knockout.js - Resetting dropdown by manual subscription doesn't work depending on what observable was subscribed to -

I searched online and tried to understand this behavior and work hard but I just could not find out that this behavior Why is it possible that I am missing something fundamental here?

I would appreciate some hints / resources / answers.

Consider this Bela -

Why it Resets Product Selection

  // Whenever the category changes, the product selection Reset self.category.subscribe (function () {self.productName (undefined);});  

While this is not it?

  // Whenever the category changes, reset product selections self.categoryName.subscribe (function () {self.productName (undefined);});  

It must be done from the order in which the subscribe event The other is called relative to the computed properties computed and subscribe properties of D are said in the same order when they were viewed There is a change on the property. Here's what is happening in each case, this is the best thing, as I can tell (Kendo has not read the source, so there is some guess):

category.subscribe:

Code> Category

Code due to change in category Updated property is updated category

Note: productName is still the old value at this point

category. ProductName

Change the calculation value of product the event is converted the property calculated due to the change in Product Name

Note: productName is undefined now

all dependent Computed properties and membership events have been completed on c productName and the product list undefined >

catego RyName.subscribe:

1. The category dropdown is manipulated by the user, the new value is set
categoryName < category name view is updated due to change in / code>
2. category category

   Note: Due to the change in productName

3. the product still has the old value at this point

4. Complete all dependent-computed properties and membership events category Has been updated, so updated on the basis of kendoDropDownList new products list and the current ( of productName

   No undefined ) value

   I tested the candodeupdownlist Ode> and it chooses the first option even if you have productName Dummy string such as 'asdf' is set to. It shows only empty if the value is empty string ( '' ) or undefined .

   Event is to be converted to the value of productName

Note: productName is Undefined now

5. class does not update it again because it Products are not dependent on or productName , but should update Candodeupdualist

   < / P>
   Down is created first (in this example, it is in step 5). If you add logic to optionLabel in kendoDropDownList , then it will work as expected, even then.

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If you enter categoryName.subscribe before, category = ko.computed (...) First, then the whole cycle begins before productName to undefined which will be a way to fix it. Here is a Bella:

Another way is to describe the optionLabel parameter as KandodaproductionList option hash as described in step 8. >