In my method that writes to a database, I handle errors as shown in the code below. In catch (DbUpdateException ex) I want to re-throw the exception and catch it in the last catch (Exception ex).
Is that possible and how to do that? Code below doesn't do that.
using (Entities context = new Entities())
{
try
{
context.Office.Add(office);
retVal = context.SaveChanges();
}
catch (DbUpdateException ex)
{
SqlException innerException = ex.GetBaseException() as SqlException;
if (innerException != null && innerException.Number == (int)SQLErrorCode.DUPLICATE_UNIQUE_CONSTRAINT)
{
throw
new Exception("Error ocurred");
}
//This is momenty where exception is thrown.
else
{
throw ex;
}
}
catch (Exception ex)
{
throw
new Exception("Error");
}
}
The following would be better:
context.Office.Add(office);
retVal = context.SaveChanges();
Let the except bubble up. No need to catch stuff if all you are going to do is re-throw.
Note: throw ex; will reset the stack trace - you want to do throw; normally.
If you want to catch exceptions from other catches then they cannot be on the same level.
Your current code has this structure:
try
{
}
catch (...)
{
}
catch (...)
{
}
You need to change it to:
try
{
try
{
}
catch (...)
{
// throw X
}
}
catch (...)
{
// catch X here
}
But you should think very carefully if you really want/need this. It does not look like a productive error handling pattern.
And see this answer for the 4 different ways to (re)throw an exception and their consequences.
have you tried try nesting your try...catch blocks?
using (Entities context = new Entities())
{
try
{
try
{
context.Office.Add(office);
retVal = context.SaveChanges();
}
catch (DbUpdateException ex)
{
SqlException innerException = ex.GetBaseException() as SqlException;
if (innerException != null && innerException.Number == (int)SQLErrorCode.DUPLICATE_UNIQUE_CONSTRAINT)
{
throw new Exception("Error ocurred");
}
//This is momenty where exception is thrown.
else
{
throw ex;
}
}
}
catch (Exception ex)
{
throw new Exception("Error");
}
}
A try-catch processes only one catch block and they are evaluated in order. Therefore, if you really need this functionality you'll need to put a try-catch inside of a try-catch, like this:
using (Entities context = new Entities())
{
try
{
try
{
context.Office.Add(office);
retVal = context.SaveChanges();
}
catch (DbUpdateException ex)
{
SqlException innerException = ex.GetBaseException() as SqlException;
if (innerException != null && innerException.Number == (int)SQLErrorCode.DUPLICATE_UNIQUE_CONSTRAINT)
{
throw
new Exception("Error ocurred");
}
//This is momenty where exception is thrown.
else
{
throw ex;
}
}
}
catch (Exception ex)
{
throw
new Exception("Error");
}
}
Try this:
void YourMethod()
{
using (Entities context = new Entities())
{
try
{
context.Office.Add(office);
retVal = context.SaveChanges();
}
catch (DbUpdateException ex)
{
SqlException innerException = ex.GetBaseException() as SqlException;
if (innerException != null && innerException.Number == (int)SQLErrorCode.DUPLICATE_UNIQUE_CONSTRAINT)
{
throw
new Exception("Error ocurred");
}
//This is momenty where exception is thrown.
else
{
throw ex;
}
}
}
}
Then when you call your method enclose it with try catch block
try
{
YourMethod()
}
catch (Exception ex)
{
throw
new Exception("Error");
}
When you plan to nest your try-catch-block as described by "paul" be aware of the exception type:
using (Entities context = new Entities())
{
try
{
try
{
context.Office.Add(office);
retVal = context.SaveChanges();
}
catch (DbUpdateException ex)
{
SqlException innerException = ex.GetBaseException() as SqlException;
if (innerException != null && innerException.Number == (int)SQLErrorCode.DUPLICATE_UNIQUE_CONSTRAINT)
{
// this exception will be catched too in outer try-catch block <--------
throw new Exception("Error ocurred");
}
//This is momenty where exception is thrown.
else
{
throw ex;
}
}
}
// Catch (DbUpdateException ex) if you plan to have the rethrown exception to be catched <------------
catch (Exception ex)
{
throw new Exception("Error");
}
}
Related
In my API, I have over 25 API controllers, in every controller, using the following code to catch exception, I think it is too many code here, any good suggestion for the structure, thanks.
try
{
*code here*
}
catch (UnauthorizedAccessException ex)
{
}
catch (BadRequestException ex)
{
}
catch (HttpRequestException ex)
{
}
catch (TimeoutRejectedException ex)
{
}
catch (FileNotFoundException ex)
{
}
catch (SqlException ex)
{
}
catch (ValidationException ex)
{
}
catch (Exception ex)
{
}
Any simple way to do that.
IF
you plan to handle each exception separately - your approach is the way to go. I suggest to use this "ugly" code simply because it is more readable. If all your exceptions have common handling (for example logging) - you can use only catch (Exception e) and call your logging methods. This will work for all types of exceptions.
OR
If you decide that some of your exceptions might have common handling - you can go with:
try
{
// do
}
catch (Exception e)
{
if (e is BadRequestException ||
e is HttpRequestException ||
e is TimeoutRejectedException )
{
// Log exception
}
}
OR
A good approach is to use a delegate for exception handling. Since you're going to log exceptions, the delegate will handle this.
Action<Exception> HandleError = (e) => {
// Log exception
};
catch (UnauthorizedAccessException e) { HandleError(e); }
catch (BadRequestException e) { HandleError(e); }
catch (HttpRequestException e) { HandleError(e); }
OR
You can combine the first and the second approach
if (e is BadRequestException ||
e is HttpRequestException ||
e is TimeoutRejectedException )
{
HandleError(e);
}
Is there a way to get the inner-most exception without using :
while (e.InnerException != null) e = e.InnerException;
I'm looking for something like e.MostInnerException.
To extend on Hans Kesting's comment, an extension method might come in handy:
public static Exception GetInnerMostException(this Exception e)
{
if (e == null)
return null;
while (e.InnerException != null)
e = e.InnerException;
return e;
}
Here is another answer that differs a bit: you can create an enumerator.
With
public static IEnumerable<Exception> EnumerateInnerExceptions(this Exception ex)
{
while (ex.InnerException != null)
{
yield return ex.InnerException;
ex = ex.InnerException;
}
}
You can do
try
{
throw new Exception("1", new Exception("2", new Exception("3", new Exception("4"))));
}
catch (Exception ex)
{
foreach (var ie in ex.EnumerateInnerExceptions())
{
Console.WriteLine(ie.Message);
}
}
So, technically, you are not longer using a while loop a visible way :)
The best way to explain my question is with the following pseudo-code:
try
{
//Do work
}
catch (SqlException ex)
{
if (ex.Number == -2)
{
debugLogSQLTimeout(ex);
}
else
{
//How to go to 'Exception' handler?
}
}
catch (Exception ex)
{
debugLogGeneralException(ex);
}
Exception ex = null;
try
{
//Do work
}
catch (SqlException sqlEx)
{
ex = sqlEx;
if (ex.Number == -2)
{
//..
}
else
{
//..
}
}
catch (Exception generalEx)
{
ex = generalEx;
}
finally()
{
if (ex != null) debugLogGeneralException(ex);
}
The first catch clause that matches is the only one that can possibly run on the same try block.
The best way I can think of to do what you're attempting is to include casts and conditionals in the more general type:
try
{
//Do work
}
catch (Exception ex)
{
var sqlEx = ex as SqlException;
if (sqlEx != null && sqlEx.Number == -2)
{
debugLogSQLTimeout(ex);
}
else
{
debugLogGeneralException(ex);
}
}
If you find yourself writing this over and over again throughout your data layer, at least take the time to encapsulate it in a method.
I do not believe there is any way to do this as the catch blocks are in different scopes. There's no way to re-throw without exiting the try block and no way to 'call' the final catch block because it's only triggered during an exception.
I would suggest the same as roman m above and just make the same call. Otherwise you have to do something really bad. Like the below crazy code which you should never ever use but i included because it does something like what you want.
In general I think what you are doing is controlling normal flow via exceptions which isn't recommended. If you are trying to track for timeouts, you should probably just handle that another way.
Note that you could do something like the code below with the insanity of a goto statement, but i included it so no one can forget what a bad idea this is. =)
void Main()
{
Madness(new NotImplementedException("1")); //our 'special' case we handle
Madness(new NotImplementedException("2")); //our 'special' case we don't handle
Madness(new Exception("2")); //some other error
}
void Madness(Exception e){
Exception myGlobalError;
try
{
throw e;
}
catch (NotImplementedException ex)
{
if (ex.Message.Equals("1"))
{
Console.WriteLine("handle special error");
}
else
{
myGlobalError = ex;
Console.WriteLine("going to our crazy handler");
goto badidea;
}
}
catch (Exception ex)
{
myGlobalError = ex;
Console.WriteLine("going to our crazy handler");
goto badidea;
}
return;
badidea:
try{
throw myGlobalError;
}
catch (Exception ex)
{
Console.WriteLine("this is crazy!");
}
}
// Define other methods and classes here
I'm trying to catch a duplicate key violation. I can see the System.OleDB.OleDBException in the Intellisense pop up, but the inner exception is null. How do I access the Error Code in the System.OleDB.OleDBException?
Greg
try
{
MyData.ConExec(sSQL);
}
catch (Exception ex)
{
OleDbException innerException = ex.InnerException as OleDbException;
if (innerException.ErrorCode == -2147217873)
{
// handle exception here..
}
else
{
throw;
}
}
don't declare an instance of the exception. It will surely return empty if you do.
try
{
MyData.ConExec(sSQL);
}
catch (OleDbException ex)
{
// handle excpetion here...
if (ex.ErrorCode == -2147217873)
{
}
}
catch (Exception e)
{
// if other exception will occur
}
I have this code:
con = new iDB2Connection(connectString);
try { con.Open(); }
catch (iDB2ConnectionTimeoutException ex)
{ Console.WriteLine(ex.Message); }
catch (iDB2DCFunctionErrorException ex)
{ Console.WriteLine(ex.Message); }
catch (AccessViolationException ex)
{ Console.WriteLine(ex.Message); }
Close connection
if (con != null)
{
try
{
Console.WriteLine("CRASH IS AFTER THIS");
if (con.State != ConnectionState.Closed)
{
con.Close();
}
}
catch (iDB2ConnectionTimeoutException ex)
{
Console.WriteLine(ex.Message);
}
catch (iDB2DCFunctionErrorException ex)
{
Console.WriteLine(ex.Message);
}
catch (AccessViolationException ex)
{
Console.WriteLine(ex.Message);
}
catch (iDB2Exception ex)
{
Console.WriteLine(ex.Message);
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
finally
{
}
}
But I still get this nasty message when the Close connection is being run:
Unhandled Exception: IBM.Data.DB2.iSeries.iDB2DCFunctionErrorException: An unexp
ected exception occurred. Type: System.AccessViolationException, Message: Attem
pted to read or write protected memory. This is often an indication that other m
emory is corrupt.. ---> System.AccessViolationException: Attempted to read or wr
ite protected memory. This is often an indication that other memory is corrupt.
at IBM.Data.DB2.iSeries.CwbDc.DcDnIsAlive(Int32 functionNumber, IntPtr connec
tionHandle, IntPtr nullParm)
at IBM.Data.DB2.iSeries.MPConnection.IsAlive()
--- End of inner exception stack trace ---
at IBM.Data.DB2.iSeries.MPConnection.IsAlive()
at IBM.Data.DB2.iSeries.MPConnectionManager.GetConnection(iDB2Connection piDB
2Connection)
at IBM.Data.DB2.iSeries.iDB2Connection.Open()
I get this when I know the iSeries is down for maintenance.
How do I handle this so that the C# console application continues on?
Why don't you put it in the Finally block and use only one try/catch?
con = new iDB2Connection(connectString);
try
{
con.Open();
}
catch (iDB2ConnectionTimeoutException ex)
{
Console.WriteLine(ex.Message);
}
catch (iDB2DCFunctionErrorException ex)
{
Console.WriteLine(ex.Message);
}
catch (AccessViolationException ex)
{
Console.WriteLine(ex.Message);
}
finally
{
if (con != null && con.State == ConnectionState.Open)
con.Close();
}