Here I will teach you how can merge two datatables :
You can whatch the video here
Private Sub MergeDatatable()
Dim dt1 As New DataTable
Dim dt2 As New DataTable
dt1.Columns.Add("Id")
dt1.Columns.Add("Name")
Dim dtrow1 As DataRow
dtrow1 = dt1.NewRow
dtrow1("Id") = 12
dtrow1("Name") = "Mehran"
dt1.Rows.Add(dtrow1)
dt2.Columns.Add("Id")
dt2.Columns.Add("Name")
Dim dtrow2 As DataRow
dtrow2 = dt2.NewRow
dtrow2("Id") = 12
dtrow2("Name") = "Nush"
dt2.Rows.Add(dtrow2)
dt1.Merge(dt2)
End Sub
Click here to convert this Vb.net code to C#