Convert Var/Text to String for get-method

[walch]

Hello!
I want to define a variable (or text) that I can change multiple times (10x). The variable should carry the name of different canvas objects and be read in by getCanvas() (see below). I assume that an object of type Var/Text is returned and getCanvas asks for a string. Unfortunately, none of my attempts at a solution work! Could you please help me?
Thanks!
Christin

newButton("B1", "+"),                                                   
newButton("B2", "+"),
newCanvas("C1",780,20 )
  .settings.add( "right at 100%", "middle at 50%", getButton("B1").print())
  .css( "border" , "solid 1px black" ),    
newCanvas("C2",780,20 )
  .settings.add( "right at 100%", "middle at 50%", getButton("B2").print())
  .css( "border" , "solid 1px black" )
  .settings.hidden(),
newVar("canvasnr", "C2"),
getButton("B1")
  .callback(getCanvas(getVar("canvasnr")).settings.visible()), //here is the problem

[Jeremy]

Hello Christin,

You cannot use a reference to a PennController element inside a getX command, because the execution of (plain) JavaScript is immediate, but that of PennController commands is delayed

What you can do is use a Function element in which you manipulate the PennController elements by accessing their methods and attributes:

getButton("B1")
  .callback( newFunction( ()=>{
    try { getCanvas( getVar("canvasnr")._element.value ).visible()._runPromises(); } 
    catch (e) { }
  }).call() )

Jeremy

[walch]

Thanks a lot! It works! But if I now change the variable at the same time, it only works for the first button and not for any others. What is the reason for this?

 getButton("B1")
  .callback( newFunction( ()=>{
    try { getCanvas( getVar("canvasnr")._element.value ).visible()._runPromises();
    setVar("canvasnr", C3); // set the value of canvasnr to 3
    }
    catch (e) { }
  }).call() ),
        getButton("B2")
  .callback( newFunction( ()=>{
    try { getCanvas( getVar("canvasnr")._element.value ).visible()._runPromises();
    setVar("canvasnr", C4); // set the value of canvasnr to 3
    }
    catch (e) { }
  }).call() ),
        getButton("B3")
  .callback( newFunction( ()=>{
    try { getCanvas( getVar("canvasnr")._element.value ).visible()._runPromises();
    setVar("canvasnr", C5); // set the value of canvasnr to 3
    } // ...

[Jeremy]

There is no javascript function called setVar. What you can do is:

getButton("B1")
  .callback( 
    newFunction( ()=>{
      try { getCanvas( getVar("canvasnr")._element.value ).visible()._runPromises(); }
      catch (e) { }
    }).call()
    ,
    getVar("canvasnr").set("C3")
  )

Jeremy

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