下拉菜单默认选择值

Question

This is a Dropdown control where I am binding the data, after bind I am putting the select statement. Even though the index is kept to 0 always select comes last like this:

Current output:

india
Auz
US
--select--

Required output:

--select--
india
AUZ
US

My Code

ddlcounty.DataSource = dtNew;
ddlcounty.DataTextField = "Weight";
ddlcounty.DataValueField = "Weight";
ddlcounty.DataBind();

ddlcounty.Items.Add("--Select--");
ddlcounty.SelectedValue = "0";

What is the change required here?

Thanks

Answer 1

You're doing your binding first.

When you get to the part where you are adding your default condition, you're actually adding to the end of the list.

Instead of :-

ddlcounty.Items.Add("--Select--");

Do :-

ddlcounty.Items.Insert(0, new ListItem("--Select--"));

This will insert your default option as the first element of Items .

Announced edit

You won't need :-

ddlcounty.SelectedValue = 0;

.. as if you don't explicitly specify, the first item in a drop down list is automatically selected.

If, however, you want to be explicit about it, you can do the following:-

ddlcounty.Items.Insert(0, new ListItem("--Select--","0"));
ddlcounty.SelectedValue = 0;

Answer 2

Would you please try below way:

Just set AppendDataBoundItems to true and Insert a ListItem as selected, and 'ClearSelection' before selecting item as below.

ddlcounty.AppendDataBoundItems = true;
ddlcounty.DataSource = dtNew;
ddlcounty.DataTextField = "Weight";
ddlcounty.DataValueField = "Weight";
ddlcounty.DataBind();

ddlcounty.ClearSelection();
ddlcounty.Items.Insert(0, new ListItem { Value = "0", Text = "--Select--", Selected = true });
ddlcounty.SelectedValue = "0";

Answer 3

You could also declare the "select one" ListItem declaratively in your aspx page like so

 <asp:DropDownList ID="ddUIC" runat="server" AppendDataBoundItems="true" Width="200px" BackColor="White" Font-Size="10px" SelectedValue='<%# Bind("Weight") %>' DataTextField="Weight" DataValueField="Weight" >
     <asp:ListItem Text="Select One" Value=""></asp:ListItem>
 /asp:DropDownList>

But your AppendDataBoundItems would have to be set to true

And you could still perform your databinding on the backend.