ASP.Net/ADO.net Database/DataColumn

Add DataColumn to DataTable

<%@ Page Language="C#" %>
<%@ import Namespace="System.Data" %>
<%@ import Namespace="System.Data.SqlClient" %>
<script runat="server">
    void Page_Load(object sender, EventArgs e)
    {
      if (!Page.IsPostBack)
        BindData();
    }
    
    
    IEnumerable ItemsInCart()
    {
       DataTable dt = new DataTable();
       DataRow dr;
    
       dt.Columns.Add(new DataColumn("ProductID", typeof(int)));
       dt.Columns.Add(new DataColumn("Name", typeof(string)));
       dt.Columns.Add(new DataColumn("Price", typeof(float)));
    
       for (int i = 0; i < 10; i++)
       {
          dr = dt.NewRow();
    
          dr[0] = i+1;
          dr[1] = "Item " + i.ToString();
          dr[2] = (float) 1.2 * i;
    
          dt.Rows.Add(dr);
       }
    
       DataView dv = new DataView(dt);
       return dv;
    }
    
    
    string GetProductDescription(int ID)
    {
      return "This is the description for product " + ID.ToString() + "...";
    }
    
    
    void BindData()
    {
      dgCart.DataSource = ItemsInCart();
      dgCart.DataBind();
    }
    
    
    void dgCart_ItemCommand(object sender, DataGridCommandEventArgs e)
    {
      Response.Write("A button was clicked...");
    }
</script>
<form runat="server">
  <asp:DataGrid runat="server" id="dgCart"
        AutoGenerateColumns="False"
        Font-Name="Verdana"
        Font-Size="8pt"
        OnItemCommand="dgCart_ItemCommand">
  
    <HeaderStyle HorizontalAlign="Center" 
                 Font-Bold="True"
                 Font-Size="11pt" 
                 BackColor="Navy" 
                 ForeColor="White" />
  
    <Columns>
      <asp:ButtonColumn Text="Remove" 
                        ButtonType="PushButton"
                        HeaderText="Remove" />
      <asp:ButtonColumn Text="Details" 
                        ButtonType="PushButton"
                        HeaderText="Details" />
              
      <asp:BoundColumn DataField="Name" HeaderText="Product Name" />
      <asp:BoundColumn DataField="Price" 
                       HeaderText="Price"
                       ItemStyle-HorizontalAlign="right"
                       DataFormatString="{0:c}" />
    </Columns>
  </asp:DataGrid>
</form>