ASP.NET, User Control and ViewState lost the correct data into try get into the user control event

Good afternoon, I have an ASP.NET web page and I created a user control that has some properties that I need to always be retrievable.
ViewState was added to keep information, but the drawback now is that when adding the same control on the same asp.net page and from within a function of the control I want to retrieve the value of the property, this will retrieve the last value entered in the ViewState .

How to do OnClick on selected item in “dynamic” ASP.NET DropDownList without using JavaScript

Currently, there is 2 values in my DropDownList which is viewProduct and editProduct. So when the user selects one of the value, it will direct user to the particular function in ASP.NET. I have tried OnSelectedIndexChanged, but it seems like not working on the dynamic DropDownList.
Here is my code: