Convert List<T> to ObservableCollection<T> in WP7

I don't know if it's just too late or what, but I don't see how to do this...

What I'm expecting to do, and what the object browser says is there, is this:

var oc = new ObservableCollection<T>( new List<T>() );

But ObservableCollection<T> has a single parameterless constructor. The object browser says there is 2 overloads where List and IEnuerable should be able to be passed in.

Is there something wrong with my setup? Are the constructors not on the phone version? (that would be strange)

If this really doesn't exist, what is the standard way of doing this with WP7 now?

Solution 1:

ObservableCollection has several constructors which have input parameter of List<T> or IEnumerable<T>:
List<T> list = new List<T>();
ObservableCollection<T> collection = new ObservableCollection<T>(list);

Solution 2:

Apparently, your project is targeting Windows Phone 7.0. Unfortunately the constructors that accept IEnumerable<T> or List<T> are not available in WP 7.0, only the parameterless constructor. The other constructors are available in Silverlight 4 and above and WP 7.1 and above, just not in WP 7.0.

I guess your only option is to take your list and add the items into a new instance of an ObservableCollection individually as there are no readily available methods to add them in bulk. Though that's not to stop you from putting this into an extension or static method yourself.

var list = new List<SomeType> { /* ... */ };
var oc = new ObservableCollection<SomeType>();
foreach (var item in list)
    oc.Add(item);

But don't do this if you don't have to, if you're targeting framework that provides the overloads, then use them.

Solution 3:

To convert List<T> list to observable collection you may use following code:

var oc = new ObservableCollection<T>();
list.ForEach(x => oc.Add(x));

Solution 4:

You'll have to write your own extension method to do this:

    public static class CollectionEx
    {
      /// <summary>
      /// Copies the contents of an IEnumerable list to an ObservableCollection
      /// </summary>
      /// <typeparam name="T">The type of objects in the source list</typeparam>
      /// <param name="enumerableList">The source list to be converted</param>
      /// <returns>An ObservableCollection containing the objects from the source list</returns>
      public static ObservableCollection<T> ToObservableCollection<T>( this IEnumerable<T> enumerableList )
      {
        if( enumerableList != null ) {
          // Create an emtpy observable collection object
          var observableCollection = new ObservableCollection<T>();

          // Loop through all the records and add to observable collection object
          foreach( var item in enumerableList ) {
            observableCollection.Add( item );
          }

          // Return the populated observable collection
          return observableCollection;
        }
        return null;
      }
    }

Solution 5:

Extension method from this answer IList<T> to ObservableCollection<T> works pretty well

public static ObservableCollection<T> ToObservableCollection<T>(this IEnumerable<T> enumerable) {
  var col = new ObservableCollection<T>();
  foreach ( var cur in enumerable ) {
    col.Add(cur);
  }
  return col;
}