ASP.NET: Dealing with object types as parameters when updating in ObjectDataSource

How do you guys update let's say for example a FormView with an ObjectDataSource source. The DataObjectTypeName is a class which I have already marked with a DataObject attribute. Now, I want to customize the update process and add some custom data to the parameter. What do we need to do so?

Example: I have a BLL class which let's call it "ProductsBLL" and a data class "Product".

I declare the following ObjectDataSource control:

<asp:ObjectDataSource ID="ObjectDataSource1" runat="server" 
DataObjectTypeName="Product" OldValuesParameterFormatString="original_{0}"
SelectMethod="GetProduct" TypeName="Assembly.ProductsBLL" 
UpdateMethod="UpdateProduct">
  <UpdateParameters>
    <asp:Parameter Name="product" Type="Object" />
  </UpdateParameters>
  <SelectParameters>
    <asp:QueryStringParameter Name="productID" QueryStringField="ProdID" Type="Int32" />
  </SelectParameters>
</asp:ObjectDataSource>

Given that the Update method in the ProductsBLL class accepts a Product object as a parameter. Now, before the update takes place, I want to add a custom data to the Product parameter. How can I do that?

Solution

I'm not sure exactly what your question is (you need to be more specific), but the general flow is as follows:

Your GridView is linked to an ObjectDataSource.
Your ObjectDataSource is linked to a Biz Logic layer via the TypeName property - This is the class that will be instantiated for performing data operations. (call it ProductsBLL for example).
It also uses an DataObjectTypeName property which is the type of object being retrieved/updated/deleted by the BLL. (say, Product)
Also, it specifies the methods in the BLL to call whenever an action is invoked (UpdateMethod, SelectMethod, etc.) (say, ProductsBLL.UpdateProducts, ProductsBLL.DeleteProducts)
Your BLL object then performs custom operations such as validation logic on the data received from the ObjectDataSource and calls your Datalayer to perform the actual updation/deletion from the database. (say, ProductsDataLayer.UpdateProduct())

If you need more information, please edit your question to be more specific.

Edit (after edit to original question):

Modifying the Product parameter before update would be as simple as:

// In Biz Logic Layer.
public int UpdateProduct(Product p)
{
  // Modify the ProductName and the Price properties of this Product.
  p.ProductName = "Product " + p.ProductName;
  p.Price = 0.95 * p.Price;

  // Call DataLayer.
  return ProductDL.UpdateProduct(p.ID, p.ProductName, p.Quantity, p.Price);
}

where the ProductDL.UpdateProduct might look like:

public int UpdateProduct
  (
    string productID,
    string productName,
    int productQty,
    float productPrice
    )

And, so on.