下拉列表问题

Question

我尝试向下拉列表中添加一个新项目。我希望将添加的项目放置在下拉列表的第一个位置。我该怎么做

   I want this to be a first option
   ListItem itemspecial = new ListItem();
   itemspecial.Value = "-1";
   itemspecial.Text = "Please select specialization";
   ddlSpecialization.Items.Add(itemspecial);

    ddlSpecialization.DataTextField = "Description";
    ddlSpecialization.DataValueField = "Id";
    ddlSpecialization.DataSource = objspecial.GetAll();
    ddlSpecialization.DataBind();

Answer 1

在插入之前先进行数据绑定...

ddlSpecialization.DataTextField = "Description";
ddlSpecialization.DataValueField = "Id";
ddlSpecialization.DataSource = objspecial.GetAll();
ddlSpecialization.DataBind();

ddlSpecialization.Items.Insert(0, new ListItem("Please select specialization", "-1"));

Answer 2

您可以使用 DropDownList 的 Insert 函数来完成此操作：

ListItem itemspecial = new ListItem();
itemspecial.Value = "-1";
itemspecial.Text = "Please select specialization";
ddlSpecialization.Items.Insert(0, itemspecial);

ddlSpecialization.DataTextField = "Description";
ddlSpecialization.DataValueField = "Id";
ddlSpecialization.DataSource = objspecial.GetAll();
ddlSpecialization.DataBind();

Answer 3

使用
-- ddlSpecialization.Items.insertAt(itemspecial,0);<-指定第一个索引，