How to add an item to a drop down list in asp.net

问题

I have the following code

protected void Page_Load(object sender, EventArgs e)
{
        DRPFill();
        if (!IsPostBack)
        {
            DropDownList1.Items.Add("Add New");
        }
}

    public void DRPFill()
    {
        if (!IsPostBack)
        {
            //Object
            AddMajor objMajor = new AddMajor();

            //Data Table
            DataTable dtMajor = objMajor.find();

            //Data Source
            DropDownList1.DataSource = dtMajor;
            DropDownList1.DataValueField = "MajorID";
            DropDownList1.DataTextField = "MajorName";

            //Data Bind
            DropDownList1.DataBind();
        }
    }

I want to add the "Add new" at a specific index

---

but I am not sure of the

---

syntax

回答1:

Try this, it will insert the list item at index 0;

DropDownList1.Items.Insert(0, new ListItem("Add New", ""));

回答2:

Which specific index? If you want 'Add New' to be first on the dropdownlist you can add it though the code like this:

<asp:DropDownList ID="DropDownList1" AppendDataBoundItems="true" runat="server">
     <asp:ListItem Text="Add New" Value="0" />
</asp:DropDownList>

If you want to add it at a different index, maybe the last then try:

ListItem lst = new ListItem ( "Add New" , "0" );

DropDownList1.Items.Insert( DropDownList1.Items.Count-1 ,lst);

回答3:

Try following code;

DropDownList1.Items.Add(new ListItem(txt_box1.Text));

来源：https://stackoverflow.com/questions/17468956/how-to-add-an-item-to-a-drop-down-list-in-asp-net