Don't put these lines in your For loop:
Dim query As String = "Select * from customer where meter_num = @meter_num"
conn.Open()
Dim command As New SqlCommand(query, conn)
command.Parameters.AddWithValue("@meter_num", meter_number)
Dim da As New SqlDataAdapter(command)
Dim ds As New DataSet
da.Fill(ds, "customer")
dt_sample.DataSource = ds.Tables(0)
conn.Close()
And construct your query like this:
Dim query As String = "Select * from customer where meter_num IN @meter_numbers"
[Edit] see the solution by Richard Deeming, or try one of the methods mentioned here:
sql server - Parameterize an SQL IN clause - Stack Overflow[
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