Database Error Handling In Vb.net
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here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn http://stackoverflow.com/questions/4969193/catch-database-connection-error more about Stack Overflow the company Business Learn more about hiring developers or posting http://www.homeandlearn.co.uk/NET/nets5p1.html ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Catch database connection error up vote 2 down vote favorite database error Is there a way to catch a database exception and then redirect to an error page? I have a data access class that I use to make a sql connection and then functions that call it to execute my SQL commands. My problem is that if my database is not available I cannot catch that error. Here is the code I am using in my class: Protected Function GetConnection() database error handling As SqlConnection Dim ret_conn As SqlConnection ret_conn = New SqlConnection(System.Web.Configuration.WebConfigurationManager.ConnectionStrings("EUCNET00617").ToString()) ret_conn.Open() GetConnection = ret_conn End Function .net asp.net vb.net share|improve this question edited Feb 11 '11 at 13:34 John Saunders 138k20175321 asked Feb 11 '11 at 12:51 Mike 27031640 2 did you ever read about "try..catch" blocks?!? msdn.microsoft.com/en-us/library/fk6t46tz%28v=VS.90%29.aspx –BertuPG Feb 11 '11 at 12:58 2 You shouldn't really open your connection until you need it, and then you should close it immediately when you're done with it. So your consuming code would be conn = GetConnection() ... conn.Open() ... PerformDataPull() ... conn.Close(). Opening the connection where you have it is too easy to lead to the possibility of orphaned connections. –Joel Etherton Feb 11 '11 at 13:21 add a comment| 3 Answers 3 active oldest votes up vote 1 down vote accepted What you're looking for is the try/catch/finally construct. This allows you to capture an exception (error) and react to it. Protected Function GetConnection() As SqlConnection Dim ret_conn As SqlConnection Try ret_conn = New SqlConnection(System.Web.Configuration.WebConfigurationManager.ConnectionStrings("EUCNET00617").ToString()) ret_conn.Open() GetConnection = ret_conn Catch exceptionThatICaught as System.Exception ' You could also perform logging of details from exceptionThatICaught here GetConnection = Null End Try End Function Now, your GetConnection function will return Null when it
for Beginners Error Handling and Debugging in VB .NET Debugging your code is something you will need to do. Unless you write perfect code every time, there's no getting away from it. In this section, we'll take a look at ways you can track down errors using VB.NET. Types of Error Programming errors are generally broken down into three types: Design-time, Runtime, and Logic errors. A Design-time error is also known as a syntax error. These occur when the environment you're programming in doesn't understand your code. These are easy to track down in VB.NET, because you get a blue wiggly line pointing them out. If you try to run the programme, you'll get a dialogue box popping up telling you that there were Build errors. Runtime errors are a lot harder to track down. As their name suggests, these errors occur when the programme is running. They happen when your programme tries to do something it shouldn't be doing. An example is trying to access a file that doesn't exist. Runtime errors usually cause your programme to crash. If and when that happens, you get the blame. After all, you're the programmer, and you should write code to trap runtime errors. If you're trying to open a database in a specific location, and the database has been moved, a Runtime error will occur. It's your job to predict a thing like this, and code accordingly. Logic errors also occur when the programme is running. They happen when your code doesn't quite behave the way you thought it would. A classic example is creating an infinite loop of the type "Do While x is greater than 10". If x is always going to be greater than 10, then the loop has no way to exit, and just keeps going round and round. Logic errors tend not to crash your programme. But they will ensure that it doesn't work properly. In the next few pages, we'll take a closer look at all three types of error. Move on to Design Time Errors in VB .NET --> Back to the VB NET Contents Page ©