How to use Try..Catch ..Finally in ASP.NET?
This is a new error handling mechanism in ASP.NET, so as in ASP.NET. Well we have three blocks of code, were each block has it own functionality. The Try…Catch…Finally block of code surrounds the code where an exception might occur. 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. Since the catch block is specific to the type of error we want to catch, we will often use multiple Catch blocks in our Try…Catch…Finally structure.
A simple Database operation
Dim mySqlConnection as New SqlConnection (ConnectionString)
Dim mySqlCommand as SqlCommand
Dim strSql as String
strSql = “insert into yourtable (f1, f2) values (’f1′, ‘f2′)”
mySqlCommand = new SqlCommand(strSql, mySqlConnection)
Try
mySqlConnection.Open()
mySqlCommand.ExecuteReader(CommandBehavior.CloseConnection)
Message.text = “New Forward information added”
Catch SQLexc as sqlexception
Message.text = Message.text + sqlexc.tostring()
Catch exc as exception
if Instr(1, exc.tostring, “duplicate key”) > 0 then
Message.text = Message.text + “Cannot insert duplicate values.”
else
Message.text = Message.text + exc.tostring()
end if
Finally
mySqlConnection.Close()
End Try