Question

How can i change the Message of an Exception object in C#?

Bonus Chatter

The Message property of Exception is read-only:

public virtual string Message { get; }

Additional Reading

The same question, in PHP, was answered, “You can’t”, but gave a workaround:

You can however determine it’s class name and code, and throw a new one, of the same class, with same code, but with different message.

How can i determine an exception’s class name, and throw a new one of the same class, but with a different message, in C#?

e.g.:

catch (Exception e)
{
   Exception e2 = Activator.CreateInstance(e.GetType());
   throw e2;
}

doesn’t work because the Message property of an exception is read-only and .NET. See original question.

---

Update

i tried catching each type of exception i expect:

try
{
    reader.Read();
}
catch (OleDbException e)
{
   throw new OleDbException(e, sql);
}
catch (SqlException e)
{
   throw new SqlException (e, sql);
}
catch (IBM.DbException e)
{
   throw new IBM.DbException(e, sql);
}
catch (OdbcException e)
{
   throw new OdbcException (e, sql);
}
catch (OracleException e)
{
   throw new OracleException (e, sql);
}

Except that now my code forces a dependency on assemblies that won’t be present in every solution.

Also, now the exception seems to come from my code, rather than the line that threw it; i lose the exception’s location information

Answer 1

i found the solution in a blog post linked from a news site:

catch (Exception e)
{
   Exception e2 = (Exception)Activator.CreateInstance(e.GetType(), message, e);
   throw e2;
}

It’s not perfect (you lose your stack trace); but that’s the nature of .NET.