Passing Custom Class Objects from one component to another in C#

Replies to This Discussion

Permalink Reply by David Rutten on July 22, 2015 at 8:13am

If you don't output a type which implements IGH_Goo, Grasshopper will try its best to convert your data into goo. When it fails, it will wrap it up in a GH_ObjectWrapper, which is a sort of bare-bones goo type.

If you don't want your data messed with, then you should put it in a GH_ObjectWrapper yourself and cut out the middle man.

What you cannot do is share instances of a type which is not known to both the sender code and the recipient code. Outputting an instance of a type which is defined in the sender cannot be converted into that type by the receiver because the receiver doesn't have access to that type definition. So that's the big constraint you have to work around. You can choose to use an existing type, maybe share data as a String or a Dictionary or something.

Permalink Reply by Arend on July 25, 2015 at 8:58am

I've also encountered this error when using referencing a .gha component inside a C# block (even when using IGH_Goo implementations), that casting such an object from a C# block to a custom component will give this kind of error. The workaround is what david describes below: take the generic data out from the .gha file and put it in a seperate dll.

Permalink Reply by David Stasiuk on July 22, 2015 at 8:36am

I'd suggest you simply use VS (or VS Express) and compile a simple library where you keep any tools or custom classes that you use with any frequency. Then you just reference your .dll wherever you want to use your classes.

Permalink Reply by Martin Henriksen on April 5, 2016 at 11:35pm

here is a very simple example of what David suggests:

build this as dll from VS:

namespace GHscriptHelper
{
   public class passObjectAround
   {
      public int num;
      public string text;

      public passObjectAround(int val, string val2)
      {
         num = val;
         text = val2;
      }
   }
}

then reference the dll in both c#-components in the attached gh file.

Attachments:

• PassObjectAround.gh, 6 KB