DropDownList在PostBack之后丢失索引

Question

我有一个下拉列表,我从SQL服务器填充数据.

我在Page_Init()事件中动态填充下拉列表.根据值,选择ListItem.

现在的问题是,当我在下拉列表中选择另一个项目时,在回发后,选择将重置为下拉列表中的第一个项目.

这是我的代码的基本版本,它不起作用:

        ArrayList AD_Group_Members = ActiveDirectory.GetMemberOfGroup("AD-Group");
        ArrayList ListMachines = SQLQuery.Read("Database", "SELECT idVM, RandomString, Computername, Owner, FROM VM ORDER BY Computername");

        for (int i = 0; i < ListMachines.Count; i++)
        {
            String RandomString = ((Hashtable)ListMachines[i])["RandomString"].ToString();
            String Owner = ((Hashtable)ListMachines[i])["Owner"].ToString();
            DropDownList DropDownList_Owner = new DropDownList();
            DropDownList_Owner.ID = "DropDownList_Owner_" + RandomString;
            DropDownList_Owner.Width = Unit.Percentage(95);
            DropDownList_Owner.AutoPostBack = true;
            DropDownList_Owner.EnableViewState = true;
            DropDownList_Owner.SelectedIndexChanged += DropDownList_Owner_SelectedIndexChanged;
            Div_Test.Controls.Add(DropDownList_Owner);
            for (int y = 0; y < AD_Group_Members.Count; y++)
            {
                ListItem ListItem = new ListItem();
                ListItem.Value = Owner;
                ListItem.Text = ((Hashtable)AD_Group_Members[y])["GivenName"].ToString() + " " + ((Hashtable)AD_Group_Members[y])["Surname"].ToString();
                if (((Hashtable)AD_Group_Members[y])["Username"].ToString().Equals(Owner))
                {
                    ListItem.Selected = true;
                }
                DropDownList_Owner.Items.Add(ListItem);
            }
        }

我的代码中的问题在哪里,它不起作用而是示例.预先感谢

Answer 1

您必须在pageload下填充此条件下的下拉列表.因为在每个帖子上都会再次填充您的ddl并丢失其选定的索引.

if (!IsPostBack)
{
    //PopulateYourDDL here
}