common error page in ASP.NET - asp.net

Question

How to setup a common error page in ASP.NET website?
Also how to handel the error in Data Access Layer by common error page?

Answer 1

In my current project I'm sticking with Application_Error in the global.asax for showing the end-users a uniform error page in case of any unhandled errors. I added a sendmail call to mail certain exceptions to a mail address to get a better insight in what went wrong (you can't rely on customers/visitors to properly describe the problem).
After sending the mail and/or logging the problem I redirect users to a error.html with a generic errormessage.
In my DAL I try/catch most of the critical functions and show a warning/error accordingly (I return a status/message to show if for example a connection couldn't be made/timed out).

Answer 2

This is the pattern I tend to start with when starting a new app. Apologies this is in VB.NET ;)
In the global.asax Server.Transfer to your custom Error page.
Sub Application_Error(ByVal sender As Object, ByVal e As EventArgs)
Server.Transfer("~/Error.aspx", False)
End Sub
Then in your custom error page.
Private Sub Page_Load
Response.Clear()
Dim err As Exception = Server.GetLastError
...
End Sub
Now you can test the Type of the exception. You'll need to recurse down through the inner exceptions as the parent exception will be probably be a general web exception. Get your DAL to throw a custom typed exception and you can test for that and handle differently.

Answer 3

here i am explaining the way to implement a custom error page feature.
Step by step implementation
Creating Error Page : Develop an error page (the page that has to be displayed when error occurs) in the root directory. Lets think that the name of the error page is ErrorPage.aspx
Configuring Web.Config : write the following code in Web.Config
<configuration>
<system.web>
<customErrors mode="On" defaultRedirect="~\ErrorPage.aspx"/>
</system.web>
</configuration>
Thats it!!! Now if any error occurs it will redirect to the error page. Now Sometimes we need to display the error. In that case we can write few lines of code in Global.asax
void Application_Error(object sender, EventArgs e)
{
Exception ex = Server.GetLastError().GetBaseException();
Session["LastException"] = ex.ToString();
}
As the exception has been captured and stored in the Session now we can show the message from the session. So we can write the following lines in ErrorPage.aspx.cs
protected void Page_Load(object sender, EventArgs e)
{
lblDisplayError.Text = Session["LastException"].ToString();
}
And we will be able to see the error on the label of ErrorPage.
Hope it will work fine.
Thanks
Pritom Nandy