Question

如何使用dropdownlist项将值插入数据库，我想要的是选择Item然后当我按下提交按钮时，数值将使用asp.net vb.net代码保存到sql server数据库，问题是，它总是在sqlserver数据库中保存0值，即使我选择1,2,3或4，问题是javascript，如果我删除javascript它可以选择我想要的值并且没有问题，但我需要如果它已经被选中，它将禁用该值，以避免重复数据库，有人可以帮助我弄清楚javascript，如果我尝试按下保存按钮，你可以看到下拉列表返回到其默认值0然后重置，而不是保存我从下拉列表中选择的值，感谢.............

   <%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb"           
   Inherits="_Default"  Debug="true"%>

   <!DOCTYPE html>

   <html xmlns="http://www.w3.org/1999/xhtml">
  <head runat="server">

   <title></title>
   </head>
   <body>

     <form id="form1" runat="server">
       <div>
          <asp:DropDownList ID = "frst" runat="server" AutoPostBack="true">
           <asp:ListItem value="0">Select</asp:ListItem>
           <asp:ListItem value="1">1</asp:ListItem>
           <asp:ListItem value="2">2</asp:ListItem>
           <asp:ListItem value="3">3</asp:ListItem>
           <asp:ListItem value="4">4</asp:ListItem>         
          </asp:DropDownList>
            <asp:DropDownList ID = "secnd" runat="server">
       <asp:ListItem value="0">Select</asp:ListItem>
           <asp:ListItem value="1">1</asp:ListItem>
           <asp:ListItem value="2">2</asp:ListItem>
           <asp:ListItem value="3">3</asp:ListItem>
           <asp:ListItem value="4">4</asp:ListItem>         
            </asp:DropDownList>    

               <asp:Button ID="btnSave" runat="server" Text="Save"       
        OnClick="btnSave_Click" />
        <asp:Label ID="lblmsg" runat="server"></asp:Label> 

    </div>


   <script type="text/javascript">
   var ids = ['frst', 'secnd'];

    NodeList.prototype.forEach = HTMLCollection.prototype.forEach =    
      Array.prototype.forEach;
   var selected = [];
   ids = makeid(ids);
   var opts = find(ids);
   updateS(opts);
   massdisabler(opts);
   assignFunc(ids, disabler);

    function assignFunc(i, func) { //done
   var x;
   for (x = 0; x < i.length; ++x) {
    i[x].onchange = function () {
        func(this);
     };
   } 
  }

   function disabler(i) {
   console.log(selected);
   updateS(opts);
   massdisabler(opts);
  }

  function makeid(i) { //done
   var o = [];
   i.forEach(function (v) {
    o.push(document.getElementById(v))
   });
  return o;
  }

  function find(ids) { //done
   var o = {};
   for (var i = 0; i < ids.length; ++i) {
    o[i] = {};
    ids[i].children.forEach(function (v, n) {
        o[i][n] = v;
    });
    }

   return o;
  }

  function massdisabler(op) { //done
  var y = Object.keys(op).length;
  for (var x = 0; x < y; x++) {
    var t = 0,
        l = Object.keys(opts[x]).length;
    for (var v = 0; v < l; v++) {
        t = op[x][v];

        if (selected.some(function (k) {
            if (t.value == k) {
                return true;
        }
        })) {
            t.setAttribute("disabled", "disabled");
        } else {
            t.removeAttribute("disabled");
        }
      }
    }
  }

  function updateS(op) { //done
  var s = [],
    y = Object.keys(op).length;

   for (var x = 0; x < y; x++) {

    var t = 0,
        l = Object.keys(opts[x]).length;

    for (var v = 0; v < l; v++) {
        t = op[x][v];
        var yn = s.some(function (k) {
            if (t.value == k) {
                return true;
            }
        });
        if (t.selected && (!yn)) s.push(t.value);
      }
   }
   selected = s;
   }
  </script>

  </form>

  </body>   
   </html>

有人可以帮助我正在尝试修改我的代码请不要downvote我只是一个初学者，谢谢这是整个代码请帮助我我这样做几个星期：

    Protected Sub btnSave_Click(sender As Object, e As EventArgs)
    Dim cs As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Dim cn As SqlConnection = New SqlConnection(cs)
    Dim cmd As SqlCommand = New SqlCommand()
    cmd.Connection = cn
    cmd.CommandType = CommandType.Text
    cmd.CommandText = "insert into Names values(@FirstValue,@SecondValue)"
    cmd.Parameters.Clear()
    cmd.Parameters.AddWithValue("@FirstValue", frst.SelectedItem.Value)
    cmd.Parameters.AddWithValue("@SecondValue", secnd.SelectedItem.Value)
    If cn.State = ConnectionState.Closed Then
        cn.Open()
    End If
    cmd.ExecuteNonQuery()
    cn.Close()
    lblmsg.Text = "Data entered successfully!!!"

End Sub

Answer 1

取viewstate或hiddenfield并将dropdownlist SelectedValue分配给其中任何一个。

您的问题将得到解决。

下拉列表启用禁用值

1 个答案: