Question

当我尝试获取

中的所选项目时，我有aspx和aspx.cs文件

DropDownList

它始终将项目设为0索引

<div style="text-align:center">
             <b>Scegliere il nome del report *  </b>  &nbsp;
             <asp:DropDownList id="dropdownlist1" style="width:250px;" runat="server"></asp:DropDownList>
            <br />
            <br /> 

            <br /> 
            <b>Scegliere la data del report </b>  &nbsp; 
            <asp:TextBox runat="server" ID="txtSchedDate" name="txtSchedDate" type="text" cssclass="datebox" style="height:20px;" ReadOnly="true"/>
            <br />
            <br />
            <br />
            <asp:Button ID="Button1" runat="server" Text="Pubblica" OnClientClick="" OnClick="Button1_Click" />
            <br />
            <br />
            <br />
            <br />
            <asp:Label ID="Label1" Font-Names="Arial" Font-Size="15px" runat="server" ForeColor="Red" Font-Bold="True" Text=""></asp:Label>
            <div id="divUpload" style="display:none">
            <div  style="width:200pt;;text-align:center;">Pubblicando...</div>
            </div>
        </div>

c＃代码

  protected double size = 1;
  private string connectionString;
  private OracleConnection connection;
  private OracleCommand processNumQuery;
  private int indexdropitem;

  protected void Page_Load(object sender, EventArgs e)
  {


    if (Request["CONNECTSTRING"] == null && Session["CONNECTSTRING"] == null)
    {
        Response.Redirect("sessionup.asp?type=Pubreport");
    }
    else
    {
        if (Request["CONNECTSTRING"] != null)
        {
            connectionString = Request["CONNECTSTRING"].ToString();
        }
        else
        {
            connectionString = Session["CONNECTSTRING"].ToString();
        }


        if (connectionString.IndexOf("DSN=") >= 0)
        {
            Utility util = new Utility();
            connectionString = util.ConnStr(connectionString);
        }
        Session["CONNECTSTRING"] = connectionString;
        connection = new OracleConnection(connectionString);
        connection.Open();

    }
    if (!IsPostBack)
    {
            processNumQuery = new OracleCommand("select distinct nome_report from rpg_notification",connection);
            OracleDataReader reader = processNumQuery.ExecuteReader();

            while (reader.Read())
            {
                dropdownlist1.Items.Insert(0, new ListItem(reader.GetString(0), ""));
            }
            reader.Close();
    }
    }


     protected void Button1_Click(object sender, EventArgs e)
     {

    Response.Write("try :" + dropdownlist1.SelectedIndex + " - " + txtSchedDate.Text + " - " + dropdownlist1.Items[dropdownlist1.SelectedIndex].Text + " - " + Request["txtSchedDate"] + " - ");
     }

我想获得0指数，那我该怎么办？

Answer 1

ASP.NET不够“智能”，无法传递提交的下拉列表的实际选定索引。相反，它取决于浏览器发送所选的值，然后取决于具有不同值的项目。

如果有相同值的项目并且其中一个被选中，则服务器端SelectedIndex将返回具有该值的第一个项目的索引。我刚刚创建了一个快速测试并且证明是正确的。（不熟悉任何.NET小提琴，对不起）

在您的特定情况下，由于该行，所有项目都为空值：

dropdownlist1.Items.Insert(0, new ListItem(reader.GetString(0), ""));

要“修复”您的问题，只需添加一个值：

string myValue = reader.GetString(0);
dropdownlist1.Items.Insert(0, new ListItem(myValue, myValue));

Answer 2

这应该有用......只是出于调试目的，尝试拨打dropdownlist1.SelectedItem.Text而不是dropdownlist1.Items[dropdownlist1.SelectedIndex].Text，看看你得到了什么

asp DropDownList总是选择0索引并进行回发检查

2 个答案: