How to add a row to a datatable?

I face a stupid problem here. Cannot find an error and do not really know how to fix this.

I'm adding an i开发者_运维知识库tem into datatable on selected index changed. Everything works, except only the last item is shown in dt. I always has the latest item and all others are gone. i suppose this is because I initialize it in the wrong place but still cannot find a solution.

 Dim dt As DataTable = New DataTable()
   Protected Sub Page_Load(sender As Object, e As System.EventArgs)   Handles Page.Load
        dt.Columns.Add("dr1")
        dt.Columns.Add("dr2")
    End Sub
Protected Sub ddlTest_SelectedIndexChanged(sender As Object, e As System.EventArgs) Handles ddlTest.SelectedIndexChanged
            Dim row As DataRow = dt.NewRow()
            row(0) = "Test!"
            row(1) ="Test"
            dt.Rows.Add(row)
        End If
    End Sub

This always shows only last item in list. How do I do this correct way?

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Unless I am mistaken, you create a new DataTable every time a user hits the page.

You need to persist the row to a real database or perhaps make your DataTable shared (static in C#) instead.

Shared dt As DataTable = New DataTable()