From 36d4a1280f375e503655eb5518c359874c51b781 Mon Sep 17 00:00:00 2001 From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com> Date: Tue, 9 Sep 2025 18:46:49 +0000 Subject: [PATCH 1/8] Initial plan From 27c062ed04f31bb4e7ba4305bf98a6620e68a6c0 Mon Sep 17 00:00:00 2001 From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com> Date: Tue, 9 Sep 2025 18:57:41 +0000 Subject: [PATCH 2/8] Add comprehensive examples to BC42328.md to improve clarity Co-authored-by: BillWagner <493969+BillWagner@users.noreply.github.com> --- docs/visual-basic/misc/bc42328.md | 245 +++++++++++++++--- .../misc/snippets/bc42328/AddressOfExample.vb | 82 ++++++ .../snippets/bc42328/AddressOfExample.vbproj | 9 + 3 files changed, 295 insertions(+), 41 deletions(-) create mode 100644 docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vb create mode 100644 docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj diff --git a/docs/visual-basic/misc/bc42328.md b/docs/visual-basic/misc/bc42328.md index 89ba3c35ddf91..d22815bab8185 100644 --- a/docs/visual-basic/misc/bc42328.md +++ b/docs/visual-basic/misc/bc42328.md @@ -24,29 +24,46 @@ Visual Basic allows you to assign methods to delegates even when their signature ## When this warning occurs -This warning appears when Visual Basic can handle the assignment through relaxed conversion, making the explicit `AddressOf` unnecessary. For example: +This warning appears when Visual Basic can handle the assignment through relaxed conversion, making the explicit `AddressOf` unnecessary. -```vb -' Event delegate expects (sender As Object, e As EventArgs) -Public Event SomeEvent As EventHandler - -' Method with exact signature - no warning -Sub Handler1(sender As Object, e As EventArgs) - ' Implementation -End Sub - -' Method with omitted parameters - causes BC42328 -Sub Handler2() - ' Implementation -End Sub +### Complete example showing the warning -' Using AddHandler with exact match - no warning -AddHandler SomeEvent, AddressOf Handler1 +Here's a realistic scenario where you'll encounter BC42328: -' Using AddHandler with relaxed conversion - causes BC42328 -AddHandler SomeEvent, AddressOf Handler2 +```vb +Public Class FileProcessor + ' Define an event using the standard EventHandler delegate + ' EventHandler expects: Sub(sender As Object, e As EventArgs) + Public Event ProcessingComplete As EventHandler + + ' Method with exact signature - no warning + Private Sub OnProcessingComplete(sender As Object, e As EventArgs) + Console.WriteLine($"Processing completed by {sender}") + End Sub + + ' Method with simplified signature - this causes BC42328 warning + Private Sub OnSimpleComplete() + Console.WriteLine("Processing is done!") + End Sub + + Public Sub StartProcessing() + ' This works fine - exact signature match + AddHandler ProcessingComplete, AddressOf OnProcessingComplete + + ' This generates BC42328 warning: + ' "The 'AddressOf' expression has no effect in this context because + ' the method argument to 'AddressOf' requires a relaxed conversion + ' to the delegate type of the event" + AddHandler ProcessingComplete, AddressOf OnSimpleComplete + + ' Simulate completion + RaiseEvent ProcessingComplete(Me, EventArgs.Empty) + End Sub +End Class ``` +When you compile this code, Visual Basic shows the BC42328 warning for the second `AddHandler` statement because `OnSimpleComplete` doesn't match the `EventHandler` signature exactly. + ## Why AddressOf appears to have "no effect" The warning message states that `AddressOf` "has no effect" because Visual Basic must create a wrapper delegate for the relaxed conversion regardless. The `AddressOf` operator doesn't change how the compiler handles the conversion: the same result occurs whether you use `AddressOf` or not in relaxed conversion scenarios. @@ -57,36 +74,163 @@ However, `AddressOf` is still syntactically required in `AddHandler` and `Remove ## To correct this error -You have several options depending on your needs: +You have several options depending on your needs. Using the `FileProcessor` example from above, here are the different ways to resolve the BC42328 warning: -- **Assign to a variable first (preserves exact semantics):** +### Option 1: Assign to a variable first (preserves exact semantics) - ```vb - Dim handler As EventHandler = AddressOf Handler2 - AddHandler SomeEvent, handler - ``` +```vb +Public Sub StartProcessing() + ' Create delegate variable first - this eliminates the warning + Dim handler As EventHandler = AddressOf OnSimpleComplete + AddHandler ProcessingComplete, handler +End Sub +``` -- **Match the delegate signature exactly:** +### Option 2: Match the delegate signature exactly - ```vb - Sub Handler2(sender As Object, e As EventArgs) - ' Implementation - use parameters or ignore them - End Sub - ``` +```vb +' Change the method signature to match EventHandler exactly +Private Sub OnSimpleComplete(sender As Object, e As EventArgs) + ' You can ignore the parameters if you don't need them + Console.WriteLine("Processing is done!") +End Sub -- **Use a lambda expression:** +Public Sub StartProcessing() + ' Now this works without warning + AddHandler ProcessingComplete, AddressOf OnSimpleComplete +End Sub +``` - ```vb - AddHandler SomeEvent, Sub() Handler2() - ``` +### Option 3: Use a lambda expression -- **Use the `Handles` clause if appropriate:** +```vb +Public Sub StartProcessing() + ' Wrap the method call in a lambda that matches the signature + AddHandler ProcessingComplete, Sub(sender, e) OnSimpleComplete() + + ' Or create a more complex lambda inline + AddHandler ProcessingComplete, + Sub(sender, e) + Console.WriteLine($"Event from {sender}") + OnSimpleComplete() + End Sub +End Sub +``` - ```vb - Sub Handler2() Handles someObject.SomeEvent - ' Implementation - End Sub - ``` +### Option 4: Use the `Handles` clause (if appropriate) + +```vb +Public Class FileProcessor + ' Declare the event source with WithEvents + Private WithEvents processor As FileProcessor + + ' Use Handles clause - no AddHandler needed + Private Sub OnSimpleComplete() Handles processor.ProcessingComplete + Console.WriteLine("Processing is done!") + End Sub +End Class +``` + +### Option 5: Direct assignment to delegate variable + +```vb +Public Sub StartProcessing() + ' Assign to delegate variable then use with AddHandler + Dim handler As EventHandler = AddressOf OnSimpleComplete + AddHandler ProcessingComplete, handler +End Sub +``` + +## Complete working example + +Here's a full example demonstrating the warning and multiple solutions: + +```vb +Imports System + +Public Class DocumentProcessor + ' Standard .NET event using EventHandler + Public Event DocumentProcessed As EventHandler + + ' Custom event with different signature + Public Event StatusChanged As Action(Of String) + + ' Handlers with different signatures + + ' Exact match for EventHandler - no warning + Private Sub OnDocumentProcessed_Exact(sender As Object, e As EventArgs) + Console.WriteLine("Document processed (exact signature)") + End Sub + + ' Simplified handler - causes BC42328 with EventHandler + Private Sub OnDocumentProcessed_Simple() + Console.WriteLine("Document processed (simple)") + End Sub + + ' Handler for custom event - exact match + Private Sub OnStatusChanged_Exact(message As String) + Console.WriteLine($"Status: {message}") + End Sub + + ' Handler with ignored parameters - causes BC42328 with custom event + Private Sub OnStatusChanged_Simple() + Console.WriteLine("Status changed") + End Sub + + Public Sub DemonstrateWarnings() + Console.WriteLine("Setting up event handlers...") + + ' These work without warnings (exact matches) + AddHandler DocumentProcessed, AddressOf OnDocumentProcessed_Exact + AddHandler StatusChanged, AddressOf OnStatusChanged_Exact + + ' These generate BC42328 warnings (relaxed conversions) + AddHandler DocumentProcessed, AddressOf OnDocumentProcessed_Simple + AddHandler StatusChanged, AddressOf OnStatusChanged_Simple + + ' Fire the events + RaiseEvent DocumentProcessed(Me, EventArgs.Empty) + RaiseEvent StatusChanged("Processing complete") + End Sub + + Public Sub DemonstrateSolutions() + Console.WriteLine("Using solutions to avoid warnings...") + + ' Solution 1: Assign to variable first + Dim handler1 As EventHandler = AddressOf OnDocumentProcessed_Simple + AddHandler DocumentProcessed, handler1 + + ' Solution 2: Use lambda expression + AddHandler DocumentProcessed, Sub(s, e) OnDocumentProcessed_Simple() + + ' Solution 3: Direct assignment to delegate variable + Dim handler2 As Action(Of String) = AddressOf OnStatusChanged_Simple + AddHandler StatusChanged, handler2 + + ' Fire the events + RaiseEvent DocumentProcessed(Me, EventArgs.Empty) + RaiseEvent StatusChanged("All solutions work") + End Sub +End Class + +Module Program + Sub Main() + Dim processor As New DocumentProcessor() + + Console.WriteLine("=== Demonstrating BC42328 Warning ===") + processor.DemonstrateWarnings() + + Console.WriteLine() + Console.WriteLine("=== Demonstrating Solutions ===") + processor.DemonstrateSolutions() + + Console.WriteLine("Press any key to exit...") + Console.ReadKey() + End Sub +End Module +``` + +This example shows how the warning occurs in realistic scenarios and demonstrates multiple ways to resolve it. ## When you can ignore this warning @@ -95,8 +239,27 @@ This warning is often safe to ignore when: - Your handler method intentionally omits parameters it doesn't need. - You're using a simpler method signature for cleaner code. - The performance impact is negligible for your application. +- You're prototyping or writing quick utility code where clarity matters more than efficiency. -The relaxed conversion works correctly; this warning just indicates a minor efficiency consideration. +The relaxed conversion works correctly; this warning just indicates a minor efficiency consideration. The compiler creates a wrapper delegate automatically, which adds a small performance overhead but doesn't affect functionality. + +### Example of when ignoring is appropriate + +```vb +Public Class QuickLogger + Public Event LogMessage As Action(Of String, DateTime) + + ' Simple handler that ignores the timestamp parameter + Private Sub WriteToConsole() + Console.WriteLine("Something was logged") + End Sub + + Public Sub SetupLogging() + ' This generates BC42328, but it's fine for simple scenarios + AddHandler LogMessage, AddressOf WriteToConsole + End Sub +End Class +``` ## See also diff --git a/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vb b/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vb new file mode 100644 index 0000000000000..e3a6329493f2e --- /dev/null +++ b/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vb @@ -0,0 +1,82 @@ +Imports System + +Public Class DocumentProcessor + ' Standard .NET event using EventHandler + Public Event DocumentProcessed As EventHandler + + ' Custom event with different signature + Public Event StatusChanged As Action(Of String) + + ' Handlers with different signatures + + ' Exact match for EventHandler - no warning + Private Sub OnDocumentProcessed_Exact(sender As Object, e As EventArgs) + Console.WriteLine("Document processed (exact signature)") + End Sub + + ' Simplified handler - causes BC42328 with EventHandler + Private Sub OnDocumentProcessed_Simple() + Console.WriteLine("Document processed (simple)") + End Sub + + ' Handler for custom event - exact match + Private Sub OnStatusChanged_Exact(message As String) + Console.WriteLine($"Status: {message}") + End Sub + + ' Handler with ignored parameters - causes BC42328 with custom event + Private Sub OnStatusChanged_Simple() + Console.WriteLine("Status changed") + End Sub + + Public Sub DemonstrateWarnings() + Console.WriteLine("Setting up event handlers...") + + ' These work without warnings (exact matches) + AddHandler DocumentProcessed, AddressOf OnDocumentProcessed_Exact + AddHandler StatusChanged, AddressOf OnStatusChanged_Exact + + ' These generate BC42328 warnings (relaxed conversions) + AddHandler DocumentProcessed, AddressOf OnDocumentProcessed_Simple + AddHandler StatusChanged, AddressOf OnStatusChanged_Simple + + ' Fire the events + RaiseEvent DocumentProcessed(Me, EventArgs.Empty) + RaiseEvent StatusChanged("Processing complete") + End Sub + + Public Sub DemonstrateSolutions() + Console.WriteLine("Using solutions to avoid warnings...") + + ' Solution 1: Assign to variable first + Dim handler1 As EventHandler = AddressOf OnDocumentProcessed_Simple + AddHandler DocumentProcessed, handler1 + + ' Solution 2: Use lambda expression + AddHandler DocumentProcessed, Sub(s, e) OnDocumentProcessed_Simple() + + ' Solution 3: Direct assignment to delegate variable + Dim handler2 As Action(Of String) = AddressOf OnStatusChanged_Simple + AddHandler StatusChanged, handler2 + + ' Fire the events + RaiseEvent DocumentProcessed(Me, EventArgs.Empty) + RaiseEvent StatusChanged("All solutions work") + End Sub +End Class + +Module Program + Sub Main() + Dim processor As New DocumentProcessor() + + Console.WriteLine("=== Demonstrating BC42328 Warning ===") + processor.DemonstrateWarnings() + + Console.WriteLine() + Console.WriteLine("=== Demonstrating Solutions ===") + processor.DemonstrateSolutions() + + Console.WriteLine("Press any key to exit...") + Console.ReadKey() + End Sub +End Module \ No newline at end of file diff --git a/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj b/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj new file mode 100644 index 0000000000000..5a06255081c8d --- /dev/null +++ b/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj @@ -0,0 +1,9 @@ + + + + Exe + net8.0 + BC42328Example + + + \ No newline at end of file From 41b855587af3dcf9b16128d5c6954b67f762f8de Mon Sep 17 00:00:00 2001 From: Bill Wagner Date: Wed, 10 Sep 2025 10:12:52 -0400 Subject: [PATCH 3/8] Apply suggestions from code review --- docs/visual-basic/misc/bc42328.md | 2 +- docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/docs/visual-basic/misc/bc42328.md b/docs/visual-basic/misc/bc42328.md index d22815bab8185..c495c640ee4cd 100644 --- a/docs/visual-basic/misc/bc42328.md +++ b/docs/visual-basic/misc/bc42328.md @@ -28,7 +28,7 @@ This warning appears when Visual Basic can handle the assignment through relaxed ### Complete example showing the warning -Here's a realistic scenario where you'll encounter BC42328: +Here's one scenario where you'll encounter BC42328: ```vb Public Class FileProcessor diff --git a/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj b/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj index 5a06255081c8d..843c94316783f 100644 --- a/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj +++ b/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj @@ -2,7 +2,7 @@ Exe - net8.0 + net9.0 BC42328Example From aee332a4a4be2b841a9184f220c7fd589062c0be Mon Sep 17 00:00:00 2001 From: Bill Wagner Date: Thu, 11 Sep 2025 10:18:57 -0400 Subject: [PATCH 4/8] Apply suggestions from code review Co-authored-by: Genevieve Warren <24882762+gewarren@users.noreply.github.com> --- docs/visual-basic/misc/bc42328.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/docs/visual-basic/misc/bc42328.md b/docs/visual-basic/misc/bc42328.md index c495c640ee4cd..8546b9efb3499 100644 --- a/docs/visual-basic/misc/bc42328.md +++ b/docs/visual-basic/misc/bc42328.md @@ -28,7 +28,7 @@ This warning appears when Visual Basic can handle the assignment through relaxed ### Complete example showing the warning -Here's one scenario where you'll encounter BC42328: +The following example shows one scenario that produces BC42328: ```vb Public Class FileProcessor @@ -74,7 +74,7 @@ However, `AddressOf` is still syntactically required in `AddHandler` and `Remove ## To correct this error -You have several options depending on your needs. Using the `FileProcessor` example from above, here are the different ways to resolve the BC42328 warning: +You have several options depending on your needs. Using the `FileProcessor` example from previously, here are the different ways to resolve the BC42328 warning: ### Option 1: Assign to a variable first (preserves exact semantics) From 57bd2e4c4614de49b351c089c99bf1bb260ab1d6 Mon Sep 17 00:00:00 2001 From: Bill Wagner Date: Thu, 11 Sep 2025 10:19:09 -0400 Subject: [PATCH 5/8] Apply suggestions from code review Co-authored-by: Genevieve Warren <24882762+gewarren@users.noreply.github.com> --- docs/visual-basic/misc/bc42328.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/docs/visual-basic/misc/bc42328.md b/docs/visual-basic/misc/bc42328.md index 8546b9efb3499..85039088e6585 100644 --- a/docs/visual-basic/misc/bc42328.md +++ b/docs/visual-basic/misc/bc42328.md @@ -143,7 +143,7 @@ End Sub ## Complete working example -Here's a full example demonstrating the warning and multiple solutions: +The following full example demonstrates the warning and multiple solutions: ```vb Imports System From bafe8e785626b199f9b26866fbface9d14cbe1bc Mon Sep 17 00:00:00 2001 From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com> Date: Thu, 11 Sep 2025 14:27:17 +0000 Subject: [PATCH 6/8] Move large inline code example to snippet file and use proper reference Co-authored-by: BillWagner <493969+BillWagner@users.noreply.github.com> --- docs/visual-basic/misc/bc42328.md | 85 +------------------ .../snippets/bc42328/AddressOfExample.vbproj | 2 +- 2 files changed, 2 insertions(+), 85 deletions(-) diff --git a/docs/visual-basic/misc/bc42328.md b/docs/visual-basic/misc/bc42328.md index 85039088e6585..673a51aac8571 100644 --- a/docs/visual-basic/misc/bc42328.md +++ b/docs/visual-basic/misc/bc42328.md @@ -145,90 +145,7 @@ End Sub The following full example demonstrates the warning and multiple solutions: -```vb -Imports System - -Public Class DocumentProcessor - ' Standard .NET event using EventHandler - Public Event DocumentProcessed As EventHandler - - ' Custom event with different signature - Public Event StatusChanged As Action(Of String) - - ' Handlers with different signatures - - ' Exact match for EventHandler - no warning - Private Sub OnDocumentProcessed_Exact(sender As Object, e As EventArgs) - Console.WriteLine("Document processed (exact signature)") - End Sub - - ' Simplified handler - causes BC42328 with EventHandler - Private Sub OnDocumentProcessed_Simple() - Console.WriteLine("Document processed (simple)") - End Sub - - ' Handler for custom event - exact match - Private Sub OnStatusChanged_Exact(message As String) - Console.WriteLine($"Status: {message}") - End Sub - - ' Handler with ignored parameters - causes BC42328 with custom event - Private Sub OnStatusChanged_Simple() - Console.WriteLine("Status changed") - End Sub - - Public Sub DemonstrateWarnings() - Console.WriteLine("Setting up event handlers...") - - ' These work without warnings (exact matches) - AddHandler DocumentProcessed, AddressOf OnDocumentProcessed_Exact - AddHandler StatusChanged, AddressOf OnStatusChanged_Exact - - ' These generate BC42328 warnings (relaxed conversions) - AddHandler DocumentProcessed, AddressOf OnDocumentProcessed_Simple - AddHandler StatusChanged, AddressOf OnStatusChanged_Simple - - ' Fire the events - RaiseEvent DocumentProcessed(Me, EventArgs.Empty) - RaiseEvent StatusChanged("Processing complete") - End Sub - - Public Sub DemonstrateSolutions() - Console.WriteLine("Using solutions to avoid warnings...") - - ' Solution 1: Assign to variable first - Dim handler1 As EventHandler = AddressOf OnDocumentProcessed_Simple - AddHandler DocumentProcessed, handler1 - - ' Solution 2: Use lambda expression - AddHandler DocumentProcessed, Sub(s, e) OnDocumentProcessed_Simple() - - ' Solution 3: Direct assignment to delegate variable - Dim handler2 As Action(Of String) = AddressOf OnStatusChanged_Simple - AddHandler StatusChanged, handler2 - - ' Fire the events - RaiseEvent DocumentProcessed(Me, EventArgs.Empty) - RaiseEvent StatusChanged("All solutions work") - End Sub -End Class - -Module Program - Sub Main() - Dim processor As New DocumentProcessor() - - Console.WriteLine("=== Demonstrating BC42328 Warning ===") - processor.DemonstrateWarnings() - - Console.WriteLine() - Console.WriteLine("=== Demonstrating Solutions ===") - processor.DemonstrateSolutions() - - Console.WriteLine("Press any key to exit...") - Console.ReadKey() - End Sub -End Module -``` +:::code language="vb" source="snippets/bc42328/AddressOfExample.vb"::: This example shows how the warning occurs in realistic scenarios and demonstrates multiple ways to resolve it. diff --git a/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj b/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj index 843c94316783f..5a06255081c8d 100644 --- a/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj +++ b/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vbproj @@ -2,7 +2,7 @@ Exe - net9.0 + net8.0 BC42328Example From f5891fbb7a89377796b312c28da7887cad9673bb Mon Sep 17 00:00:00 2001 From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com> Date: Thu, 11 Sep 2025 14:34:55 +0000 Subject: [PATCH 7/8] Replace inline code with snippet reference to eliminate duplication Co-authored-by: BillWagner <493969+BillWagner@users.noreply.github.com> --- docs/visual-basic/misc/bc42328.md | 72 ++++++------------- .../misc/snippets/bc42328/AddressOfExample.vb | 2 + 2 files changed, 23 insertions(+), 51 deletions(-) diff --git a/docs/visual-basic/misc/bc42328.md b/docs/visual-basic/misc/bc42328.md index 673a51aac8571..95ad2aa7fdc7d 100644 --- a/docs/visual-basic/misc/bc42328.md +++ b/docs/visual-basic/misc/bc42328.md @@ -30,39 +30,9 @@ This warning appears when Visual Basic can handle the assignment through relaxed The following example shows one scenario that produces BC42328: -```vb -Public Class FileProcessor - ' Define an event using the standard EventHandler delegate - ' EventHandler expects: Sub(sender As Object, e As EventArgs) - Public Event ProcessingComplete As EventHandler - - ' Method with exact signature - no warning - Private Sub OnProcessingComplete(sender As Object, e As EventArgs) - Console.WriteLine($"Processing completed by {sender}") - End Sub - - ' Method with simplified signature - this causes BC42328 warning - Private Sub OnSimpleComplete() - Console.WriteLine("Processing is done!") - End Sub - - Public Sub StartProcessing() - ' This works fine - exact signature match - AddHandler ProcessingComplete, AddressOf OnProcessingComplete - - ' This generates BC42328 warning: - ' "The 'AddressOf' expression has no effect in this context because - ' the method argument to 'AddressOf' requires a relaxed conversion - ' to the delegate type of the event" - AddHandler ProcessingComplete, AddressOf OnSimpleComplete - - ' Simulate completion - RaiseEvent ProcessingComplete(Me, EventArgs.Empty) - End Sub -End Class -``` +:::code language="vb" source="snippets/bc42328/AddressOfExample.vb" id="DocumentProcessor"::: -When you compile this code, Visual Basic shows the BC42328 warning for the second `AddHandler` statement because `OnSimpleComplete` doesn't match the `EventHandler` signature exactly. +When you compile this code, Visual Basic shows the BC42328 warning for the `AddHandler` statements that use relaxed delegate conversion. ## Why AddressOf appears to have "no effect" @@ -74,15 +44,15 @@ However, `AddressOf` is still syntactically required in `AddHandler` and `Remove ## To correct this error -You have several options depending on your needs. Using the `FileProcessor` example from previously, here are the different ways to resolve the BC42328 warning: +You have several options depending on your needs. Using the `DocumentProcessor` example from previously, here are the different ways to resolve the BC42328 warning: ### Option 1: Assign to a variable first (preserves exact semantics) ```vb -Public Sub StartProcessing() +Public Sub DemonstrateHandler() ' Create delegate variable first - this eliminates the warning - Dim handler As EventHandler = AddressOf OnSimpleComplete - AddHandler ProcessingComplete, handler + Dim handler As EventHandler = AddressOf OnDocumentProcessed_Simple + AddHandler DocumentProcessed, handler End Sub ``` @@ -90,29 +60,29 @@ End Sub ```vb ' Change the method signature to match EventHandler exactly -Private Sub OnSimpleComplete(sender As Object, e As EventArgs) +Private Sub OnDocumentProcessed_Simple(sender As Object, e As EventArgs) ' You can ignore the parameters if you don't need them - Console.WriteLine("Processing is done!") + Console.WriteLine("Document processed (simple)") End Sub -Public Sub StartProcessing() +Public Sub DemonstrateHandler() ' Now this works without warning - AddHandler ProcessingComplete, AddressOf OnSimpleComplete + AddHandler DocumentProcessed, AddressOf OnDocumentProcessed_Simple End Sub ``` ### Option 3: Use a lambda expression ```vb -Public Sub StartProcessing() +Public Sub DemonstrateHandler() ' Wrap the method call in a lambda that matches the signature - AddHandler ProcessingComplete, Sub(sender, e) OnSimpleComplete() + AddHandler DocumentProcessed, Sub(sender, e) OnDocumentProcessed_Simple() ' Or create a more complex lambda inline - AddHandler ProcessingComplete, + AddHandler DocumentProcessed, Sub(sender, e) Console.WriteLine($"Event from {sender}") - OnSimpleComplete() + OnDocumentProcessed_Simple() End Sub End Sub ``` @@ -120,13 +90,13 @@ End Sub ### Option 4: Use the `Handles` clause (if appropriate) ```vb -Public Class FileProcessor +Public Class DocumentHandler ' Declare the event source with WithEvents - Private WithEvents processor As FileProcessor + Private WithEvents processor As DocumentProcessor ' Use Handles clause - no AddHandler needed - Private Sub OnSimpleComplete() Handles processor.ProcessingComplete - Console.WriteLine("Processing is done!") + Private Sub OnDocumentComplete() Handles processor.DocumentProcessed + Console.WriteLine("Document processing is done!") End Sub End Class ``` @@ -134,10 +104,10 @@ End Class ### Option 5: Direct assignment to delegate variable ```vb -Public Sub StartProcessing() +Public Sub DemonstrateHandler() ' Assign to delegate variable then use with AddHandler - Dim handler As EventHandler = AddressOf OnSimpleComplete - AddHandler ProcessingComplete, handler + Dim handler As EventHandler = AddressOf OnDocumentProcessed_Simple + AddHandler DocumentProcessed, handler End Sub ``` diff --git a/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vb b/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vb index e3a6329493f2e..39ae891067d4f 100644 --- a/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vb +++ b/docs/visual-basic/misc/snippets/bc42328/AddressOfExample.vb @@ -1,5 +1,6 @@ Imports System +' Public Class DocumentProcessor ' Standard .NET event using EventHandler Public Event DocumentProcessed As EventHandler @@ -64,6 +65,7 @@ Public Class DocumentProcessor RaiseEvent StatusChanged("All solutions work") End Sub End Class +' Module Program Sub Main() From dae600689e4ecd96cb33c0d94da5d19af4b8b709 Mon Sep 17 00:00:00 2001 From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com> Date: Thu, 11 Sep 2025 22:09:19 +0000 Subject: [PATCH 8/8] Remove redundant "Complete working example" section as requested Co-authored-by: BillWagner <493969+BillWagner@users.noreply.github.com> --- docs/visual-basic/misc/bc42328.md | 8 -------- 1 file changed, 8 deletions(-) diff --git a/docs/visual-basic/misc/bc42328.md b/docs/visual-basic/misc/bc42328.md index 95ad2aa7fdc7d..d5d3e0072b052 100644 --- a/docs/visual-basic/misc/bc42328.md +++ b/docs/visual-basic/misc/bc42328.md @@ -111,14 +111,6 @@ Public Sub DemonstrateHandler() End Sub ``` -## Complete working example - -The following full example demonstrates the warning and multiple solutions: - -:::code language="vb" source="snippets/bc42328/AddressOfExample.vb"::: - -This example shows how the warning occurs in realistic scenarios and demonstrates multiple ways to resolve it. - ## When you can ignore this warning This warning is often safe to ignore when: