Question

为什么在DropDownList中设置了AutoPostBack不能触发SelectedIndexChanged事件？

在SelectedIndexChanged事件中设断点也无效,只有当点击提交按钮时才能进入SelectedIndexChanged事件，这个怪。请高手指点！

SelectedIndexChanged事件Register.aspx文件中相关代码如下：
<TR>
<TH>现在所在地</TH>
<TD>
<asp:DropDownList class=t_input ID="province" runat="server" OnSelectedIndexChanged="province_SelectedIndexChanged" AutoPostBack="True">
</asp:DropDownList> <span id="chprovince"></span>
<asp:DropDownList class=t_input ID="city" runat="server">
</asp:DropDownList>  <span id="chcity"></span>
<FONT color=red>*</FONT> </TD></TR>

Register.aspx.cs代码如下：
public partial class Register : System.Web.UI.Page
{
//连接server字符串
static string connString = DBConnection.ConnectinString_st;

protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
fn_ProvinceBind();
}
//province_SelectedIndexChanged(null, null);
//string sValue = this.province.SelectedValue;
//fn_CityBind(this.province.SelectedValue);

//this.submit.Attributes.Add("onclick", "javascript:return checkForm();");
}

protected void province_SelectedIndexChanged(object sender, EventArgs e)
{
string sValue = this.province.SelectedValue;
fn_CityBind(sValue);
}

private void fn_ProvinceBind()
{
SqlDataSource data = new SqlDataSource();
data.ConnectionString = connString;
data.SelectCommand = "Province_List";
//data.SelectParameters.Add("active", TypeCode.Int32, "2");
data.SelectCommandType = SqlDataSourceCommandType.StoredProcedure;
this.province.DataSource = (DataView)data.Select(DataSourceSelectArguments.Empty);
this.province.DataTextField = "Name";
this.province.DataValueField = "ID";
this.province.DataBind();
this.province.Items.Insert(0, new ListItem("==请选择省份==", "0"));
}

private void fn_CityBind(string provinceid)
{
SqlDataSource data = new SqlDataSource();
data.ConnectionString = connString;
data.SelectCommand = "City_List_SelectByID";
data.SelectParameters.Add("ProvinceID", TypeCode.Int32, provinceid);
data.SelectCommandType = SqlDataSourceCommandType.StoredProcedure;
this.city.DataSource = (DataView)data.Select(DataSourceSelectArguments.Empty);
this.city.DataTextField = "Name";
this.city.DataValueField = "ID";
this.city.DataBind();
this.city.Items.Insert(0, new ListItem("==请选择城市==", "0"));
}

}

Answer 1

可以的，怎么会因为设置了属性就不能触发事件了呢？