visibility attribute

Mr Cully

I think this is a simple question but Im new to asp.net so give me a break!!! i have a drop down menu and i want to make different labels visible when different values are selected from the dropdown menu, i dont wan to have to use a button to submit tho, any suggestions?

Mike Ellison

You can set the AutoPostBack attribute of the DropDownList control to true, then code for the SelectedIndexChanged event. Something like this should work:

<% @Page Language="c#" %>
<script runat="server">
void ddSelectionChange(Object sender, EventArgs e)
{
// hide all labels to start with
lbl1.Visible = false;
lbl2.Visible = false;
lbl3.Visible = false;

// determine the value of the selected drop down list item
string sID = dd.SelectedItem.Value;

// make that label visible
if (sID != null && sID != "")
{
    Control c = FindControl(sID);
    c.Visible = true;
}

}
</script>

<form runat="server">
    <asp:DropDownList id="dd" runat="server"
                      AutoPostBack="True"
                      OnSelectedIndexChanged="ddSelectionChange" >
    
        <asp:ListItem Value="lbl1" Text="First Label" Selected="True" />
        <asp:ListItem Value="lbl2" Text="Second Label" />
        <asp:ListItem Value="lbl3" Text="Third Label" />
        
    </asp:DropDownList>
    
    <asp:Label id="lbl1" runat="server" visible="true"
               text="This is Label 1" />

    <asp:Label id="lbl2" runat="server" visible="false"
               text="This is Label 2" />

    <asp:Label id="lbl3" runat="server" visible="false"
               text="This is Label 3" />
    
</form>

</body>
</html>

Mr Cully

ah i see great thanks, i forgot to change the autopostback attribute to true