Remove callback from TextField

Hello to everyone.
I register an event like this:

Code (CSharp):

1. textFieldExample.Q(TextField.textInputUssName).RegisterCallback<KeyUpEvent>(e => functionExample("hello"));

Now i am trying to remove it but i can't in any way, any suggestions?

 

You can do it like that:

Code (CSharp):

1.     private void OnEnable()
2.     {
3.         root = GetComponent<UIDocument>().rootVisualElement;
4.         var tf = root.Q<TextField>("my-textfield");
5.         tf.Q(TextField.textInputUssName).RegisterCallback<KeyUpEvent>(keyUpAction);
6.  
7.         tf.Q(TextField.textInputUssName).UnregisterCallback<KeyUpEvent>(keyUpAction);
8.     }
9.  
10.     private void keyUpAction(KeyUpEvent evt)
11.     {
12.         Debug.Log("hello");
13.     }

 

okay but i need to pass some parameters to the function, how can i do that?

 

There are several ways to do that, one is to create a class like so:

Code (CSharp):

1.     class actionClass
2.     {
3.         public string Parameter { get; set; }
4.         public void keyUpAction(KeyUpEvent evt)
5.         {
6.             Debug.Log(Parameter);
7.         }
8.     }

then:

Code (CSharp):

1.         var ac = new actionClass();
2.         ac.Parameter = "hello";
3.         tf.Q(TextField.textInputUssName).RegisterCallback<KeyUpEvent>(ac.keyUpAction);

and when you need to change the parameter you simply do:

Code (CSharp):

1.     ac.Parameter = "world";

 

You can also store a parameter in the visual element userData field.