Breaking/exit nested for in vb.net
vb.netFor LoopNested Loopsvb.net Problem Overview
How do I get out of nested for or loop in vb.net?
I tried using exit for but it jumped or breaked only one for loop only.
How can I make it for the following:
for each item in itemList
for each item1 in itemList1
if item1.text = "bla bla bla" then
exit for
end if
end for
end for
vb.net Solutions
Solution 1 - vb.net
Unfortunately, there's no exit two levels of for
statement, but there are a few workarounds to do what you want:
-
Goto. In general, using
goto
is considered to be bad practice (and rightfully so), but usinggoto
solely for a forward jump out of structured control statements is usually considered to be OK, especially if the alternative is to have more complicated code.For Each item In itemList For Each item1 In itemList1 If item1.Text = "bla bla bla" Then Goto end_of_for End If Next Next end_of_for:
-
Dummy outer block
Do For Each item In itemList For Each item1 In itemList1 If item1.Text = "bla bla bla" Then Exit Do End If Next Next Loop While False
or
Try For Each item In itemlist For Each item1 In itemlist1 If item1 = "bla bla bla" Then Exit Try End If Next Next Finally End Try
-
Separate function: Put the loops inside a separate function, which can be exited with
return
. This might require you to pass a lot of parameters, though, depending on how many local variables you use inside the loop. An alternative would be to put the block into a multi-line lambda, since this will create a closure over the local variables. -
Boolean variable: This might make your code a bit less readable, depending on how many layers of nested loops you have:
Dim done = False For Each item In itemList For Each item1 In itemList1 If item1.Text = "bla bla bla" Then done = True Exit For End If Next If done Then Exit For Next
Solution 2 - vb.net
Put the loops in a subroutine and call return
Solution 3 - vb.net
For i As Integer = 0 To 100
bool = False
For j As Integer = 0 To 100
If check condition Then
'if condition match
bool = True
Exit For 'Continue For
End If
Next
If bool = True Then Continue For
Next
Solution 4 - vb.net
Make the outer loop a while loop, and "Exit While" in the if statement.
Solution 5 - vb.net
I've experimented with typing "exit for" a few times and noticed it worked and VB didn't yell at me. It's an option I guess but it just looked bad.
I think the best option is similar to that shared by Tobias. Just put your code in a function and have it return when you want to break out of your loops. Looks cleaner too.
For Each item In itemlist
For Each item1 In itemlist1
If item1 = item Then
Return item1
End If
Next
Next
Solution 6 - vb.net
If I want to exit a for-to loop, I just set the index beyond the limit:
For i = 1 To max
some code
if this(i) = 25 Then i = max + 1
some more code...
Next`
Poppa.
Solution 7 - vb.net
Insert a boolean value check in your loop:
If MyBreak Then
Exit Sub
End If
Where MyBreak is toggled by a button or label clicked.