I'm working on a homework assignment for one of my classes and having a problem getting my drop down list working they way I need it to.

So what I need to do is choose one thing on a list and when the user clicks submit, a panel will appear with the corresponding text and images. 

I made it work with radio buttons, but when I went back to check the assignment requirements, the instructor was a drop down list .

This is the code for the radio button:

if (rdoCapricorn.Checked)
 {
            pnlRead.Visible = true;
            pnlHoroscopes.Visible = true;

            lblSign.Text = "Capricorn";
            imgHoroscope.ImageUrl = "~/signs/capricorn.png";
            lblHoroscope.Text = "blah blah blah";
}

So the problem I am having is doing the same thing with a drop down list.

I tried using the following lines for the if statement:

if (ddlZodiac.SelectedItem = "Capricorn")

if (ddlZodiac.SelectedIndex = 0)

if (ddlZodiac.DataValueField = "Capricorn")

if (ddlZodiac.DataTextFormatString = "Capricorn")

and I getting an error "cannot implicitly convert type string (or int) to bool".   I even tried the .ToString at the end of SelectedItem but I get another error which says, "cannot assign to ToString because it is a 'method group'".  I don't fully understand the errors which I think is why I'm having a problem.

There has to be simple solution to this that I am completely missing.  I don't think our instructor covered.  I'm not sure if this makes a difference, but the drop down list has an SqlDataSource called "theZodiac".

below is the code to display the drop down list and code for the database:

            <asp:DropDownList ID="ddlZodiac" runat="server" 
                DataSourceID="theZodiac" 
                DataTextField="Sign" DataValueField="Sign">
            </asp:DropDownList>


            <asp:SqlDataSource ID="theZodiac" runat="server" 
                ConnectionString="<%$ ConnectionStrings:ConnectionString %>" 
                SelectCommand="SELECT [Sign] FROM [zodiacSign]">
            </asp:SqlDataSource>

I'm sorry if this seems like a lot.  I'm very new to ASP.Net, so I want to know how to make it work and why the methods I was trying above did not so I know for future reference.

Thanks in advance to anyone who replies!