Private Sub InitDataset()
        Dim lDataTable As New DataTable
        Dim lDataColum As DataColumn
        Dim lDataRow As DataRow

        lDataColum = New DataColumn
        lDataColum.DataType = System.Type.GetType("System.String")
        lDataColum.ColumnName = "FileName"
        lDataTable.Columns.Add(lDataColum)

        lDataColum = New DataColumn
        lDataColum.DataType = System.Type.GetType("System.String")
        lDataColum.ColumnName = "Extension"
        lDataTable.Columns.Add(lDataColum)

        lDataColum = New DataColumn
        lDataColum.DataType = System.Type.GetType("System.String")
        lDataColum.ColumnName = "Lenght"
        lDataTable.Columns.Add(lDataColum)

        lDataColum = New DataColumn
        lDataColum.DataType = System.Type.GetType("System.Date")
        lDataColum.ColumnName = "Date"
        lDataTable.Columns.Add(lDataColum)

        mDts = New DataSet
        mDts.Tables.Add(lDataTable)
    End Sub

Como crear un DataTable a mano y editar sus columnas y filas bajo código.

Make and edit DataTable in code

VB.NET