can anyone explain it by a clear example in ASP.NETĬan you please put a litle more shade light on this topic This is not enough,because u give some c# and asp.net coding I think in the "Finally" section need to check that the connection open or not, because if something fail in the mySqlConnection.Open() then the mySqlConnection.Close() also throws an error, because there is no open connection. Try catch worked great in vb.net thanks for the article Why ask for a url if you arent going to link to it? even if it has nofollow? i dont get it do yall need some seo help? im The article is simple and easy to understand.
#Visual basic net try catch how to#
How to show error messages in try & catch in ASP.NET? How to save the logfiles of log4net in testfile,if database connection is problem from web.config LinksĮtyjyhnfghngc xvcvbhyrgbbdgdvcbcxvhsfghsdfhfhgdfh The ability to nest try structures is available so that we can use a second Try structure to cover exceptions. Well, errors can occur within the Catch portion of the Try structures, and cause further exception to occur. Can you imagine, when we should use nested try statements. So, Exit Try statement can be best used were we need to execute the cleanup routines. Once the Exit Try statement is executed, the control goes to the Finally block.
The objective of this statement is to break out of the Try or Catch block. We can also have the Exit Try statement inside any of the try.catch block. As I said earlier, finally block contains cleanup routines for exception situations. When all the statements inside the catch blocks are executed, the finally block comes into the picture. In the above example, we have two catch blocks, one which captures a general exception and the other one which traps the SqlException. Each Catch block may have a different error/exception trapping mechanism. Catching all these exception is now very easy with the Catch block. Basically, we have two major statements inside the try block which may result in an exception/error.Īs I said, any exception can occur during a database operation. So, we have a Try block, which contains the statements such as opening the connection and executing the operation. We should anticipate all these errors while performing a database operation. The possible chances while performing a database operation are invalid connection string, database server too busy resulting in connection time out, database server not currently running etc etc. Well, in the above example we were trying to insert some values to a database table. Message.text = Message.text + exc.tostring() Message.text = Message.text + "Cannot insert duplicate values." If Instr(1, exc.tostring, "duplicate key") > 0 then Message.text = Message.text + sqlexc.tostring() Message.text = "New Forward information added" MySqlCommand.ExecuteReader(CommandBehavior.CloseConnection) MySqlCommand = new SqlCommand(strSql, mySqlConnection) StrSql = "insert into yourtable (f1, f2) values ('f1', 'f2')" A simple Database operationĭim mySqlConnection as New SqlConnection (ConnectionString) Since the catch block is specific to the type of error we want to catch, we will often use multiple Catch blocks in our structure.
#Visual basic net try catch code#
The simple Try statement comes before the block of code, the Catch block of code is where we specify what type of error to look for, and the Finally block of code is always executed and contains cleanup routines for exception situations. The block of code surrounds the code where an exception might occur. Well we have three blocks of code, were each block has it own functionality. This is a new error handling mechanism in VB.NET, so as in ASP.NET. We can also call the try.catch mechanism as "Exception Handling" What is Now in ASP.NET we have a new error handling mechanism which was already their in other languages such as C, C++ and JAVA. But we were not able to handle all exception/errors efficiently. In ASP 3.0 we saw the new ASP object called Error Object. We were having only limited options available for error handling in Classic ASP such as, "On Error Resume Next". We can also call the try.catch mechanism asĮrror handling in Classic ASP was not the best.
Print Add To Favorites Email To Friend Rate This ArticleĮrror handling in Classic ASP was not the best.