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- #Visual basic net try catch upgrade
- #Visual basic net try catch full
- #Visual basic net try catch code
- #Visual basic net try catch plus
#Visual basic net try catch code
' This shold never happen as this code is an error handler! ' SubProcedure1 has the example of a multiple line TRY block with a block of code executed in the event of an error Private Sub ClearRememberedErrorObjectValues() ' Using Err.Clear (or "On Error GoTo -1 ") gets around this and facilitates the whole TRY CATCH block scenario I am using there. ' will actually NOT pass execution to the ALabel: label BUT the error is paseed to the procedure that called this procedure. ' If Err.Clear has not be used, then the next "On Error GoTo ALabel" that is used in this or the procedure that called it ' Err.Clear is used to clear the raised exception and set the err object to nothing (ie err.number to 0) ' so that the same error can be re-raised ' Note that the next line will reset the error object to 0, the variables above are used to remember the values ' This function has to be declared in the same scope as the variables it refers to Private Sub RememberThenClearTheErrorObject() Also of interest might be the procedure ManageErrSource which makes the Err.Source property store the procedure where the error occurred. I use the above techniques with various labels to simulate the sometimes useful functionality that Visual basic TRY CATCH blocks give, which I think have their place in writing readable code.Īdmittedly this technique creates a few more lines of code than a nice VB try catch statement, but it's not too messy and pretty easy to get your head around. So therefore it is mostly best to use: On Error Goto -1Īs using Err.clear You would often need to write Err.Clear Ie Err.Clear removes an "On Error Goto" that is currently in place. (NOTE that On Error Goto 0 is different from the above)Īlso important to note is that Err.Clear resets it to zero but it is actually equivalent to: On Error Goto -1 On Error Goto -1 ' Which I think is less clear! You can stop a procedure being in the "I'm handling an error" state by clearing the exception (setting err to nothing so the err.number property becomes 0) by using Err.clear When it is in this state, if another "On Error Goto" label2 statement is executed it will NOT goto label2, but raises and error which is passed to the code that called the procedure. When you use on error goto Label1 the procedure enters into a state of "I'm handling an error" as an exception has been raised. (It works but I'm interested to know what other people make of it and for any suggestions you might like to make.) MessageBox.Show(arg1.ToString(), Application.The code below is pretty self explanatory: just copy and paste it all into a module and run it, it provides a few use cases and many explanatory comments in the text. MessageBox.Show(var1.ToString(), Application.ProductName) Var1 = Convert.ToInt32(1 / (( double) arg1))
#Visual basic net try catch upgrade
MessageBox.Show( CStr(arg1), Application.ProductName)Ĭ#.NET code generated by the Visual Basic Upgrade Companion public void ErrorHandling( int arg1) MessageBox.Show( CStr(var1), Application.ProductName) Public Sub ErrorHandling( ByRef arg1 As Integer) VB.NET code generated by the Visual Basic Upgrade Companion If the resulting language is C# the “try catch” generation is mandatory.
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NET “Try Catch” blocks by applying special refactor techniques, as well as the same error management patterns from VB6 if needed. The Visual Basic Upgrade Companion is able to generate VB.NET source code using the. Public Sub ErrorHandling( ByRef arg1 As Short) VB.NET code generated by the Upgrade Wizard The Upgrade Wizard converts it using the same error management statements as in the original VB6 source code. MsgBox Err.Description,, "Error" End Sub Public Sub ErrorHandling(arg1 As Integer) The flow control of this source code extract will jump to the “ErrorHandler:” label in case there is an arithmetic error. The following VB6 extract shows a simple usage of the “On Error” statement to avoid a possible division by zero. NET, it is also necessary to convert the Err Object.
#Visual basic net try catch full
NET equivalent “try … catch” blocks.Īs part of the full conversion of the Visual Basic 6 Error handling schema (On Error.
#Visual basic net try catch plus
All unused labels are removed from the resulting code, plus the most commonly used “On Error” patterns are currently recognized and replaced for native. The Visual Basic Upgrade Companion is able to remove unstructured “spaghetti code” and convert it to structured. These patterns are complex to read in VB6 and need to be removed from the resulting code for the sake of maintainability. Also, VB6 features in-code labels that can be used to create confusable “jump” patterns. NET languages have different error handling techniques while VB.NET is able to support a small subset of VB6 error handling keywords, C#.NET is not.