问题
I'm trying to disable the first item in a drop-down list, which is linked to a "submit" button.
On first loading the page, I want the list to display to the first item in the list, --Select-- without being able to select it.
Following the responses to this question, I'm using:
dd.Items[0].Attributes.Add("disabled", "disabled");
where dd refers to the DropdownList..
This works well but only if I activate it after the submit button is clicked. This means that when the page first loads, I can still select the first item.
If I put the above code in the Page_Load method, the list defaults to the next item and --Select-- is no longer displayed.
Does anyone know a way to have the list continue to display the first item but disable selection of it?
回答1:
Per Robert's request, I copied my comment as the answer:
"You could either disable the submit button if the index of your dropdown is 0 (--Select--), or you could check if the index is 0 when the user hits your submit button and just return (or do nothing)."
回答2:
I think you want to do this:
<asp:DropDownList ID="DropDownList1" runat="server" AppendDataBoundItems="true">
<asp:ListItem Text="--Select One--" Value="" />
</asp:DropDownList>
来源：https://stackoverflow.com/questions/14198870/disable-first-item-in-dropdownlist