<p>I am having a listbox in ASP.net. I am populating the listbox values from another listbox in a page dynamically. During postbacks the values of output listbox are not persisted.
(while going to another page and come back to this page).</p>

<p>Please suggest some good answer. EnableViewstate = "true" is not working.</p>

Are you doing anything in Page_Load that should be in a
```
```
if(!IsPostBack) {}
```
```
Initialization code in load needs to only be called when the page is first loaded, not on postbacks.
If you are going to another page and then coming back to this page, I think you need to preserve the information yourself in the Session and then restore it when you come back to the page.