try..catch problem

ooloife

In a windows program, if an exception thrown by the program is caught by the system, it will prompt the program to error, and then the program automatically closes, so you must catch the exception yourself to prevent the program from closing automatically. This is one use of try catch, and the other is Custom error message.

hzjbwl

Let me post the important code: Microsoft demo
1. public System.Data.DataSet Retrieve (string sql)
{
SQL.SqlConnection dbConn = null;
System.Data.DataSet ds = new System.Data.DataSet () ;;

try
{
dbConn = new SQL.SqlConnection (this.sConnection);

SQL.SqlCommand dbCmd;
dbCmd = new SQL.SqlCommand (sql, dbConn);

SQL.SqlDataAdapter dbAdapter;
dbAdapter = new SQL.SqlDataAdapter (dbCmd);

dbConn.Open ();
dbAdapter.Fill (ds);
}
catch (Exception ex)
{
throw ex;
}
finally
{
try {dbConn.Close ();}
catch {}
}

return ds;
}






2. The statement captured centrally is

Application.ThreadException + = new ST.ThreadExceptionEventHandler (App.OnAppException);

// setup cleanup routine for normal app shutdown ...
Application.ThreadExit + = new System.EventHandler (App.OnAppExit);

Since the ex captured in 1 is thrown without doing anything, it will eventually be handled centrally by ThreadException in 2. If it is not captured, the ThreadException in 2 can also be handled centrally, so why add it?

need_free

When debugging, if you don't try it yourself, it is very likely that you won't see the exception during debugging.
Another thing is that what you see is a demo in itself, which means that you must try, and the processing given is just an example. Of course, you can add other exception handling logic yourself.
It is definitely beneficial to add appropriate exception handling when writing code. It is more convenient to put the code skeleton there in advance and write the exception handling logic when appropriate.

xiezhe001

General exception handling method:
   1. Do nothing, ignore the exception directly
   2. Handle the exception directly (for example, perform some operations, pop up a personalized dialog box, prompt the problem)
   3.Retry the operation and handle the exception when the number is reached
   4.Rethrow the exception and let the superior handle the exception
   5.Record to log for easy viewing.

xiezhe001

It is sometimes useful for the superior to handle this exception. So rethrow it after catching the exception

savage698

Rethrowing can be processed by the above.If your block does not process, it does not mean that it is not processed.
If it is a more common exception or not a more detailed exception, the outer frame should handle it. This design is more reasonable