Question

我遇到了asp：DropDownList的问题。仅当页面不是PostBack时（当页面首先加载时）才绑定它。但它会在回发后继续选择第一项。

这里有一些代码：

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
        getRegions();
}

private void getRegions()
{
    SqlConnection con = new SqlConnection(sqlconnString);
    try
    {
        con.Open();
        SqlCommand cmd = new SqlCommand("select region, emails from Regions", con);
        cmd.CommandType = CommandType.Text;
        SqlDataReader rdr = cmd.ExecuteReader();
        cmbRegion.Items.Clear();
        ListItem li = new ListItem("Select region", "Select region");
        cmbRegion.Items.Add(li);
        while (rdr.Read())
        {
            li = new ListItem((string)rdr["region"], (string)rdr["emails"]);
            cmbRegion.Items.Add(li);

        }
    }
    catch (Exception ex)
    {
        throw ex;
    }
    finally
    {
        con.Close();
    }
}

Answer 1

试试这个

ListItem li = new ListItem("Select region", "");
cmbRegion.Items.Insert(0,li);

Answer 2

cmbRegion.Items.Insert(0,new ListItem("-- Select --","00"));

C＃中的DropDownList选择回发后的默认（第1个）项

2 个答案: