DetailsView image updating problem

I have DetailsView with users Info (Name, Email, Picture). That DetailsView control can be edited. Values are from DataBase

 protected void DVUserInfoShow_ItemUpdating(object sender, DetailsViewUpdateEventArgs e)
{


    FileUpload EditAvatar = (FileUpload)DVUserInfoShow.FindCont开发者_Python百科rol("EditAvatar");
    if (EditAvatar.HasFile)
    {
        string image_path = "~/images/user_images/" + EditAvatar.FileName;
        EditAvatar.SaveAs(Server.MapPath(image_path));
        e.NewValues["Avatar"] = EditAvatar.FileName;

    }

    else
    {
        e.NewValues["Avatar"] = e.OldValues["Avatar"];
    }



}

The problem is with e.NewValues["Avatar"] = e.OldValues["Avatar"];, when user updates his name and email, the picture value is set to null. And that code doesn't work. What I'm doing wrong?

---

OldValues collection is only available when DetailView is bounded with a declarative DataSource, otherwise OldValues collection will contain null in ItemUpadting event.

What you can do is inside DVUserInfoShow_ItemUpdating event, get current data from database and save in some local variables.