This code Reset ur Datatable every click event Create DataTable once and add value in another event
Dim Table1 As DataTable
Table1 = New DataTable("Medicines")
Dim medname As DataColumn = New DataColumn("Medicine Name")
medname.DataType = System.Type.GetType("System.String")
medname.MaxLength = 500
Table1.Columns.Add(medname)
Dim dosage As DataColumn = New DataColumn("Dosage")
dosage.DataType = System.Type.GetType("System.String")
dosage.MaxLength = 500
Table1.Columns.Add(dosage)
Dim freq As DataColumn = New DataColumn("Frequency")
freq.DataType = System.Type.GetType("System.String")
freq.MaxLength = 500
Table1.Columns.Add(freq)