@hemang_1711 I have just gone back to your original post and I see again what originally confused me.
If you recall, I asked about GraphParam, which you are trying to access in your QML. I looked for this in your model implementation, but your model does not have a role "GraphParam".
You do have a role "GraphList", which seems to return the first element of the list member named GraphParam in the GraphModelItem struct in your implementation. Although GraphParam is the name of the struct member, QML does not know anything about this name. It only sees the names you have defined in your roles.
