Q:

I'm not getting drop down list value related forms using panel control

after getting drop down list as output, while selecting the users in drop down list i'm not getting related forms? review the code.i used panel control for 3 user detail tables
 protected void Page_Load(object sender, Eventargs e)
        {
        if (!IsPostBack)
        {
            AdminPanel.Visible = false;
            TeacherPanel.Visible = false;
            StudentPanel.Visible = false;
        }
    }
    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (DropDownList1.SelectedValue == "-1")
        {
            AdminPanel.Visible = false;
            TeacherPanel.Visible = false;
            StudentPanel.Visible = false;
        }
        else if (DropDownList1.SelectedValue == "admin")
        {
            AdminPanel.Visible = true;
            TeacherPanel.Visible = false;
            StudentPanel.Visible = false;
        }
        else if (DropDownList1.SelectedValue == "teacher")
        {
            AdminPanel.Visible = false;
            TeacherPanel.Visible = true;
            StudentPanel.Visible = false;
        }
        else
        {
            AdminPanel.Visible = false;
            TeacherPanel.Visible = false;
            StudentPanel.Visible = true;
        }
    }

A:

Your question did not provide enough information, but let me take a swing, because it is the common mistake people make regarding DropDownList.
If you want to post back the form to server after selecting the DropDownList, you need to set AutoPostBack="True".
<asp:DropDownList 
    ID="DropDownList1" 
    runat="server"
    AutoPostBack="True"
    OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
</asp:DropDownList>

