gridview command filed button not firing inside update panel

im trying to fire an event on button click inside gridview , im using updatepanel , but nothing is fired . below is my code .

aspx:

<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager><div><asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Always"><ContentTemplate><div><asp:Label ID="theid" runat="server" Visible="false"></asp:Label><asp:Label ID="txpath" runat ="server" Visible="false"></asp:Label><asp:GridView CssClass="myGridClass" ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="id"
 OnRowEditing="OnRowEditing" OnRowCancelingEdit="OnRowCancelingEdit" 
OnRowDeleting="OnRowDeleting" 
                 OnRowDataBound = "OnRowDataBound" OnSelectedIndexChanged = "OnSelectedIndexChanged" OnRowCommand="GridView1_RowCommand" ><Columns><asp:TemplateField HeaderText="Choose"><ItemTemplate><asp:CheckBox ID="chkRow" runat="server" OnCheckedChanged="GetSelectedRecords"   /></ItemTemplate><ItemStyle Width="20px"></ItemStyle></asp:TemplateField><asp:TemplateField  HeaderText="File Name" ItemStyle-Width="50"><ItemTemplate><asp:Label ID="Number" runat="server" Text='<%# Eval("Name") %>'></asp:Label></ItemTemplate><EditItemTemplate><asp:TextBox ID="Number" runat="server" Text='<%# Eval("Name") %>'></asp:TextBox></EditItemTemplate><ItemStyle Width="250px"></ItemStyle></asp:TemplateField><asp:TemplateField HeaderText="Page number" ItemStyle-Width="100"><ItemTemplate><asp:Label ID="IssueDate" runat="server" Text='<%# Eval("PagesNumber") %>'></asp:Label></ItemTemplate><EditItemTemplate><asp:TextBox ID="IssueDate" runat="server" Text='<%# Eval("PagesNumber") %>'></asp:TextBox></EditItemTemplate><ItemStyle Width="100px"></ItemStyle></asp:TemplateField><asp:TemplateField ShowHeader="False"><ItemTemplate><asp:Button ID="Button1" runat="server" Text="Button" CommandArgument="<%# ((GridViewRow) Container).RowIndex %>" /></ItemTemplate></asp:TemplateField></Columns></asp:GridView>

</ContentTemplate>

</asp:UpdatePanel>

<asp:Label ID="lbl111" runat="server"></asp:Label></div>

aspx.cs:

 protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
    {
        int index = Convert.ToInt32(e.CommandArgument);
        lbl111.Text = GridView1.Rows[index].Cells[1].Text;
    }

Any help please ?