判断是否有选择RadioButtonList

写Javascript来判断是否有对RadioButtonList选项选择，效果如下：

准备好RadioButtonList数据源：

Imports Microsoft.VisualBasic

Namespace Insus.NET
    Public Class Cosmetic
        Private _ID As Integer
        Private _Type As String
        Private _Name As String
        Private _Weight As Decimal
        Private _UM As String

        Public Property ID As Integer
            Get
                Return _ID
            End Get
            Set(value As Integer)
                _ID = value
            End Set
        End Property

        Public Property Type As String
            Get
                Return _Type
            End Get
            Set(value As String)
                _Type = value
            End Set
        End Property

        Public Property Name As String
            Get
                Return _Name
            End Get
            Set(value As String)
                _Name = value
            End Set
        End Property

        Public Property Weight As Decimal
            Get
                Return _Weight
            End Get
            Set(value As Decimal)
                _Weight = value
            End Set
        End Property
        Public Property UM As String
            Get
                Return _UM
            End Get
            Set(value As String)
                _UM = value
            End Set
        End Property

        Public Sub New()

        End Sub

        Public Sub New(id As Integer, type As String, name As String, weight As Decimal, um As String)
            Me._ID = id
            Me._Type = type
            Me._Name = name
            Me._Weight = weight
            Me._UM = um
        End Sub

        Public Function GetData() As List(Of Cosmetic)
            Dim o As New List(Of Cosmetic)
            Dim c As New Cosmetic(1, "滋润霜", "玉兰油", 50, "g")
            o.Add(c)

            Dim c1 As New Cosmetic(2, "滋润霜", "雅诗兰黛", 100, "g")
            o.Add(c1)

            Dim c2 As New Cosmetic(3, "滋润霜", " 兰蔻", 80, "g")
            o.Add(c2)

            Dim c3 As New Cosmetic(4, "滋润霜", "欧莱雅", 60, "g")
            o.Add(c3)

            Dim c4 As New Cosmetic(5, "滋润霜", "芭比波朗", 120, "g")
            o.Add(c4)

            Return o
        End Function
    End Class


End Namespace

在aspx放一个RadioButtonList控件和一个铵钮：

化妆品：<asp:RadioButtonList ID="RadioButtonListCosmetic" runat="server" RepeatColumns="10" RepeatDirection="Horizontal"></asp:RadioButtonList>
      <br />
      <asp:Button ID="Button1" runat="server" Text="Select" />

在aspx.vb中，为RadioButtonList绑定数据源，当然绑定数据源下面的代码中，还得引用命名空间 Imports Insus.NET

 Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
        If Not IsPostBack Then
            Data_Binding()
        End If
    End Sub

    Private Sub Data_Binding()
        Dim objCosmetic As New Cosmetic()

        Me.RadioButtonListCosmetic.DataSource = objCosmetic.GetData()
        Me.RadioButtonListCosmetic.DataTextField = "Name"
        Me.RadioButtonListCosmetic.DataValueField = "ID"
        Me.RadioButtonListCosmetic.DataBind()
    End Sub

接下来是演示开始，写Javascript代码：

<script type="text/javascript">
        function CheckIsSelected() {
            var rbl = document.getElementById("<%=RadioButtonListCosmetic.ClientID%>");
            var radio = rbl.getElementsByTagName("input");
            var isSelect = false;
            for (var i = 0; i < radio.length; i++) {
                if (radio[i].checked) {
                    isSelect = true;
                    break;
                }
            }
            if (!isSelect) {
                alert("请选择一个选项。");
            }
            return isSelect;
        }
    </script>

最后是为铵钮Button写客户端事件

<asp:Button ID="Button1" runat="server" Text="Select" OnClientClick="return CheckIsSelected()" />