在formview中三个dropdownlist联动的.而且我还要将DropDownlist 与SqlDataSource中的字段绑定.联动现在不行了.也不能在第二次刷新页面了.

    <asp:FormView ID="frmvProsPect" runat="server" DefaultMode="Insert" DataSourceID="sqlContract" OnItemInserting="frmvProsPect_ItemInserting" >
        <EditItemTemplate>
        
                                    <di>
                                       <div>Prospect&nbsp; Information</div>
                                       <div></div>
                                       <div>Prospect Form</div>
                                <table style=" width:800px;">
                                        <tr>
                                            <td>BA</td>
                                            <td>
                                                    <asp:DropDownList ID="ddlBA" runat="server" AutoPostBack="True" DataTextField="BAName" DataValueField="BAName" AppendDataBoundItems="True" OnSelectedIndexChanged="ddlBA_SelectedIndexChanged" CssClass="dropdownlist" DataSourceID="sqlBA" SelectedValue='<%# Bind("BA") %>'>
                                                        <asp:ListItem>Please Select BA...</asp:ListItem>
                                                    </asp:DropDownList>
                                            </td>
                                            <td>Region</td>
                                            <td>
                                                
                                                   <asp:DropDownList ID="ddlRegion" runat="server" AutoPostBack="True" DataTextField="RegionName" DataValueField="ID" AppendDataBoundItems="True" OnSelectedIndexChanged="ddlRegion_SelectedIndexChanged" CssClass="dropdownlist" DataSourceID="sqlRegion">
                                                       <asp:ListItem Selected="True">Please Select Region...</asp:ListItem>
                                                    </asp:DropDownList>
                                            </td>
                                            <td style="height: 23px">
                                                Area</td>
                                                
                                            
                                            <td>
                                                <asp:DropDownList ID="ddlProvince" runat="server" DataTextField="Province" DataValueField="Province" AppendDataBoundItems="True" CssClass="dropdownlist" DataSourceID="sqlProvince" SelectedValue='<%# Bind("Province") %>'>
                                                    <asp:ListItem>Please Select Area...</asp:ListItem>
                                                    </asp:DropDownList>
                                            </td>
                                        </tr>
                                </table>
                          <div>Distributor Information</div>
                        <table style=" width:800px;">
                                <tr>
                                    <td>
                                       Distributor Chinese Name</td>
                                    <td>
                                        <asp:TextBox ID="txtDistributorCN" runat="server" CssClass="textbox" Text='<%# Bind("DistributeCn") %>'></asp:TextBox></td>
                                    
                                    <td>
                                      Distributor Code
                                    </td>
                                    <td align="left">
                                       
                                                <asp:TextBox ID="txtDistributorCode" runat="server" CssClass="textbox" Text='<%# Bind("DistributeCode") %>'></asp:TextBox></td>
                                </tr>
      
                            <tr>
                                <td >
                                  Distributor English Name
                                </td>
                                <td s>
                                   <asp:TextBox ID="txtDistributorEN" runat="server" CssClass="textbox" Text='<%# Bind("DistributeEn") %>'></asp:TextBox></td>
                                <td>
                                </td>
                                <td>
                                   </td>
                            </tr>
                    </table>
                <table>
                      
                    <tr>
                        <td>
                            Account Entry Type</td>
                        <td>
                            <asp:DropDownList ID="ddlAccountEntryType" runat="server" CssClass="dropdownlist">
                                <asp:ListItem Selected="True">Please Select...</asp:ListItem>
                                <asp:ListItem>Existing RD Cust</asp:ListItem>
                            </asp:DropDownList></td>
                        <td>
                        Competitor Instruments</td>
                        <td>
                            <asp:DropDownList ID="ddlCompetitor_Instruments" runat="server" DataSourceID="sqlCompInstrument" DataTextField="InstrumentName" DataValueField="InstrumentName" EnableViewState="False" AppendDataBoundItems="True" CssClass="dropdownlist" Width="160px">
                                <asp:ListItem Selected="True">Please Select...</asp:ListItem>
                            </asp:DropDownList></td>
                    </tr>
            </table>
           <div>Instrument Information</div>
            <table>
                <tr>
                    <td>
                        Instrument Quantity</td>
                    <td align="left">
                        
                            <asp:TextBox ID="txtOrder_Qty" runat="server" CssClass="textbox" Text='<%# Bind("DeliveryQty") %>'></asp:TextBox>
                    </td>
                </tr>
             
            </table>
            <table style="width:800px">
                    <tr>
                        <td>Contract Type</td>
                        <td>
                                    <asp:DropDownList ID="ddlContractType" runat="server" CssClass="dropdownlist" SelectedValue='<%# Bind("ContractType") %>'>
                                        <asp:ListItem Value="IPA">Placed</asp:ListItem>
                                        <asp:ListItem Value="DFC">Duty Free</asp:ListItem>
                                        <asp:ListItem Value="NormalSO">Sales</asp:ListItem>
                                        <asp:ListItem>Hybrid</asp:ListItem>
                                    </asp:DropDownList>
                        </td>
                     </tr>         
                <tr>
                    <td>
                        Instrument/System</td>
                    <td>
                        <asp:DropDownList ID="dlInstrument_Type" runat="server" AutoPostBack="True" DataSourceID="sqldsInstrument" DataTextField="InstrumentName" DataValueField="InstrumentCode" OnSelectedIndexChanged="dlInstrument_Type_SelectedIndexChanged" CssClass="dropdownlist">
                            <asp:ListItem>Please Select...</asp:ListItem>
                        </asp:DropDownList>
                    </td>
                    <td>
                        <asp:Label ID="lblExtension" runat="server" Text="Existing  Instrument" Visible="False" Width="113px"></asp:Label></td>
                    <td >
                        <asp:DropDownList ID="ddlExtensionList" runat="server" Visible="False" CssClass="dropdownlist" >
                        </asp:DropDownList><asp:Label ID="lblMessage" runat="server" Text="No Existing Instrument"
                            Visible="False"></asp:Label></td>
                </tr>
            </table>
                                       
        
            </EditItemTemplate>
    </asp:FormView>