C#

class BaseClass {
   public int value1;
}
class DerivedClass : BaseClass {
   public int value2;
}

static void Main() {
   DerivedClass dc = new DerivedClass();
   BaseClass bc = dc; //works

   BaseClass bc2 = new BaseClass();
   DerivedClass dc2 = (DerivedClass)bc2; //fails at runtime because BaseClass doesn't have all the functionality of the DerivedClass
}

rahul21 wrote:

Inside the selected index changed event of combobox I write this line of code:-

rahul21 wrote:

I am using connected architecture.

If your application is intended for international use with a variety of keyboards, the use of Send could yield unpredictable results and should be avoided

Blumen wrote:

new protected member declared in sealed class

I dont use any unmanaged objects, so I need to dispose only connection and command object in this class. Could anyone help me with this error?

Blumen wrote:

But dispose is a method of base class, so is it okay to remove the virtual keyword?

Blumen wrote:

Does that mean I have to override dispose on my class

Blumen wrote:

and make class sealed

Blumen wrote:

ObjectDatasource control in ADO.NET 2.0. So will this control call my class's Dispose()

public class CustomerDal
{
  public void AddCustomer(...){
     using(SqlConnection connection = new SqlConnection(...))
     using(SqlCommand command = new SqlCommand(connection,...)){
        // your code
     }
  }
}

Pete O'Hanlon wrote:

They give broad brush guidelines that people tend to end up as treating as gospel.

Pete O'Hanlon wrote:

This is the whole problem with FxCop (and utility's like it). They give broad brush guidelines that people tend to end up as treating as gospel.

Pete O'Hanlon wrote:

This suggestion only makes sense if your SqlConnection/SqlCommand objects are member variables.

Pete O'Hanlon wrote:

If they are a local variable then there is no sense in using IDisposable to manage this.