CODEWITHSUNDEEP
vb.netbyrefbyval
Henry Penton
Henry Penton

Reputation: 97

Using ByRef and ByVal

I'm fairly new to programming and I was told that I should be passing things using ByRef and ByVal, but when I do so, I get an error saying:

Error   3   Method 'Private Sub Activate_Click(ByRef intIDToChange As Integer, sender As Object, e As System.EventArgs)' 
cannot handle event 'Public Event Click(sender As Object, e As System.EventArgs)' because they do not have a compatible signature.  
F:\Dropbox\Gooby Backup\School Work\Computing\Unit 4\Room Booking Client\WindowsApplication1\ActivateDeactivate\Activate Deactivate.vb  32  129 WindowsApplication1

I start my sub with:

Private Sub Activate_Click(ByRef intIDToChange As Integer, sender As System.Object, e As System.EventArgs) Handles Activate.Click

Upvotes: 0

Views: 953

Answers (3)

Steve
Steve

Reputation: 96

It sounds like the event handler you've declared there (Activate_Click) doesn't match the event definition for ActivateClick.

Try changing to:

Private Sub Activate_Click(ByVal intIDToChange As Integer, ....) Handles Activate.Click

ByVal sends the value of the variable via the parameter, whereas ByRef sends the variable (meaning changes made in the subroutine affect the calling routines variable).

More detailed answer here: http://social.msdn.microsoft.com/Forums/en-US/vbgeneral/thread/07b9d3b9-5658-49ed-9218-005564e8209e/

Upvotes: 0

Ravindra Gullapalli
Ravindra Gullapalli

Reputation: 9178

You have to define your method as

Private Sub Activate_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Activate.Click

because the button click event takes only two arguments.

If you want to use the variable intIDToChange, provide that as a class level variable like

private intIDToChange as Integer and update it in Activate_Click.

Upvotes: 0

MarcinJuraszek
MarcinJuraszek

Reputation: 125640

You can't handle Activate.Click with your method, because you have additional Integer parameter which is not compatible with Event signature.

Event signature

Click(sender As Object, e As System.EventArgs)

Your method

Activate_Click(ByRef intIDToChange As Integer, sender As System.Object, e As System.EventArgs)

Upvotes: 2

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