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--- trycatch [2018/01/28 07:13] – created wolfgangriedmann
+++ trycatch [2018/08/20 04:05] (current) – wolfgangriedmann
@@ Line 1: / Line 1: @@
 ====== Try - Catch ======
-The Try - Catch operators are very important, and should be used where an error can occurr, for example if a file that needs to be read does not exist, you are specifying an invalid path, the current user has not the rights to read and so forth - please read the documentation about [[https://docs.microsoft.com/en-us/dotnet/api/system.io.file.readalltext|System.IO.File.ReadAllText()]] to see what type of exceptions there are.
+The ''Try - Catch'' block is very important, and should be used where an error can occur, for example if a file that needs to be read does not exist, you are specifying an invalid path, the current user has not the rights to read and so forth - please read the documentation about [[https://docs.microsoft.com/en-us/dotnet/api/system.io.file.readalltext|System.IO.File.ReadAllText()]] to see what type of exceptions there are.
 In classic VO and Win32 applications, you had to check the return value of an operation, and then eventually ask for more details.
@@ Line 7: / Line 7: @@
 The .NET Framework works differently: it produces an exception, and it is the programmers responsability to treat it correctly.
-A sample:<code>
+A sample:<code visualfoxpro>using System.IO
+function TestException() as void
+local cBuffer as string
+try
+cBuffer := File.ReadAllText( "c:\temp\This is an  invalid filename : txt" )
+catch oEx as ArgumentException
+System.Console.WriteLine( "invalid argument:" + oEx:Message + " in argument " + oEx:ParamName )
+catch oEx as NotSupportedException
+System.Console.WriteLine( "invalid path: " + oEx:Message )
+catch oEx as Exception
+System.Console.WriteLine( "Error reading the file: " + oEx:Message )
+end try
+return</code>
+If you don't use the ''Try - Catch'' block, your program is terminated with a unspecified error, and you will not be able to understand what really occurred.
+Please see also here: [[exceptions|Exceptions]]