Heyo, not very familiar with C#, much less Unity, and I'm apparently doing something wrong, here's my code, THe only error I get is:

'Invalid Expression Term "="'

    bool currentlydown;
// further up the script
void Start() {
        currentlydown = false;
    }
// later up the script
void Update() {
if ((Input.GetKeyDown("W") || Input.GetKeyDown("A") || Input.GetKeyDown("S") || Input.GetKeyDown("D")) && currentlydown === false) {
            anim.SetBool("Walking", true);
            currentlydown = true;
        } else if (!(Input.GetKeyDown("W") || Input.GetKeyDown("A") || Input.GetKeyDown("S") || Input.GetKeyDown("D")) && currentlydown === true){
            anim.SetBool("Walking", false);
            currentlydown = false;
        }
    }

Any and all help is appreciated!

CodePudding user response：

• You're using === (I assume from JavaScript?). C# does not have a === operator, only ==.

• JavaScript has === in order to require that the types of the operands are also strictly the same. C# is statically-typed and most types are not directly comparable so a === operator isn't necessary.

• Also, when comparing reference-types (object, string, etc) the == operator (by default) only checks that both operands (which are references) point to the same single object in memory (almost-but-not-quite a pointer-comparison) which necessarily implies the types are identical, even if cast to different reference-types:

  interface IFoobar {}
  class Foobar : IFoobar {};
  
  Foobar  a = new Foobar();
  Object  b = a;
  IFoobar c = a;
  
  // Even though `a` and `b` have different reference-types (`Object` vs `IFoobar`) they point to the same object in-memory, so a type-check is unnecessary.
  Console.WriteLine( b == c ); // "true"
  
  // Whereas with value-types you'll get a compiler error:
  Int32 x = 123;
  String y = "abc";
  
  Console.WriteLine( x == y ); // <-- This won't compile because Int32 and String cannot be compared.
  

• So change your code to use ==.

• You can also simplify your logic and make your code more readable by moving the Input.GetKeyDown() checks and storing that in a local bool isWasd.

Like so:

bool currentlydown;
// further up the script
void Start()
{
    currentlydown = false;
}

// later up the script
void Update() {

    bool isWasd = Input.GetKeyDown("W")
            ||
            Input.GetKeyDown("A")
            ||
            Input.GetKeyDown("S")
            ||
            Input.GetKeyDown("D");

    if( isWasd && currentlydown == false )
    {
        anim.SetBool("Walking", true);
        currentlydown = true;
    }
    else if ( !(isWasd) && currentlydown == true ){
        anim.SetBool("Walking", false);
        currentlydown = false;
    }
}

• When working with bool (System.Boolean) values, you don't need do if( boolValue == true ) or if( !(boolValue == true) ) or if( boolValue == false ), you can do if( boolValue ) and if( !boolValue ).

Like so:

// later up the script
void Update()
{
    bool isWasd =
        Input.GetKeyDown("W")
        ||
        Input.GetKeyDown("A")
        ||
        Input.GetKeyDown("S")
        ||
        Input.GetKeyDown("D");

    if( isWasd && !currentlydown)
    {
        anim.SetBool("Walking", true);
        currentlydown = true;
    }
    else if( !isWasd && currentlydown )
    {
        anim.SetBool("Walking", false);
        currentlydown = false;
    }
}