C# Using Error Handling
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you, helping each other. Join them; it only takes a minute: Sign up C# using statement catch error up vote 28 down vote favorite 14 I am just looking at the using statement, I have always known what it does but until now not tried using it, I have come up with the below code: using c# error handling framework (SqlCommand cmd = new SqlCommand(reportDataSource, new SqlConnection(Settings.Default.qlsdat_extensionsConnectionString))) { cmd.CommandType = CommandType.StoredProcedure; cmd.Parameters.Add("@Year", SqlDbType.Char, 4).Value = year; cmd.Parameters.Add("@startDate", SqlDbType.DateTime).Value = start; cmd.Parameters.Add("@endDate", SqlDbType.DateTime).Value = end; cmd.Connection.Open(); DataSet dset = new DataSet(); new SqlDataAdapter(cmd).Fill(dset); this.gridDataSource.DataSource = dset.Tables[0]; } This seems to work but is there any point in this since as far as I can tell I would still need to enclose this in a try catch block to catch unforseen errors e.g. sql server down. Am I missing something? As far as I can currently see it just stops me closing and disposing of cmd but there will be more lines of code due to the try catch still being needed. c# using using-statement share|improve this question edited Aug 12 '10 at 19:18 John Saunders 138k20175320 asked Oct 30 '08 at 0:58 PeteT 7,8142371125 add a comment| 16 Answers 16 active oldest votes up vote 18 down vote accepted This code should be as follows to ensure timely closing of the connection. Closing just the command doesn't close
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C# Error Handling Techniques
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Samples Basic Client Client Avoiding Problems with the Using Statement Avoiding Problems with the Using Statement Avoiding Problems with the Using error handling in c# best practices Statement Client Interoperability Address Headers Channel Factory Expected Exceptions Retrieve Metadata Avoiding Problems with the Using Statement Typed Client TOC Collapse the table of content Expand the table of content This documentation is archived and is http://stackoverflow.com/questions/248961/c-sharp-using-statement-catch-error not being maintained. This documentation is archived and is not being maintained. Avoiding Problems with the Using Statement .NET Framework (current version) Other Versions Visual Studio 2010 .NET Framework 4 Visual Studio 2008 .NET Framework 3.5 .NET Framework 3.0 This sample demonstrates how you should not use the C# "using" statement to automatically clean up resources when using a typed client. This sample is based on the Getting Started Sample that implements https://msdn.microsoft.com/en-us/library/aa355056(v=vs.110).aspx a calculator service. In this sample, the client is a console application (.exe) and the service is hosted by Internet Information Services (IIS).Note The setup procedure and build instructions for this sample are located at the end of this topic.This sample shows two of the common problems that occur when using the C# "using" statement with typed clients, as well as code that correctly cleans up after exceptions.The C# "using" statement results in a call to Dispose(). This is the same as Close(), which may throw exceptions when a network error occurs. Because the call to Dispose() happens implicitly at the closing brace of the "using" block, this source of exceptions is likely to go unnoticed both by people writing the code and reading the code. This represents a potential source of application errors.The first problem, illustrated in the DemonstrateProblemUsingCanThrow method, is that the closing brace throws an exception and the code after the closing brace does not execute: Copy using (CalculatorClient client = new CalculatorClient()) { ... } // <-- this line might throw Console.WriteLine("Hope this code wasn't important, because it might not happen."); Even if nothing inside the using block throws an exception or all exceptions inside the using block are caught, the Console.Writeline might not happen because the implicit Dispose()
resources Windows Server 2012 resources Programs MSDN subscriptions Overview Benefits Administrators Students Microsoft Imagine Microsoft Student Partners ISV Startups TechRewards Events Community Magazine Forums Blogs Channel 9 Documentation APIs and reference https://msdn.microsoft.com/en-us/library/bb397417.aspx Dev centers Retired content Samples We’re sorry. The content you requested has been removed. You’ll be auto redirected in 1 second. MSDN Library MSDN Library MSDN Library MSDN Library Design Tools Development Tools and Languages Mobile and Embedded Development .NET Development Office development Online Services Open Specifications patterns & practices Servers and Enterprise Development Speech Technologies Web Development Windows Desktop App Development TOC error handling Collapse the table of content Expand the table of content This documentation is archived and is not being maintained. This documentation is archived and is not being maintained. Complete Example for Error Handlers Other Versions Visual Studio 2010 .NET Framework 4 Visual Studio 2008 This code example includes elements for both page-level and application-level exception handling. Code Example Files The example consists c# error handling of the following files: Web.config Global.asax Default.aspx ExceptionUtility (to be put in the App_Code folder) GenericErrorPage.aspx HttpErrorPage.aspx Http404ErrorPage.aspx DefaultRedirectErrorPage.aspx Web.config The following example shows the Web.config file. The customErrors section specifies how to handle errors that occur with file types that are mapped to ASP.NET, such as .aspx, .asmx, and .ashx files. (In IIS 6.0 and in IIS 7.0 in classic mode, static content files such as .html and .jpg files are not mapped to ASP.NET.) The settings in the example customErrors section cause any unhandled HTTP 404 (file not found) errors to be directed to the Http404ErrorPage.aspx file. These HTTP 404 errors would occur if a request were made for an .aspx file, .asmx file, and so on and if the requested file did not exist. All other unhandled errors in ASP.NET files are directed to the DefaultRedirectErrorPage.aspx file. If static content files are not handled by ASP.NET, a request for a nonexistent .html or .jpg file does not cause a redirect to the Http404ErrorPage.aspx file. If you want ASP.NET to handle requests for all file types, you can configure IIS to map file-name extension