dropdownlist联动问题

Question

大家帮我看看这个代码哪里有问题.
现在DDL无法获取到值.
 protected void DetailsView1_ModeChanging(object sender, DetailsViewModeEventArgs e)
    {
        DetailsView1.ChangeMode(DetailsViewMode.Edit);
        DetailsView1.DataBind();
        if (e.NewMode == DetailsViewMode.Edit)
        {
            if (!IsPostBack)
            {
                DropDownList ddl1 = (DropDownList)this.DetailsView1.Rows[3].Cells[1].FindControl("ddljz");
                SqlConnection con = jizhong.createConnection();
                con.Open();
                SqlCommand cmd = new SqlCommand("select * from jizhong", con);
                SqlDataReader sdr = cmd.ExecuteReader();
                ddl1.DataSource = sdr;
                ddl1.DataTextField = "jzName";
                ddl1.DataValueField = "jzID";
                ddl1.DataBind();
            }
        }
    }

Answer 1

 DropDownList ddl1 = (DropDownList)this.DetailsView1.Rows[3].Cells[1].FindControl("ddljz");
确定是第三行？

Answer 2

 if (!IsPostBack)
写在事件里有屁用啊

Answer 3

protected void DetailsView1_ModeChanging(object sender, DetailsViewModeEventArgs e)
    {
        DetailsView1.ChangeMode(DetailsViewMode.Edit);
        DetailsView1.DataBind();
        if (e.NewMode == DetailsViewMode.Edit)
        {
                DropDownList ddl1 = (DropDownList)this.DetailsView1.Rows["这个可能要先获取索引吧 如果有4行数据的话 你这里可以写3"].Cells[1].FindControl("ddljz");
                SqlConnection con = jizhong.createConnection();
                con.Open();
                SqlCommand cmd = new SqlCommand("select * from jizhong", con);
                SqlDataReader sdr = cmd.ExecuteReader();
                ddl1.DataSource = sdr;
                ddl1.DataTextField = "jzName";
                ddl1.DataValueField = "jzID";
                ddl1.DataBind();
        }
       
    }

Answer 4

protected void DetailsView1_ModeChanging(object sender, DetailsViewModeEventArgs e)
    {
        DetailsView1.ChangeMode(DetailsViewMode.Edit);
        DetailsView1.DataBind();
        if (e.NewMode == DetailsViewMode.Edit)
        {
                DropDownList ddl1 = (DropDownList)this.DetailsView1.Rows[3].Cells[1].FindControl("ddljz");
                SqlConnection con = jizhong.createConnection();
                con.Open();
                SqlCommand cmd = new SqlCommand("select * from jizhong", con);
                SqlDataReader sdr = cmd.ExecuteReader();
                ddl1.DataSource = sdr;
                ddl1.DataTextField = "jzName";
                ddl1.DataValueField = "jzID";
                ddl1.DataBind();
        }
       
    }
去掉了ISPOSTBACK,ddljz还是获取不到数据库的值.在帮我看看

Answer 5

我也遇到过这样的问题，我是这样解决的
zai Page_Load里面
 if (!IsPostBack)
  {
//获取数据源
//绑定
  }
参考