asp.net file upload inside formview always return false (not in updatepanel)

Question

I am using fileupload control inside formview edittemplate

    <asp:FileUpload ID="fileup_profilfoto" runat="server" />
      <asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ErrorMessage="Sadece şu formatlar (.jpg, .bmp, .png, .gif)" ValidationExpression="^.*\.(jpg|JPG|png|PNG|bmp|BMP|gif|GIF)$" ControlToValidate="fileup_profilfoto" ForeColor="#00C0CC"></asp:RegularExpressionValidator>

It was working.But I added an updatepanel then it didnt work,and then I remowed update panel.But it's still return false (hasfile)

  protected void frmviewProfil_ItemUpdating(object sender, FormViewUpdateEventArgs e)
    {
        try
        {
            FileUpload fileup_profilfoto = (FileUpload)frmviewProfil.FindControl("fileup_profilfoto");
            if (fileup_profilfoto.HasFile)
            {
                //do something
            }
           else
            {
            //do something
            }
          }
      }

always goes else scopes.

Answer 1

hi use triggers to achive that

 <asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="conditional">
  <Triggers>
    <asp:PostBackTrigger ControlID="Button1" />
 </Triggers>
 <ContentTemplate>
   <asp:Label ID="Label1" runat="server"></asp:Label><br /><br />
   <asp:FileUpload ID="FileUpload1" runat="server" />
   <asp:Button ID="Button1" runat="server" Text="Upload" OnClick="Button1_Click" />
  </ContentTemplate>
 </asp:UpdatePanel>

code behind

  protected void Button1_Click(object sender, EventArgs e)
  {
      if (FileUpload1.HasFile)
      {
          Label1.Text = FileUpload1.FileName;
      }
  }