c# - Add values to DropDownList that's not represented in the db and still get SelectedValue asp.net -

i have couple of dropdownlists in gridview customer table binds selected value db.

i noticed if have 1 customer , edit customers gender it's not possible because populate dropdownlists select distinct gender customer , first customer either herr or frau , can choose value.

i thinking solve problem using union select select gender ( select gender = 'herr' union select gender = 'frau' )as gender bring both alternatives error message 'dropdownlist1'** has selectedvalue invalid because not exist in list of items**

so question how can add alternatives dropdownliststhat's not presented in db , still bind selectedvalue?

<edititemtemplate>                 <asp:dropdownlist id="dropdownlist3" runat="server" datasourceid="sqldatasource1" datatextfield="gender" datavaluefield="gender" selectedvalue='<%# bind("gender") %>'>                 </asp:dropdownlist>                 <asp:sqldatasource id="sqldatasource1" runat="server" connectionstring="<%$ connectionstrings:eventconnectionstring %>" selectcommand="select distinct [gender] [customer]"></asp:sqldatasource>             </edititemtemplate>             <itemtemplate>                 <asp:label id="label2" runat="server" text='<%# bind("gender") %>'></asp:label>             </itemtemplate> 

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thanks answers, need change in code behind make work?

here code behind.

protected void page_load(object sender, eventargs e)         {          }      protected void lbinsert_click(object sender, eventargs e)     {         event.insertparameters["gender"].defaultvalue = ((dropdownlist)gridview1.footerrow.findcontrol("ddlgender")).selectedvalue;         event.insertparameters["lastname"].defaultvalue = ((textbox)gridview1.footerrow.findcontrol("txtlastname")).text;         event.insertparameters["firstname"].defaultvalue = ((textbox)gridview1.footerrow.findcontrol("txtfirstname")).text;         event.insertparameters["street"].defaultvalue = ((textbox)gridview1.footerrow.findcontrol("txtstreet")).text;         event.insertparameters["housenr"].defaultvalue = ((textbox)gridview1.footerrow.findcontrol("txthousenr")).text;         event.insertparameters["zip"].defaultvalue = ((textbox)gridview1.footerrow.findcontrol("txtzip")).text;         event.insertparameters["city"].defaultvalue = ((textbox)gridview1.footerrow.findcontrol("txtcity")).text;         event.insertparameters["phone"].defaultvalue = ((textbox)gridview1.footerrow.findcontrol("txtphone")).text;         event.insertparameters["email"].defaultvalue = ((textbox)gridview1.footerrow.findcontrol("txtemail")).text;         event.insertparameters["company"].defaultvalue = ((textbox)gridview1.footerrow.findcontrol("txtcompany")).text;         event.insertparameters["active"].defaultvalue = ((dropdownlist)gridview1.footerrow.findcontrol("ddlactive")).selectedvalue;          event.insert();     }