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Windows Phone: Rate My App

If you want your app to succeed one thing you need is reviews. More importantly you need good reviews!

Stats show that if an app has a rating of 4 stars or above it will do significantly better than an app with less. The higher the number of reviews, the more believable that rating is.

One issue you may have though is how to get reviews. Sadly most users don't rate apps unless they really like it or hate it. The Windows Phone OS also does nothing to prompt people to rate apps, so if you want to build up reviews then your going to need to do the prompting yourself.

The code to direct someone to the review page in the store for your app is quite simple. But even better is the fact Nokia have produced sample code that does the whole process!

Once you've integrated the code on the 5th launch of your app the user will see a prompt asking them to rate your app. If they choose not to then they will be prompted to send you feedback via email.

If they didn't rate your app then on the 10th launch they will be prompted again.

Now getting good reviews is slightly harder, for that your actually going to have to build a good app that people like.

You can download the Rate My App code from Nokia here.

ASP.NET Session Timeout

A users session on an ASP.NET site by default will time-out after 20 minutes. This however can be changed through either the web.config file or IIS.

To edit through the web.config file you need to edit the sessionState tag under system.web

1<system.web>
2  <sessionState timeout="30"></sessionState>
3</system.web>

Or through IIS click on your site name and then click Session State under the ASP.NET heading. There will be a field labeled Time-out (in minutes).

The value you enter for time-out must be an integer.

Help it doesn't seem to work!

If your sessions still seem like there timing out after 20 minutes it could be because your site isn't very active.

The application pool for your site also has an idle time-out that is set by default to 20 minutes. When the idle time-out is reached it will cause your application pool to recycle and therefore loose any active sessions (that's assuming you have the session state mode set to In Proc). Therefore it is a good idea to increase this to whatever you have set the session time-out to.

To do this go to your sites application pool in IIS, click advanced settings on the right and then look for the Idle Time-out (minutes) setting and update this to be the same as your session time-out value.

Caching data using static objects

One classic scenario of website speed issues relates to retrieving data from a database and often it is the same data being retrieved over and over again. For example storing some of your site settings in the database was originally a great idea as it meant your admin users could configure them through an admin, but now every request from your real users is doing a database call to look up this information.

A way to reduce these database calls is to create a static object that will keep hold of the information once its been retrieved. This could simply be an int or string or it could be something more complex like a List or Dictionary that we keep adding to.

Lets use an example where we are retrieving details of a room. The room can have multiple properties including Name, Capacity and Description. Or database contains multiple instances of rooms that is repeatedly requested.

Rather than accessing the database directly we can create a function that will first look up the value in a List object and if it is not found then revert to loading the information from the database. If the information was retrieved from a database then we also add it to the list for future use.

code for looking retrieving the data

As the List is a static object it will continue to hold the information of the rooms for the life of the application. Some things to watch out for however:

  • Static objects will be the same for all users, they are not related to a session
  • Static objects are accessible across all threads so you need to be aware that anything you change in the static object will be changing on all threads
  • When you return the object you wanted you will most likely be returning a reference to the existing object not just its value

With these things in mind, whenever you are updating the list (adding, removing etc) make sure you create necessary locks so that only 1 thread executes at a time. In the example this has been done when we check for the existence of the item and then go to load it. Without the lock it would be possible for 2 threads to do the check and then both go to load the values. If this were to happen we would end up with 2 instances of room in our list. Even worse if we were using a dictionary instead of a list the second instance would cause an exception when it tried to add it to the dictionary. With the lock the second thread will wait for the first to finish executing before it runs the code.

HTML5 Series - Array

If your going to do any sort of JavaScript programming it's not going to be long until you have to work with an array, so there's a few array functions you need to know about.

Push and Pop
Push and Pop are functions that add and remove items from an array. The easiest way to understand what they are doing is to imagine your array as a stack of paper. When you push and item onto the array it's the same as putting it on the top of your pile. When you Pop an item off it's the same as taking the top item from the pile.

1var myArray = [] // Declare a new array
2myArray.push("Red");
3myArray.push("Blue");
4 
5var value1 = myArray.pop();
6var value2 = myArray.pop();
7 
8alert(value1); // should alert the value Blue
9alert(value2); // should alert the value Red

Foreach loop
Probably one of the most useful functions for an array is the for each loop. A for each loop is essentially calling a function for each item in the array (hence for each). This is particularly useful in all kinds of scenarios.

1var myArray = ["blue", "red", "green"];
2 
3myArray.forEach(function (x) {
4    alert(x);
5});

Filter
As the name suggests filtering is a way to find items in your array. If you know C# then it works in a similar way to a lambda expression. The filter function takes a parameter of a function. Like the forEach loop the function is called on each item in the array, the function must then returns either true or false depending on if the filter criteria matched.

In this example notice that the result of myArray.filter is being assigned to another variable. This is because applying the filter wont actually remove items from the myArray array.

1var myArray = ["blue", "red", "green"];
2 
3var results = myArray.filter(function(x) {
4    if (x == "blue")
5        return true;
6    else
7        return false;
8})
9 
10results.forEach(function (x) {
11    alert(x);
12});

Some, Every
The some and every functions can be used to see if some items in the array match a criteria of if all of them do. They return either true or false.

Like the filter function, a function is passed as the criteria and returns either true or false.

1var myArray = ["blue", "red", "green"];
2 
3alert(myArray.some(function (x) {
4    if (x == "blue")
5        return true;
6    else
7        return false;
8})); // Alerts true as 1 item in the array is blue
9 
10alert(myArray.every(function (x) {
11    if (x == "blue")
12        return true;
13    else
14        return false;
15})); // Alerts false as not every item in the array is blue

Concat
Concat is used to combine 2 arrays into 2 new array.

1var myArray = ["blue", "red", "green"];
2var myArray2 = ["yellow", "orange"];
3 
4var myArray3 = myArray.concat(myArray2);

Slice
Slice lets you create a new array from an existing by letting you specify the start and end item. Those items and the others between then form the new array.

1var myArray = ["blue", "red", "green"];
2var myArray2 = myArray.slice(2, 3); // selects red and green
3

Splice
Splice can be used to add and remove items in an array. The function has the syntax:

arrayName.splice(index, how many, items to add);

Note: the index value starts at 0.

For example in our colour array we could add yellow and orange in between red and green with the following:

1var myArray = ["blue", "red", "green"];
2myArray.splice(2, 0, "yellow", "orange");
3 
4myArray.forEach(function (x) {
5    alert(x);
6});

Alternatively we could replace red and green with yellow and orange.

1var myArray = ["blue", "red", "green"];
2myArray.splice(1, 2, "yellow", "orange");
3 
4myArray.forEach(function (x) {
5    alert(x);
6});

A couple of others

Sort - Sorts the array into alphabetical order

Reverse - Reverses the order of the array