Created a WCF service and published in IIS. I tried to access this service in windows phone7 so i implement it by installing json.net from Nuget package. Got Serialization of json in correct format.But Deserialization of json fails in webClient_OpenReadCompleted method. I given my code template here
private void webClient_OpenReadCompleted(object sender, DownloadStringCompletedEventArgs e)
{
string s = e.Result.ToString();
Customer deserCustomers = JsonConvert.DeserializeObject<Customer>(s);
int id=deserCustomers.CustomerId;
string n = deserCustomers.CustomerName;
lstCustomer.ItemsSource = deserCustomers.ToString();
}
While reaching the below code got exception as follows:
Customer deserializedCustomers = JsonConvert.DeserializeObject(s);
An exception of type 'Newtonsoft.Json.JsonSerializationException' occurred in Newtonsoft.Json.DLL but was not handled in user code.
Give me suggestions to solve this error
Actually is quite simple , you should just make your class interface of a list, because your json is array something like:
public class Customer:List<object>
{
public int CustomerId{get; set;}
public string CustomerName{get; set;}
}
than everything is pretty basic
var deserCustomers = JsonConvert.DeserializeObject<Customer>(s);
foreach (var cust in deserCustomers)
{
....
}
hope it's work (:
Related
In an ASP.NET MVC web application, I have created the following entity:
[Table("tblEmployee")]
public class Employee
{
public int EmployeeId { get; set; }
public string Name { get; set; }
public string Gender { get; set; }
public string City { get; set; }
}
But, when I try to retrieve data from a database table called tblEmployee using Entity Framework, I get an error. What I have done until now is:
Created a database MVCDemo with "." as server name and using Windows authentication containing a table called tblEmployee
Installed Entity Framework
Added EmployeeContext.cs class file to Models folder
Code:
namespace MVCDemo.Models
{
public class EmployeeContext : DbContext
{
public DbSet<Employee> Employees { get; set; }
}
}
Added a connection string to web.config file in the root directory
<connectionSrtings>
<add name="EmployeeContext"
connectionString="server=.; database=MVCDemo; integrated security=SSPI"
providerName="System.Data.SqlClient;" />
</connectionSrtings>
Added Details actionResult to EmployeeController to show employee details:
namespace MVCDemo.Controllers
{
public class EmployeeController : Controller
{
// GET: Employee
public ActionResult Details(int id)
{
EmployeeContext employeeContext = new EmployeeContext();
Employee employee = employeeContext.Employees.Single(e => e.EmployeeId == id);
return View(employee);
}
}
}
Finally, I added the following code to Global.asax to prevent initialization:
Database.SetInitializer<MVCDemo.Models.EmployeeContext>(null);
The problem is when I run the application I get this error:
HTTP Error 500.19 - Internal Server Error
The requested page cannot be accessed because the related configuration data for the page is invalid.
and when I comment connection strings out and try to reach
http://localhost:60613/Employee/Details/1
to show details of 1st employee, I get this error:
System.Data.Entity.Core.EntityException: 'The underlying provider failed on Open.'SqlException: Cannot attach the file 'C:\Users\arya\source\repos\MVCDemo\MVCDemo\App_Data\MVCDemo.Models.EmployeeContext.mdf' as database 'MVCDemo.Models.EmployeeContext'.
Check your tag name, it is incorrect. It will trigger the error definitely.
<connectionSrtings>
It should be:
<connectionStrings>
Update:
Since you have another issue, fix the last part of your connection string:
providerName="System.Data.SqlClient;
Remove the semi-colon at the end of SqlClient.
This is because if you have the database named MVCDemo in the SQL Server then its fine, otherwise code first approach looking for MVCDemo database in SQL Server. If you dont have the database in SQL Server, then try this connection string to create the mdf file first.
connectionString="Data Source=(LocalDb)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\aspnet-MVCDemo-20200820010246.mdf;Initial Catalog=aspnet-MVCDemo-20200820010246;Integrated Security=True"
First of all, I couldn't see your database connection. Yes you have teached the table but you didn't tell the program where to put those infos. Something like:
optionsBuilder.UseSqlServer("Data Source=databaseName")
Second possible reason is your program don't know where to go at the beginning. I had those error before and solved it with using default map.
Third reason, this probably not true but, you wrote "connectionSrtings" wrong. As I say, it's probably not that but I wanted to mention if it is.
I am quite new to ASP .NET core, so please help. I would like to avoid database round trip for ASP .NET core application. I have functionality to dynamically add columns in datagrid. Columns settings (visibility, enable, width, caption) are stored in DB.
So I would like to store List<,PersonColumns> on server only for actual session. But I am not able to do this. I already use JsonConvert methods to serialize and deserialize objects to/from session. This works for List<,Int32> or objects with simple properties, but not for complex object with nested properties.
My object I want to store to session looks like this:
[Serializable]
public class PersonColumns
{
public Int64 PersonId { get; set; }
List<ViewPersonColumns> PersonCols { get; set; }
public PersonColumns(Int64 personId)
{
this.PersonId = personId;
}
public void LoadPersonColumns(dbContext dbContext)
{
LoadPersonColumns(dbContext, null);
}
public void LoadPersonColumns(dbContext dbContext, string code)
{
PersonCols = ViewPersonColumns.GetPersonColumns(dbContext, code, PersonId);
}
public static List<ViewPersonColumns> GetFormViewColumns(SatisDbContext dbContext, string code, Int64 formId, string viewName, Int64 personId)
{
var columns = ViewPersonColumns.GetPersonColumns(dbContext, code, personId);
return columns.Where(p => p.FormId == formId && p.ObjectName == viewName).ToList();
}
}
I would like to ask also if my approach is not bad to save the list of 600 records to session? Is it better to access DB and load columns each time user wants to display the grid?
Any advice appreciated
Thanks
EDIT: I have tested to store in session List<,ViewPersonColumns> and it is correctly saved. When I save object where the List<,ViewPersonColumns> is property, then only built-in types are saved, List property is null.
The object I want to save in session
[Serializable]
public class UserManagement
{
public String PersonUserName { get; set; }
public Int64 PersonId { get; set; }
public List<ViewPersonColumns> PersonColumns { get; set; } //not saved to session??
public UserManagement() { }
public UserManagement(DbContext dbContext, string userName)
{
var person = dbContext.Person.Single(p => p.UserName == userName);
PersonUserName = person.UserName;
PersonId = person.Id;
}
/*public void PrepareUserData(DbContext dbContext)
{
LoadPersonColumns(dbContext);
}*/
public void LoadPersonColumns(DbContext dbContext)
{
LoadPersonColumns(dbContext, null);
}
public void LoadPersonColumns(DbContext dbContext, string code)
{
PersonColumns = ViewPersonColumns.GetPersonColumns(dbContext, code, PersonId);
}
public List<ViewPersonColumns> GetFormViewColumns(Int64 formId, string viewName)
{
if (PersonColumns == null)
return null;
return PersonColumns.Where(p => p.FormId == formId && p.ObjectName == viewName).ToList();
}
}
Save columns to the session
UserManagement userManagement = new UserManagement(_context, user.UserName);
userManagement.LoadPersonColumns(_context);
HttpContext.Session.SetObject("ActualPersonContext", userManagement);
HttpContext.Session.SetObject("ActualPersonColumns", userManagement.PersonColumns);
Load columns from the session
//userManagement build-in types are set. The PersonColumns is null - not correct
UserManagement userManagement = session.GetObject<UserManagement>("ActualPersonContext");
//The cols is filled from session with 600 records - correct
List<ViewPersonColumns> cols = session.GetObject<List<ViewPersonColumns>>("ActualPersonColumns");
Use list for each column is better than use database.
you can't create and store sessions in .net core like .net framework 4.0
Try Like this
Startup.cs
public void ConfigureServices(IServiceCollection services)
{
//services.AddDbContext<GeneralDBContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
services.AddMvc().AddSessionStateTempDataProvider();
services.AddSession();
}
Common/SessionExtensions.cs
sing Microsoft.AspNetCore.Http;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
namespace IMAPApplication.Common
{
public static class SessionExtensions
{
public static T GetComplexData<T>(this ISession session, string key)
{
var data = session.GetString(key);
if (data == null)
{
return default(T);
}
return JsonConvert.DeserializeObject<T>(data);
}
public static void SetComplexData(this ISession session, string key, object value)
{
session.SetString(key, JsonConvert.SerializeObject(value));
}
}
}
Usage
==> Create Session*
public IActionResult Login([FromBody]LoginViewModel model)
{
LoggedUserVM user = GetUserDataById(model.userId);
//Create Session with complex object
HttpContext.Session.SetComplexData("loggerUser", user);
return Json(new { status = result.Status, message = result.Message });
}
==> Get Session data*
public IActionResult Index()
{
//Get Session data
LoggedUserVM loggedUser = HttpContext.Session.GetComplexData<LoggedUserVM>("loggerUser");
}
Hope this is helpful. Good luck.
This is an evergreen post, and even though Microsoft has recommended serialisation to store the object in session - it is not a correct solution unless your object is readonly, I have a blog explaining all scenario here and i have even pointed out the issues in GitHub of Asp.Net Core in issue id 18159
Synopsis of the problems are here:
A. Serialisation isn't same as object, true it will help in distributed server scenario but it comes with a caveat that Microsoft have failed to highlight - that it will work without any unpredictable failures only when the object is meant to be read and not to be written back.
B. If you were looking for a read-write object in the session, everytime you change the object that is read from the session after deserialisation - it needs to be written back to the session again by calling serialisation - and this alone can lead to multiple complexities as you will need to either keep track of the changes - or keep writing back to session after each change in any property. In one request to the server, you will have scenarios where the object is written back multiple times till the response is sent back.
C. For a read-write object in the session, even on a single server it will fail, as the actions of the user can trigger multiple rapid requests to the server and not more than often system will find itself in a situation where the object is being serialised or deserialised by one thread and being edited and then written back by another, the result is you will end up with overwriting the object state by threads - and even locks won't help you much since the object is not a real object but a temporary object created by deserialisation.
D. There are issues with serialising complex objects - it is not just a performance hit, it may even fail in certain scenario - especially if you have deeply nested objects that sometimes refer back to itself.
The synopsis of the solution is here, full implementation along with code is in the blog link:
First implement this as a Cache object, create one item in IMemoryCache for each unique session.
Keep the cache in sliding expiration mode, so that each time it is read it revives the expiry time - thereby keeping the objects in cache as long as the session is active.
Second point alone is not enough, you will need to implement heartbeat technique - triggering the call to session every T minus 1 min or so from the javascript. (This we anyways used to do even to keep the session alive till the user is working on the browser, so it won't be any different
Additional Recommendations
A. Make an object called SessionManager - so that all your code related to session read / write sits in one place.
B. Do not keep very high value for session time out - If you are implementing heartbeat technique, even 3 mins of session time out will be enough.
How do you map additional properties of an exception to your custom fault contract when using Enterprise Library 6's Exception Handling Application Block?
This article describes the FaultContractPropertyMapping the same way this one does. If you have a fault contract like so:
[DataContract]
public class SalaryCalculationFault
{
[DataMember]
public Guid FaultID { get; set; }
[DataMember]
public string FaultMessage { get; set; }
}
How do you add another property and map it to the original exception? Lets say I want to show the Stored Procedure name to the client using a new property:
[DataMember]
public string StoredProcedureName { get; set; }
I try editing the mapping shown on page 90 of the "Developer's Guide to Microsoft Enterprise Library-Preview.pdf" which can be found here but it does not seem to work. My new mapping looks like this:
var mappings = new NameValueCollection();
mappings.Add("FaultID", "{Guid}");
mappings.Add("FaultMessage", "{Message}");
mappings.Add("StoredProcedureName", "{Procedure}"); //SqlException has a Procedure property
And here is the policy.
var testPolicy = new List<ExceptionPolicyEntry>
{
{
new ExceptionPolicyEntry(typeof(SqlException),
PostHandlingAction.ThrowNewException,
new IExceptionHandler[]
{
new FaultContractExceptionHandler(typeof(SalaryCalculationFault), mappings)
})
}
};
var policies = new List<ExceptionPolicyDefinition>();
policies.Add(new ExceptionPolicyDefinition(
"TestPolicy", testPolicy));
exManager = new ExceptionManager(policies);
ExceptionPolicy.Reset();
ExceptionPolicy.SetExceptionManager(exManager);
When I do this and catch the FaultException on the client and inspect it, the StoredProcedureName is always empty. Why doesn't it map from the SqlException to the new property in my fault exception?
It turns out you shouldn't actually place the code you expect an exception for inside of the ExceptionManager.Processs() method. I was doing this before:
exManager.Process(() => wimDAL.Execute_NonQueryNoReturn(sc), "TestPolicy");
Insead, just execute the code as normal.
wimDAL.Execute_NonQueryNoReturn(sc);
This does not follow what the "Developer's Guide to Microsoft Enterprise Library-Preview.pdf" says but I guess the documentation is still a work in progress. I hope this helps someone else.
I'm using WCF custom Validator with HTTPS (.NET 4.5). Validate on success returns Customer object which I would like to use later. Currently I'm able to do it with Static variables which I like to avoid if possible. I tried to use HttpContext which becomes null in main thread. My understanding Validate runs under different thread. Is there any way I could share session info without involving DB or File share. See related threads here and here.
In Authentication.cs
public class CustomValidator : UserNamePasswordValidator
{
public override void Validate(string userName, string password)
{
//If User Valid then set Customer object
}
}
In Service.cs
public class Service
{
public string SaveData(string XML)
{
//Need Customer object here. Without it cannot save XML.
//HttpContext null here.
}
}
I can suggest you an alternative approach. Assuming that the WCF service is running in ASP.Net compatibility mode and you are saving the customer object to session storage. Create a class such as AppContext
The code would look something like this
public class AppContext {
public Customer CurrentCustomer {
get {
Customer cachedCustomerDetails = HttpContext.Current.Session[CUSTOMERSESSIONKEY] as Customer;
if (cachedCustomerDetails != null)
{
return cachedCustomerDetails;
}
else
{
lock (lockObject)
{
if (HttpContext.Current.Session[CUSTOMERSESSIONKEY] != null) //Thread double entry safeguard
{
return HttpContext.Current.Session[CUSTOMERSESSIONKEY] as Customer;
}
Customer CustomerDetails = ;//Load customer details based on Logged in user using HttpContext.Current.User.Identity.Name
if (CustomerDetails != null)
{
HttpContext.Current.Session[CUSTOMERSESSIONKEY] = CustomerDetails;
}
return CustomerDetails;
}
}
}
}
The basic idea here is to do lazy loading of data, when both WCF and ASP.Net pipelines have executed and HTTPContext is available.
Hope it helps.
Alright this should have been easier. Since the way UserNamePasswordValidator works, I needed to use custom Authorization to pass UserName/Password to the main thread and get customer info again from the database. This is an additional DB call but acceptable workaround for now. Please download code from Rory Primrose's genius blog entry.
I am having a minor problem with WCF service proxies where the message contains List<string> as a parameter.
I am using the 'Add Service reference' in Visual Studio to generate a reference to my service.
// portion of my web service message
public List<SubscribeInfo> Subscribe { get; set; }
public List<string> Unsubscribe { get; set; }
These are the generated properties on my MsgIn for one of my web methods.
You can see it used ArrayOfString when I am using List<string>, and the other takes List<SubscribeInfo> - which matches my original C# object above.
[System.Runtime.Serialization.DataMemberAttribute(EmitDefaultValue=false)]
public System.Collections.Generic.List<DataAccess.MailingListWSReference.SubscribeInfo> Subscribe {
get {
return this.SubscribeField;
}
set {
if ((object.ReferenceEquals(this.SubscribeField, value) != true)) {
this.SubscribeField = value;
this.RaisePropertyChanged("Subscribe");
}
}
}
[System.Runtime.Serialization.DataMemberAttribute(EmitDefaultValue=false)]
publicDataAccess.MailingListWSReference.ArrayOfString Unsubscribe {
get {
return this.UnsubscribeField;
}
set {
if ((object.ReferenceEquals(this.UnsubscribeField, value) != true)) {
this.UnsubscribeField = value;
this.RaisePropertyChanged("Unsubscribe");
}
}
}
The ArrayOfString class generated looks like this. This is a class generated in my code - its not a .NET class. It actually generated me a class that inherits from List, but didn't have the 'decency' to create me any constructors.
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.CodeDom.Compiler.GeneratedCodeAttribute("System.Runtime.Serialization", "3.0.0.0")]
[System.Runtime.Serialization.CollectionDataContractAttribute(Name="ArrayOfString", Namespace="http://www.example.com/", ItemName="string")]
[System.SerializableAttribute()]
public class ArrayOfString : System.Collections.Generic.List<string> {
}
The problem is that I often create my message like this :
client.UpdateMailingList(new UpdateMailingListMsgIn()
{
Email = model.Email,
Name = model.Name,
Source = Request.Url.ToString(),
Subscribe = subscribeTo.ToList(),
Unsubscribe = unsubscribeFrom.ToList()
});
I really like the clean look this gives me.
Now for the actual problem :
I cant assign a List<string> to the Unsubscribe property which is an ArrayOfString - even though it inherits from List. In fact I cant seem to find ANY way to assign it without extra statements.
I've tried the following :
new ArrayOfString(unsubscribeFrom.ToList()) - this constructor doesn't exist :-(
changing the type of the array used by the code generator - doesn't work - it always gives me ArrayOfString (!?)
try to cast List<string> to ArrayOfString - fails with 'unable to cast', even though it compiles just fine
create new ArrayOfString() and then AddRange(unsubscribeFrom.ToList()) - works, but I cant do it all in one statement
create a conversion function ToArrayOfString(List<string>), which works but isn't as clean as I want.
Its only doing this for string, which is annoying.
Am i missing something? Is there a way to tell it not to generate ArrayOfString - or some other trick to assign it ?
Any .NET object that implements a method named "Add" can be initialized just like arrays or dictionaries.
As ArrayOfString does implement an "Add" method, you can initialize it like this:
var a = new ArrayOfString { "string one", "string two" };
But, if you really want to initialize it based on another collection, you can write a extension method for that:
public static class U
{
public static T To<T>(this IEnumerable<string> strings)
where T : IList<string>, new()
{
var newList = new T();
foreach (var s in strings)
newList.Add(s);
return newList;
}
}
Usage:
client.UpdateMailingList(new UpdateMailingListMsgIn()
{
Email = model.Email,
Name = model.Name,
Source = Request.Url.ToString(),
Subscribe = subscribeTo.ToList(),
Unsubscribe = unsubscribeFrom.To<ArrayOfString>()
});
I prefer not to return generic types across a service boundary in the first place. Instead return Unsubscribe as a string[], and SubscriptionInfo as SubscriptionInfo[]. If necessary, an array can easily be converted to a generic list on the client, as follows:
Unsubscribe = new List<string>(unsubscribeFrom);
Subscribe = new List<SubscriptionInfo>(subscribeTo);
Too late but can help people in the future...
Use the svcutil and explicitly inform the command line util that you want the proxy class to be serialized by the XmlSerializer and not the DataContractSerializer (default). Here's the sample:
svcutil /out:c:\Path\Proxy.cs /config:c:\Path\Proxy.config /async /serializer:XmlSerializer /namespace:*,YourNamespace http://www.domain.com/service/serviceURL.asmx
Note that the web service is an ASP.NET web service ok?!
If you are using VS 2008 to consume service then there is an easy solution.
Click on the "Advanced..." button on the proxy dialog that is displayed when you add a Service Reference. In the Collection Type drop down you can select System.Generic.List. The methods returning List should now work properly.
(Hope this is what you were asking for, I'm a little tired and the question was a tad difficult for me to read.)