Gotcha: MarkerReached event of MediaElement returns new Markers

I just checked in the implementation code for a new feature for ClipFlair Studio’s Captions/Revoicing component:

When playing back recorded (or loaded from a WAV or MP3 file) audio for a caption/revoicing entry, the playback is now limited to the duration of the respective caption, (End-Start) time that is (btw that component has a duration column too that is hidden by default and can be shown by flipping it with the gear button on its titlebar and selecting the respective option to show the column).

The original audio is not affected and is stored in whole inside the saved state of the component/activity, so that you can adjust the caption entries timerange at any time to fit all or part of that recorded audio entry if you wish.

Will see into adding an “Limit playback” option to the backpanel of that component (it will default to true/checked) for any ClipFlair activities that don’t use the Start/End/Duration columns (e.g. if some activity just wants a grid of Captions and Audio entries for practicing and maybe for comparing to audio samples provided by the activity author or teacher at the optional “Comments (Audio)” column).

While implementing this feature, there were some “gotchas” that caused me some headache to spot:

1) When MediaOpened event is called by the MediaElement control, the Markers collection has just been reset and you need at that point to add your TimelineMediaMarker that will notify you when the playback limit point has been reached to stop the playback. In the case above this event is called after recording some audio or loading some WAV or MP3 audio file at an AudioRecorderControl (one is used at each row of the captions grid)

2) One shouldn’t remove an added marker at MediaEnded or MediaFailed events. This is since those will fire at each revoicing entry playback, whereas the MediaOpened while only occur once when the Audio property is populated at the AudioRecorderControl. As I mention above, MediaElement clears the Markers collection every time new content is loaded to it, so we need not worry about removing the marker we had added before.

3) Maybe the least obvious issue and the one that caused me most of headache to spot was that the MediaElement’s MarkerReached event gets back a MediaMarker that isn’t the same Marker instance as the one you had added to the Markers collection. So you have to use the Text property of the marker when you create it and then compare with the text from the one you got in the event to see if they are equal strings (btw, when C# compares strings it does it by content even if you use == instead of Equals method, unlike Java, where you shouldn’t use == to compare strings)

Suggestion: Case adaptive text replacement in Visual Studio editor

Have again suggested this long before to Visual Studio team, but since Visual Studio 2013 has a “Send a Frown” feature, I’ve sent it again with some suggestions on how it could be implemented.

I need some clever replace in cases like that one shown in the screenshot below, where I have the implementation of a Sounds property and want to clone that and rename it to Music (this is useful when repeating a coding pattern, but more importantly can use this when refactoring code and need to rename something).

When doing replace on the selection, replacing "sounds" to "music", I want the word/target phrase to detect the casing of the source word/phrase and keep the same casing style, that is:
- IsSoundsOn should become IsMusicOn
- soundsOn should become musicOn

As you can understand now I have to do 3 replacement operations, having selected the option "Case sensitive":
- Sounds to Music
- sounds to music

I’d rather have an option "Case adaptive" or something like that (marketing people might call this "Smart replace").




Implementation-wise, every time it detects the source text (case insensitive search), it would check if it is found in one of the following casings:
- first letter non-capital
- first letter capital
- all letters small
- all letters capitals

and when replacing with the target text it would apply the same casing state to it (affecting just the first letter of the target or all letters depending on which of the above casing states were detected for the source string at each position it was found in the source text)

Fix: TortoiseHg not commiting files

It seems that sometimes TortoiseHg Mercurial (Hg) client on Windows fails to remove a 0-byte-sized file named “wlock” (a write lock to avoid simultaneous write to a local repository) in the “.hg” subfolder that holds a local repository.

This results in the Commit dialog never commiting changed/removed/added files and you have to press Close there and confirm cancelation of the commit action. After trying multiple times and even rebooting I realized that deleting that “wlock” file fixed the issue and could then open up TortoiseHg commit dialog again to retry the commit action (luckily it remembers the commit message from the last effort, you just have to select which files to commit again.

The default seems to be to commit only modified files, thus if files have been removed or added you have to select them. Note that selecting the 3-state checkbox at the top selects/deselects all files quickly.

Then you can proceed from the “Hg Workbench” dialog (available when you right click in Windows Explorer the folder name that contains the “.hg” subfolder) to sync the local changes with any external repository you’re using. Hg is a distributed version control, unlike other centralized ones, so you can commit even without a network connection available, since it is commiting to the local repository.

Gotcha: Worksheets property is read-only, Sheets is not – Excel Workbook

My contribution to:


Seems Worksheets property is read-only

Returns a Sheets collection that represents all the worksheets in the specified workbook. Read-only Sheets object.

whereas Sheets is the real thing where you can also add Sheets dynamically

A collection of all the sheets in the specified or active workbook.

Suggestion: Making Intellisense in Visual Studio more Intelligent

Just sent this to the Visual Studio team via the “send a frown” button:

pressing CTRL+SPACE after "buttonDropDown." (see screenshot) seems to give me suggestions of members of buttonDropDown that aren’t a fit to the Rectangle object that I’m trying to assign to

I suppose you do so since I could eventually drill down into more properties of those objects

you could think of it as a tree though and from the current object’s (buttonDropDown) members give me as suggestions only those that satisfy condition X, where condition X would be defined recursively as "is a Rectangle or has members that satisfy X". Could maybe have some max depth in that case down to which you check and have an option at the end of the popup to show all members to pick from

another idea (easier to implement) is to show on top of the popup the members that are Rectangle and then the rest of the members separated visually, however I think the former suggestion is possible to implement and more powerful, plus could be combined with this later suggestion



2014 in review

The stats helper monkeys prepared a 2014 annual report for this blog.

Here’s an excerpt:

The concert hall at the Sydney Opera House holds 2,700 people. This blog was viewed about 52,000 times in 2014. If it were a concert at Sydney Opera House, it would take about 19 sold-out performances for that many people to see it.

Click here to see the complete report.

Categories: Posts

HowTo: Install .NET 3.5 component in Windows 8.1

I just installed .NET 3.5 on a Windows Enterprise 8.1 system that was failing to bring the needed files from the network

To do this I opened a command prompt with elevated rights and ran a single command, having the Windows DVD at drive F:

Dism /online /enable-feature /featurename:NetFx3 /All /Source:F:\sources\sxs /LimitAccess

as explained at this article:


1) if you have the Windows DVD in .ISO file, with a double click it mounts it to a virtual drive on Windows 8, so you can do similarly (you look at My Computer or the folder it opens after mounting to see what drive letter it used)

2) to run command prompt with elevated (administrator) rights, I searched for "cmd" (it is cmd.exe) and right click at the result found to then select "Run as administrator".


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