private void notifyUserButton_Click(object sender, System.EventArgs e)
{
try
{
Cursor = System.Windows.Forms.Cursors.WaitCursor;
StringBuilder sb = new StringBuilder();
sb.Append("Scenario: Notify the user when an exception occurs");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("1. An exception occurs and is detected in the Business layer.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("2. The Business layer specifies the \"Notify Policy\" as the exception handling policy.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("3. The \"Notify Policy\" is configured to first log the exception, then replace the exception with a new one, and finally return to the application by recommending a rethrow.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("4. The exception is propagated to and caught by the UI layer.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("5. The UI layer catches the exception and calls the \"Global Policy\", which displays the exception in a message box.");
sb.Append(Environment.NewLine);
DisplayScenarioStart(sb.ToString());
AppService svc = new AppService();
svc.ProcessAndNotify();
Cursor = System.Windows.Forms.Cursors.Arrow;
}
catch (Exception ex)
{
ProcessUnhandledException(ex);
}
}
private void replaceExceptionButton_Click(object sender, System.EventArgs e)
{
try
{
Cursor = System.Windows.Forms.Cursors.WaitCursor;
StringBuilder sb = new StringBuilder();
sb.Append("Scenario: Replace the original exception with another before propagating");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("1. UI layer calls into business layer.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("2. A SecurityException exception occurs and is detected in the business layer.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("3. The business layer specifies the \"Replace Policy\" as the exception handling policy.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("4. The \"Replace Policy\" is configured to use a replace handler to replace the original exception with an ApplicationException exception.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("5. The rethrowAction is set to \"Throw\", resulting in the new exception being thrown by the block upon completion of the handler chain execution.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("6. The new exception is caught and displayed.");
DisplayScenarioStart(sb.ToString());
AppService svc = new AppService();
svc.ProcessWithReplace();
}
catch (Exception ex)
{
ProcessUnhandledException(ex);
}
}
private void suppressExceptionButton_Click(object sender, System.EventArgs e)
{
try
{
Cursor = System.Windows.Forms.Cursors.WaitCursor;
StringBuilder sb = new StringBuilder();
sb.Append("Scenario: Process and resume execution");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("1. UI layer calls into business layer.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("2. A SecurityException occurs and is detected in the business layer.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("3. The business layer specifies the \"Handle and Resume Policy\" as the exception handling policy.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("4. The \"Handle and Resume Policy\" is configured with a rethrowAction of \"None\", resulting in execution being resumed upon completion of the handler chain execution.");
DisplayScenarioStart(sb.ToString());
AppService svc = new AppService();
svc.ProcessAndResume();
this.resultsTextBox.Text += "Exception processed, execution resumed.";
Cursor = System.Windows.Forms.Cursors.Default;
}
catch (Exception ex)
{
ProcessUnhandledException(ex);
}
}
private void propagateOriginalExceptionButton_Click(object sender, System.EventArgs e)
{
try
{
Cursor = System.Windows.Forms.Cursors.WaitCursor;
StringBuilder sb = new StringBuilder();
sb.Append("Scenario: Propagate original exception");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("1. UI layer calls into business layer.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("2. A System.Exception occurs and is detected in the business layer.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("3. The business layer specifies the \"Propagate Policy\" as the exception handling policy.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("4. The \"Propagate Policy\" is configured to recommend a rethrow upon return from processing the exception handlers.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("5. Control is returned to the business layer, which rethrows the original exception.");
sb.Append(Environment.NewLine);
sb.Append(Environment.NewLine);
sb.Append("6. The original exception is caught and displayed.");
DisplayScenarioStart(sb.ToString());
AppService svc = new AppService();
svc.ProcessWithPropagate();
}
catch (Exception ex)
{
ProcessUnhandledException(ex);
}
}
