FileUpload and UpdatePanel: ScriptManager.RegisterPostBackControl works the second time

Question

I\'m developing an ASP.NET application with C# and Visual Studio 2008 SP1. I\'m using WebForms.

I have an ASPX page with two UpdatePanels, one on the left that holds

Answer 1

I had to combine both advices here. I am using an UpdatePanel to dynamically load an UserControl and the FileUpload is in the UserControl. I had to:

• RegisterPostBackControl in the user control's Page_Load

• add enctype="multipart/form-data" to the form element of the page, which contains the update panel, the code Page.Form.Attributes.Add("enctype", "multipart/form-data"); didn't work for me, it had to be in the aspx

Hope this helps.