Application Management Blocks

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What is the Application Management Blocks

Rekha Singh · Answer

Exception Management Application Block What is Exception Management Application Block ? Provides a simple and flexible mechanism for publishing exception information through an ExceptionManager class. Also supports filtering and creating your own exception publishers to publish data to sources other than files and event logs using text and XML. Also provides a BaseApplicationException class from which to derive, which collects additional environmental information. Why? Use it as the basis for your exception handling framework. Ideal for applications that use exception chaining or wrapping and pass exceptions up the call stack. Custom publishers can be used to log exception information to shared databases. Configuring the Exception Management Application Block To use the EMAB in an ASP.NET Web application you need to add some settings to the Web.config file to indicate that the EMAB should be used and what, if any, custom publishers should be used. The basic settings in the Web.config look like the following: configuration > configSections > section name = "exceptionManagement" type = "Microsoft.ApplicationBlocks.ExceptionManagement.ExceptionManagerSectionHandler, Microsoft.ApplicationBlocks.ExceptionManagement" /> configSections > exceptionManagement mode = "on" /> system.web > ... system.web > configuration > The element in the section specifies that there is an section. The section, then, indicates that the EMAB should perform exception publishing. This configuration uses just the default publisher. You can also indicate that one or more custom publishers should be used through the following syntax: configuration > ... exceptionManagement mode = "on" > publisher assembly = "assembly" type = "namespace.className" /> exceptionManagement > ... configuration > Here a single, custom publisher is used. Assuming you've created a custom publisher class, you simply specify its assembly and type in the appropriate attributes of the element. A Real-World Example of the Exception Management Application Block in Action! I've used the EMAB in several projects I've worked on. Typically I create a custom publisher that adds the exception's details to a database table. The following shows my custom publisher class, my Web.config settings, and an example ASP.NET Web page. Custom Publisher Imports Microsoft.ApplicationBlocks.ExceptionManagement Imports System.Web Imports System.Data.SqlClient Imports Microsoft.ApplicationBlocks.Data Public Class DBExceptionPublisher Implements IExceptionPublisher Public Sub Publish(ByVal exception As System.Exception, _ ByVal additionalInfo As NameValueCollection, _ ByVal configSettings As NameValueCollection) _ Implements IExceptionPublisher.Publish Try SqlHelper.ExecuteNonQuery(GlobalConnectionString, CommandType.StoredProcedure, "sp_AddException" , _ New SqlParameter( "@Message" , exception.Message)) Catch ex As Exception HttpContext.Current.Response.Write( "FATAL ERROR: " & _ ex.StackTrace & " " & ex.Message) HttpContext.Current.Response.Flush() HttpContext.Current.Response.End() End Try End Sub End Class The above is a very simple custom publisher (a shortened version of the custom publisher I use in practice). Notice that the class implements the IExceptionPublisher interface (which is defined in the Microsoft.ApplicationBlocks.ExceptionManagement namespace). The Publish() method uses the DAAB to run the sp_AddException stored procedure, passing in the Exception's Message property. (In a real scenario, you'd likely be interested in additional Exception properties...) Note that it, itself, uses a Try ... Catch block - this is because there may be an exception in accessing the database! In such a case, an ugly FATAL ERROR message is emitted to the end user's screen. (It would be prudent to email the administrator here, and perhaps redirect the user to a prettier error page.) Once this class has been created and compiled, the next step is to configure the ASP.NET Web application's Web.config file. Assuming that the DBExceptionPublisher is compiled into an assembly named MyProjectExceptionBlock, with a default namespace of MyProjectExceptionBlock, the configuration syntax would look like: configuration > ... exceptionManagement mode = "on" > publisher assembly = "MyProjectExceptionBlock" type = "MyProjectExceptionBlock.DBExceptionPublisher" /> exceptionManagement > ... configuration > Finally, let's look at an example ASP.NET Web page's code-behind class. Again, notice that to publish an exception we simply call the ExceptionManagement class's Publish() method. This consults the Web.config file, loads the proper custom publisher, and invokes its Publish() method, thereby publishing the exception details into the database. An ASP.NET Web page code-behind class Imports Microsoft.ApplicationBlocks.ExceptionManagement Public Class logon Inherits System.Web.UI.Page Private Sub Page_Load(ByVal sender as Object, ByVal e as EventArgs) Try ... do something that might cause an exception ... Catch ex as Exception ExceptionManager.Publish(ex) End Try End Sub ... End Class What Does the Configuration Management Application Block Include? The source code for the Configuration Management Application Block is provided, together with QuickStart sample applications, which you can use to test the block's functionality. The Configuration Management Application Block also includes comprehensive documentation to help you work with and learn about the code provided.The Visual Studio® .NET Projects Microsoft Visual Basic® .NET and Microsoft Visual C#® .NET source code is supplied for the Configuration Management Application Block, along with QuickStart Sample applications (also in both languages) that you can use to test common scenarios. This helps increase your understanding of how the Configuration Management Application Block works. You are also free to customize the source code to suit your specific requirements. Both the Visual Basic .NET and C# version of the Microsoft.ApplicationBlocks.ConfigurationManagement projects can be compiled to produce two assemblies named Microsoft.ApplicationBlocks.ConfigurationManagement.dll and Microsoft.ApplicationBlocks.ConfigurationManagement.Interfaces.dll. These assemblies contain all the classes and interfaces that comprise the block. The download also contains the following QuickStart projects: 1- Microsoft.ApplicationBlocks.ConfigurationManagement.Quickstarts.Read 2- This QuickStart shows how to read data from a variety of data stores using the Configuration Management Application Block. 3-Microsoft.ApplicationBlocks.ConfigurationManagement.Quickstarts.Write 4- This QuickStart shows how to write data to a variety of data stores using the Configuration Management Application Block. 5- Microsoft.ApplicationBlocks.ConfigurationManagement.Quickstarts.Hashtable 6- This QuickStart demonstrates the special support built into the Configuration Management Application Block for application configuration data stored in Hashtable objects. System Requirements- To run the Configuration Management Application Block, you need the following: 1- Microsoft Windows® 2000, Windows XP Professional, or Microsoft Windows Server 2003 2- Microsoft .NET Framework version 1.1 3- Visual Studio .NET 2003 (recommended but not required)

Lalit M · Answer

hi, you will get your answer from this links http://www.dotnetjohn.com/articles.aspx?articleid=96 http://www.developer.com/net/article.php/3102591/Programming-with-the-Exception-Management-Application-Block-in-NET.htm

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