asp.net - When selecting value from dropdown list, it is resetting all other dropdown values -

when selecting value country drop-down list resetting value of other drop-down list boxes , selected country getting reset.

the country drop-down list, state drop-down list , district drop-down list dependent.

private void binddropdownlist(dropdownlist ddl, string query, string text, string value, string defaulttext) { string constring = configurationmanager.connectionstrings["constring"].connectionstring; sqlcommand cmd = new sqlcommand(query); using (sqlconnection con = new sqlconnection(constring)) { using (sqldataadapter sda = new sqldataadapter()) {             cmd.connection = con;             con.open();             ddl.datasource = cmd.executereader();             ddl.datatextfield = text;             ddl.datavaluefield = value;             ddl.databind();             con.close();         } } ddl.items.insert(0, new listitem(defaulttext, "0")); }  protected void gcountry2_selectedindexchanged(object sender, eventargs e) {     gstate2.enabled = false;     gdistrict2.enabled = false;     gstate2.items.clear();     gdistrict2.items.clear();     //gstate2.items.insert(0, new listitem("select state", "0"));     //gdistrict2.items.insert(0, new listitem("select city", "0"));     int countryid = int.parse(gcountry2.selecteditem.value);     if (countryid > 0)     {         string query = string.format("select stateid, statename states countryid = {0}", countryid);         binddropdownlist(gstate2, query, "statename", "stateid", "select state");         gstate2.enabled = true;         page.setfocus(f2.clientid);     } } protected void gstate2_selectedindexchanged1(object sender, eventargs e) {     gdistrict2.enabled = false;     gdistrict2.items.clear();     //gdistrict2.items.insert(0, new listitem("select city", "0"));     int stateid = int.parse(gstate2.selecteditem.value);     if (stateid > 0)     {         string query = string.format("select cityid, cityname cities stateid = {0}", stateid);         binddropdownlist(gdistrict2, query, "cityname", "cityid", "select city");         gdistrict2.enabled = true;         page.setfocus(f2.clientid);           } 

there easier way want. bind dropdowns declaratively. this.

<%-- .aspx file. --%> <%-- populate country ddl --%> <asp:dropdownlist id="ddcountry" runat="server" datatextfield="countryname"     datavaluefield="countryid"     appenddatabounditems="true" datasourceid="sqlcountry" autopostback="true">     <asp:listitem value="0" text="- select country -"></asp:listitem> </asp:dropdownlist> <asp:sqldatasource id="sqlcountry" runat="server" connectionstring="<%$ connectionstrings:connstring %>"     selectcommand="select countryid,countryname dbo.countries"> </asp:sqldatasource>  <%-- populate state ddl --%> <asp:dropdownlist id="ddstate" runat="server" datatextfield="statename"     datavaluefield="stateid"    datasourceid="sqlstate" autopostback="true" ondatabound="ddstate_databound"> </asp:dropdownlist> <asp:sqldatasource id="sqlstate" runat="server" connectionstring="<%$ connectionstrings:connstring %>"     selectcommand="select stateid, statename dbo.states countryid=@countryid">     <selectparameters>         <%-- bind parameter parent control --%>         <asp:controlparameter defaultvalue="0" controlid="ddcountry" propertyname="selectedvalue" name="countryid" type="int32" />     </selectparameters> </asp:sqldatasource>  <%-- populate district ddl --%> <asp:dropdownlist id="dddistrict" runat="server" datatextfield="cityname"     datavaluefield="cityid"    datasourceid="sqldistrict" autopostback="true" ondatabound="dddistrict_databound"> </asp:dropdownlist> <asp:sqldatasource id="sqldistrict" runat="server" connectionstring="<%$ connectionstrings:connstring %>"     selectcommand="select cityid, cityname dbo.cities stateid=@stateid">     <selectparameters>         <asp:controlparameter defaultvalue="0" controlid="ddstate" propertyname="selectedvalue" name="stateid" type="int32" />     </selectparameters> </asp:sqldatasource> 

you need code behind add "-- select --" items 2 last dropdowns.

// .aspx.cs protected void ddstate_databound(object sender, eventargs e) {     ddstate.items.insert(0, new listitem("--select state--", "0")); } protected void dddistrict_databound(object sender, eventargs e) {     dddistrict.items.insert(0, new listitem("--select city--", "0")); }