ASP.net: Everything is fine, but Autopostback is not working in cascading dropdownlist. Why?
Check the following code:
<%@ Page Language="VB" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <script runat="server"> Protected Sub ddlState_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) ddlCity.Items.Clear() ddlCity.Items.Add("Select City") Select Case ddlState.SelectedValue Case "MS" ddlCity.Items.Add("Aurangabad") ddlCity.Items.Add("Mumbai") ddlCity.Items.Add("Pune") Case "GU" ddlCity.Items.Add("Vadodara") ddlCity.Items.Add("Surat") Case "KA" ddlCity.Items.Add("Bangalore") Case "AP" ddlCity.Items.Add("Hyderabad") End Select End Sub </script> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> </head> <body> <form id="form1" runat="server"> State: <asp:DropDownList ID="ddlState" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddlState_SelectedIndexChanged"> <asp:ListItem Value="">Select State</asp:ListItem> <asp:ListItem Value="MS">Maharashtra</asp:ListItem> <asp:ListItem Value="GU">Gujrat</asp:ListItem> <asp:ListItem Value="KA">Karnataka</asp:ListItem> <asp:ListItem Value="AP">Andhra Pradesh</asp:ListItem> </asp:DropDownList> City: <asp:DropDownList ID="ddlCity" runat="server"> </asp:DropDownList> <asp:Button ID="submit" runat="server" Text="Button" /> </form> </body> </html>
Answer:
There is some bug with asp.net when you use a button with Id="submit", it cancels Autopostback. Simply change Id="btnSubmit", Autopostback will start working.
<asp:Button ID="submit" runat="server" Text="Button" />
Change to
<asp:Button ID="btnSubmit" runat="server" Text="Button" />
Hope this helps you and saves your time.
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