In C#, the throw
statement can be used in two different ways:
- by specifying an expression
- without specifying an expression
By specifying an expression
In the software development context, an expression is a value or anything that executes and ends up being a value. The expression shall be
implicitly convertible to System.Exception, and the result of evaluating the expression is converted to System.Exception
before being thrown.
try
{
}
catch(Exception exception)
{
// code that uses the exception
throw exception; // The exception stack trace is cleared up to this point.
}
In this case, the stack trace, will be cleared, losing the list of method calls between the
original method that threw the exception and the current method.
Without specifying an expression
This syntax is supported only in a catch block, in which case, that statement re-throws the exception currently being handled by that
catch block, preserving the stack trace.
try
{
}
catch(Exception exception)
{
// code that uses the exception
throw; // The stack trace of the initial exception is preserved.
}
Exceptions
It is allowed using the thrown exception as an argument and wrapping it in another exception.
try
{
}
catch(Exception exception)
{
throw new Exception("Additional information", exception);
}
