Hi,
Increase your griedview control width property.
to show controls side by side
<footertemplate>
<table width="100%" align="center"><tr><td> <asp:DropDownList ID="ddlVendorname" runat="server" AppendDataBoundItems="true" DataSource='<%# GetVendor() %>'
DataTextField="VendorName" DataValueField="CusVenID">
<asp:ListItem Value="-1">-Select-
</td><td>
<asp:RequiredFieldValidator ID="reqfvVendorName" runat="server" ControlToValidate="ddlVendorname"
InitialValue="-1" ValidationGroup="FtrowValidation" ErrorMessage="select Vendor"
Display="Dynamic" Text="*">
</td></tr></table>
</footertemplate>
All the Best