Formatting double decimal value to single decimal place in ASP.Net GridView using C#

How do i reduce the decimal Rows_Ordered in GridView to something like this 8.4 instead of this 8.44444444444444long numbers behind 8?

                      <asp:GridView runat="server" ID="gvSell"  Width="100%" CssClass="table table-striped table-bordered responsive" AutoGenerateColumns="False" DataKeyNames="SellId" >
                          <Columns>
                              <asp:BoundField DataField="SellId" HeaderText="SellId" SortExpression="SellId" InsertVisible="False" ReadOnly="True" />
                              <asp:BoundField DataField="UserName" HeaderText="UserName" SortExpression="UserName" />
                              <asp:BoundField DataField="CustomerName" HeaderText="CustomerName" SortExpression="CustomerName" />
                              <asp:BoundField DataField="CustomerAddress" HeaderText="CustomerAddress" SortExpression="CustomerAddress" />
                              <asp:BoundField DataField="CustomerPhone" HeaderText="CustomerPhone" SortExpression="CustomerPhone" />
                              <asp:BoundField DataField="ProductCategory" HeaderText="ProductCategory" SortExpression="ProductCategory" />
                              <asp:BoundField DataField="RowPrice" HeaderText="RowPrice" SortExpression="RowPrice" />
                              <asp:BoundField DataField="PaymentStatus" HeaderText="PaymentStatus" SortExpression="PaymentStatus" />
                              <asp:BoundField DataField="Rows_Ordered" HeaderText="Rows_Ordered" SortExpression="Rows_Ordered" />
                              <asp:BoundField DataField="Cartons" HeaderText="Cartons" SortExpression="Cartons" />
                              <asp:BoundField DataField="TotalAmount" HeaderText="TotalAmount" SortExpression="TotalAmount" />
                              <asp:BoundField DataField="Balance" HeaderText="Balance" SortExpression="Balance" />
                              <asp:BoundField DataField="OrderDate" HeaderText="OrderDate" SortExpression="OrderDate" />
                          </Columns>

                         <EmptyDataTemplate>
                             <asp:Label ID="Labelsal" runat="server" Text="No Sales found" Font-Bold="True" Font-Size="Large"></asp:Label>
                         </EmptyDataTemplate>
                      </asp:GridView>