Creating an event handler for a submit button in ASP.NET

Question

I've created a web form which contains different checkbox lists, then I created a submit button. How can I write an event handler in the button so that it shows a different result for different options? For example: if the user checked "apple" and "banana" from checkboxList1 and "Lettuce" from checkboxList3 then pressed the button, the result would appear in a new page, let's say: result= vegetarian.

PS: I'm using ASP.NET in Visual Studio 2008

I tried to look it up on Youtube but I didn't find anything

Answer 1

So, say this markup:

<h4>Pizzia Toppings</h4>

<div style="float:left;border:solid 1px;padding:8px">
    <asp:CheckBoxList ID="FoodGroup1" runat="server">
        <asp:ListItem>Green Peppers</asp:ListItem>
        <asp:ListItem>Onions</asp:ListItem>
        <asp:ListItem>Mushrooms</asp:ListItem>
    </asp:CheckBoxList>
</div>

<div style="float:left;border:solid 1px;padding:8px;margin-left:20px">
    <asp:CheckBoxList ID="FoodGroup2" runat="server">
        <asp:ListItem>Red Peppers</asp:ListItem>
        <asp:ListItem>Tomatos (fresh)</asp:ListItem>
        <asp:ListItem>Spinach</asp:ListItem>
    </asp:CheckBoxList>
</div>

<div style="float:left;width:200px;border:solid 1px;padding:8px;margin-left:20px">
    <asp:CheckBoxList ID="FoodGroup3" runat="server">
        <asp:ListItem>Ham</asp:ListItem>
        <asp:ListItem>Pepperoni</asp:ListItem>
        <asp:ListItem>Ground Beef</asp:ListItem>
        <asp:ListItem>Salami</asp:ListItem>
    </asp:CheckBoxList>
</div>

<div style="clear:both;height:15px"></div>

<asp:Button ID="Button1" runat="server" 
    Text="Submit" CssClass="btn"
    OnClick="Button1_Click" />

And then the code for this button:

Protected Sub Button1_Click(sender As Object, e As EventArgs)

    Dim sFoodType As String = ""

    ' check food group 1 (Vegatarin)
    For Each MyChoice As ListItem In FoodGroup1.Items
        If MyChoice.Selected Then
            sFoodType = "Vegetarian"
        End If
    Next

    ' check food group 2 (Vegatarin)
    For Each MyChoice As ListItem In FoodGroup2.Items
        If MyChoice.Selected Then
            sFoodType = "Vegetarian"
        End If
    Next
    ' check food group 3 (Meats)
    For Each MyChoice As ListItem In FoodGroup3.Items
        If MyChoice.Selected Then
            sFoodType = "Non Vegetarian"
        End If
    Next

    ' save this result, and then jump to next page
    Session("FoodType") = sFoodType
    Response.Redirect("FoodTypeResult.aspx")

End Sub

And on the next page we navigate to we have this markup:

        <h3>Food type choosen</h3>
        <asp:Label ID="Label1" runat="server" Font-Size="Large">

        </asp:Label>

And code for that 2nd page to show the food group type:

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

    If Not IsPostBack Then
        Label1.Text = Session("FoodType")
    End If

End Sub

So, the result is this:

So, to create the "event" for the button? You can type in the markup, or just double click on the button, do so should jump you to code behind for the given button, and thus a event will have been created for that one button.