After updating to ABP v3.0.0, I started getting DbContext disposed exception when running parallel requests to repository that create new UnitOfWork like this:
using (var uow = _unitOfWorkManager.Begin(TransactionScopeOption.RequiresNew))
I looked in the source code and found some code in AsyncLocalCurrentUnitOfWorkProvider that I don't understand. When setting current uow, it sets property in wrapper:
private static readonly AsyncLocal<LocalUowWrapper> AsyncLocalUow = new AsyncLocal<LocalUowWrapper>();
private static void SetCurrentUow(IUnitOfWork value)
{
lock (AsyncLocalUow)
{
if (value == null)
{
if (AsyncLocalUow.Value == null)
{
return;
}
if (AsyncLocalUow.Value.UnitOfWork?.Outer == null)
{
AsyncLocalUow.Value.UnitOfWork = null;
AsyncLocalUow.Value = null;
return;
}
AsyncLocalUow.Value.UnitOfWork = AsyncLocalUow.Value.UnitOfWork.Outer;
}
else
{
if (AsyncLocalUow.Value?.UnitOfWork == null)
{
if (AsyncLocalUow.Value != null)
{
AsyncLocalUow.Value.UnitOfWork = value;
}
AsyncLocalUow.Value = new LocalUowWrapper(value);
return;
}
value.Outer = AsyncLocalUow.Value.UnitOfWork;
AsyncLocalUow.Value.UnitOfWork = value;
}
}
}
private class LocalUowWrapper
{
public IUnitOfWork UnitOfWork { get; set; }
public LocalUowWrapper(IUnitOfWork unitOfWork)
{
UnitOfWork = unitOfWork;
}
}
That does not look thread-safe, as any thread can set new UnitOfWork and then dispose it.
Is it a bug? I can use my own implementation of ICurrentUnitOfWorkProvider, without wrapping, but I'm not sure if that is correct.
Update
I can't give an example with DbContext disposed exception, but here is one with null reference exception in repository.GetAll() method. I think it has the same reason.
namespace TestParallelEFRequest
{
public class Ent1 : Entity<int> { public string Name { get; set; } }
public class Ent2 : Entity<int> { public string Name { get; set; } }
public class Ent3 : Entity<int> { public string Name { get; set; } }
public class Ent4 : Entity<int> { public string Name { get; set; } }
public class DomainStartEvent : EventData {}
public class DBContext : AbpDbContext {
public DBContext(): base("Default") {}
public IDbSet<Ent1> Ent1 { get; set; }
public IDbSet<Ent2> Ent2 { get; set; }
public IDbSet<Ent3> Ent3 { get; set; }
public IDbSet<Ent4> Ent4 { get; set; }
}
public class TestService : DomainService, IEventHandler<DomainStartEvent>
{
private readonly IRepository<Ent1> _rep1;
private readonly IRepository<Ent2> _rep2;
private readonly IRepository<Ent3> _rep3;
private readonly IRepository<Ent4> _rep4;
public TestService(IRepository<Ent1> rep1, IRepository<Ent2> rep2, IRepository<Ent3> rep3, IRepository<Ent4> rep4) {
_rep1 = rep1;_rep2 = rep2;_rep3 = rep3;_rep4 = rep4;
}
Task HandleEntityes<T>(IRepository<T> rep, int i) where T : class, IEntity<int> {
return Task.Run(() => {
using (var uow = UnitOfWorkManager.Begin(TransactionScopeOption.RequiresNew)) {
Thread.Sleep(i); // Simulating work
rep.GetAll(); // <- Exception here
}
});
}
public void HandleEvent(DomainStartEvent eventData) {
using (var uow = UnitOfWorkManager.Begin(TransactionScopeOption.RequiresNew)) {
var t1 = HandleEntityes(_rep1, 10);
var t2 = HandleEntityes(_rep2, 10);
var t3 = HandleEntityes(_rep3, 10);
var t4 = HandleEntityes(_rep4, 1000);
Task.WaitAll(t1, t2, t3, t4);
}
}
}
[DependsOn(typeof(AbpEntityFrameworkModule))]
public class ProgrammModule : AbpModule
{
public override void PreInitialize() { Configuration.DefaultNameOrConnectionString = "Default"; }
public override void Initialize()
{
IocManager.RegisterAssemblyByConvention(Assembly.GetExecutingAssembly());
Database.SetInitializer<DBContext>(null);
}
}
class Program {
static void Main(string[] args) {
using (var bootstrapper = AbpBootstrapper.Create<ProgrammModule>()) {
bootstrapper.Initialize();
bootstrapper.IocManager.Resolve<IEventBus>().Trigger(new DomainStartEvent());
Console.ReadKey();
}
}
}
}
ActionBase, ActionA, ActionB and ActionC are Entities (from a database). ActionA, ActionB and ActionC are derived type of ActionBase.
ActionB and ActionC implements ISpecialAction with a SpecialProperty.
ex :
public interface ISpecialAction
{
Guid SpecialProperty { get; }
}
public partial class ActionBase
{
public objectX OnePropertyBase { get; set; }
}
public partial class ActionA : ActionBase
{
public objectY OnePropertyA { get; set; }
}
public partial class ActionB:ActionBase,ISpecialAction
{
public objectZ OnePropertyB { get; set; }
public Guid SpecialProperty
{
get
{
return OnePropertyB.ID;
}
}
}
public partial class ActionC : ActionBase ,ISpecialAction
{
public objectW OnePropertyC { get; set; }
public Guid SpecialProperty
{
get
{
return OnePropertyC.ID;
}
}
}
My problem is that SpecialProperty is build from other Properties of the objects (ActionB or ActionC) and when the cast (to ISpecialAction) is done, OtherProperty and OtherProperty2 are null.
I tried :
GetActionBase().ToList().Where(x=>x is ISpecialAction && ((dynamic) x).SpecialProperty== p_SpecialProperty);
GetActionBase().ToList().Where(x=>x is ISpecialAction && ((ISpecialAction) x).SpecialProperty== p_SpecialProperty);
GetActionBase().ToList().OfType<ISpecialAction>().Where(x => x.SpecialProperty== p_SpecialProperty).Cast<ActionBase>();
return GetActionOnGoing().ToList().OfType<ICityAction>().Cast<ActionBase>().Where(x => ((dynamic)x).CityId == p_CityId);
remark : OfType<> doesn't works with an Interface in Linq to entities but is ok in Linq to object
How do I access my property interface without knowing the type of the object?
I might missed something but this is Ok with the code you provided :
public class objectX
{
}
public class objectY
{
}
public class objectZ
{
public Guid ID { get { return Guid.NewGuid();} }
}
public class objectW
{
public Guid ID { get { return new Guid(); } }
}
class Program
{
private static Guid p_SpecialProperty;
static void Main(string[] args)
{
var result = GetActionBase().ToList().Where(x => x is ISpecialAction && ((dynamic)x).SpecialProperty == p_SpecialProperty).FirstOrDefault();
var result1 = GetActionBase().ToList().Where(x => x is ISpecialAction && ((ISpecialAction)x).SpecialProperty == p_SpecialProperty).FirstOrDefault();
var result2 = GetActionBase().ToList().OfType<ISpecialAction>().Where(x => x.SpecialProperty == p_SpecialProperty).Cast<ActionBase>().FirstOrDefault();
}
private static IEnumerable<ActionBase> GetActionBase()
{
return new List<ActionBase> {new ActionA{OnePropertyA= new objectY()}, new ActionB{OnePropertyB=new objectZ()},new ActionC{OnePropertyC=new objectW()} };
}
}
Not sure if I exactly understand your question, but could you try using an intermediate interface, such as:
public interface ISpecialActionB : ISpecialAction
{
objectZ OnePropertyB { get; set; }
}
public class ActionB : ActionBase, ISpecialActionB
{
//same stuff
}
and casting to that instead.
var b = new ActionB{OnePropertyB = new Whatever()};
var bAsSpecial = b as ISpecialActionB;
var whatever = b.OnePropertyB; // should not be null
It' ok.
Your example run very well without problem so I searched in a other way : AutoMapper.
l_List.Actions = Mapper.Map<List<ActionBase>, Action[]>(l_ActionManagement.GetActionBySpecialId(l_Special.ID).ToList());
The problem was not interfaces or Linq queries but it was that automapper need an empty constructor and in this constructor, I need to initialize OnePropertyB and OnePropertyC to compute SpecialProperty.
Thanks
inspired by this answer I'm trying to map a property on a model class to an expression based on the actual entity.
These are the two classes involved:
public class Customer
{
public string FirstName { get; set; }
public string LastName { get; set; }
public int Id { get; set; }
public DateTime? BirthDate { get; set; }
public int CustomerTypeId { get; set; }
}
public class CustomerModel
{
...
public bool HasEvenId { get; set; }
}
An example of a possible expression I'd like to convert is:
Expression<Func<CustomerModel, bool>> from = model => model.HasEvenId;
Expression<Func<Customer, bool>> to = entity => ((entity.Id % 2) == 0);
The problem is that I have to expose an OData endpoint via ASP.NET WebAPI but I need to make some operations on the entities before I can them, hence the need of a model class and the need to translate the expression based on the model that I could receive as an OData query in an expression based on the entity, that I would use to query EF4.
This is where I got so far:
private static readonly Dictionary<Expression, Expression> Mappings = GetMappings();
private static Dictionary<Expression, Expression> GetMappings()
{
var mappings = new Dictionary<Expression, Expression>();
var mapping = GetMappingFor((CustomerModel model) => model.HasEvenId, (Customer customer) => (customer.Id%2) == 0);
mappings.Add(mapping.Item1, mapping.Item2);
return mappings;
}
private static Tuple<Expression, Expression> GetMappingFor<TFrom, TTo, TValue>(Expression<Func<TFrom, TValue>> fromExpression, Expression<Func<TTo, TValue>> toExpression)
{
MemberExpression fromMemberExpression = (MemberExpression) fromExpression.Body;
return Tuple.Create<Expression, Expression>(fromMemberExpression, toExpression);
}
public static Expression<Func<TTo, bool>> Translate<TFrom, TTo>(Expression<Func<TFrom, bool>> expression, Dictionary<Expression, Expression> mappings = null)
{
if (expression == null)
return null;
string parameterName = expression.Parameters[0].Name;
parameterName = string.IsNullOrWhiteSpace(parameterName) ? "p" : parameterName;
var param = Expression.Parameter(typeof(TTo), parameterName);
var subst = new Dictionary<Expression, Expression> { { expression.Parameters[0], param } };
ParameterChangeVisitor parameterChange = new ParameterChangeVisitor(parameterName);
if (mappings != null)
foreach (var mapp in mappings)
subst.Add(mapp.Key, parameterChange.Visit(mapp.Value));
var visitor = new TypeChangeVisitor(typeof(TFrom), typeof(TTo), subst);
return Expression.Lambda<Func<TTo, bool>>(visitor.Visit(expression.Body), param);
}
public IQueryable<CustomerModel> Get()
{
var filterExtractor = new ODataFilterExtractor<CustomerModel>();
Expression<Func<CustomerModel, bool>> expression = filterExtractor.Extract(Request);
Expression<Func<Customer, bool>> translatedExpression = Translate<CustomerModel, Customer>(expression, Mappings);
IQueryable<Customer> query = _context.Customers;
if (translatedExpression != null)
query = query.Where(translatedExpression);
var finalQuery = from item in query.AsEnumerable()
select new CustomerModel()
{
FirstName = item.FirstName,
LastName = item.LastName,
Id = item.Id,
BirthDate = item.BirthDate,
CustomerTypeId = item.CustomerTypeId,
HasEvenId = (item.Id % 2 ) == 0
};
return finalQuery.AsQueryable();
}
where:
ODataFilterExtractor is a class that extract the $filter expression from the RequestMessage we receive;
ParameterChangeVisitor just changes all the ParameterExpression to a new one having the provided string as parameter name;
In addition, I changed the VisitMember method of the answer linked above in this way:
protected override Expression VisitMember(MemberExpression node)
{
// if we see x.Name on the old type, substitute for new type
if (node.Member.DeclaringType == _from)
{
MemberInfo toMember = _to.GetMember(node.Member.Name, node.Member.MemberType, BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic).SingleOrDefault();
if (toMember != null)
{
return Expression.MakeMemberAccess(Visit(node.Expression), toMember);
}
else
{
if (_substitutions.Select(kvp => kvp.Key).OfType<MemberExpression>().Any(me => me.Member.Equals(node.Member)))
{
MemberExpression key = _substitutions.Select(kvp => kvp.Key).OfType<MemberExpression>().Single(me => me.Member.Equals(node.Member));
Expression value = _substitutions[key];
// What to return here?
return Expression.Invoke(value);
}
}
}
return base.VisitMember(node);
}
Thanks for you help.
I took the liberty of modifying your code just a hair but this does the trick,
public class Customer
{
public string FirstName { get; set; }
public string LastName { get; set; }
public int Id { get; set; }
public DateTime? BirthDate { get; set; }
public int CustomerTypeId { get; set; }
}
public class CustomerModel
{
public string FullName { get; set; }
public bool HasEvenId { get; set; }
}
sealed class AToBConverter<TA, TB> : ExpressionVisitor
{
private readonly Dictionary<ParameterExpression, ParameterExpression> _parameters = new Dictionary<ParameterExpression, ParameterExpression>();
private readonly Dictionary<MemberInfo, LambdaExpression> _mappings;
protected override Expression VisitParameter(ParameterExpression node)
{
if (node.Type == typeof(TA))
{
ParameterExpression parameter;
if (!this._parameters.TryGetValue(node, out parameter))
{
this._parameters.Add(node, parameter = Expression.Parameter(typeof(TB), node.Name));
}
return parameter;
}
return node;
}
protected override Expression VisitMember(MemberExpression node)
{
if (node.Expression == null || node.Expression.Type != typeof(TA))
{
return base.VisitMember(node);
}
Expression expression = this.Visit(node.Expression);
if (expression.Type != typeof(TB))
{
throw new Exception("Whoops");
}
LambdaExpression lambdaExpression;
if (this._mappings.TryGetValue(node.Member, out lambdaExpression))
{
return new SimpleExpressionReplacer(lambdaExpression.Parameters.Single(), expression).Visit(lambdaExpression.Body);
}
return Expression.Property(
expression,
node.Member.Name
);
}
protected override Expression VisitLambda<T>(Expression<T> node)
{
return Expression.Lambda(
this.Visit(node.Body),
node.Parameters.Select(this.Visit).Cast<ParameterExpression>()
);
}
public AToBConverter(Dictionary<MemberInfo, LambdaExpression> mappings)
{
this._mappings = mappings;
}
}
sealed class SimpleExpressionReplacer : ExpressionVisitor
{
private readonly Expression _replacement;
private readonly Expression _toFind;
public override Expression Visit(Expression node)
{
return node == this._toFind ? this._replacement : base.Visit(node);
}
public SimpleExpressionReplacer(Expression toFind, Expression replacement)
{
this._toFind = toFind;
this._replacement = replacement;
}
}
class Program
{
private static Dictionary<MemberInfo, LambdaExpression> GetMappings()
{
var mappings = new Dictionary<MemberInfo, LambdaExpression>();
var mapping = GetMappingFor(model => model.HasEvenId, customer => (customer.Id % 2) == 0);
mappings.Add(mapping.Item1, mapping.Item2);
mapping = GetMappingFor(model => model.FullName, customer => customer.FirstName + " " + customer.LastName);
mappings.Add(mapping.Item1, mapping.Item2);
return mappings;
}
private static Tuple<MemberInfo, LambdaExpression> GetMappingFor<TValue>(Expression<Func<CustomerModel, TValue>> fromExpression, Expression<Func<Customer, TValue>> toExpression)
{
return Tuple.Create(((MemberExpression)fromExpression.Body).Member, (LambdaExpression)toExpression);
}
static void Main()
{
Expression<Func<CustomerModel, bool>> source = model => model.HasEvenId && model.FullName == "John Smith";
Expression<Func<Customer, bool>> desiredResult = model => (model.Id % 2) == 0 && (model.FirstName + " " + model.LastName) == "John Smith";
Expression output = new AToBConverter<CustomerModel, Customer>(GetMappings()).Visit(source);
Console.WriteLine("The two expressions do {0}match.", desiredResult.ToString() == output.ToString() ? null : "not ");
Console.ReadLine();
}
}
Another solution would be to use AutoMapper to map complex types and modify the resulting expression query with an ExpressionTransformer before it gets executed. I will try to explain with a complete sample:
Model classes
Some POCO classes just for holding data.
public enum CostUnitType
{
None = 0,
StockUnit = 1,
MachineUnit = 2,
MaintenanceUnit = 3
}
public class CostUnit
{
public string CostUnitId { get; set; }
public string WorkplaceId { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public CostUnitType Type { get; set; }
public override string ToString()
{
return CostUnitId + " " + Name + " " + Type;
}
}
public class StockUnit
{
public string Id { get; set; }
public string Name { get; set; }
}
public class MachineUnit
{
public string Id { get; set; }
public string Name { get; set; }
}
public class MaintenanceUnit
{
public string Id { get; set; }
public string Name { get; set; }
}
The ExpressionTransformer class
Most of the time, using the Mapper static class is fine, but sometimes you need to map the same types with different configurations, so you need to explicitly use an IMappingEngine like this:
var configuration = new ConfigurationStore(new TypeMapFactory(), MapperRegistry.Mappers);
var engine = new MappingEngine(configuration);
The way to create a MappingEngine is not obvious at all. I had to dig in the source code to find how it was done.
public static class ExpressionTransformer
{
private static readonly MappingEngine Mapper;
/// <summary>
/// Initializes the <see cref="ExpressionTransformer"/> class.
/// Creates an instance of AutoMapper. Initializes mappings.
/// </summary>
static ExpressionTransformer()
{
ConfigurationStore configurationStore = new ConfigurationStore(new TypeMapFactory(), MapperRegistry.Mappers);
// Create mapping
// Maps Id from StockUnit to CostUnitId from CostUnit
configurationStore.CreateMap<StockUnit, CostUnit>()
.ForMember(m => m.CostUnitId, opt => opt.MapFrom(src => src.Id));
// Maps Id from MachineUnit to CostUnitId from CostUnit
configurationStore.CreateMap<MachineUnit, CostUnit>()
.ForMember(m => m.CostUnitId, opt => opt.MapFrom(src => src.Id));
// Maps Id from MaintenanceUnit to CostUnitId from CostUnit
configurationStore.CreateMap<MaintenanceUnit, CostUnit>()
.ForMember(m => m.CostUnitId, opt => opt.MapFrom(src => src.Id));
// Create instance of AutoMapper
Mapper = new MappingEngine(configurationStore);
}
public static Expression<Func<TDestination, bool>> Tranform<TSource, TDestination>(Expression<Func<TSource, bool>> sourceExpression)
{
// Resolve mappings by AutoMapper for given types.
var map = Mapper.ConfigurationProvider.FindTypeMapFor(typeof(TSource), typeof(TDestination));
if (map == null)
{
throw new AutoMapperMappingException(string.Format("No Mapping found for {0} --> {1}.", typeof(TSource).Name, typeof(TDestination).Name));
}
// Transform from TSource to TDestination with specified mappings
var visitor = new ParameterTypeVisitor<TSource, TDestination>(sourceExpression, map.GetPropertyMaps());
var expression = visitor.Transform();
return expression;
}
private class ParameterTypeVisitor<TSource, TDestination> : ExpressionVisitor
{
private readonly Dictionary<string, ParameterExpression> _parameters;
private readonly Expression<Func<TSource, bool>> _expression;
private readonly IEnumerable<PropertyMap> _maps;
public ParameterTypeVisitor(Expression<Func<TSource, bool>> expression, IEnumerable<PropertyMap> maps)
{
_parameters = expression.Parameters
.ToDictionary(p => p.Name, p => Expression.Parameter(typeof(TDestination), p.Name));
_expression = expression;
_maps = maps;
}
public Expression<Func<TDestination, bool>> Transform()
{
return (Expression<Func<TDestination, bool>>) Visit(_expression);
}
protected override Expression VisitMember(MemberExpression node)
{
if (node.Member.DeclaringType == typeof(TSource))
{
var memberName = node.Member.Name;
var member = _maps.FirstOrDefault(p => typeof(TSource) == node.Expression.Type
&& p.SourceMember.Name == memberName);
if (member != null)
{
// Return Property from TDestination
var expression = Visit(node.Expression);
return Expression.MakeMemberAccess(expression, member.DestinationProperty.MemberInfo);
}
}
return base.VisitMember(node);
}
protected override Expression VisitParameter(ParameterExpression node)
{
var parameter = _parameters[node.Name];
return parameter;
}
protected override Expression VisitLambda<T>(Expression<T> node)
{
var expression = Visit(node.Body);
return Expression.Lambda(expression, _parameters.Select(x => x.Value));
}
}
}
Usage
To Convert an expression we just need to call Transform Method of ExpressionTransformer class
Expression<Func<StockUnit, bool>> stockQuery = unit => unit.Id == "0815" && unit.Name == "ABC";
// Call Transform<TSource, TDestination> method.
Expression<Func<CostUnit, bool>> costUnitQuery = ExpressionTransformer.Tranform<StockUnit, CostUnit>(stockQuery);
Result
I am trying to send some serialized data to the view and bind it to the knockout code. I am using json.net library for serialization because I want to pass the constants of an enum to the view ( and not the underlying integers.) I am not sure how my controller returning Json data should look like. Here is the sample code:
My view model that will be serialized:
public class FranchiseInfoViewModel
{
public string FolderName { get; set; }
[JsonConverter(typeof(StringEnumConverter))]
public LobbyTemplateOptions LobbyTemplate { get; set; }
public List<LobbyTemplateOptions> LobbyTemplates { get; set; }
public void Initialize()
{
FolderName = "Test";
LobbyTemplate = LobbyTemplateOptions.G;
LobbyTemplates = new List<LobbyTemplateOptions>
{
LobbyTemplateOptions.G,
LobbyTemplateOptions.H,
LobbyTemplateOptions.I
};
Enum:
[JsonConverter(typeof(StringEnumConverter))]
public enum LobbyTemplateOptions
{
G = 7,
H = 8,
I = 9
}
My knockout code:
$(function () {
omega.FranchiseInfo = (function () {
var FolderName = ko.observable();
var LobbyTemplates = ko.observableArray([]);
$.getJSON("FranchiseData", function (data) {
FolderName(data.FolderName);
for (var i = 0; i < data.LobbyTemplate.length; i++) {
LobbyTemplates.push(data.LobbyTemplate[i]);
}
});
return {
folderName: FolderName,
lobbyTemplates: LobbyTemplates
}
} ());
ko.applyBindings(omega.FranchiseInfo);
})
}
I am wondering how my controller that passes serialized Json data to the view should look like as I have not used json.net and I am relatively new to programming:
Controller passing the Json data to the view:
public JsonResult FranchiseData()
{
FranchiseInfoViewModel franchiseInfoViewModel = new FranchiseInfoViewModel();
franchiseInfoViewModel.MapFranchiseInfoToFranchiseInfoViewModel();
string json = JsonConvert.SerializeObject(franchiseInfoViewModel);
// this is how I do it with the default Json serializer
// return Json(franchiseInfoViewModel, JsonRequestBehavior.AllowGet);
}
I would be very gratefull if somebody can post a working example of my controller. Thank You!
You need to implement JsonNetResult.
public class JsonNetResult : ActionResult
{
public Encoding ContentEncoding { get; set; }
public string ContentType { get; set; }
public object Data { get; set; }
public JsonSerializerSettings SerializerSettings { get; set; }
public Formatting Formatting { get; set; }
public JsonNetResult()
{
SerializerSettings = new JsonSerializerSettings();
}
public override void ExecuteResult(ControllerContext context)
{
if (context == null)
throw new ArgumentNullException("context");
HttpResponseBase response = context.HttpContext.Response;
response.ContentType = !string.IsNullOrEmpty(ContentType)
? ContentType
: "application/json";
if (ContentEncoding != null)
response.ContentEncoding = ContentEncoding;
if (Data != null)
{
JsonTextWriter writer = new JsonTextWriter(response.Output) { Formatting = Formatting };
JsonSerializer serializer = JsonSerializer.Create(SerializerSettings);
serializer.Serialize(writer, Data);
writer.Flush();
}
}
}
To use it, in your case you need to rewrite controller method in this way:
public ActionResult FranchiseData()
{
FranchiseInfoViewModel franchiseInfoViewModel = new FranchiseInfoViewModel();
franchiseInfoViewModel.MapFranchiseInfoToFranchiseInfoViewModel();
JsonNetResult jsonNetResult = new JsonNetResult();
jsonNetResult.Formatting = Formatting.Indented;
jsonNetResult.Data = franchiseInfoViewModel;
return jsonNetResult;
}
(implementation of JsonNetResult above was taken this blog post
http://james.newtonking.com/archive/2008/10/16/asp-net-mvc-and-json-net.aspx )
I created a local db with helper app project. and deployed it from isolate storage to installation folder,i added to project directory with content build action by add existing item. my problem is that i want to insert data, but i don't know how to move the db file to isolate storage to insert and data must add to my .sdf file that is locate in my project directory also.
Souphia,
While learning to use WP, I wrote a simple application that tracked tasks.
One version of that app stored all task data in Sql on the phone.
You can read the post and download all the code for the app here:
http://www.ritzcovan.com/2012/02/building-a-simple-windows-phone-app-part-3/
But, here is some of the code from that project:
First we have the model class decorated with the appropriate attributes:
[Table]
public class Task : INotifyPropertyChanged, INotifyPropertyChanging
{
[Column(IsDbGenerated = false, IsPrimaryKey = true, CanBeNull = false)]
public string Id
{
get { return _id; }
set
{
NotifyPropertyChanging("Id");
_id = value;
NotifyPropertyChanging("Id");
}
}
[Column]
public string Name
{
get { return _name; }
set
{
NotifyPropertyChanging("Name");
_name = value;
NotifyPropertyChanged("Name");
}
}
[Column]
public string Category
{
get { return _category; }
set
{
NotifyPropertyChanging("Category");
_category = value;
NotifyPropertyChanged("Category");
}
}
[Column]
public DateTime? DueDate
{
get { return _dueDate; }
set
{
NotifyPropertyChanging("DueDate");
_dueDate = value;
NotifyPropertyChanged("DueDate");
}
}
[Column]
public DateTime? CreateDate
{
get { return _createDate; }
set
{
NotifyPropertyChanging("CreateDate");
_createDate = value;
NotifyPropertyChanged("CreateDate");
}
}
[Column]
public bool IsComplete
{
get { return _isComplete; }
set
{
NotifyPropertyChanging("IsComplete");
_isComplete = value;
NotifyPropertyChanged("IsComplete");
}
}
[Column(IsVersion = true)] private Binary _version;
private string _id;
private bool _isComplete;
private DateTime? _createDate;
private DateTime? _dueDate;
private string _name;
private string _category;
public event PropertyChangedEventHandler PropertyChanged;
public event PropertyChangingEventHandler PropertyChanging;
public void NotifyPropertyChanged(string property)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(property));
}
public void NotifyPropertyChanging(string property)
{
if (PropertyChanging != null)
PropertyChanging(this, new PropertyChangingEventArgs(property));
}
}
In the constructor in app.xaml.cs, I have the following:
TaskMasterDataContext = new TaskMasterDataContext();
if (!TaskMasterDataContext.DatabaseExists())
{
TaskMasterDataContext.CreateDatabase();
DatabaseHelper.SetupDatabase(TaskMasterDataContext);
}
and here is the TaskMasterDataContext.cs code
public class TaskMasterDataContext : DataContext
{
public TaskMasterDataContext() : base("Data Source=isostore:/TaskMasterData.sdf")
{
}
public Table<Task> Tasks;
}
public static class DatabaseHelper
{
public static void SetupDatabase(TaskMasterDataContext dataContext)
{
string category = string.Empty;
var tasks = new List<Task>();
for (int i = 0; i < 20; i++)
{
tasks.Add(new Task()
{
Id = System.Guid.NewGuid().ToString(),
Category = GetCategoryString(i),
CreateDate = DateTime.Now,
DueDate = DateTime.Now.AddDays(new Random().Next(1, 30)),
IsComplete = false,
Name = String.Format("{0} Task # {1}", GetCategoryString(i), i)
});
}
dataContext.Tasks.InsertAllOnSubmit(tasks);
dataContext.SubmitChanges();
}
private static string GetCategoryString(int i)
{
if (i%2 == 0)
return "home";
if (i%3 == 0)
return "personal";
return "work";
}
}
The DatabaseHelper class is just there to populate the DB with some test data after its created.
I hope this helps.