I can't seem to be able to read a custom enum attribute using the following code:
public class CustomAttribute : Attribute
{
public CultureAttribute (string value)
{
Value = value;
}
public string Value { get; private set; }
}
public enum EnumType
{
[Custom("value1")]
Value1,
[Custom("value2")]
Value2,
[Custom("value3")]
Value3
}
...
var memInfo = typeof(CustomAttribute).GetMember(EnumType.Value1.ToString());
// memInfo is always empty
var attributes = memInfo[0].GetCustomAttributes(typeof(CustomAttribute), false);
Not sure if I am just missing something obvious here or if there is an issue with reading custom attributes in Mono/MonoMac.
You should call the GetMember() on the type that has the given member of course :) In this case that's EnumType not CustomAttribute.
Also fixed what I assume to be copy-paste error with the attribute constructor.
Complete working test code (you should know with 23k reps that we prefer these to half-made programs that we have to complete ourselves ;)):
using System;
public class CustomAttribute : Attribute
{
public CustomAttribute (string value)
{
Value = value;
}
public string Value { get; private set; }
}
public enum EnumType
{
[Custom("value1")]
Value1,
[Custom("value2")]
Value2,
[Custom("value3")]
Value3
}
class MainClass
{
static void Main(string[] args)
{
var memInfo = typeof(EnumType).GetMember(EnumType.Value1.ToString());
Console.WriteLine("memInfo length is {0}", memInfo.Length);
var attributes = memInfo[0].GetCustomAttributes(typeof(CustomAttribute), false);
Console.WriteLine("attributes length is {0}", attributes.Length);
}
}
See in operation.
Related
I'm doing a little project for school where I try to do a spreadsheet program, and I have two classes, I will be simplifying this with pseudocode a little bit so it's not too messy.
class DocumentController {
Document doc // This is a class with a CRUD on a document (It haves
// Sheets and every Sheet haves a Table full of Cells)
Parser p
getValueOfCell (sheetName, positionX, positionY) {
returns value of a cell in a sheet in the position x,y
}
setCell (String expression, sheetName, positionX, positionY) {
//Somewhere here we need to use p.evaluate()
}
}
class Parser {
DocumentController docController;
evaluate (expression: String) {
//Somewhere here, I need to use method getCell from Document
// for evaluating the expression (The expressions have
// references to other cells so the Parser need to resolve
// these references)
...
return value of the expression (float, integer, string, whatever)
}
}
So apparently my teacher said to me that this is a bad design, because these classes are too coupled and this is a code smell. Can someone explain me why is this so bad? How can I make a better design?
Thank you, sorry if I made some typos or the code is not legible
I think you want something like:
Class Main{
public void main(){
DocumentController dc = new DocumentController();
//you can get ahold of the parser by
Parser p = dc.getParser();
}
}
Class Parser{
DocumentController dc;
public Parser(DocumentController dc){
this.dc = dc;
}
//your methods
}
Class DocumentController{
Parser p;
public DocumentController(){
this.p = new Parser(this);
}
public Parser getParser(){
return this.p;
}
//your methods
}
Although there are probably better ways of doing this instead like passing your object to the method when you need it. Something like
Class Main{
public void main(){
DocumentController dc = new DocumentController();
Parser p = new Parser();
p.myParserMethod(dc);
dc.myDocMethod(p);
}
}
Class Parser{
public myParserMethod(DocumentController dc){
//you can use the same documentController object here
}
}
Class DocumentController{
public myDocMethod(Parser p){
//you can use your parser object here
}
}
hope that helps
It looks like you want to format value by some key expression. If yes, then we can create mapping between this key expression and format classes. Then we can use Factory pattern to create desired objects to format your cell value.
Let me show a simple example via C#.
So this is a DocumentController:
public class DocumentController
{
private DocumentService _documentService;
public DocumentController()
{
_documentService = new DocumentService(); // this dependency can be
// resolved by IoC container
}
public void GetValueCell(int docId, string sheetName, int positionX,
int positionY)
{
_documentService.GetValueCell(docId, sheetName, positionX,
positionY);
}
public void SetCell(int docId, string expression, string sheetName, int
positionX, int positionY, object value)
{
_documentService.SetCell(docId, expression, sheetName, positionX,
positionY, value);
}
}
And this is a service which will execute logic related to Document:
public class DocumentService
{
private DocumentRepository _documentRepository;
public DocumentService()
{
_documentRepository = new DocumentRepository();
}
public string GetValueCell(int docId, string sheetName, int positionX, int positionY)
{
Document document = _documentRepository.GetById(docId);
return document.GetCellValue(sheetName, positionX, positionY);
}
public void SetCell(int docId, string expression, string sheetName, int
positionX, int positionY, object value)
{
Document document = _documentRepository.GetById(docId);
document.SetCellValue(expression, sheetName, positionX, positionY,
value);
}
}
It is unknown how you get Document, but it is possible to use repository pattern for that purpose.
public class DocumentRepository
{
public Document GetById(int id) { throw new NotImplementedException(); }
}
and this is a Document class:
public class Document
{
private object[][] _cells;
public Document(int x)
{
_cells = new object[x][];
}
public string GetCellValue(string sheetName, int positionX, int positionY)
{
return string.Empty;
}
public void SetCellValue(string expression, string sheetName, int
positionX, int positionY, object value)
{
FormatterType formatterType = new
FormatterTypeToExpression().FormatterByExpression[expression];
Formatter formatter = new FormatterFactory().
FormatterByFormatterType[formatterType];
object formattedCell = formatter.Format(value);
_cells[positionX][positionY] = formattedCell;
}
}
and this is a mapping between FormatterType and your key expression:
public class FormatterTypeToExpression
{
public Dictionary<string, FormatterType> FormatterByExpression { get; set; } =
new Dictionary<string, FormatterType>
{
{ "string", FormatterType.String}
// here you write expressions and foramtters
};
}
This is a formatter type:
public enum FormatterType
{
String, Number, Decimal, Whatever
}
Then you need something like factory to take a formatter:
public abstract class Formatter
{
public abstract object Format(object value);
}
And abstract class which will define behavior of derived formatter classes:
public class FormatterString : Formatter
{
public override object Format(object value)
{
return "I am a formatted string value";
}
}
An example how FormatterFactory could look like:
public class FormatterFactory
{
public Dictionary<FormatterType, Formatter> FormatterByFormatterType { get; set; }
= new Dictionary<FormatterType, Formatter>
{
{ FormatterType.String, new FormatterString()}
// here you write FormatterType and formatters
};
}
I have to send a request object via Refit which contains 2 IEnumerable and one string, but for some reason I can't send the object forward.
I've tried to use all the paramets from the interface. Ex: [Query(CollectionFormat.Csv)] or Multi / Pipes but no success.
I've also tried to create my own CustomUrlParameterFormatter but unfortunately here I'm stuck, because I don't see a good way to retrieve the name of the property from the object request that I'm sending.
The code for CustomUrlParameterFormatter
public class CustomUrlParameterFormatter : IUrlParameterFormatter
{
public string Format(object value, ParameterInfo parameterInfo)
{
if(value is IEnumerable enumerable)
{
var result = ToQueryString(enumerable, parameterInfo.Name);
return result;
}
return string.Empty;
}
public static string ToQueryString(IEnumerable query, string parameterName)
{
var values = query.Cast<object>().Select(ToString).ToArray();
var separator = parameterName + "=";
return values.Any() ? separator + string.Join("&" + separator, values) : "";
}
public static string ToString(object value)
{
var json = JsonConvert.SerializeObject(value).Replace("\\\"", "\"").Trim('"');
return Uri.EscapeUriString(json);
}
}
The Call from the IService that I'm using
[Get("/TestMethod")]
Task<HttpResponseMessage> TestMethod([Query]TestRequestDTO requestDTO, [Header("X-Correlation-ID")] string correlationId);
The Request object
public class TestRequestDTO
{
public IEnumerable<long> EnumOne { get; set; }
public IEnumerable<long> EnumTwo { get; set; }
public string MethodString { get; set; }
}
Also the RefitClient configuration
var refitSettings = new RefitSettings();
refitSettings.UrlParameterFormatter = new CustomUrlParameterFormatter();
services.AddRefitClient<IService>(refitSettings)
.ConfigureHttpClient(c => c.BaseAddress = new Uri(settings.Services.IService));
What I'm trying to achieve is something like
TestMethod?EnumOne =123&EnumOne =321&EnumTwo=123&EnumTwo=321&methodString=asdsaa
and instead I'm receiving other behavior
without CustomUrlParameterFormatter()
TestMethod?EnumOne=System.Collections.Generic.List`1%5BSystem.Int64%5D&EnumTwo=System.Collections.Generic.List`1%5BSystem.Int64%5D&MethodString=sdf
is there a way to map a DTO using MatStruct which have a few final data members as well and cannot have a default constructor , like :
public class TestDto {
private final String testName;
private int id;
private String testCase;
public TestDto(String testName) {
this.testName = testName;
}
public String getTestName() {
return testName;
}
public int getId() {
return id;
}
public String getTestCase() {
return testCase;
}
public void setId(int id) {
this.id = id;
}
public void setTestCase(String testCase) {
this.testCase = testCase;
}
}
please suggest how could this DTO be mapped using MapStruct.
You can use #ObjectFactory that would construct an instance of your DTO.
For example:
#Mapper
public interface MyMapper {
#ObjectFactory
default TestDto create() {
return new TestDto("My Test Name");
}
//the rest of the mappings
}
You can also enhance the #ObjectFactory to accept the source parameter, that you can use to construct the TestDto. You can even use a #Context as an Object Factory.
NB: You don't have to put the #ObjectFactory method in the same Mapper, or even a MapStruct #Mapper. You can put it in any class (or make it static) and then #Mapper(uses = MyFactory.class)
My complex type wouldn't pass from Show to Init method even with configured MvxJsonNavigationSerializer as specified here Custom types in Navigation parameters in v3
public class A
{
public string String1 {get;set;}
public string String2 {get;set;}
public B ComplexObject1 {get;set;}
}
public class B
{
public double Double1 {get;set;}
public double Double2 {get;set;}
}
When I pass instance of object A to ShowViewModel method I receive this object with String1 & String2 deserialized correctly but CopmlexObject1 is null.
How to deal with complex object MvvmCross serialization?
I believe there may be some gremlins in that previous answer - will log as an issue :/
There are other possible routes to achieve this type of complex serializable object navigation still using Json and overriding parts of the framework, but actually I think that it might be better to just use your own BaseViewModel's to do serialization and deserialization - e.g. use serialization code like:
public class BaseViewModel
: MvxViewModel
{
private const string ParameterName = "parameter";
protected void ShowViewModel<TViewModel>(object parameter)
where TViewModel : IMvxViewModel
{
var text = Mvx.Resolve<IMvxJsonConverter>().SerializeObject(parameter);
base.ShowViewModel<TViewModel>(new Dictionary<string, string>()
{
{ParameterName, text}
});
}
}
with deserialization like:
public abstract class BaseViewModel<TInit>
: MvxViewModel
{
public void Init(string parameter)
{
var deserialized = Mvx.Resolve<IMvxJsonConverter>().DeserializeObject<TInit>(parameter);
RealInit(deserialized);
}
protected abstract void RealInit(TInit parameter);
}
then a viewModel like this:
public class FirstViewModel
: BaseViewModel
{
public IMvxCommand Go
{
get
{
return new MvxCommand(() =>
{
var parameter = new A()
{
String1 = "Hello",
String2 = "World",
ComplexObject = new B()
{
Double1 = 42.0,
Double2 = -1
}
};
ShowViewModel<SecondViewModel>(parameter);
});
}
}
}
can navigate to something like:
public class SecondViewModel
: BaseViewModel<A>
{
public A A { get; set; }
protected override void RealInit(A parameter)
{
A = parameter;
}
}
A small addition to Stuart's answer to add type safety:
public class BaseViewModel: MvxViewModel {
protected bool ShowViewModel<TViewModel, TInit>(TInit parameter) where TViewModel: BaseViewModel<TInit> {
var text = Mvx.Resolve<IMvxJsonConverter>().SerializeObject(parameter);
return base.ShowViewModel<TViewModel>(new Dictionary<string, string> { {"parameter", text} });
}
}
public abstract class BaseViewModel<TInit> : BaseViewModel {
public void Init(string parameter)
{
var deserialized = Mvx.Resolve<IMvxJsonConverter>().DeserializeObject<TInit>(parameter);
RealInit(deserialized);
}
protected abstract void RealInit(TInit parameter);
}
ShowViewModel method now takes the same parameter type that the RealInit method instead of an object type. Also, BaseViewModel<TInit> inherits from BaseViewModel so their instances can also call the new ShowViewModel method.
The only drawback is that you have to explicitly specify the parameter type in the call like this:
ShowViewModel<StoreInfoViewModel, Store>(store);
In a ASP.NET Web API project, I've got a custom type with a TypeConverter that handles the to and from for string conversions, as described here:
http://blogs.msdn.com/b/jmstall/archive/2012/04/20/how-to-bind-to-custom-objects-in-action-signatures-in-mvc-webapi.aspx
The custom type is used as a property in my model and this works great. The json for my model object includes my custom object as the string value created from my TypeConverter.
So then I switch the request to accept XML instead and the TypeConverter is no longer invoked and my object is incorrectly serialized.
How to I get the XML serializer to utilize the TypeConverter as the JSON one does. The article referenced made it sound like the use of TypeConverters, when present, was a predictable feature. If it is completely at the whim of the serializer then making APIs that express data in both XML and JSON in a consistent way is nearly impossible.
Sample code from the article, plus a bit of context:
[TypeConverter(typeof(LocationTypeConverter))]
public class Location
{
public int X { get; set; }
public int Y { get; set; }
// Parse a string into a Location object. "1,2" --> Loc(X=1,Y=2)
public static Location TryParse(string input)
{
var parts = input.Split(',');
if (parts.Length != 2)
{
return null;
}
int x,y;
if (int.TryParse(parts[0], out x) && int.TryParse(parts[1], out y))
{
return new Location { X = x, Y = y };
}
return null;
}
public override string ToString()
{
return string.Format("{0},{1}", X, Y);
}
}
public class LocationTypeConverter : TypeConverter
{
public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
{
if (sourceType == typeof(string))
{
return true;
}
return base.CanConvertFrom(context, sourceType);
}
public override object ConvertFrom(ITypeDescriptorContext context,
System.Globalization.CultureInfo culture, object value)
{
if (value is string)
{
return Location.TryParse((string) value);
}
return base.ConvertFrom(context, culture, value);
}
}
Create a model with that class:
public class SampleModel
{
public int One { get; set;}
public string Two { get; set;}
public Location Three { get; set;}
}
Create a ApiController with a method like this:
public SampleModel Get()
{
return new SapleModel { One = 1, Two = "Two", Three = new Location { X = 111, Y = 222 } };
}
That's it. Using fiddler and try them both and note that Location serializes using the converter into the single-line comma-seperated format like this (Three="111,222") with Json but not with XML.