Develop Reference

How test if UseDeveloperExceptionPage middleware is been called in ASP.NET Core?

I'm situation really tricky. I need test if the UseDeveloperExceptionPage middleware is being called when an exception is thrown.
As an attempt to achieve that goal I wrote a bunch of ancillary code.
DiagnosticExceptionAssembly.cs
namespace TestProjectSample
{
internal static class DiagnosticExceptionAssembly
{
internal const string Assembly = "Microsoft.AspNetCore.Diagnostics.UnhandledException";
}
}
ExceptionMessage.cs
namespace TestProjectSample
{
public struct ExceptionMessage
{
public string Message { get; set; }
}
}
ExceptionMessageObserver.cs
using System;
namespace TestProjectSample
{
public class ExceptionMessageObserver : IExceptionMessage
{
public string Message { get; set; }
public void OnCompleted()
{
throw new NotImplementedException();
}
public void OnError(Exception error)
{
throw new NotImplementedException();
}
public void OnNext(ExceptionMessage value)
{
Message = value.Message;
}
}
public interface IExceptionMessage : IObserver<ExceptionMessage>
{
string Message { get; set; }
}
}
ExceptionObserver.cs
using System;
using System.Collections.Generic;
using System.Reflection;
namespace TestProjectSample
{
public class ExceptionObserver : IObserver<KeyValuePair<string, object>>
{
private readonly IObserver<ExceptionMessage> _exceptionMessage;
public ExceptionObserver(IObserver<ExceptionMessage> exceptionMessage)
{
_exceptionMessage = exceptionMessage;
}
public void OnCompleted()
{
throw new NotImplementedException();
}
public void OnError(Exception error)
{
throw new NotImplementedException();
}
public void OnNext(KeyValuePair<string, object> value)
{
switch (value.Key)
{
case DiagnosticExceptionAssembly.Assembly:
var exceptionPayload = value.Value
.GetType()
.GetTypeInfo()
.GetDeclaredProperty("Exception")?
.GetValue(value.Value) as string;
_exceptionMessage.OnNext(new ExceptionMessage {Message = exceptionPayload});
break;
}
}
}
}
ExceptionSubscriber.cs
using System;
using System.Diagnostics;
namespace TestProjectSample
{
public class ExceptionSubscriber : IObserver<DiagnosticListener>
{
private readonly IObserver<ExceptionMessage> _exceptionMessage;
public ExceptionSubscriber(IObserver<ExceptionMessage> exceptionMessage)
{
_exceptionMessage = exceptionMessage;
}
public void OnCompleted()
{
throw new NotImplementedException();
}
public void OnError(Exception error)
{
throw new NotImplementedException();
}
public void OnNext(DiagnosticListener value)
{
if (string.Equals(DiagnosticExceptionAssembly.Assembly, value.Name))
{
value.Subscribe(new ExceptionObserver(_exceptionMessage));
}
}
}
}
DevExceptionPageFacts.cs
using System.Diagnostics;
using System.Net;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.TestHost;
using Microsoft.Extensions.Hosting;
using Xunit;
namespace TestProjectSample
{
public class DevExceptionPageFacts
{
private readonly IHostBuilder _hostBuilder;
private static readonly IExceptionMessage ExceptionMessage = new ExceptionMessageObserver();
public DevExceptionPageFacts()
{
FactSubscriber();
_hostBuilder = GenerateExceptionHostBuilder();
}
private static IHostBuilder GenerateExceptionHostBuilder()
{
return new HostBuilder()
.ConfigureWebHost(builder =>
{
builder.UseTestServer();
builder.Configure(applicationBuilder =>
{
applicationBuilder.UseDeveloperExceptionPage();
applicationBuilder.Run(context => throw new HttpResetTestException(1));
});
});
}
private static void FactSubscriber()
{
DiagnosticListener.AllListeners.Subscribe(new ExceptionSubscriber(ExceptionMessage));
}
[Fact]
public async Task Throw_DevelopmentPageException()
{
var host = await _hostBuilder.StartAsync();
using var client = host.GetTestClient();
var response = await client.GetAsync("/");
Assert.Equal(HttpStatusCode.InternalServerError, response.StatusCode);
Assert.NotNull(ExceptionMessage.Message);
}
}
}
Investigating the source code of UseDeveloperExceptionPage I have noted an injection of DiagnosticSource so that I have decided create a class to listen to when an exception is thrown and caught by middleware. However my test does not pass. Could anyone know how to make this test pass?

Parameterless Constructor Using ObservableCollection in XAML

I have edited the question. Thanks for the comments below.
It looks like my issue was with a parameterless constructor to declare the class in XAML. However, I can't seem to figure out how to get a parameterless constructor with an observable collection. Please see my code below:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Xml.Serialization;
using System.ComponentModel;
using System.Collections.ObjectModel;
namespace LinkKing.Classes
{
[Serializable()]
public class TheLinks
{
public string linkID;
public string parentID;
public string link;
public DateTime dateAdded;
public int stepAdded;
public string img;
[System.Xml.Serialization.XmlElement("Link")]
public string Link
{
get { return link; }
set { link = value; }
}
[System.Xml.Serialization.XmlElement("DateAdded")]
public DateTime DateAdded
{
get { return dateAdded; }
set { dateAdded = value; }
}
[System.Xml.Serialization.XmlElement("StepAdded")]
public int StepAdded
{
get { return stepAdded; }
set { stepAdded = value; }
}
[System.Xml.Serialization.XmlElement("LinkID")]
public string LinkID
{
get { return linkID; }
set { linkID = value; }
}
[System.Xml.Serialization.XmlElement("ParentID")]
public string ParentID
{
get { return parentID; }
set { parentID = value; }
}
[System.Xml.Serialization.XmlElement("IMG")]
public string IMG
{
get { return img; }
set { img = value; }
}
public TheLinks(string linkID, string parentID, string link, DateTime dateAdded, int stepAdded, string img) : base()
{
this.Link = link;
this.DateAdded = dateAdded;
this.StepAdded = stepAdded;
this.LinkID = linkID;
this.ParentID = parentID;
this.IMG = img;
}
}
public class MyLinks : ObservableCollection<TheLinks>
{
public MyLinks() : base()
{
}
}
}
The error I get is The Type does not include any accessible constructors.
I appreciate everyone's help.

Just based on the code, you have no public parameterless constructor for MyLinks. If you did you would find it on local.
Also usually if it's MVVM, I think having a different namespace for the ViewModel would be better.
Maybe it would also make sense to make your fields (i.e. public string linkID;public string parentID; up to public string img;) private too since you don't access them from outside the class anyway.

Xamarin.Forms: How to have a Pie Chart using data from the Database?

I'm creating a Xamarin.Forms Portable Application wherein I was able to display a Pie Chart using OxyPlot. My chart only has pre-defined items. What I want to do is to make the items from my DATABASE in Visual Studio to be displayed on the Chart and not the pre-defined items.
I have 2 projects in one Solution. The WebFormsProject and the Xamarin.Forms (Portable)
In my WebFormsProject, I created a SalesController where I used LINQ expression to get all the data in the database that I need. I also created a SalesViewModel there where I have declared all the Properties I have. I tried to test it in my WEB API if it does return a value or not, and IT DOES RETURN A VALUE.
In my PORTABLE project, I have a created Sales model that has exactly the same Properties with my SalesViewModel in the WebFormsProject. I also have a SalesVM.cs wherein I tried to access the records from the WebFormsProject by using SalesServices and RestClient.
I have tried using these codes but it didn't work. What do you think is the reason behind this?
Here are my codes:
WebForms
1.) SalesViewModel.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace WebFormsDemo.ViewModel
{
public class SalesViewModel
{
public int Id { get; set; }
public int ORDER_ID { get; set; }
public int ORDER_DETAILS_ID { get; set; }
public int PRODUCT_ID { get; set; }
public string PRODUCT_CODE { get; set; }
public string NET_AMOUNT { get; set; }
}
}
2.) SalesController.cs
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http;
using System.Web.Http.Description;
using WebFormsDemo;
using WebFormsDemo.ViewModel;
namespace WebFormsDemo.Controllers
{
public class SalesController : ApiController
{
private EBMSEntities db = new EBMSEntities();
// GET: api/Sales
public IQueryable<SalesViewModel> GetSalesViewModels()
{
//return db.SalesViewModels;
var sales = from order in db.ORDERs
join order_detail in db.ORDER_DETAILS
on order.ORDER_ID equals order_detail.ORDER_ID
join prod in db.PRODUCTs
on order_detail.PRODUCT_ID equals prod.PRODUCT_ID
orderby order_detail.TOTAL_AMT_PER_ITEM descending
//group prod by prod.PRODUCT_CODE
group order_detail by prod.PRODUCT_CODE into od
select new SalesViewModel
{
PRODUCT_CODE = od.Key,
NET_AMOUNT = od.Sum(p => p.TOTAL_AMT_PER_ITEM).ToString(),
};
return sales;
}
// GET: api/Sales/5
[ResponseType(typeof(SalesViewModel))]
public IHttpActionResult GetSalesViewModel(int id)
{
SalesViewModel salesViewModel = db.SalesViewModels.Find(id);
if (salesViewModel == null)
{
return NotFound();
}
return Ok(salesViewModel);
}
// PUT: api/Sales/5
[ResponseType(typeof(void))]
public IHttpActionResult PutSalesViewModel(int id, SalesViewModel salesViewModel)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
if (id != salesViewModel.Id)
{
return BadRequest();
}
db.Entry(salesViewModel).State = EntityState.Modified;
try
{
db.SaveChanges();
}
catch (DbUpdateConcurrencyException)
{
if (!SalesViewModelExists(id))
{
return NotFound();
}
else
{
throw;
}
}
return StatusCode(HttpStatusCode.NoContent);
}
// POST: api/Sales
[ResponseType(typeof(SalesViewModel))]
public IHttpActionResult PostSalesViewModel(SalesViewModel salesViewModel)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
db.SalesViewModels.Add(salesViewModel);
db.SaveChanges();
return CreatedAtRoute("DefaultApi", new { id = salesViewModel.Id }, salesViewModel);
}
// DELETE: api/Sales/5
[ResponseType(typeof(SalesViewModel))]
public IHttpActionResult DeleteSalesViewModel(int id)
{
SalesViewModel salesViewModel = db.SalesViewModels.Find(id);
if (salesViewModel == null)
{
return NotFound();
}
db.SalesViewModels.Remove(salesViewModel);
db.SaveChanges();
return Ok(salesViewModel);
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
db.Dispose();
}
base.Dispose(disposing);
}
private bool SalesViewModelExists(int id)
{
return db.SalesViewModels.Count(e => e.Id == id) > 0;
}
}
}
.
XamarinFormsPortable
1.) Sales.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace XamarinFormsDemo.Models
{
public class Sales
{
public int Id { get; set; }
public int ORDER_ID { get; set; }
public int ORDER_DETAILS_ID { get; set; }
public int PRODUCT_ID { get; set; }
public string PRODUCT_CODE { get; set; }
public double NET_AMOUNT { get; set; }
}
}
2.) SalesVM.cs
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using OxyPlot;
using OxyPlot.Series;
using OxyPlot.Xamarin.Forms;
using Xamarin.Forms;
using System.Runtime.CompilerServices;
using XamarinFormsDemo.Models;
using System.Collections.ObjectModel;
using XamarinFormsDemo.Services;
namespace XamarinFormsDemo.ViewModels
{
public class SalesVM
{
private List<Sales> salesmodel { get; set; }
public List<Sales> SalesModelvm
{
get
{
return salesmodel;
}
set
{
salesmodel = value;
OnPropertyChanged();
}
}
public SalesVM()
{
InitializeDataAsync();
}
private async Task InitializeDataAsync()
{
var salesServices = new SalesServices();
SalesModelvm = await salesServices.GetSalesAsync();
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
var handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
3.) SalesServices.cs
using Plugin.RestClient;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using XamarinFormsDemo.Models;
namespace XamarinFormsDemo.Services
{
public class SalesServices
{
public async Task<List<Sales>> GetSalesAsync()
{
RestClient_Sales<Sales> restClient = new RestClient_Sales<Sales>();
var salesList = await restClient.GetSalesAsync();
return salesList;
}
}
}
4.) RestClient.cs
public class RestClient_Sales<T>
{
private const string WebServiceUrl = "http://localhost:50857/api/Sales/";
public async Task<List<T>> GetSalesAsync()
{
var httpClient = new HttpClient();
var json = await httpClient.GetStringAsync(WebServiceUrl);
var taskModels = JsonConvert.DeserializeObject<List<T>>(json);
return taskModels;
}
}

error when trying to add object to dictionary

I got a code with a list which im trying to change to dictionary. my problem its that in 'BankRates.cs' i fail to add objects to my dictionary. i get error :no overload of method 'Add' takes 1 argument...can some explain why?? (i understand i should add a string to the function but when i try to add empty one to make it compile, the dictionary contains only one nonfunctional object)
i have this 4 cs files:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Converter
{
class Currency
{
//members
//getters and setters
public string Code { get; set; }
public string Name { get; set; }
public double Rate { get; set; }
public double Unit { get; set; }
public string Country { get; set; }
//constractor
public Currency(string code, string name, double rate, double unit, string country)
{
this.Code = code;
this.Name = name;
this.Rate = rate;
this.Unit = unit;
this.Country = country;
}
//override ToString method for visualization
public override string ToString()
{
return (Name + "-" +Code);
}
}
}
currencyDictionary:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Converter
{
class CurrencyDic
{
//setter and getter
public Dictionary<string,Currency> currencyDic { get; set; }
//constractor
public CurrencyDic()
{
currencyDic = new Dictionary<string,Currency>();
}
public CurrencyDic(Dictionary<string,Currency> cur)
{
currencyDic = new Dictionary<string,Currency>(cur);
}
// implements foreach
public IEnumerator<Currency> GetEnumerator()
{
foreach (Currency cur in currencyDic.Values) { yield return cur;}
}
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Converter
{
interface IBankRates
{
void GetRates();
double Convert(Currency from, Currency to, double amount);
}
}
and the last one:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.IO;
using System.Threading.Tasks;
using System.Xml;
using System.Xml.Linq;
using System.Runtime.Remoting.Messaging;
namespace Converter
{
class BankRates:IBankRates
{
private string Bank_URL = "http://www.boi.org.il/currency.xml";
CurrencyDic currencyDic = new CurrencyDic();
public void GetRates()
{
XDocument xdoc = new XDocument();
try
{
xdoc = XDocument.Load(Bank_URL);}
catch (XmlException)
{
MessageBox.Show("Failed to load Xml file");
System.Environment.Exit(1);
}
//load the xml
var allCurencies = from currency in xdoc.Descendants("CURRENCY") //linq query
select new
{
Name = currency.Descendants("NAME").First().Value,
Unit = currency.Descendants("UNIT").First().Value,
Code = currency.Descendants("CURRENCYCODE").First().Value,
Cuntry = currency.Descendants("COUNTRY").First().Value,
Rate = currency.Descendants("RATE").First().Value
};
foreach (var currency in allCurencies)
{
currencyDic.currencyDic.Add(new Currency(currency.Code, currency.Name,
double.Parse(currency.Rate),
double.Parse(currency.Unit), currency.Cuntry));
}
}
//returns the list
public CurrencyDic getDic()
{
return currencyDic;
}
//makes the converting calculation
public double Convert(Currency from,Currency to, double amount)
{
double inRate, outRate, excangeRate;
inRate = from.Rate / from.Unit;
outRate = to.Rate / to.Unit;
excangeRate = inRate / outRate;
return (amount * excangeRate);
}
}
}

Handcrafted Strongly Typed ADO.net DataTable - Can it be cleaner?

I have recently come across a very simple Typed DataTable (without using a .XSD)(I've lost author's URL so I can't credit him) but it looks like there's a lot of duplicated code (Such as the Add/Remove/GetNewRow methods).
I've tried to push the repetitive methods into a super class, but I have issues due to the Employee needing to be generic. I was hoping to get StackOverflow's collective hive mind to suggest some ideas to clean this up? (If it's even possible at all?)
using System;
using System.Data;
using System.Collections;
using System.Data.SqlClient;
namespace TypedDataSet {
public class Employees : DataTable {
protected SqlDataAdapter _adapter;
public Employees() {
string connectionString = TypedDataSet.Properties.Settings.Default.ConnectionString;
_adapter = new System.Data.SqlClient.SqlDataAdapter("SELECT Id, Firstname, Surname FROM Employee", connectionString);
_adapter.Fill(this);
}
public Employee this[int index] {
get { return (Employee)Rows[index]; }
}
public void Add(Employee row) {
Rows.Add(row);
}
public void Remove(Employee row) {
Rows.Remove(row);
}
public Employee GetNewRow() {
Employee row = (Employee)NewRow();
return row;
}
protected override DataRow NewRowFromBuilder(DataRowBuilder builder) {
return new Employee(builder);
}
public IEnumerator GetEnumerator() {
return Rows.GetEnumerator();
}
protected override Type GetRowType() {
return typeof(Employee);
}
}
public class Employee : DataRow {
internal Employee(DataRowBuilder builder)
: base(builder) {
}
public Int64 Id {
get { return (Int64)base["Id"]; }
set { base["Id"] = value; }
}
public string FirstName {
get { return (string)base["Firstname"]; }
set { base["Firstname"] = value; }
}
public string Surname {
get { return (string)base["Surname"]; }
set { base["Surname"] = value; }
}
}
}

I believe that I've answered my question, kind of. I've had to use .net 4.0 to get the results that I was hoping for specificially the dynamic type.
So changing the existing class in the question:
Employee.cs
using System;
using System.Data;
using System.Collections;
using System.Data.Common;
namespace TypedDataSet {
public class Employees : BaseModel<Employee> {
public Employees(bool loadAll) {
DbDataAdapter adapter = base.Adapter("SELECT * FROM Employees");
adapter.Fill(this);
}
protected override DataRow NewRowFromBuilder(DataRowBuilder builder) {
return new Employee(builder);
}
}
public class Employee : DataRow {
internal Employee(DataRowBuilder builder)
: base(builder) {
}
public Int64 Id {
get { return (Int64)base["Id"]; }
set { base["Id"] = value; }
}
public string FirstName {
get { return (string)base["Firstname"]; }
set { base["Firstname"] = value; }
}
public string Surname {
get { return (string)base["Surname"]; }
set { base["Surname"] = value; }
}
}
}
And now introducing BaseModel that the above class inherits
BaseModel.cs
using System;
using System.Data;
using System.Collections;
using System.Data.Common;
using System.Data.SqlClient;
namespace TypedDataSet {
public class BaseModel<T> : DataTable {
protected DbDataAdapter _adapter;
protected string _connectionString = TypedDataSet.Properties.Settings.Default.ConnectionString;
public BaseModel() {
}
protected DbDataAdapter Adapter(string sql) {
_adapter = new System.Data.SqlClient.SqlDataAdapter(sql, _connectionString);
SqlCommandBuilder cb = new SqlCommandBuilder((SqlDataAdapter)_adapter);
return _adapter;
}
public dynamic this[int index] {
get { return Rows[index]; }
}
public void Add(dynamic row) {
Rows.Add(row);
}
public void Remove(dynamic row) {
Rows.Remove(row);
}
public void Save() {
_adapter.Update(this);
this.AcceptChanges();
}
public dynamic GetNewRow() {
dynamic row = (dynamic)NewRow();
return row;
}
public IEnumerator GetEnumerator() {
return Rows.GetEnumerator();
}
protected override Type GetRowType() {
return typeof(T);
}
}
}
Which allows me to consume the class using the following code:
Employees employees = new Employees(true);
Employee employee = employees.GetNewRow();
employee.FirstName = "Greg";
employee.Surname = "Focker";
employees.Add(employee);
employees.Save();
foreach (Employee e in employees) {
Console.WriteLine(e.FirstName + ' ' + e.Surname);
}
I hope to evolve this further overtime so future StackOverflow users if you're interested in this little project take a look at http://bitbucket.org/Mozketo/typeddataset/ where I hope to host the code.