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Posts Tagged ‘HowTo’

HowTo: Hide HTML markup from non-signedin users at MonoX Social CMS

At MonoX Social CMS, which I use at both ClipFlair Social and Trafilm websites, I was in the need of hiding some HTML markup when the user is not signed-in.

The solution for this is to add runat="server" to the HMTL element one wants to hide and then set the Visible property that the object acquires due to the runat clause. The Visible property is set using some special syntax to access the MonoX API like below:

<ul runat="server"
      Visible="<% $Code: Page.User.Identity.IsAuthenticated %>"  >

</ul>

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HowTo: Copy effective-computed CSS style for specific HTML paragraph

I’m in the process of setting up a temporary landing page for the trafilm project, where I need apart from showing the trafilm logo to also show some text description about the project, till I set up an instance of MonoX Social CMS for it, like the one in ClipFlair’s Community website (ClipFlair Social).

Since ClipFlair Social has some nice text styling, I decided to borrow the style of one of its home page paragraphs, using Firefox web browser’s developer tools (accessible via F12 key).

Being at the Inspector tab of the dev tools (which is the default when they first open), using the “Pick element” tool (first one on the dev tools pane’s toolbar on the left), I select the paragraph that looks nicely styled and I go to the Computed tab at the Style view, then press CTR+A to select all computed style CSS declarations for that paragraph element and press CTRL+C or right click and select Copy to copy them to the clipboard.

Screenshot 2016-01-25 13.41.19

If pasted (CTRL+V) in some text editor like Window’s Notepad that looks like a big ugly line, since they contain Unix-style line-endings, that is LF (linefeed) and not Windows-style ones (CRLF, Carriage Return + Line Feed), but editors like Wordpad or Notepad++ can show them nicely and even convert line endings from Unix to Windows and vice-versa if you wish so (e.g. in Notepad++ the respective actions are at Edit / EOL Conversion menu).

image

So, this is the copied Computed CSS style for that paragraph:

border-bottom-color: #333;
border-bottom-style: none;
border-bottom-width: 0px;
border-image-outset: 0 0 0 0;
border-image-repeat: stretch stretch;
border-image-slice: 100% 100% 100% 100%;
border-image-source: none;
border-image-width: 1 1 1 1;
border-left-color: #333;
border-left-style: none;
border-left-width: 0px;
border-right-color: #333;
border-right-style: none;
border-right-width: 0px;
border-top-color: #333;
border-top-style: none;
border-top-width: 0px;
color: #333;
cursor: default;
font-family: "Open Sans",sans-serif;
font-size: 14px;
font-weight: 400;
letter-spacing: 0px;
line-height: 24px;
margin-bottom: 20px;
margin-left: 0px;
margin-right: 0px;
margin-top: 0px;
padding-bottom: 10px;
padding-left: 0px;
padding-right: 0px;
padding-top: 0px;
-moz-border-bottom-colors: none;
-moz-border-left-colors: none;
-moz-border-right-colors: none;
-moz-border-top-colors: none;

As you can see, it has lots of stuff that isn’t needed, unless you want to be sure your style doesn’t get affected by style of parent elements. In my case I decided to trim it down a bit:

color: #333;
font-family: "Open Sans",sans-serif;
font-size: 14px;
font-weight: 400;
letter-spacing: 0px;
line-height: 24px;
margin-bottom: 20px;
margin-left: 0px;
margin-right: 0px;
margin-top: 0px;
padding-bottom: 10px;
padding-left: 0px;
padding-right: 0px;
padding-top: 0px;

Adding around the text above (which is represented by the CSS comment /* … */ below) a CSS selector to wrap those declarations in order to make a proper CSS rule-set:

p {

/* … */

}

and passing to CSS LINT tool to help us clean up the CSS we get no errors, but several warnings:

image

For example, as explained at W3Schools.com, in CSS one can use shorthand margin and padding properties:

The margin property is a shorthand property for the following individual margin properties:

  • margin-top
  • margin-right
  • margin-bottom
  • margin-left

CSS has properties for specifying the padding for each side of an element:

  • padding-top
  • padding-right
  • padding-bottom
  • padding-left

…so one wonders why Firefox Dev Tools don’t spit those out with that order and give them in bottom, left, right and top order instead.

Also instead of 0px, one is suggested to always write 0 instead, since zero will always be zero irrespective of the CSS units used for it (at least for the currently available CSS unit systems that is). This is merely to save in bandwidth I think, since 0px is better, suggesting to anyone modifying this value in the future they’d better use “px” [pixels] instead of say “pt” [points]).

So we clean up this CSS into (pay attention to the order of values in margin and padding shorthand declarations, which is top, right, bottom, left, that is clockwise starting from the top side of the HTML elements targeted via the CSS rule selector, which is a paragram – p – in our case):

p {

   color: #333;
  font-family: "Open Sans",sans-serif;
  font-size: 14px;
  font-weight: 400;
  letter-spacing: 0;
  line-height: 24px;
  margin: 0 0 20px 0;
  padding: 0 0 10px 0;

}

Pasting at CSS LINT online tool again we get no warnings anymore (apart from no errors):

image

One might also remove the redundant space chars at the end of each line that Firefox places when copy-pasting the style declarations. Notepad++ can do it via Edit / Blank Operations / Trim Trailing Space menu command:

image

HowTo: show inner exception message if available, else outer one

Sometimes when you catch an exception in .NET, the message it prints out isn’t very informative, since it is wrapping another exception that had been thrown a bit inner in the code. That exception is in that case accessible via InnerException of the Exception instance.

That inner exception is also an Exception, so one would like to use its Message instead of the outer exception’s one, if an inner exception exists and, only if an inner exception doesn’t exist use the caught exception’s message. Here’s a clean-looking pattern I’ve coined up to achieve this while working on the TrackingCam application:

try

{

  //…

}

catch (Exception e)

{

  MessageBox.Show((e.InnerException ?? e).Message);

}

the ?? operator returns e.InnerException if it is not null, else falls back to returning e. Those two results are both of type Exception, so you can use Message on them, by putting the ?? operator’s expression in parentheses.

HowTo: Pause and Resume Speech Recognition with Microsoft engines

At SpeechTurtle application, I’ve just added speech feedback (voicing of a command) when an available command is executed using a mouse click on its name.

That could also help the user learn the expected pronunciation in English in case the speech recognition engine doesn’t understand some of the commands as voiced by the user. One can assume most of what the Speech Synthesis engine outputs to be recognizable by the Speech Recognition engine.

An issue with this approach though, is that the Speech Recognition can be fired accidentally by the speech synthesis commands, if the speech recognition engine doesn’t handle this case automatically, ignoring synthesized speech that is being generated in parallel by the speech engine.

In fact this can also be a security issue, with a malicious agent delivering voice commands to your system via some audio or video file/stream they lure you into listening/watching, or some web page they lure you into visiting (even if a webpage is not malicious, it might have been served and hosting a malicious ad by an ad network).

So, we need some way to pause the speech recognition while speaking, to avoid misfiring of recognition, since from my experience, the speech synthesis and recognition engines from .NET’s System.Speech namespace on recent Windows versions (tried with Windows 10) do have this issue.

In SpeechLib (that SpeechTurtle uses via the SpeechLib NuGet package), I’ve added commands Pause and Resume to the ISpeechRecognition interface (defined in SpeechLib.Models project and respective NuGet package and implemented at SpeechLib.Recognition and SpeechLib.Recognition.KinectV1 projects and NuGet packages).

So, in SpeechTurtle, I can do:

public void SpeakCommand(string command)
{   
  speechRecognition.Pause(); //pause the speech recognizer
  speechSynthesis.Speak(command);   
  speechRecognition.Resume();
}

Note the pattern used in SpeechRecognition.cs to retry 10 times to pause the speech recognition engine, since errors are thrown if one tries to Stop it or Set its audio input to none while it is trying to perform some recognition.

public void Pause()
{   
  for (int i=0; i<10; i++) //(re)try 10 times
  //(since we wait 100 ms at failure below before retrying, max wait is 1000ms=1sec)
    try
    {       
      SetInputToNone();
      return; //exit retry loop if succeeded
    }
  catch //catch and ignore any error saying that recognition is currently running
    {       
      Thread.Sleep(100); //retry in 100ms
    }
}

Update 1:

After more testing, it seems the above approach with the loop and try/catch won’t work

if one uses the async versions of Speech Recognition methods, since the exceptions are thrown from another thread. In that case one need to add a global exception handler.

Update 2:

After lots of trial and error, I ended up with this working pattern for Pause and Resume in SpeechLib’s SpeechRecognition.cs (note that paused is a bool(ean) field of that class, defaulting to false and PAUSE_LOOP_SLEEP is a const(ant) int(eger) set to 10 (msec):

public void Pause()
{   
  paused = true;
  speechRecognitionEngine.RequestRecognizerUpdate();
}
 
public void Resume()
{   
  paused = false;
}

At the constructor of that SpeechRecognition class I do:

  speechRecognitionEngine.RecognizerUpdateReached +=
(s, e) => {
while (paused) Thread
.Sleep(PAUSE_LOOP_SLEEP); };

I do a loop at RecognizerUpdateReached event handler to make sure the Speech Recognition

thread is waiting for the pause field to change value back to false. That event occurs after the call to RequestRecognizerUpdate in Pause method (which is done after first setting paused=true there).

HowTo: Get and combine executable path with subfolder and filename

Based on others answers at

http://stackoverflow.com/questions/3123870/find-the-location-of-my-applications-executable-in-wpf-c-or-vb-net

here’s an example that shows how to remove the executable name from the path and combine the result with some subfolder and filename:

At my updated version of Hotspotizer (http://github.com/birbilis/Hotspotizer), I’ve just added support for loading a Gesture Collection file at startup, if found at Library\Default.hsjson, by using the following code:

const string GESTURE_COLLECTION_LIBRARY_PATH = "Library"
const string DEFAULT_GESTURE_COLLECTION = "Default.hsjson"

//...

LoadGestureCollection(
  Path.Combine(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location),
  GESTURE_COLLECTION_LIBRARY_PATH,
  DEFAULT_GESTURE_COLLECTION));

HowTo: Reinstall a new Windows 10 build after reverting to older build

At http://www.askvg.com/fix-windows-10-insider-preview-build-10240-not-appearing-on-windows-update/ it writes:

NOTE:

If you previously had a new Windows 10 build installed in your computer and then reverted back to an older build, you’ll lose access to the new build and it’ll no longer be offered as an upgrade option. Deleting the number for that build from the list at HKEY_LOCAL_MACHINE\SOFTWARE\
  Microsoft\WindowsSelfHost\Applicability\RecoveredFrom key in Registry Editor seems to restore the ability to upgrade. Thanks to our reader "thedicemaster" for this info…

This is useful to know and unfortunately it means that some users may get stuck to an older Windows 10 version. Unless Microsoft has it set like that so that they’ll get automatically the next Windows build (ship the one they were trying to install hoping it fixed the issue they were having). Of course this will work if Microsoft keeps on pushing new builds often, not if they end up updating the OS build once a year or more rare in the future as Windows 10 matures.

To open Registry Editor you can click the Search icon (next to the Windows Start menu icon) at the Windows 10 Taskbar and write RegEdit.exe, then it should offer you a result that says “Run command” that you can click to launch it.

Screenshot 2015-11-23 13.44.22

After that, expand the respective tree nodes (that is HKEY_LOCAL_MACHINE, then SOFTWARE, then Microsoft, then Windows, then WindowsSelfHost) from the side pane and right click and delete the “RecoveredFrom” node.

Then try Windows Update again from State menu / Settings / Update & Security and tell it again to check for updates. In case it still doesn’t offer the updates, wait for 1-2 days and try again.

HowTo: Remove unused references and using clauses in Visual Studio

I recently posted a list of the VS2015 extensions I use on my main machine at: https://zoomicon.wordpress.com/2015/11/13/visual-studio-2015-extensions-i-use/

From that list of extensions I use the Productivity Power Tools one, it has a "Power Commands > Remove and Sort Usings" action that one can right click and run on the whole solution. Much easier than opening it for each

There is another nice extension called ResolveUR that is not available for VS2015, but only for VS2013 (think you can edit its .vsix and make it work for it too though, see the process for other similar extension explained at https://devio.wordpress.com/2014/12/03/remove-unused-references-with-visual-studio-2013/). I usually open up the solution in VS2013 too just to run that. Resharper also has such functionality as shown at:

https://www.jetbrains.com/resharper/help/Refactorings__Remove_Unused_References.html

Alternative is to use the Copy References extension and right click a reference under the References subtree of a project, then select "Copy Reference", then Remove the reference and rebuild that project. If rebuild fails, then right click at the References again and select Paste Reference. Then repeat till you remove all references that are not needed

In fact one should FIRST remove all unused using clauses and THEN remove unused references. That is because some files like App.xaml.cs, AssemblyInfo.cs may have using clauses that they don’t really use. So unless those using clauses are removed, the compiler thinks respective references to assemblies those namespaces were at are needed

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