Why can the player jump as many times as they want? [c#]

Can not figure how to make it so the player can only jump once.
Anyone any idea what I'm doing wrong?

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. [RequireComponent(typeof(Rigidbody2D))]
5. public class SAExamplePlayerController : MonoBehaviour
6. {
7.     public Animator animator;
8.     public SpriteRenderer sprite;
9.     public BoxCollider2D boxCol;
10.     public float runSpeed;
11.     public float jumpForce;
12.  
13.     public Rigidbody2D Body { get; private set; }
14.     public bool IsJumping   { get; private set; }
15.     public bool IsGrounded  { get; private set; }
16.  
17.     private void Awake()
18.     {
19.         Body = GetComponent<Rigidbody2D>();
20.     }
21.  
22.     private void OnCollisionEnter2D(Collision2D col)
23.     {
24.         foreach(ContactPoint2D contact in col.contacts)
25.         {
26.             if(contact.normal.y == 1.0f)
27.             {
28.                 IsGrounded = true;
29.                 animator.SetBool("IsGrounded", IsGrounded);
30.                 break;
31.             }
32.         }
33.     }
34.  
35.     private void OnCollisionExit2D(Collision2D col)
36.     {
37.         foreach (ContactPoint2D contact in col.contacts)
38.         {
39.             if (contact.normal.y == 1.0f)
40.             {
41.                 IsGrounded = false;
42.                 animator.SetBool("IsGrounded", IsGrounded);
43.                 break;
44.             }
45.         }
46.     }
47.  
48.     private void Update()
49.     {
50.  
51.         float horizontal = Input.GetAxisRaw("Horizontal");
52.        
53.         if (horizontal > 0.0f)
54.         {
55.             Body.velocity = new Vector2(runSpeed, Body.velocity.y);
56.             sprite.flipX = false;
57.             animator.SetBool("Running", true);
58.         }
59.         else if (horizontal < 0.0f)
60.         {
61.             Body.velocity = new Vector2(-runSpeed, Body.velocity.y);
62.             sprite.flipX = true;
63.             animator.SetBool("Running", true);
64.         }
65.         else
66.         {
67.             Body.velocity = new Vector2(0.0f, Body.velocity.y);
68.             animator.SetBool("Running", false);
69.         }
70.  
71.         if(Input.GetButtonDown("Jump"))
72.             Jump();
73.  
74.         animator.SetFloat("VelocityY", Body.velocity.y);
75.     }
76.    
77.     public void Jump()
78.     {
79.         if(!IsJumping && IsGrounded)
80.         {
81.             Body.AddForce(Vector2.up * jumpForce, ForceMode2D.Force);
82.         }
83.     }
84. }
85.  

 

Where does your player start initially? Have you done any debugging? In general, using Raycasts is more reliable for collision detection.

 

I don't see where you change your isjumping variable