Warning: file_get_contents(/data/phpspider/zhask/data//catemap/1/asp.net/30.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181
asp.net下拉控件的数据绑定列表_Asp.net_Vb.net_Drop Down Menu - Fatal编程技术网

asp.net下拉控件的数据绑定列表

asp.net下拉控件的数据绑定列表,asp.net,vb.net,drop-down-menu,Asp.net,Vb.net,Drop Down Menu,早上好。 我有一个下拉列表控件,当选择一个特定的项目时,另一个下拉列表将基于该选择填充。背后的代码如下 Imports System.IO Partial Class Data Inherits System.Web.UI.Page Private Property _futureslist As List(Of String) Property FuturesList As List(Of String) Get Return _futureslist End

早上好。 我有一个下拉列表控件,当选择一个特定的项目时,另一个下拉列表将基于该选择填充。背后的代码如下

Imports System.IO
Partial Class Data
Inherits System.Web.UI.Page
Private Property _futureslist As List(Of String)
Property FuturesList As List(Of String)
    Get
        Return _futureslist
    End Get
    Set(value As List(Of String))
        Dim strText As String =    File.ReadAllText(HttpContext.Current.Server.MapPath("~/DataFiles/AvailableFutures.txt"))
        Dim arytext() As String = strText.Split(",")
        For i As Integer = 0 To arytext.Count - 1
            value.Add(arytext(i))
        Next
        _futureslist = value
    End Set

End Property
Protected Sub ddlMain_SelectedIndexChanged(sender As Object, e As System.EventArgs) Handles ddlMain.SelectedIndexChanged
    If Not IsPostBack Then

        If ddlMain.SelectedItem.Text = "Futures" Then
            ddlMainsub1.DataSource = _futureslist
            ddlMainsub1.DataBind()

        End If
    End If
End Sub
End Class
创建列表属性所读取的文件格式如下:; 玉米 小麦 咖啡


因此,当主下拉选择项为“Futures”时,第二个下拉值将数据绑定到FuturesList属性。任何帮助都将不胜感激

设置“ddlMain”的
AutoPostBack=True
,然后在

Protected Sub ddlMain_SelectedIndexChanged(sender As Object, e As System.EventArgs) Handles ddlMain.SelectedIndexChanged
 ddlMainsub1.Items.Clear()
 'bound items here to DropDownList2
End Sub  

希望能有帮助。祝你好运。

可能是你需要删除“如果不是IsPostBack然后”复选框Autopsy?我的.NET版本没有做到这一点。看起来有人的手机上有Autocorrect=true。=)你不知道尸检=自动回邮你成功了吗?