Question

我尝试从c＃代码中更改下拉列表选定值：

<repeater >
   <repeater> 
      <dropdown>

我将aspx页面中的数据源添加到下拉列表中每件事都很好..但我想改变下拉列表的选定值能够在编辑表时向用户显示先前选择的名称

protected void PrepairDropDownList(object sender,EventArgs e)
    {
        shiftrepeater.DataBind();
        if (shiftrepeater.Items.Count > 0)
        {
            for (int shiftcount = 0; shiftcount < shiftrepeater.Items.Count; shiftcount++)
            {
                Repeater temp = (Repeater)shiftrepeater.Items[shiftcount].FindControl("saturdayrepeater");
                if (temp.Items.Count > 0)
                {
                    for (int count = 0; count < temp.Items.Count; count++)
                    {
                        DropDownList ds = (DropDownList)temp.Items[count].FindControl("userdropdown");
                        HiddenField hf = (HiddenField)temp.Items[count].FindControl("hiddenid");//contain the id if the field 
                        SarcShiftUser user = CRUD<SarcShiftUser>.Get(int.Parse(hf.Value)); //a method to select a user with a specific id and add it to object from class sarcshiftuser

                        if (user.id == 0)
                            ds.SelectedValue = "";
                        else
                        {
                            ds.SelectedValue = user.user_id + "";

                        }
                    }
                }

            }
        }
        shiftrepeater.DataBind();
    }

我将此方法添加到转发器的Onload：但没有任何改变，以前的名字没有显示

P.S：用户对象正确且user.user_id也正确 P.S 2：我试图添加一个ds.DataBind（）;在更改所选内容但发出错误后：

System.ArgumentOutOfRangeException: 'userdropdown' has a SelectedValue which is invalid because it does not exist in the list of items.

Answer 1

设置SelectedItem DropdownList的最安全方法是设置SelectedIndex，如下所示：

ds.SelectedIndex = ds.Items.IndexOf(ds.Items.FindByValue(user.user_id.ToString()));

更改嵌套转发器中下拉列表的选定值

1 个答案: