Question

i’m writing a dll which is a wrapper to a access database. and i’m pretty new to c# in general as my background is in web development LAMP with perl, i’m not sure what’s a good way to return error to a calling app in case they pass the wrong parameters to my functions or what not.

I have no idea as of now except to probably do some msgbox or throw some exceptions but i don’t know where to start looking. Any help or resources would be more than useful 🙂

thanks~

Answer 1

You probably don’t want to display message dialogs from within your dll, that’s the job of the client application, as part of the presentation layer.

.Net library assemblies typically bubble up exceptions to the host application, so that’s the approach I’d look at.

public static class LibraryClass
{
    public static void DoSomething(int positiveInteger)
    {
        if (positiveInteger < 0)
        {
            throw new ArgumentException("Expected a positive number", "positiveInteger");
        }
    }
}

Then it’s up to your host application to handle those exceptions, logging and displaying them as appropriate.

try
{
    LibraryClass.DoSomething(-3);
}
catch(ArgumentException argExc)
{
    MessageBox.Show("An Error occurred: " + argExc.ToString());
}