This example will display a grid with edit option, on edit of item complete row is got edited in the form of TEXT BOX and COMBO BOX
Just you have to copy this in your aspx file.
i have used 2 data source item 1st for displaying the information in the grid and update the information & other display the information into grid Combo box
< asp:SqlDataSource ID="productsDataSource"
Runat="server" SelectCommand="SELECT Products.ProductID, Products.ProductName, Products.CategoryID, Categories.CategoryName FROM Products INNER JOIN Categories ON Products.CategoryID = Categories.CategoryID"
UpdateCommand="UPDATE Products SET ProductName = @ProductName, CategoryID = @CategoryID WHERE (ProductID = @ProductID)"
ConnectionString="
<%$ ConnectionStrings:NorthwindConnectionString %>
">
< UpdateParameters >
< asp:Parameter Type="String" Name="ProductName" > </asp:Parameter >
< asp:Parameter Type="Int32" Name="CategoryID"> </asp:Parameter >
< asp:Parameter Name="ProductID" ></asp:Parameter >
</UpdateParameters >
</asp:SqlDataSource>
<asp:SqlDataSource ID="categoryDataSource" Runat="server"
SelectCommand="SELECT CategoryID, CategoryName FROM Categories ORDER BY CategoryName"
ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"> </asp:SqlDataSource>
this is the grid view
<asp:GridView ID="GridView4" Runat="server" DataSourceID="productsDataSource" DataKeyNames="ProductID"
AutoGenerateColumns="False" AllowPaging="True" BorderWidth="1px" BackColor="White" CellPadding="3" BorderStyle="None" BorderColor="#CCCCCC">
<FooterStyle ForeColor="#000066" BackColor="White"></FooterStyle>
<PagerStyle ForeColor="#000066" HorizontalAlign="Left" BackColor="White"></PagerStyle>
<HeaderStyle ForeColor="White" Font-Bold="True" BackColor="#006699"></HeaderStyle>
<Columns>
<asp:CommandField ShowEditButton="True"></asp:CommandField>
<asp:BoundField ReadOnly="True" HeaderText="ProductID" InsertVisible="False" DataField="ProductID" SortExpression="ProductID"></asp:BoundField>
<asp:BoundField HeaderText="ProductName" DataField="ProductName" SortExpression="ProductName"></asp:BoundField>
<asp:TemplateField SortExpression="CategoryName" HeaderText="CategoryName">
<EditItemTemplate>
<asp:DropDownList ID="DropDownList1" Runat="server" DataSourceID="categoryDataSource"
DataTextField="CategoryName" DataValueField="CategoryID" SelectedValue='<%# Bind("CategoryID") %>'>
</asp:DropDownList>
</EditItemTemplate>
<ItemTemplate>
<asp:Label Runat="server" Text='<%# Bind("CategoryName") %>' ID="Label1"></asp:Label>
</ItemTemplate >
</asp:TemplateField>
</Columns>
<SelectedRowStyle ForeColor="White" Font-Bold="True" BackColor="#669999"></SelectedRowStyle>
<RowStyle ForeColor="#000066"></RowStyle>
</asp:GridView>
NOTE: i have used the Northwind database. you might have to check the connection string of the DataSource.