asp.net(vb) มัน error : There is already an open DataReader associated with this Command which must be closed first

Imports System.Data
Imports System.Data.SqlClient

Partial Class _Default
    Inherits System.Web.UI.Page
    Dim Conn As SqlConnection
    Dim Cmd As SqlCommand
    Dim Cmd1 As SqlCommand
    Dim dtReader As SqlDataReader
    Dim sql As String

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        If txtaddress.Text <> "" Then
            Try
                Dim sqlx As String = "select count(cat_id) as count_ from tb_category where cat_name = '" & Me.txtaddress.Text & "'"
                Cmd1 = New SqlCommand(sqlx, Conn)
                dtReader = Cmd1.ExecuteReader()
                dtReader.Read()
                Dim count_cat As String = dtReader.Item("count_")
                dtReader.Close() 'reader close begin
                If count_cat = 0 Then
                    sql = "insert into tb_category(cat_name) values('" & Me.txtaddress.Text & "')"
                    Cmd = New SqlCommand(sql, Conn)
                    Dim sta As String = Cmd.ExecuteNonQuery()
                    If sta Then
                        Me.lblText.Text = "บันทึกข้อมูลเรียบร้อย"
                        Me.lblText.ForeColor = Drawing.Color.Green
                        GridView1.DataBind()
                    Else
                        Me.lblText.Text = "เกิดข้อผิดพลาด"
                        Me.lblText.ForeColor = Drawing.Color.Red
                    End If
                Else
                    Me.lblText.Text = "ข้อมูลมีอยู่ในระบบแล้ว กรุณาตรวจสอบ.."
                    Me.lblText.ForeColor = Drawing.Color.Blue
                End If

            Catch ex As Exception
                Me.Label1.Visible = True
                Me.Label1.Text = "Error : " & ex.ToString()
            End Try
        Else
            Me.lblText.Text = "กรุณากรอกข้อมูล"
            Me.lblText.ForeColor = Drawing.Color.Red
            Me.txtaddress.Focus()
        End If
    End Sub
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Dim strConnString As String
        strConnString = "Server=localhost\HUSOC;Uid=user_husoc_ci;PASSWORD=1842531;database=db_husoc_ci;Max Pool Size=400;Connect Timeout=600;"
        Conn = New SqlConnection(strConnString)
        Conn.Open()

    End Sub
End Class