Ajax calendar extender doesn't set textbox value

Question

Hi,

I've got a code:

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

                <asp:CalendarExtender ID="TextBox1_CalendarExtender" runat="server" 
                    Enabled="True" TargetControlID="TextBox1">
                </asp:CalendarExtender>

and it works. When i click textbox i've got a popup ajax extender, and when I choose some date from this it set it as as a text in textbox1.

But when I use:

 <asp:Button ID="Button1" runat="server" Text="Save" OnClick="Button1_Click" />

enter code here
   protected void Button1_Click(object sender, EventArgs e)
        {
  _task.PlannedStart = Convert.ToDateTime(TextBox1.Text);
}

value of TextBox1 is null

Answer 1

IsPostBack is guilty :)

Problem fixed