Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim SQLData As New System.Data.SqlClient.SqlConnection(\"Data Source=.\\
try changing your code to
TextBox1.Text = String.Join(", ", table.AsEnumerable().Select(Function(r) r.Field(Of Integer)("seat_select")).ToArray()
hope this helps