After weeks of researching for answer, I finally came up with the solution of how to validate objects within a FormView using ASP.NET 2.0 programming language.

Assuming you have a FormView, and you require users to update information to the SQL database. There is a RadioButtonList and a TextBox. The entry within the textbox is optional, but it will be mandatory if one of the option is chosen. Take for example, the screen-shot below.

(find out how to solve the validation issue...)

Task: To validate that the texbox is populated with information if the radio button selection is "Reject".

Procedure:

1. From the Formview, specify the following command:
   

   OnItemUpdating = "ValidateReject"

   This is inserted in the line containing:
   

   <asp:FormView ID=... OnItemUpdating="ValidateReject"...>

2. Write the following C# code for ValidateReject:
   

   protected void ValidateReject(object sender, FormViewUpdateEventArgs e)
   {
   FormViewRow row = MyFormView.Row;
   RadioButtonList list = (RadioButtonList)row.FindControl("MyRadioButtonList");
   string y1 = list.SelectedValue;
   labelShow.Text = null;
   if (y1 == "Reject")
   {
   TextBox Text1 = (TextBox)row.FindControl("textbox1");
   string x1 = Text1.Text;
   if (x1 == null || x1 == "")
   {
   labelShow.Text = "<font color=\"red\">Rejection Without Reasons!</font>";
   e.Cancel = true;
   }
   else
   labelShow.Text = null;
   }
   }

3. I have also included a text label to indicate the reason:
   

   <asp:Label ID="labelShow" runat="server" />

With a few line of codes, you can easily validate any information from the FormView! In addition, this can also be extended to DetailsView as well!