Unityのボタン押下でMainCameraを移動するスクリプトを実装したが、「ArgumentNullException: Value cannot be null.」のエラーが発生

実現したいこと

Buttonオブジェクトを押した結果、MainCameraの視点が切り替わるようにしたいです。

発生している問題・分からないこと

ボタン押下時に下記エラーが発生した。

エラーメッセージ

error
1ArgumentNullException: Value cannot be null.
2Parameter name: key
3System.Collections.Generic.Dictionary`2[TKey,TValue].FindEntry (TKey key) (at <31687ccd371e4dc6b0c23a1317cf9474>:0)
4System.Collections.Generic.Dictionary`2[TKey,TValue].get_Item (TKey key) (at <31687ccd371e4dc6b0c23a1317cf9474>:0)
5CameraManager.<Start>b__14_2 () (at Assets/Scripts/MainCamera/CameraManager.cs:88)
6UnityEngine.Events.InvokableCall.Invoke () (at <6ff3bcb667574bf9a8630184172fcfbf>:0)
7UnityEngine.Events.UnityEvent.Invoke () (at <6ff3bcb667574bf9a8630184172fcfbf>:0)
8UnityEngine.UI.Button.Press () (at ./Library/PackageCache/com.unity.ugui@1.0.0/Runtime/UI/Core/Button.cs:70)
9UnityEngine.UI.Button.OnPointerClick (UnityEngine.EventSystems.PointerEventData eventData) (at ./Library/PackageCache/com.unity.ugui@1.0.0/Runtime/UI/Core/Button.cs:114)
10UnityEngine.EventSystems.ExecuteEvents.Execute (UnityEngine.EventSystems.IPointerClickHandler handler, UnityEngine.EventSystems.BaseEventData eventData) (at ./Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/ExecuteEvents.cs:57)
11UnityEngine.EventSystems.ExecuteEvents.Execute[T] (UnityEngine.GameObject target, UnityEngine.EventSystems.BaseEventData eventData, UnityEngine.EventSystems.ExecuteEvents+EventFunction`1[T1] functor) (at ./Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/ExecuteEvents.cs:272)
12UnityEngine.EventSystems.EventSystem:Update() (at ./Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/EventSystem.cs:530)
13

該当のソースコード

C#
1using System.Collections;
2using System.Collections.Generic;
3using UnityEngine;
4using UnityEngine.UI;
5
6public class CameraManager : MonoBehaviour
7{
8    public static CameraManager Instance { get; private set; }
9
10    public string CurrentPositionName { get; private set; }
11
12    public GameObject ButtonLeft;
13    public GameObject ButtonRight;
14    public GameObject ButtonBack;
15
16    private class CameraPositionInfo
17    {
18        public Vector3 Position { get; set; }
19        public Vector3 Rotate { get; set; }
20        public MoveNames MoveNames { get; set; }
21    }
22
23    private class MoveNames
24    {
25        public string Left { get; set; }
26        public string Right { get; set; }
27        public string Back { get; set; }
28    }
29
30    private Dictionary<string, CameraPositionInfo> _CameraPositionInfoes = new Dictionary<string, CameraPositionInfo>
31    {
32        {
33            "Door",
34            new CameraPositionInfo
35            {
36                Position = new Vector3(715,150,530),
37                Rotate = new Vector3(0,0,0),
38                MoveNames = new MoveNames
39                {
40                    Left = "RoomLeft",
41                    Right = "RoomRight"
42                }
43            }
44        },
45        {
46            "RoomRight",
47            new CameraPositionInfo
48            {
49                Position = new Vector3(715,150,530),
50                Rotate = new Vector3(0,72,0),
51                MoveNames = new MoveNames
52                {
53                    Left = "Door",
54                }
55            }
56        },
57        {
58            "RoomLeft",
59            new CameraPositionInfo
60            {
61                Position = new Vector3(715,150,530),
62                Rotate = new Vector3(0,288,0),
63                MoveNames = new MoveNames
64                {
65                    Left = "Door",
66                }
67            }
68        },
69
70    };
71
72    // Start is called before the first frame update
73    void Start()
74    {
75        Instance = this;
76        ChangeCameraPosition("Door");
77
78        ButtonBack.GetComponent<Button>().onClick.AddListener(() =>
79        {
80            ChangeCameraPosition(_CameraPositionInfoes[CurrentPositionName].MoveNames.Back);
81        });
82        ButtonLeft.GetComponent<Button>().onClick.AddListener(() =>
83        {
84            ChangeCameraPosition(_CameraPositionInfoes[CurrentPositionName].MoveNames.Left);
85        });
86        ButtonRight.GetComponent<Button>().onClick.AddListener(() =>
87        {
88            ChangeCameraPosition(_CameraPositionInfoes[CurrentPositionName].MoveNames.Right);
89        });
90
91    }
92
93    public void ChangeCameraPosition(string positionName)
94    {
95        if (CurrentPositionName == null) return;
96        CurrentPositionName = positionName;
97        GetComponent<Camera>().transform.position = _CameraPositionInfoes[CurrentPositionName].Position;
98        GetComponent<Camera>().transform.rotation = Quaternion.Euler(_CameraPositionInfoes[CurrentPositionName].Rotate);
99    }
100
101}