Why using this way class attributes are omitted?

Hi,i have a question about why this way works to access the attributes and in the other way the stay omitted.

This work

 using UnityEngine;                
 using System.Collections;
 
 public class Keyboard_Class : MonoBehaviour 
 {                       
         public char[] Name;                
         public GameObject Button;       
         public KeyCode Value;             
         public char[] Charcter;                                                                                        
 }
 

This does not work to access the attributes

 using UnityEngine;                
 using System.Collections;
 
 public class Keyboard_Class : MonoBehaviour 
 {
     public class Keyboard                   
     {
         public char[] Name;                 
         
         public class Key                    
         {
             public GameObject Button;       
             public Input Value;             
             public char[] Charcter;         
             
         public  Key()                   
         {
             Button=null;
             Value=null;
             Charcter=null;
         }
         
         public Key(GameObject button,Input myvalue,char[] mychar)          
         {
             Button=button;            
             Value=myvalue;
             Charcter=mychar;
         }
         
         
         }
     public Keyboard()                            
     {
     Name=null;                
     }
     public Keyboard(char[] name)
     {
         int i=0;
         for(;i<name.Length;i++)Name[i]=name[i];              
         Name[i]='\0';                                             
     }
     
     }

 }

PS.I see a error in the image.Instead Key.Value , I put key.Name or key.Key, okay? xD