README.md

December 5, 2022 · View on GitHub

ASP.NET Global Error Handler (with html report & email functionality)

Description

Globally capture errors and exceptions in your ASP.NET site. Admin(s) can be emailed a detailed HTML report of the error, then redirect the user to a friendly error page. 100% C#, no external objects needed.

More Info


Submitted On
By	Joel Thoms
Level	Beginner
User Rating	5.0 (25 globes from 5 users)
Compatibility	C#, ASP.NET
Category	Debugging and Error Handling
World	.Net (C#, VB.net)
Archive File

API Declarations

Source Code

/* Author: Joel Thoms

Website: http://www.joel.net
Email: (contact me through website)
Date: 02.05.2003
Copyright 2003 Joel Thoms
Description:
HtmlError generates an HTML error message from the generated Exception. HtmlError also includes
a routine to email the error message to the admin(s).
This object can be used to capture individual errors, though it's best use is to globally capture
errors using Global.asax. Both examples are provided.
Usage and Examples:
Here is an example on how to capture a simple division by zero error.
[C#]
```
 // Division by zero error example
```
```
 try {
```
```
 	int x = 0;
```
```
 	x = 1 / x;
```
```
 } catch (Exception Ex) {
```

 	// Display Error Message to the browser

 	Response.Write(HtmlError.getHtmlError(Ex));

```
 	// Don't Specify SMTP Server
```

 	HtmlError.sendHtmlError(Ex, "YOUR-EMAIL@ADDRESS.COM");

```
 	// Specify SMTP Server
```

 	//HtmlError.sendHtmlError(Ex, "YOUR-EMAIL@ADDRESS.COM", "your.smtp-server.com");

```
 }
```
[VB.NET]
```
 ' Division by zero error example
```
```
 Try
```
```
 	Dim x As Integer = 0
```
```
 	x = 1 / x
```
```
 Catch Ex As Exception
```

 	' Display Error Message to the browser

 	Response.Write(HtmlError.getHtmlError(Ex))

```
 	' Don't Specify SMTP Server
```

 	HtmlError.sendHtmlError(Ex, "YOUR-EMAIL@ADDRESS.COM")

```
 	' Specify SMTP Server
```

 	'HtmlError.sendHtmlError(Ex, "YOUR-EMAIL@ADDRESS.COM", "your.smtp-server.com")

```
 End Try
```
Here is an example on globally capturing errors using the Global.asax file.
[C#]

 protected void Application_Error(Object sender, EventArgs e) {

```
 	// Don't Specify SMTP Server
```

 	HtmlError.sendHtmlError(Context.Error.GetBaseException(), "YOUR-EMAIL@ADDRESS.COM");

```
 	// Specify SMTP Server
```

 	//HtmlError.sendHtmlError(Context.Error.GetBaseException(), "YOUR-EMAIL@ADDRESS.COM", "your.smtp-server.com");

 	// Redirect User to Friendly Error Page

```
 	Response.Redirect("/error.aspx");
```
```
 }
```
[VB.NET]

 Sub Application_Error(ByVal sender As Object, ByVal e As EventArgs)

```
 	' Don't Specify SMTP Server
```

 	HtmlError.sendHtmlError(Context.Error.GetBaseException(), "YOUR-EMAIL@ADDRESS.COM")

```
 	' Specify SMTP Server
```

 	'HtmlError.sendHtmlError(Context.Error.GetBaseException(), "YOUR-EMAIL@ADDRESS.COM", "your.smtp-server.com")

 	' Redirect User to Friendly Error Page

```
 	Response.Redirect("/error.aspx")
```
```
 End Sub
```

*/ using System; using System.Data; using System.Web; using System.Web.Mail; using System.Collections.Specialized; ///

HtmlError Object.

public class HtmlError { public HtmlError() { } static public void sendHtmlError(Exception Ex, string email_address) { sendHtmlError(Ex, email_address, ""); } static public void sendHtmlError(Exception Ex, string email_address, string smtp_server) { MailMessage mail = new MailMessage(); mail.From = "server-errors@discountasp.net"; mail.To = email_address; mail.Subject = "Uncaptured Error"; mail.Body = getHtmlError(Ex); mail.BodyFormat = MailFormat.Html; if (smtp_server.Length > 0) SmtpMail.SmtpServer = smtp_server; SmtpMail.Send(mail); } ///

Returns HTML an formatted error message.

static public string getHtmlError(Exception Ex) { // Heading Template const string heading = "<TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0"><TD bgcolor="black" COLSPAN="2"><FONT face="Arial" color="white"> "; // Error Message Header string html = "<FONT face="Arial" size="5" color="red">Error - " + Ex.Message + "

"; // Populate Error Information Collection NameValueCollection error_info = new NameValueCollection(); error_info.Add("Message", cleanHTML(Ex.Message)); error_info.Add("Source", cleanHTML(Ex.Source)); error_info.Add("TargetSite", cleanHTML(Ex.TargetSite.ToString())); error_info.Add("StackTrace", cleanHTML(Ex.StackTrace)); // Error Information html += heading.Replace("", "Error Information"); html += CollectionToHtmlTable(error_info); // QueryString Collection html += "

" + heading.Replace("", "QueryString Collection"); html += CollectionToHtmlTable(HttpContext.Current.Request.QueryString); // Form Collection html += "

" + heading.Replace("", "Form Collection"); html += CollectionToHtmlTable(HttpContext.Current.Request.Form); // Cookies Collection html += "

" + heading.Replace("", "Cookies Collection"); html += CollectionToHtmlTable(HttpContext.Current.Request.Cookies); // Session Variables html += "

" + heading.Replace("", "Session Variables"); html += CollectionToHtmlTable(HttpContext.Current.Session); // Server Variables html += "

" + heading.Replace("", "Server Variables"); html += CollectionToHtmlTable(HttpContext.Current.Request.ServerVariables); return html; } static private string CollectionToHtmlTable(NameValueCollection collection) { // ... Template const string TD = "<FONT face="Arial" size="2">"; // Table Header string html = "\n<TABLE width="100%">\n" + " <TR bgcolor="#C0C0C0">" + TD.Replace("", " Name") + " " + TD.Replace("", " Value") + "\n"; // No Body? -> N/A if (collection.Count == 0) { collection = new NameValueCollection(); collection.Add("N/A", ""); } // Table Body for (int i = 0; i < collection.Count; i++) { html += "<TR valign="top" bgcolor="" + ((i % 2 == 0) ? "white" : "#EEEEEE") + "">" + TD.Replace("", collection.Keys[i]) + "\n" + TD.Replace("", collection[i]) + "\n"; } // Table Footer return html + ""; } static private string CollectionToHtmlTable(HttpCookieCollection collection) { // Overload for HttpCookieCollection collection. // Converts HttpCookieCollection to NameValueCollection NameValueCollection NVC = new NameValueCollection(); foreach (string item in collection) NVC.Add(item, collection[item].Value); return CollectionToHtmlTable(NVC); } static private string CollectionToHtmlTable(System.Web.SessionState.HttpSessionState collection) { // Overload for HttpSessionState collection. // Converts HttpSessionState to NameValueCollection NameValueCollection NVC = new NameValueCollection(); foreach (string item in collection) NVC.Add(item, collection[item].ToString()); return CollectionToHtmlTable(NVC); } static private string cleanHTML(string Html) { // Cleans the string for HTML friendly display return (Html.Length == 0) ? "" : Html.Replace("<", "<").Replace("\r\n", "
").Replace("&", "&").Replace(" ", " "); } }