In Need of Help Checking if object is deleted

[chris.martinez]

Hey guys,

I am wracking my brains over trying to figure out what I assume should be simple. In my example code below that is running in a backgroundworker thread, I am getting selected usernames from a list box and attempting to delete them. If the delete is successful, I would like to print Profile {profile} succcessfully deleted, and if the delete is not successful, I would like to print Profile {profile} is locked. How would I go about doing this, as .Delete() throws an exception if the profile can’t be deleted, and I cannot do backgroundworker.reportprogress from inside an exception?

Dim resObjColl As ManagementObjectCollection
Dim resObj As ManagementObject
 
For Each profile In ListBoxProfiles.SelectedItems
    resObjColl = WmiConn.ExecWmiQuery($"SELECT * FROM win32_UserProfile WHERE localpath = ""C:\\Users\\{profile}""")
 
    For Each resObj In resObjColl
        resObj.Delete()
        BackgroundWorker4.ReportProgress(10, $"Profile {profile} successfully deleted.{vbCrLf}")
    Next
 
Next

[.paul.]

Use a Try, catch block inside your inner for each loop

https://docs.microsoft.com/en-us/dot...ally-statement

[chris.martinez]

Yeah thats what I was referring to with the reportprogress from within an exception. I can try it and since it doesnt work, I can catch the exception but then I can’t report the progress from within the catch. And if I use catch ex as exception, even with Continue For, WorkerCompleted gets called and if a profile that can be deleted is after the locked profile, it doesnt get deleted.

[.paul.]

Dim resObjColl As ManagementObjectCollection
Dim resObj As ManagementObject
 
For Each profile In ListBoxProfiles.SelectedItems
    resObjColl = WmiConn.ExecWmiQuery($"SELECT * FROM win32_UserProfile WHERE localpath = ""C:\\Users\\{profile}""")
 
    For Each resObj In resObjColl
        Try
            resObj.Delete()
            BackgroundWorker4.ReportProgress(10, $"Profile {profile} successfully deleted.{vbCrLf}")
        Catch ex as exception

        Finally
            'report progress for failed delete here
        End Try
    Next
 
Next

[.paul.]

Yeah thats what I was referring to with the reportprogress from within an exception. I can try it and since it doesnt work, I can catch the exception but then I can’t report the progress from within the catch. And if I use catch ex as exception, even with Continue For, WorkerCompleted gets called and if a profile that can be deleted is after the locked profile, it doesnt get deleted.

You're saying the first error ends the background thread?

[chris.martinez]

See the reason I didnt use a finally statement was that I was under the impression that whatever I put there will execute whether or not the profile gets deleted, so if a profile is deleted wouldn’t the reportprogress happen a second time?

[.paul.]

This might help...

https://social.msdn.microsoft.com/Fo...indowssecurity

[.paul.]

See the reason I didnt use a finally statement was that I was under the impression that whatever I put there will execute whether or not the profile gets deleted, so if a profile is deleted wouldn’t the reportprogress happen a second time?

You're probably right about the finally clause

[chris.martinez]

Thanks for the link, ill check it out when I get home. Its been a pain trying to figure this out lol. I just wanna like attempt to delete the object, and if not successful then continue deleting and be able to somehow check if the object still exists or not. Its super annoying.

[.paul.]

Hold on... I got it😁
You’re deleting part of a collection that you’re looping through in a for each...
Try a standard for loop, looping from the last item backwards to the first item. Then it will work

[chris.martinez]

Hold on... I got it😁
You’re deleting part of a collection that you’re looping through in a for each...
Try a standard for loop, looping from the last item backwards to the first item. Then it will work

So you’re saying loop through the obj collection to delete the object with a standard for loop but starting backwards and it will work? I’m confused why, and to how I could still report the progress if obj.delete() fails.

[.paul.]

Removing items from a collection while looping for, each through that collection doesn't work.
Why would you want to report - $"Profile {profile} successfully deleted." if the object was not successfully deleted at all?

[chris.martinez]

Removing items from a collection while looping for, each through that collection doesn't work.
Why would you want to report - $"Profile {profile} successfully deleted." if the object was not successfully deleted at all?

Well I would only want to report that if it was successful, and continue the loop if not while printing profile is locked. I was thinking something like setting an embedded reference or label to 0 at the start of every loop, and if successful then set it to 1 and then check if the reference = 1 then print profile successfully deleted else print profile is locked. Think this would be easier?

[chris.martinez]

Removing items from a collection while looping for, each through that collection doesn't work.
Why would you want to report - $"Profile {profile} successfully deleted." if the object was not successfully deleted at all?

You mentioning to use the Finally block got me thinking... I want to print a statement whether the delete succeeds or fails, so I figured why not do it in the Finally block as you mentioned, but just check some value I can set depending on whether the object does delete or not.

So I decided to create a My.Settings boolean reference called isDeleted, and at the beginning of the try statement I set it to false, and right under the Delete() call I set it to true. If the object does delete, then the reference is set to true, and if the object cannot be deleted then an exception is thrown and the code never sets the reference isDeleted to be true. Might not be the most elegant solution, but it works

For Each resObj In resObjColl
    Try
        My.Settings.isDeleted = False
        resObj.Delete()
        My.Settings.isDeleted = True
    Catch ex As Exception
    Finally
        If My.Settings.isDeleted = True Then
            BackgroundWorker4.ReportProgress(20, $"Profile {profile} successfully deleted.{vbCrLf}")
        Else
            BackgroundWorker4.ReportProgress(20, $"Profile {profile} is locked and cannot be deleted.{vbCrLf}")
        End If
    End Try

Next

[.paul.]

You could just use a Boolean variable, doesn’t need to be My.Settings, which is generally used for persisting data

[chris.martinez]

You could just use a Boolean variable, doesn’t need to be My.Settings, which is generally used for persisting data

True..

I got stuck on the My.Settings in my head because I needed to store data from another backgroundworker thread and access it from within this backgroundworker thread. Thanks!

[.paul.]

To store and access variables from your gui thread and also your bgw thread you can use form level variables. Google variable scope to see the differences between form level and local variables...