correct?

Permalink Reply by Damien Alomar on September 1, 2010 at 7:35am

That code is really for developing compiled components, not working within a scripting component, so don't worry about the "DA.GetDataTree" line. If you're trying to do this from a scripting component, then set the item's access to Tree. Once your in your script, use the AllData method on your tree input and assign that to a list that you've created.

Permalink Reply by kermin chok on September 2, 2010 at 3:36pm

Damien,
I seem to be getting an error just trying to bring the data tree in. This is for a complied component.

Any ideas?
Thanks.
Kermin


pManager.Register_LineParam("WireFrame1", "WireFrame1", "WireFrame1 to import (Prop Num 210)", GH_ParamAccess.tree)
Dim TempDataTree As New DataTree(Of Line)
DA.GetDataTree(1, TempDataTree)



Error 1 Overload resolution failed because no accessible 'GetDataTree' can be called with these arguments:
'Public Function GetDataTree(Of T As Grasshopper.Kernel.Types.IGH_Goo)(name As String, ByRef tree As Grasshopper.Kernel.Data.GH_Structure(Of T)) As Boolean': Data type(s) of the type parameter(s) cannot be inferred from these arguments. Specifying the data type(s) explicitly might correct this error.

Permalink Reply by Jon Sargent on October 14, 2010 at 9:37am

I'm having the exact same problem. I have no trouble bringing in items or lists to my custom components, but the DA.GetDataTree line always throws this error for me.

Anyone know what's going on?

-Jon

Permalink Reply by David Rutten on October 14, 2010 at 10:42am

If you're developing 'real' components, forget DataTree. DataTree is only there to make life easier for VB and C# scripters. Compiled components need to use the class GH_Structure(Of T As IGH_Goo) in the Grasshopper.Kernel.Data namespace.

So when you declare an input parameter to have GH_ParamAccess.tree, you need to use the following inside SolveInstance:

Dim data As GH_Structure(Of GH_Line) = Nothing
If (Not DA.GetDataTree(0, data)) Then Return

Depending on the type of input parameter, you need to use different types for T.

--
David Rutten
david@mcneel.com
Poprad, Slovakia

Permalink Reply by Jon Sargent on October 14, 2010 at 12:20pm

perfect. thank you!

Permalink Reply by Jonatan Schumacher on November 30, 2011 at 10:14am

I found this tread very useful, thank you. For anyone interested in flattening input data in C#, I found that the following works:

<code> GH_Structure<GH_String> in_IDtree = new GH_Structure<GH_String>();
            if(! DA.GetDataTree<GH_String>(0,out in_IDtree)) return;
            List<GH_String> inIDList = new List<GH_String>(in_IDtree.FlattenData());</code>

 

Permalink Reply by Jon Mirtschin on December 7, 2011 at 8:34am

I might add one thing here, could be useful for someone.

If you want to "enforce" flattening refer above, but if you want to leave flattening at the discretion of the user, but set the default to be flattened when the component is added to the canvas, add a line of code like below to the register input method:

pManager[0].DataMapping = GH_DataMapping.flatten;

Cheers,

Jon