How to save a list of coordinates to isolated storage?

问题

I have a GeoCoordinate list that I want to save to storage when the application is closed, but I'm not sure how to save it to storage.

I tried saving the list using a helper class found here problem Storing a list of Objects in Isolated Storage but I think my syntax may be wrong in saving it as I'm new to using lists.This is how I tried to save the list. Can anyone point me in the right direction with saving the lit?

mycoord = Isolated_Storage_Helper.IsoStoreHelper
                                 .SaveList<mycoord>("Storage_Folder/", "Storage");

It gives me an error stating that mycoord is a field but is used as a type

mycoord is a list of coordinates created at a global level:

List<GeoCoordinate> mycoord = new List<GeoCoordinate>();

And populated in the OnNavigatedTo method:

protected override void OnNavigatedTo(NavigationEventArgs e)
{
    if (NavigationContext.QueryString.ContainsKey("GeoLat") &&  
        NavigationContext.QueryString.ContainsKey("GeoLong") &&  
        NavigationContext.QueryString.ContainsKey("pName"))
    {
        if (mycoord.Count >= 2)
        {
            //do something,draw route between points
            return;
        }
        else
        {
            var latitude = Convert.ToDouble(NavigationContext.QueryString["GeoLat"]);
            var longtitude = Convert.ToDouble(NavigationContext.QueryString["GeoLong"]);
            var MyGeoPosition = new GeoCoordinate(latitude, longtitude);
            var pushPinName = NavigationContext.QueryString["pName"];
            DrawPushPin(MyGeoPosition, pushPinName);
            mycoord.Add(MyGeoPosition);
        }
    }
    base.OnNavigatedTo(e);
}

回答1:

First create the coordinate class:

[DataContract]
class coord{
    [DataMember]
    public double lat{get;set;}
    [DataMember]
    public double lon{get;set;}
}

Now if you want to save a List<coord> You may do:

DataContractSerializer ser = new DataContractSerializer(typeof(List<coord>));
ser.WriteObject(any_file_stream, instance_of_List<coord>);

But if you want to save just a couple of coordinates, not a list IsolatedStorageSetting would be a better option.

回答2:

First create a cusom serializable object

[DataContractAttribute]
public class GeoPostionObj{
   [DataMember]
   Double lat {get;set;}
   [DataMember]
   Double lon {get; set;}

   public GeoPositionObj(double lat, double lon){
     this.lat = lat;
     this.lon = lon;
   }
}

Now you can initialize and save this object

//Where you want to save it
//We assume you already have your lat and lon retrieved 

GeoPositionObj saveObj = new GeoPositionObj(lat,lon);

EZ_Iso.IsolatedStorageAccess.SaveFile("GeoPos",saveObj);


//Then to retrieve 
GeoPositionObj retrievedObj = (GeoPositionObj)EZ_Iso.IsolatedStorageAccess.GetFile("GeoPos",typeof(GeoPositionObj));

You can find the EZ_Iso.dll here http://anthonyrussell.info/postpage.php?name=2

The DLL is free and includes documentation and source code if you are interested in how it works.

Let me know if you have any issues

来源：https://stackoverflow.com/questions/22563502/how-to-save-a-list-of-coordinates-to-isolated-storage

标签

windows-phone-8

isolatedstorage