Fail to change multiple sprite mecanim state using C# scripts

Questions & Answers
1

The problem I’m facing now is fail to change multiple sprite mecanim state using C# script. When I move my sprite, I can successfully change it from idle to backwalk state, however it limit my changes solely to backwalk state but not all other states. I want to make it like when I press right arrow key it change to rightwalk state, while press left arrow key to change it to leftwalk state and so on. Unfortunately the if else statement that I declare is not working making my changing movement only stick to one state. I wonder what mistake I made, and how I can fix my code?

I’m a newbie to Unity and not familiar with C#. I just learn it from the official Unity tutorials series. I been searching for many related question regard of the problem but still I can’t figure out the solution. This is the first question I ask at Unity community forum, sorry if I violate any rules. And I appreciate your help sincerely.

Here I attach my code:

void FixedUpdate()
    {
        float h = Input.GetAxisRaw("Horizontal");
        float v = Input.GetAxisRaw("Vertical");

        Move(h, v);
        /*
        Turning();
        */
        Animating(h, v);

        if (Input.GetKey("up"))
            anim.CrossFade("BackWalk", 0f);

        if (Input.GetKey("down"))
            anim.CrossFade("FrontWalk", 0f);
    }


enum TaoistState { Front = 0, Back = 1, Right = 2, Left = 3};

    TaoistState currentState;

    void Animating(float h, float v)
    {
        bool walkFront = h != 0f || v != 0f;
        bool walkBack = h != 0f || v != 0f;
        bool walkRight = h != 0f || v != 0f;
        bool walkLeft = h != 0f || v != 0f;

        switch (currentState)
        {
            case TaoistState.Front:
                anim.SetBool("BackWalk", walkBack);
                
                break;
            case TaoistState.Back:

                anim.SetBool("FrontWalk", walkFront);
                break;
            case TaoistState.Right:
                
                anim.SetBool("RightWalk", walkRight);
                break;
            case TaoistState.Left:
                
                anim.SetBool("RightWalk", walkLeft);
                break;
        }


    }
2

Anyone please help to answer this question! Thanks in advance.