Private Sub PrintColumnNames(dataSet As DataSet)
    Dim table As DataTable
    Dim column As DataColumn 

    ' For each DataTable, print the ColumnName.
    For Each table in dataSet.Tables
        For Each column in table.Columns
        Console.WriteLine(column.ColumnName)
        Next
    Next
End Sub

Private Sub AddColumn(table As DataTable)
    Dim column As DataColumn
    column = New DataColumn()

    With column
        .ColumnName = "SupplierID"
        .DataType = System.Type.GetType("System.String")
        .Unique = True
        .AutoIncrement = False
        .Caption = "SupplierID"
        .ReadOnly = False
    End With

    ' Add the column to the table's columns collection.
    table.Columns.Add(column)
End Sub

private void PrintColumnNames(DataSet dataSet)
{
    // For each DataTable, print the ColumnName.
    foreach(DataTable table in dataSet.Tables)
    {
        foreach(DataColumn column in table.Columns)
        {
            Console.WriteLine(column.ColumnName);
        }
    }
}

private void AddColumn(DataTable table)
{
    DataColumn column;
    column = new DataColumn();
    column.ColumnName = "SupplierID";
    column.DataType = System.Type.GetType("System.String");
    column.Unique = true;
    column.AutoIncrement = false;
    column.Caption = "SupplierID";
    column.ReadOnly = false;

    // Add the column to the table's columns collection.
    table.Columns.Add(column);
}