Error handling is very important for any serious application. It is very crucial that the application is capable of detecting the errors and take corrective measures to the maximum possible extend. If the error situation is beyond the control of the application, it should report the situation to the user/administrator so that an external action can be taken. The following are the most common ways of handling exceptions in an ASP.NET web application.Structured Exception Handling
Error Events
Custom Error Pages
Structured Exception Handling The most popular error handling is Structured Exception Handling (SEH). Most of us are familiar with it in the form of try..catch blocks. All of us use SEH a lot in whatever application that we are working on. The primary focus of SEH is to make sure that a block of code is executed correctly, and if an exception takes place, we have another piece of code which can take care of the exception and take some corrective measures if possible. SEH is used to protect the application from an exceptional situation where something unexpected happens. For example the application tries to connect to a database server and the server is not available. It is an exceptional situation or an exception :-). If such a case happens the developer can handle the situation in the catch block and take the necessary action. I have seen smart developers making use of SEH for the application logic too. for example, assume that the developer needs to open a file and display the content. Ideally he needs to check if the file exists first and then if it exists open it as follows. (This kind of programming is called DEFENSIVE Programming). If file exists
work with the file
else
take action
end if The above approach reduces the complexity of checking for the existing of the file etc. However it adds some overhead to the system. Generating and handling an exception takes some system resources. I have also seen people using SEH to branch the code execution to a specific upper function block, from inside a series of complex nested functions. For example function a calls b and b calls c and c calls d and d calls e and if the developer wants to transfer control to a specific location in any of the parent methods, he or she can make use of SEH. SEH is mostly used for procedure/function level error handling. Any code which access external resources like database connections, files/folders, URLs should always be inside try..catch blocks because they are most vulnerable for exceptions. I have experienced a lot of trouble with combo boxes too and hence would recommend that any action that you do on a combo box should be inside try/catch blocks. Another area where you might consider is working with a dataaset where a null value can cause an exception. Error EventsMost of the times we will be able to put the code into try..catch blocks. But exceptions occurs in exceptional situations. There might be several cases when we would not be able to fore-see that a given block code is vulnerable to a specific exception. Read more: Beyond Relational
Error Events
Custom Error Pages
Structured Exception Handling The most popular error handling is Structured Exception Handling (SEH). Most of us are familiar with it in the form of try..catch blocks. All of us use SEH a lot in whatever application that we are working on. The primary focus of SEH is to make sure that a block of code is executed correctly, and if an exception takes place, we have another piece of code which can take care of the exception and take some corrective measures if possible. SEH is used to protect the application from an exceptional situation where something unexpected happens. For example the application tries to connect to a database server and the server is not available. It is an exceptional situation or an exception :-). If such a case happens the developer can handle the situation in the catch block and take the necessary action. I have seen smart developers making use of SEH for the application logic too. for example, assume that the developer needs to open a file and display the content. Ideally he needs to check if the file exists first and then if it exists open it as follows. (This kind of programming is called DEFENSIVE Programming). If file exists
work with the file
else
take action
end if The above approach reduces the complexity of checking for the existing of the file etc. However it adds some overhead to the system. Generating and handling an exception takes some system resources. I have also seen people using SEH to branch the code execution to a specific upper function block, from inside a series of complex nested functions. For example function a calls b and b calls c and c calls d and d calls e and if the developer wants to transfer control to a specific location in any of the parent methods, he or she can make use of SEH. SEH is mostly used for procedure/function level error handling. Any code which access external resources like database connections, files/folders, URLs should always be inside try..catch blocks because they are most vulnerable for exceptions. I have experienced a lot of trouble with combo boxes too and hence would recommend that any action that you do on a combo box should be inside try/catch blocks. Another area where you might consider is working with a dataaset where a null value can cause an exception. Error EventsMost of the times we will be able to put the code into try..catch blocks. But exceptions occurs in exceptional situations. There might be several cases when we would not be able to fore-see that a given block code is vulnerable to a specific exception. Read more: Beyond Relational
Posts
0 comments:
Post a Comment