This is i got the solution: to insert new row if no data is their:
<asp:GridView ID="Customers" runat="server" AutoGenerateColumns="False"
DataSourceID="CustomersSqlDataSource" DataKeyNames="CustomerId" ShowFooter="true"
onrowcommand="Customers_RowCommand">
<Columns>
<asp:TemplateField HeaderText="CustomerId">
<ItemTemplate>
<%# Eval("CustomerId") %>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="FirstName">
<ItemTemplate>
<%# Eval("FirstName") %>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox runat="server" ID="EditFirstName" Text=''
<%# Bind("FirstName") %>' />
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox runat="server" ID="InsertFirstName" Text=''
<%# Bind("FirstName") %>' />
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="LastName">
<ItemTemplate>
<%# Eval("LastName") %>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox runat="server" ID="EditLastName" Text=''
<%# Bind("LastName") %>' />
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox runat="server" ID="InsertLastName" Text=''
<%# Bind("LastName") %>' />
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Commands">
<ItemTemplate>
<asp:Button runat="server" ID="Edit" Text="Edit" CommandName="Edit" />
<asp:Button runat="server" ID="Delete" Text="Delete" CommandName="Delete" />
</ItemTemplate>
<EditItemTemplate>
<asp:Button runat="server" ID="Update" Text="Update" CommandName="Update" />
<asp:Button runat="server" ID="Cancel" Text="Cancel" CommandName="Cancel" />
</EditItemTemplate>
<FooterTemplate>
<asp:Button runat="server" ID="Insert" Text="Insert" CommandName="InsertNew" />
<asp:Button runat="server" ID="Cancel" Text="Cancel" CommandName="CancelNew" />
</FooterTemplate>
</asp:TemplateField>
</Columns>
<EmptyDataTemplate>
First Name:<asp:TextBox runat="server" ID="NoDataFirstName" />
Last Name:<asp:TextBox runat="server" ID="NoDataLastName" />
<asp:Button runat="server" ID="NoDataInsert" CommandName="NoDataInsert" Text="Insert"/>
</EmptyDataTemplate>
</asp:GridView>