Two Level Dynamic DropDown Question

workib · May 3rd, 2008, 08:01 AM

I am trying to dynamicly load selections in a DropDown List based on the section that was selected in the first drop down and display a message when the button is clicked. I get an error message concerning the void on the button click. I will include all of the code for your review.

Thank you,

Brian

Mark up code
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="TwoLevelDropDown.aspx.cs" Inherits="Demos_TwoLevelDropDown" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>

    <form id="form1" runat="server">
    <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True"
        onselectedindexchanged="DropDownList1_SelectedInde xChanged">
        <asp:ListItem>Airplaine</asp:ListItem>
        <asp:ListItem>Car</asp:ListItem>
        <asp:ListItem>Train</asp:ListItem>
    </asp:DropDownList>

    <asp:DropDownList ID="DropDownList2" runat="server" AutoPostBack="false">
    </asp:DropDownList>

    <asp:Button ID="Button1" runat="server" Font-Bold="True"
        onclick="Button1_Click" Text="Selections Button" />
<div>

    </div>
</body>
</html>
</form>

C# Code

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

public partial class Demos_TwoLevelDropDown : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        string[] CarArray = new string[4] { "Ford", "Honda", "BMW", "Dodge" };
        string[] AirplaneArray = new string[3] { "Boeing 777", "Boeing 747", "Boeing 777" };
        string[] TrainArray = new string[3] { "Bullet Train", "Amtrack", "Tram" };

        if (DropDownList1.SelectedValue == "Car")
        {
            DropDownList2.DataSource = CarArray;
        }
        else if(DropDownList1.SelectedValue == "Airplane")
        {
            DropDownList2.DataSource = AirplaneArray;
        }
        else
        {
            DropDownList2.DataSource = TrainArray;
        }

    }
}
protected void Button1_Click(object sender, EventArgs e)
{
  Response.Write("You selected <b>" +
        DropDownList1.SelectedValue.ToStrng() + ": " +
        DropDownList2.SelectedValue.ToString() + "</b>");
}

Imar · May 3rd, 2008, 09:31 AM

It would help if you posted the actual error message. 9 out of 10 times, that leads to the solution directly.

Have you seen this?

DropDownList1.SelectedValue.ToStrng() + ": " +

Imar

---------------------------------------
Imar Spaanjaars
http://Imar.Spaanjaars.Com
Everyone is unique, except for me.
Author of Beginning ASP.NET 3.5 : in C# and VB, ASP.NET 2.0 Instant Results and Dreamweaver MX 2004
Want to be my colleague? Then check out this post.

workib · May 3rd, 2008, 08:41 PM

I have attached the code and the error message I am getting. Thank you for your help.

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

public partial class Demos_TwoLevelDropDown : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        string[] CarArray = new string[4] { "Ford", "Honda", "BMW", "Dodge" };
        string[] AirplaneArray = new string[3] { "Boeing 777", "Boeing 747", "Boeing 777" };
        string[] TrainArray = new string[3] { "Bullet Train", "Amtrack", "Tram" };

        if (DropDownList1.SelectedValue == "Car")
        {
            DropDownList2.DataSource = CarArray;
        }
        else if(DropDownList1.SelectedValue == "Airplane")
        {
            DropDownList2.DataSource = AirplaneArray;
        }
        else
        {
            DropDownList2.DataSource = TrainArray;
        }

    }
}
protected void Button1_Click(object sender, EventArgs e)
{
  Response.Write("You selected <b>" +
        DropDownList1.SelectedValue.ToStrng() + ": " +
        DropDownList2.SelectedValue.ToString() + "</b>");
}

Here is the error message I am getting. The void above is underlined in red.
Error 1 Expected class, delegate, enum, interface, or struct C:\BegASPNET\Site\PlanetWrox\Demos\TwoLevelDropDow n.aspx.cs 42 11 C:\...\DemosThank you,

Brian

Imar · May 4th, 2008, 03:58 AM

Apparently my previous reply didn't help? There's clearly a mistake in there. Some feedback on replies would be nice.

Anyway, looks like you have a brace too many:

}
}
protected void Button1_Click(object sender, EventArgs e)
{

Looks like you're closing the class as well there.....

Imar
---------------------------------------
Imar Spaanjaars
http://Imar.Spaanjaars.Com
Everyone is unique, except for me.
Author of Beginning ASP.NET 3.5 : in C# and VB, ASP.NET 2.0 Instant Results and Dreamweaver MX 2004
Want to be my colleague? Then check out this post.

maycao · May 7th, 2008, 07:18 AM

Brian,

I have checked your code. You are short of one line code when you bind data to the second dropdownlist.

  if (DropDownList1.SelectedValue == "Car")
        {
            DropDownList2.DataSource = CarArray;
            DropDownList2.DataBind();
        }
If you can't understand what I mean, you can send email to [email protected]

May

ilayaraja · May 7th, 2008, 08:04 AM

You have missed the following dropdownlist DropDownList2.DataBind();
and wrong brases closed... this coding will work properly

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class Default15 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        string[] CarArray = new string[4] { "Ford", "Honda", "BMW", "Dodge" };
        string[] AirplaneArray = new string[3] { "Boeing 777", "Boeing 747", "Boeing 777" };
        string[] TrainArray = new string[3] { "Bullet Train", "Amtrack", "Tram" };

        if (DropDownList1.SelectedValue == "Car")
        {
            DropDownList2.DataSource = CarArray;
            DropDownList2.DataBind();
        }
        else if (DropDownList1.SelectedValue == "Airplaine")
        {
            DropDownList2.DataSource = AirplaneArray;
            DropDownList2.DataBind();
        }
        else
        {
            DropDownList2.DataSource = TrainArray;
            DropDownList2.DataBind();
        }

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        Response.Write("You selected <b>" +
        DropDownList1.SelectedValue.ToString() + ": " +
        DropDownList2.SelectedValue.ToString() + "</b>");
    }
}

workib · May 14th, 2008, 09:18 PM

Imar,

Thank you for your help with this issue.

Brian