Problem In Custom PersistParamater in Grasshopper

Nearly, When I Coding to create an Custom Object with Custom persist paramater. I find an very strange problerm, the strange is that you actually can not find where throw the Exception at the Code. And I set an breakpoint in the "SetFilePath" Component's SoleInstance method. But the code isn't run into the method before pupup this Component Exception. So I think It is not the plobrem with the "SetFilePath"

Component's plobrem.

And It troubled me for a long time, Could help me find what wrong with code as below, and the problerm sreenshot as below:

Notice:

The paramater is set through "set one path " menu item. and the "set one path" menu item ivoke the method of "Prompt_Plural" in Custom PersistentParam know as "PathParameter" in the below.

Plobrem screenShot:

Code ScreenShot:

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Replies to This Discussion

Permalink Reply by David Rutten on December 12, 2016 at 4:17am

You should override the CastTo and CastFrom methods on your goo, and handle the cases for converting to string and GH_String.

Permalink Reply by cughudson on December 12, 2016 at 5:38pm

Thanks David, But I actually don't know why I must cast GH_String to GH_MyPath, I have never using GH_String In My Code, And I just as an base Class of GH_MyPath.

Er... I have no override the base Class's CastTo and CastFrom method, Wheather I override the two method and completely rewrite the two method and then The Object Will have no this PopUp Component Exception?

Permalink Reply by cughudson on December 12, 2016 at 8:33pm

It is So dispointed, I have rewrite the CastTo and CastFrom function , But it seem to be doesn't work. The Code is As Below:

Permalink Reply by David Rutten on December 13, 2016 at 6:57am

Can you post the code for the whole type? I don't fancy copying source code by hand from pixels on the screen.

Permalink Reply by cughudson on December 13, 2016 at 5:38pm

OH, I'm So Sorry anout this, The Whole Code about the Project is post as attach file on the Attachments Section. ThankYou

Attachments:

type.cs, 3 KB
PathComponent.cs, 3 KB
Param.cs, 3 KB

Permalink Reply by 0ddw589ypu3jv on December 13, 2016 at 8:39pm

HI,cughudson.you can just use GH_String for PathParamter;

Attachments:

Attachments:

Permalink Reply by cughudson on December 13, 2016 at 9:39pm

Ah.... Thankyou.But I want override the GH_String's ToString Method, But If I use GH_String for PathParamter, The ToString is not my want, So I must Create an Custom Param derived from GH_String to override the GH_String's method with the same name

Permalink Reply by cughudson on December 15, 2016 at 6:19pm

Sorry, David. But Could you tell me why come this exception, After I rewrite the CastTo and CastFrom Method?

Permalink Reply by cughudson on December 19, 2016 at 6:05pm

Hi David, First,I'm so apologize to inntrupt you so frequency.

To be frankly, I need you help, and The Problerm have annony me for a long time, But could you tell me what wrong with the Code, Thankyou very much.

Permalink Reply by David Rutten on December 20, 2016 at 3:49am

Sorry, missed your earlier request. Should I be looking at the PathParameter.cs and SetFilePath.cs files you attached 4 posts above this one?

Permalink Reply by cughudson on December 20, 2016 at 6:45am

Yeap, Actually，Thankyou, David.

The Code about the problerm has been post at above of this discussion by me.

the file name is "type.cs"," Param.cs "and "PathComponent.cs";

type.cs file is contain the data type definition;

Param.cs file is contain the Paramater definition we has used in PathComponent.cs

PathComponent.cs is to Create PathComponent

ThankYou.

Permalink Reply by David Rutten on December 20, 2016 at 1:30pm

I found the problem. Since you did not override the Duplicate() method on your GH_String derived type, that method would return a GH_String instead of your own type. This caused issues when a data tree containing your type was being duplicated.

See attached. I also cleaned up the rest of the code, and I removed all logic not vital to this problem.

I'm not entirely sure what additional functionality you're getting over just GH_String, but if your data is supposed to be something different from GH_String, I think it would be best if you didn't derive from GH_String either. I think deriving from GH_Goo<T> would be better.

Attachments: