how can create new row in gridview using dropdownlist input

hello frndz
i make a web page in this page i want to creat number of rows in gridview using dropdown list value. like i select creat 4 row in gridview i select 4 as list box of dropdownlist and creat 4 rows in gridview.I currently use textbox & submit link using them i creat row but i want use of dropdownlist inplace of textbox input and this input is out side the gridview. how can i do this??? plz help me my code is given below
<div>
<div style="width:330px;">
Number of rows to create:&nbsp;
<asp:TextBox ID="numberOfRowsTextBox" runat="server"></asp:TextBox>
<div style="text-align:right;">
<asp:LinkButton ID="submitLinkButton" runat="server"
onclick="submitLinkButton_Click">Submit</asp:LinkButton>
<%-- <asp:DropDownList ID="numberOfRowsTextBox" runat="server"
onselectedindexchanged="submitLinkButton_SelectedIndexChanged">
<asp:ListItem>SELECT</ ...