مشكلة في Select Statement !

السلام عليكم

ظهرت عندي مشكلة في ولا اعرف اين المشكلة تحديدا هل هي في select statement ام عند استخدام ExecuteReader()

حيث تظهر لي رسالة الخطأ التالية

Invalid attempt to read when no data is present

علما اني استخدم Microsoft visual studio 2005

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وهذا الكود:

<%@ Page Language="VB" MasterPageFile="~/MasterPage.master" Title="Untitled Page" %>
<script runat="server">
	Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs)
		'LOCAL VARIABLES
		Dim id As String = TextBox1.Text
		Dim password As String = TextBox2.Text

		'----creating the connection
		Dim cons As String = ConfigurationManager.ConnectionStrings("votingdbConnectionString").ConnectionString
		Dim con As New Data.SqlClient.SqlConnection
		con.ConnectionString = cons

		'--------creating the command
		Dim comSel As New Data.SqlClient.SqlCommand
		comSel.CommandText = "SELECT [CandidateName] FROM [CANDIDATE] WHERE ([CandidateID] = '" & id & "' AND [CandidatePassword] = '" & password & "')"
		comSel.CommandType = Data.CommandType.Text
		comSel.Connection = con
		Try
			con.Open()

			Dim rd As Data.SqlClient.SqlDataReader = comSel.ExecuteReader()

			Dim canName As String = rd.GetValue(1) ' get from column 1(second column) in DB	 
			If (rd.Read() = True) Then

				Session("name") = canName
				'moving from page to page
				Server.Transfer("cand-Page.aspx")	   
			End If

			rd.Close()

	   Catch ex As Exception
			Label4.Text = ex.Message
			Label4.Visible = True
		Finally

		End Try
		con.Close()

	End Sub

</script>

<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
	 <br />
	دخول المرشحين<br />
	<br />
	<asp:TextBox ID="TextBox1" runat="server">1234567891</asp:TextBox>
	<asp:Label ID="Label1" runat="server" Text="رقم السجل المدني"></asp:Label>

	<br />
	<asp:TextBox ID="TextBox2" runat="server" OnTextChanged="TextBox2_TextChanged" TextMode="Password"></asp:TextBox>

	<asp:Label ID="Label2" runat="server" Text="كلمة المرور"></asp:Label>  <br />
	<asp:Label ID="Label4" runat="server" Text="Label" Visible="False"></asp:Label>
	   <br />
	<asp:Button ID="Button1" runat="server" Text="الدخول" OnClick="Button1_Click" />

	<br />
</asp:Content>

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ارجو مساعدتي في معرفة الخطأ,,, وشكرا مقدما :)