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Posts tagged: solution

Solution: Windows 10: Unable to start Appstore apps

By , 08/05/2015 1:45 PM

Ok, I went ahead and upgraded to Windows 10. everything went smoothly, all my settings and installed apps preserved and work without a hitch. I am loving the interface and getting along with Cortana pretty good.

But after a while I encountered a weird issue: Appstore installed apps – e.g. Calendar, Mail etc. even Windows AppStore itself wouldn’t launch. I’d either get a cryptic error message, something along the lines “Application did not start, please contact system administrator” or very briefly a window would appear and immediately closed.

Looking into Event log was a bit more explanatory, but not too much: “Microsoft.WindowsStore_8wekyb3d8bbwe!App failed with error: Access is denied. See the Microsoft-Windows-TWinUI/Operational log for additional information.

If you google it – you will find many possible explanations of the problem and many possible ways to solve it offered, but none of those worked for me. Finally I figured it out (and Event Log entry gave me a clue): C:\Program Files\WindowsApps folder was missing necessary permissions:

WindowsApps

Namely, “ALL APPLICATION PACKAGES” was missing read & execute permissions on that folder (had to to uncheck “Hide protected operating system files” in Control Panel, File Explorer options to be able to see it). Once I added correct permissions – appstore apps started launching with no problems.

Cancel long running SQL Command in ASP.NET WebForm application

By , 04/14/2015 3:03 PM

It’s an all too common scenario when your ASP.NET page takes too long to load and the culprit is slow, long running SQL query. It shouldn’t come to this, you should optimize your DB stuff to minimize delays, but if you’re trying to decode feline genome or find alien live in the neighboring galaxies – that’s unavoidable. So the page is running and at some point you decide enough is enough and decide you need to cancel it. But you want to do it gracefully, for example slow page is in an IFRAME and you want to remain in the parent page and you don’t want to close/reload the whole thing.

There’s a way. The idea is, every time you create an SqlCommand – you add it to static (shared in VB.NET) list. If command runs successfully – you remove it from the list. But if it takes too long – you can issue an AJAX call from client page to cancel the command stored in that list.

Thanks Arsalan Tamiz for posting this solution to my question on StackOverflow. His demo project was in C# (you can download it from the above link). but since most of my projects are in VB.NET – I did a conversion with some adjustments.
Continue reading 'Cancel long running SQL Command in ASP.NET WebForm application'»

Solution: Live Writer Error “Invalid Response Document” while connecting to WordPress

By , 03/23/2015 1:02 PM

If you’re trying to connect to your WordPress blog from Windows Live Writer desktop client, you may get this dreaded error message:

Invalid Server Response – The response to the blogger.getUsersBlogs method received from the blog server was invalid:┬áInvalid response document returned from XmlRpc Server

Invalid Response

This means that instead of expected XML response your blog sent back plain html or text message which is most likely some kind of error message. To see actual message you can either trace request response in an HTTP sniffer like Fiddler or simple enter endpoint url for your blog remote access (e.g. http://your.site.com/wordpress/xmlrpc.php) into your browser address bar.
Continue reading 'Solution: Live Writer Error “Invalid Response Document” while connecting to WordPress'»

ASP.NET WebForms: Safe refresh after postback

By , 02/10/2015 6:36 PM

It’s all too commons scenario in a Web Application, you initiate a postback by clicking a button (basically submitting a form), some action is performed, perhaps database is written to, all fine and good. And then you refresh the page. Or even page is refreshed for some purpose by a client-side JavaScript code. And the dreaded “resubmit” message appears, it differs from browser to browser, e.g. Firefox would say

“To display this page, Firefox must send information that will repeat any action (such as a search or order confirmation) that was performed earlier”

And if you agree – the form is resubmitted again along with all the actions performed – not good.

This issue happens because the page is submitted via POST request and in order to refresh the page – POST request has to be resubmitted along with form action. And the solution is Post/Redirect/Get pattern. The idea is to take the page submitted via POST request and convert it into GET. In ASP.NET this can be achieved via simple Response.Redirect. You can redirect to another page or you can reload your current one:

Response.Redirect(Request.RawUrl)

This code redirects to original page URL, essentially reloading the from page server side. But now it’s a GET page, safe to refresh

WriteEndObject of JSON.NET ouptuts NULL literal

By , 01/07/2015 4:50 PM

JSON.NET is a very popular framework to process JSON data in .NET. We recently upgraded from v4 to v6 and noticed strange thing it started to output null to JSON strings created by JsonTextWriter object.

For example if JSON produced by v4 would look like this:

{"param1":"value1", "param2":"value2",
"someArray":[{"arrParam1": "arrValue1"}, {"arrParam2": "arrValue2"}]}

Same code, using v6, would prodcuce

{"param1":"value1", "param2":"value2",
"someArray":[{"arrParam1": "arrValue1"}, {"arrParam2": "arrValue2"}]null}

that extra “null” makes it invalid and unusable JSON.

The .NET function to create JSON writes it into a StringBuilder and is pretty straighforward.

  1. It starts with call to WriteStartObject method of JsonTextWriter
  2. Then it creates parameter name via WritePropertyName
  3. Depending on whether primitive value or raw string needs to be written WriteValue or WriteRaw methods are used respectfully
  4. Repeat steps 2 and 3 as needed
  5. Call to WriteEndObjectto finish writing.

This worked perfectly well when version 4 of Newtonsoft.Json.dll was used. After upgrading to version 6 last method – “WriteEndObject” began to output “null” to resulting JSON.

The solution is to use WriteRawValue method instead of WriteRaw – it still outputs raw string, but at the end WriteEndObject doesn’t output “null” anymore.

Solution: Lenovo Thinkpad w540 black LCD screen (only external monitor works)

By , 12/22/2014 5:33 PM

I spend ungodly amount of time trying to solve this issue, there were many similar issues reported on Lenovo forums, but no solutions and contacting Lenovo support is akin jumping thru hoops of fire.

The problem began after I plugged my brand new Thinkpad w540 into external monitor and set it to mode “Extended display (monitor + built-in screen). For a while everything worked fine, but then laptop own screen went black – and nothing could revive it. The external monitor worked fine and the maddening part was – when laptop booted – Lenovo logo appeared bright and shiny on laptop own screen, so I knew graphics card was OK. I ran full Lenovo System update, I updated NVidia drivers from Nvida site – nothing helped.

Then I tried to update Intel drivers for laptop’s HD Graphics 4600 card. Intel installer refused to install them because “The driver being installed is not validated for this computer“. To bypass that I

1. Unzipped the installer package into it’s own folder (you can use WinRar to unpack actual EXE or you can download Zip version of the package).
2. Went to Device Manager, right clicked on “HD Graphics 4600 card” driver and selected Update.
3. When prompted I selected “Browse my computer for driver software”
4. Selected “Let me pick from list of Device Drivers”
5. Clicked “Have disk” and browsed for an INF file inside of GRAPHICS folder of the unpacked driver files from Step 1

Installation commenced and lo and behold – laptop’s display sprang to life.

These instructions are specific to this laptop model and videocard, but I imagine they might be helpful in other similar situations. And hopefully Lenovo will take notice and finally update their drivers.

Access nested controls in ASP.NET Page PreInit event (when no Master Page is involved)

By , 11/07/2014 4:34 PM

There’re situations when you need access ASP.NET web controls very early in page lifecycle, more specifically – in Page PreInit event – and you can, but only top-level controls. But what if you need to access child/nested controls? The example below uses Infragistics WebHierarchicalDataGrid as a child of Infragistics WebSplitter, but this pretty much applies to any such scenario.

Let’s say you have following layout

<ig:WebSplitter ID="WSP" runat="server">
   <Panes>
      <ig:SplitterPane runat="server">
         <Template>

            <ig:WebHierarchicalDataGrid ID="WHG" runat="server">
            </ig:WebHierarchicalDataGrid>

         </Template>
      </ig:SplitterPane>
      <ig:SplitterPane runat="server"></ig:SplitterPane>
   </Panes>
</ig:WebSplitter>

As you can see grid “WHG” is nested withing first pane of splittet “WSP. Let’s see what happens if you try access the controls in PagePreInit event: Continue reading 'Access nested controls in ASP.NET Page PreInit event (when no Master Page is involved)'»

Access jQueryUI dialog buttons after dialog was created

By , 10/16/2014 5:00 PM

If you’re using jQuery UI Dialog, you know sometimes there’s a need to access dialog’s button objects after the dialog has already been created. This can be easily done via

$(dialogElement).dialog("option").buttons

command. One possible scenario where this can be useful – is executing specific button click function when user clicks [X] in dialog title. Imagine that buttons are set via array and the last object in this array is always something like CANCEL or NO or DISREGARD – and you want to simulate click of that last button whenever user clicks [X]. Using above command it’s pretty straightforward:

$(oDivDialog).dialog({
   //... some dialog parameters
   buttons: arrayOfButtonObjects,
   //... some more parameters
   close: function () {
      var buttons = $(this).dialog("option").buttons;
      buttons[buttons.length - 1].click();
   }
})

Line 5 begins close event which is called on dialog closing.
Line 6 retrieves array of buttons for the dialog
Line 7 calls click() function of the last button in the array

Infragistics WebDataMenu: Manual postback from client-side Click event

By , 10/07/2014 1:46 PM

There’s a a few possible scenarios when you need to manually to initiate server-side Click event of Infragistics WebDataMenu control. For example in client side click event you do some verification/user confirmation and upon positive confirmation (e.g. user clicks YES) – server-side Click event should kick in.

In a normal flow of event you can use set_cancel(bool) method to allow/disallow natural menu postback e.g.

function Menu_ItemClick(sender, eventArgs) {

   if (confirm('Are you sure?'))
       eventArgs.set_cancel(false)
   else
       eventArgs.set_cancel(true)

}

This works because this dialog stops code execution waiting for the user input. But what if you use something like jQueryUI dialog that relies on callback functions to get user feedback? In this case execution of the code continues immediately so you have to cancel postback right away and instead in the callback of the dialog initiate manual postback e.g

function Menu_ItemClick(sender, eventArgs) {

   $("#dialog").dialog({
      resizable: false,
      height:140,
      modal: true,
      buttons: {
        "Yes": function() {
          $(this).dialog("close");
          __doPostBack(sender.get_id(), 'ItemClick' + eventArgs._getPostArgs());
        },
        "No": function() {
          $(this).dialog("close");
        }
      }
   });  

   eventArgs.set_cancel(true)

}

The example above initiates modal confirmation jQuery UI dialog and immediately cancels menu postback (Line 18). Later if user clicks “Yes” button – dialog is closed and manual menu postback is initiated (Line 10) – it passes menu ID and correct postback argruments which result in server-side Click event of menu control. If user clicks “No” – dialog is closed and nothing else happens.

Solution for NFC not working on Samsung Galaxy phone

By , 10/03/2014 1:44 PM

This has been bothering me for a while – NFC refused to work on my Samsung Galaxy phone. Service was enabled and running, no errors or warning were displayed, but phone was unable to detect any NFC presence – tags, stickers, point of sale etc.

I was wrecking my mind until I realized that a while back I replaced the original Samsung Battery with a higher capacity generic one to extend battery life. But original Samsung Battery acts as an NFC antenna as well!

As soon as I put original battery in – lo and behold NFC sprang to action.

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