Fire Typeless ChangeEvent

Hello,

I have pieces of data that are tightly coupled, for example a string and an enum. With help from this post - I have created a custom VisualElement, which displays this data, and this works great!

My

CustomVisualElement 

implements from

INotifyValueChanged<string>

and

INotifyValueChanged<myEnum>

This is Fine and works if I want to register call backs for

ChangeEvent<string>

or

ChangeEvent<myEnum>

. However I have cases where I want to just check if anything changed, and I don't care about the specific data.

I could wrap my data in a struct

Code (CSharp):

1. struct MyStruct{
2. string text;
3. myEnum enum;
4. }

and implement

INotifyValueChanged<MyStruct>

, however anytime I need to fire the ChangeEvent

Code (CSharp):

1. newvalue = new MySruct(){text=TextValue, enum=EnumValue}
2. using (var newEvent = ChangeEvent<MyStruct>.GetPooled(currentvalue, newValue))
3.                 {
4.                     newEvent.target = this;
5.                     SendEvent(newEvent);
6.                 }
7. currentvalue = newValue

new'ing the struct is a bit meh, especialy when I don't care about the current/new value.

Is there a better way to Send a change event without the attached gubbins (previous value, new value)

Thanks

 

Hi, Thank you for your reply.

My use case is as followed:
When the user edits a field (either the enum or text) in the

CustomVisualElement

this enables the "Save" button in the window.
When the user clicks the "Save" button, the string/enum values inside the

CustomVisualElement

s get serialised into an object.
(I do not wish to bind directly, more of a delayed bind requiring input from the user)

Maybe a better pattern would be to store the string/enum values in the owner window; however there are multiple

CustomVisualElement

s in the tree. How would I know which

CustomVisualElement

text/enum was changed. As far as I am aware, there is no Owner parameter passed into the callback, so you don't know which VE it came from?

Currently, when saving I iterate through all the (cached)

CustomVisualElement

s and serialise their field values into an array.

Thanks

 

Hi,

Sorry for the late reply I was just letting the new implementation settle.​

This is how it was, and what lead me to write this forum post. As it meant I would have repeat code, the code once in the callback for string, and then again in the Enum. I could foresee this leading to complications in the future and wanted to know if there was a more generic ChangeEvent which I could use for all

I have done this now, and for my purpose it seems fine

I had to change the struct to a class ass otherwise it meant I would have to new up a new object anytime something was changed

Code (CSharp):

1.         private void TextChanged(ChangeEvent<string> evt)
2.         {
3.             OldData.Text = evt.previousValue;
4.             Data.Text = evt.newValue;
5.             //as a struct:
6.             //Data = new Data() { Text = evt.newValue, myEnum = Data.myEnum };
7.             using (var newEvent = ChangeEvent<Data>.GetPooled(OldData, Data))
8.             {
9.                 newEvent.target = this;
10.                 SendEvent(newEvent);
11.             }
12.         }

But I guess that's horses for courses.