I have 2 methods.
Method 1 calls a google drive service which returns an array of an object of files.
Method 2 calls the first method to get the returned list, which calls the google drive service which activates the method you see below for a "second" time.
I may be wrong but I think the recursion is causing my final list results to be doubled. Or it may be because I have declared files outside of this method. Once the line files.AddRange(....) is called by the second method it technically already contains the files from the first method. I am not quite sure how to solve my issue.
readonly Stack myStack = new Stack();
readonly HashSet<BFile> files = new Hashset<BFile>();
readonly HashSet<BFile> pushedList = new HashSet<BFile>();
public async Task<(BFile[]? files, string? error)> GetFiles(string parentId, bool includePermissions)
{
var service = service..
if (service != null)
{
var listRequest = service.Files.List();
do
{
var response = await listRequest.ExecuteAsync();
var folders = response.Files.Where(f => f.MimeType == "application/vnd.google-apps.folder");
var allOtherFiles = response.Files.Where(f => f.MimeType != "application/vnd.google-apps.folder");
files.AddRange(folders.Where(f => f.Name != "$ExclaimerSignatures").Select(f => mapFile(f)));
files.AddRange(allOtherFiles.Select(f => mapFile(f)));
var missingFiles = files.Where(f => !pushedList.Contains(f)).ToList();
missingFiles.ForEach(myStack.Push);
pushedList.UnionWith(missingFiles);
while (myStack.Count != 0)
{
var temp = (BFile)myStack.Peek();
myStack.Pop();
await GetFiles(temp.Id, true);
}
listRequest.PageToken = response.NextPageToken;
} while (listRequest.PageToken != null);
return (files.ToArray(), null);
}
else
return (null, "Something went wrong");
}
edit: to answer a question from below the only reason why I have stack with recursion tree walking is I use the stack to keep track of stuff that has been visited. I am not sure if that is bad or not, it was just simply what I came up with upon initially writing this code
I think the issue is that HashSet is not determinating BFiles like unique, and it is a reason why HashSet<BFile> files have duplicated values.
To fix it, you can override Equals and GetHashCode in your class BFile. If BFile is not your class, check if maybe it has already it implemented. If not, you can do it with the IEqualityComparer interface. Here is a simple example:
var files = new HashSet<BFile>(new Comparer());
var items = Enumerable.Empty<BFile>(); //Can be any collection
files.UnionWith(items);
class Comparer : EqualityComparer<BFile>
{
public override bool Equals(BFile? x, BFile? y) => x.Id == y.Id;
public override int GetHashCode(BFile obj) => obj.Id.GetHashCode();
}
class BFile
{
public string Id { get; set; }
public string Name { get; set; }
public byte[] Content { get; set; }
}
I hope it will help you.
Related
I actually asked a very similar question recently, but while the title mentioned classes, my content mostly referred to a tuple, and the (really great) answer reflected that. When I've tried to substitute a class in for the tuple, I get TargetParameterCountException: Parameter count mismatch. exception.
How can I get NHibernate to map to a Tuple or Class?
I have the following method to get a list of results from the database.
public static IList<T> Find<T>(DetachedCriteria crit) where T : class
{
lock (_locker)
{
return crit.GetExecutableCriteria(InstanceSession)
.List<T>();
}
}
This generally works well. However, I've changed a method that calls the method above from.
public IList<FooBarResult> FindResults(FooBarTask st)
{
return DataAccess.Find<FooBarResult>(DetachedCriteria.For<FooBarResult>()
.Add(Restrictions.Eq("Task", st))).ToList();
}
Which works, to this (as I don't want to return the whole of FooBarResult, just certain columns on it).
public IList<MyCustomClass> FindResults(FooBarTask st)
{
var typeConstructor = typeof(MyCustomClass).GetConstructors()[0];
return DataAccess.Find<MyCustomClass>(DetachedCriteria.For<FooBarResult>()
.Add(Restrictions.Eq("Task", st))
.SetProjection(
Projections.ProjectionList()
.Add(
Projections.Property("FieldOne") //this is a DateTime
)
.Add(
Projections.Property("FieldTwo") //this is a Guid
)
.SetResultTransformer(Transformers.AliasToBeanConstructor(typeConstructor))
)
);
}
And this is the class.
public class MyCustomClass
{
public MyCustomClass()
{
//placeholder
}
public MyCustomClass(DateTime FieldOne, Guid FieldTwo)
{
this.FieldOne = FieldOne;
this.FieldTwo = FieldTwo;
}
public DateTime FieldOne { get; set; }
public Guid FieldTwo { get; set; }
}
As mentioned earlier, when running the return crit.GetExecutableCriteria(InstanceSession).List<T>(); code I get a TargetParameterCountException: Parameter count mismatch. exception.
Is there any way I can make it return a list of my MyCustomClass?
I have not tested this, but you should use Transformers.AliasToBean take a look in to the aliases to let the transformer work:
public IList<MyCustomClass> FindResults(FooBarTask st)
{
var typeConstructor = typeof(MyCustomClass).GetConstructors()[0];
return DataAccess.Find<MyCustomClass>(DetachedCriteria.For<FooBarResult>()
.Add(Restrictions.Eq("Task", st))
.SetProjection(
Projections.ProjectionList()
.Add(Projections.Property("FieldOne"), "FieldOne")
.Add(Projections.Property("FieldTwo"), "FieldTwo")
)
.SetResultTransformer(Transformers.AliasToBean(typeof(MyCustomClass)))
.List<MyCustomClass>()
}
In this line:
var typeConstructor = typeof(MyCustomClass).GetConstructors()[0];
you will get the first, default constructor and its signature obviously doesn't match. The simplest fix for your case is:
var typeConstructor = typeof(MyCustomClass).GetConstructors()[1];
But the cleanest solution would be something along these lines (untested and also a bit simplified):
var typeConstructor = GetMatchingConstructorOrThrow<MyCustomClass>
(typeof(DateTime), typeof(Guid));
// ...
private ConstructorInfo GetMatchingConstructorOrThrow<T>(params Type[] requiredSignature)
where T : class
{
foreach (var c in typeof(T).GetConstructors())
{
var currentSignature = c.GetParameters().Select(p => p.ParameterType);
if (currentSignature.SequenceEqual(requiredSignature))
{
return c;
}
}
throw new NoMatchingConstructorFoundException();
}
Could some one please help me to resolved this? i'm trying to change CustomAsync to MustAsync, but i couldn't make things to work. Below is my custom method
RuleFor(o => o).MustAsync(o => {
return CheckIdNumberAlreadyExist(o)
});
private static async Task<ValidationFailure> CheckIdNumberAlreadyExist(SaveProxyCommand command)
{
if (command.Id > 0)
return null;
using (IDbConnection connection = new SqlConnection(ConnectionSettings.LicensingConnectionString))
{
var param = new DynamicParameters();
param.Add("#idnumber", command.IdNumber);
var vehicle = await connection.QueryFirstOrDefaultAsync<dynamic>("new_checkDuplicateProxyIdNumber", param, commandType: CommandType.StoredProcedure);
return vehicle != null
? new ValidationFailure("IdNumber", "Id Number Already Exist")
: null;
}
}
To make it work with the latest version of the FluentValidation, I had to use the codes like below.
RuleFor(ws => ws).MustAsync((x, cancellation) => UserHasAccess(x)).WithMessage("User doesn't have access to perform this action");
Please notice the lambda expression here MustAsync((x, cancellation) => UserHasAccess(x)), without this I was always getting an error as cannot convert from 'method group' to 'Func<Worksheet, CancellationToken, Task<bool>>
Below is my custom UserHasAccess function.
private async Task <bool> UserHasAccess(Worksheet worksheet) {
var permissionObject = await _dataProviderService.GetItemAsync(worksheet.FileItemId);
if (permissionObject is null) return false;
if (EditAccess(permissionObject.Permission)) return true;
return false;
}
I'm assuming you're using a version of FluentValidation prior to version 6, as you're not passing in a Continuation Token, so I've based my answer on version 5.6.2.
Your example code does not compile, for starters, as you're missing a semi-colon in your actual rule. You are also evaluating two different properties on the SaveProxyCommand parameter.
I've built a very small POC based on some assumptions:
Given 2 classes:
public class SaveProxyCommand {
public int Id { get; set; }
}
public class ValidationFailure {
public string PropertyName { get; }
public string Message { get; }
public ValidationFailure(string propertyName, string message){
Message = message;
PropertyName = propertyName;
}
}
And a validator:
public class SaveProxyCommandValidator : AbstractValidator<SaveProxyCommand>{
public SaveProxyCommandValidator()
{
RuleFor(o => o).MustAsync(CheckIdNumberAlreadyExists)
.WithName("Id")
.WithState(o => new ValidationFailure(nameof(o.IdNumber), "Id Number Already Exist"));
}
private static async Task<bool> CheckIdNumberAlreadyExists(SaveProxyCommand command) {
if (command.Id > 0)
return true;
var existingIdNumbers = new[] {
1, 2, 3, 4
};
// This is a fudge, but you'd make your db call here
var isNewNumber = !(await Task.FromResult(existingIdNumbers.Contains(command.IdNumber)));
return isNewNumber;
}
}
I didn't include the call to the database, as that's not part of your problem. There are a couple of things of note here:
You're not setting the .WithName annotation method, but when you're setting up a validation rule for an object you have to do this, as FluentValidation expects you to specify specific properties to be validated by default, if you pass in an entire object it just doesn't know how to report errors back.
Must/MustAsync need to return a bool/Task<bool> instead of a custom object. To get around this, you can specify a custom state to be returned when failing validation.
You can then get access to this like this:
var sut = new SaveProxyCommand { Id = 0, IdNumber = 3 };
var validator = new SaveProxyCommandValidator();
var result = validator.ValidateAsync(sut).GetAwaiter().GetResult();
var ValidationFailures = result.Errors?.Select(s => s.CustomState).Cast<ValidationFailure>();
The above does not take into account empty collections, it's just an example of how to dig into the object graph to retrieve custom state.
As a suggestion, fluentvalidation works best if you set up individual rules per property, instead of validating the entire object. My take on this would be something like this:
public class SaveProxyCommandValidator : AbstractValidator<SaveProxyCommand>{
public SaveProxyCommandValidator()
{
RuleFor(o => o.IdNumber).MustAsync(CheckIdNumberAlreadyExists)
.Unless(o => o.Id > 0)
.WithState(o => new ValidationFailure(nameof(o.IdNumber), "Id Number Already Exist"));
}
private static async Task<bool> CheckIdNumberAlreadyExists(int numberToEvaluate) {
var existingIdNumbers = new[] {
1, 2, 3, 4
};
// This is a fudge, but you'd make your db call here
var isNewNumber = !(await Task.FromResult(existingIdNumbers.Contains(numberToEvaluate)));
return isNewNumber;
}
}
This read more like a narrative, it uses the .Unless construct to only run the rule if Id is not more than 0, and does not require the evaluation of the entire object.
I have two lists which I need to compare (carOptions and custOptions).
Both of these lists are in my Customer class like below:
public class CustomerDTO
{
public int CustomerId { get; set; }
//other props removed for brevity
public List<OptionDTO> SelectedCarOptions { get; set; }
public List<OptionDTO> SelectedCustomerOptions { get; set; }
}
var existingData = _myRepository.GetDataByCustomer(customerId, year);
var existingCarOptions = existingData.Select(f => f.SelectedCarOptions);
var existingCustomerOptions = existingData.Select(f => f.SelectedCustomerOptions);
existingData is an IEnumerable of CustomerDTO and then existingCarOptions and existingCustomerOptions is an IEnumerable<List<OptionDTO>>
In the method, I have a list of IEnumerable<OptionDTO> options that gets passed in. I then break this down into car or customer based on the Enum as below:
var newCarOptions = options.Where(o => o.OptionTypeID == OptionType.CarOptions);
var newCustomerOptions = options.Where(o => o.OptionTypeID == OptionType.CustomerOptions).ToList();
What I need to do is find which options are in one collection but no in the other.
I tried as below but getting an Error on the Except (I maybe need to create my own static method in that class) but I am not sure this is the best approach really?
if (existingCarOptions.Count() != newCarOptions.Count())
{
//var test = newCarOptions.Except(existingCarOptions);
}
if (existingCustomerOptions.Count() != newCustomerOptions.Count())
{
//var test2 = newCustomerOptions.Except(existingCustomerOptions);
}
Is it also quite a bit of code in the method - I could split it out into sperate methods if required but perhaps there is a simpler way I could achieve this?
I'm assuming OptionDTO has a property called Id, which uniquely identifies an option (you have to change the code accordingly if this is not the case), you may use HashSets to quickly find unmatched OptionsDTOs, while keeping the overall time cost O(n) (where n is the max number of combined options).
Create the existing options sets:
var existingCarOptions = existingData.SelectMany(d => d.SelectedCarOptions).Select(o => o.Id);
var existingCustomerOptions = existingData.SelectMany(d => d.SelectedCustomerOptions).Select(o => o.Id);
var existingCarOptionsIds = new HashSet<int>(existingCarOptions);
var existingCustomerOptionsIds = new HashSet<int>(existingCustomerOptions );
Then you extract options missing in existing sets with:
var unmatchedCarOptions = newCarOptions.Where(o => !existingCarOptionsIds.Contains(o.Id));
var unmatchedCustomerOptions = newCustomerOptions.Where(o => !existingCustomerOptionsIds.Contains(o.Id));
If you want to compare two classes you can use IEqualityComparer
public class OptionComparer : IEqualityComparer<OptionDTO>
{
public bool Equals(OptionDTO x, OptionDTO y)
{
if (object.ReferenceEquals(x, y))
{
return true;
}
if (object.ReferenceEquals(x, null) ||
object.ReferenceEquals(y, null))
{
return false;
}
return x.OptionTypeID == y.OptionTypeID ;
}
public int GetHashCode(OptionDTO obj)
{
if (obj == null)
{
return 0;
}
return obj.OptionTypeID.GetHashCode();
}
With using this you can ıdentify that What is the concept of equality for these classes.
Now we can find different values..
public List<OptionDTO>CalculateDiffBetweenLists(List<OptionDTO> left, List<OptionDTO> right){
List<OptionDTO> optionDiff;
optionDiff = left.Except(right, new OptionComparer ()).ToList();
return optionDiff ;
}
I have stumbled upon a riddle which I can't explain, maybe someone here will be able to.
Here is a (rather lengthy but complete) code snippet:
public class Foo
{
public int ID { get; set; }
public string Name { get; set; }
public virtual ICollection<Foo> InnerFoo { get; set; }
}
public class AppContext : DbContext
{
public IDbSet<Foo> Foos { get; set; }
}
public class Initializer : DropCreateDatabaseAlways<AppContext>
{
protected override void Seed(AppContext context)
{
var list = new List<Foo>
{
new Foo {Name = "one", InnerFoo = new List<Foo>{new Foo {Name = "Four"}}},
new Foo {Name = "two"},
new Foo {Name = "three"},
};
list.ForEach(f => context.Foos.Add(f));
}
}
public class Filter
{
public static Expression<Func<Foo, bool>> GetPredicate()
{
return p => p.Name != null && p.Name.Length > 3;
}
}
class Program
{
static void Main(string[] args)
{
Database.SetInitializer(new Initializer());
using (var ctx = new AppContext())
{
var predicate = Filter.GetPredicate();
var list = ctx.Foos.Where(f => f.InnerFoo.AsQueryable().Where(predicate).Count() > 0).ToList(); // this works
// var list = ctx.Foos.Where(f => f.InnerFoo.AsQueryable().Where(Filter.GetPredicate()).Count() > 0).ToList(); // this doesn't
foreach (var s in list)
{
Console.WriteLine(s.Name);
}
}
}
}
The line that's commented out doesn't work - throws an exception at runtime - "Internal .NET Framework Data Provider error 1025.". I'm using EntityFramework.4.1.10715.0
Can anyone tell me why?
Side question: I'm looking for a way to keep filtering expressions that are used in several different classes.
The problem is that your inner Where is already within the context of an "outer Where" on ctx.Foos - so the call to Filter.GetPredicate() ends up as part of the expression tree, and the Entity Framework has no idea what it means or how to translate it into SQL.
That's why it's happening... I'm not sure of the best solution right now though, unless you can extract the predicate into a separate variable where you need it.
(As an aside, it's generally more expressive to use Any(...) than ...Count() > 0 - and in LINQ to Objects it can make a huge difference.)
You hinted towards this yourself already, but just to make it clear to future readers.
You can use the function to generate the predicate as you're doing, but you need to store the expression in an intermediate expression within your function.
i.e. change:
var list = ctx.Foos.Where(f => f.InnerFoo.AsQueryable().Where(Filter.GetPredicate()).Count() > 0).ToList();
into:
var pred = Filter.GetPredicate();
var list = ctx.Foos.Where(f => f.InnerFoo.AsQueryable().Where(pred).Count() > 0).ToList();
I'm still puzzled as to why this happens this way.
I have a function that reads a file in chunks.
public static DataObject ReadNextFile(){ ...}
And dataobject looks like this:
public DataObject
{
public string Category { get; set; }
// And other members ...
}
What I want to do is the following basically
List<DataObject> dataObjects = new List<DataObject>();
while(ReadNextFile().Category == "category")
{
dataObjects.Add(^^^^^ the thingy in the while);
}
I know it's probably not how it's done, because how do I access the object I've just read.
I think what you're looking for is:
List<DataObject> dataObjects = new List<DataObject>();
DataObject nextObject;
while((nextObject = ReadNextFile()).Category == "category")
{
dataObjects.Add(nextObject);
}
But I wouldn't do that. I'd write:
List<DataObject> dataObject = source.ReadItems()
.TakeWhile(x => x.Category == "Category")
.ToList();
where ReadItems() was a method returning an IEnumerable<DataObject>, reading and yielding one item at a time. You may well want to implement it with an iterator block (yield return etc).
This is assuming you really want to stop reading as soon as you find the first object which has a different category. If you actually want to include all the matching DataObjects,
change TakeWhile to Where in the above LINQ query.
(EDIT: Saeed has since deleted his objections to the answer, but I guess I might as well leave the example up...)
EDIT: Proof that this will work, as Saeed doesn't seem to believe me:
using System;
using System.Collections.Generic;
public class DataObject
{
public string Category { get; set; }
public int Id { get; set; }
}
class Test
{
static int count = 0;
static DataObject ReadNextFile()
{
count++;
return new DataObject
{
Category = count <= 5 ? "yes" : "no",
Id = count
};
}
static void Main()
{
List<DataObject> dataObjects = new List<DataObject>();
DataObject nextObject;
while((nextObject = ReadNextFile()).Category == "yes")
{
dataObjects.Add(nextObject);
}
foreach (DataObject x in dataObjects)
{
Console.WriteLine("{0}: {1}", x.Id, x.Category);
}
}
}
Output:
1: yes
2: yes
3: yes
4: yes
5: yes
In other words, the list has retained references to the 5 distinct objects which have been returned from ReadNextFile.
This is subjective, but I hate this pattern (and I fully recognize that I am in the very small minority here). Here is how I do it when I need something like this.
var dataObjects = new List<DataObject>();
while(true) {
DataObject obj = ReadNextFile();
if(obj.Category != "category") {
break;
}
dataObjects.Add(obj);
}
But these days, it is better to say
List<DataObject> dataObjects = GetItemsFromFile(path)
.TakeWhile(x => x.Category == "category")
.ToList();
Here, of course, GetItemsFromFile reads the items from the file pointed to by path and returns an IEnumerable<DataObject>.
List<DataObject> dataObjects = new List<DataObject>();
string category = "";
while((category=ReadNextFile().Category) == "category")
{
dataObjects.Add(new DataObject{Category = category});
}
And if you have more complicated object you can do this (like jon):
List<DataObject> dataObjects = new List<DataObject>();
var category = new DataObject();
while((category=ReadNextFile()).Category == "category")
{
dataObjects.Add(category);
}
You should look into implementing IEnumerator on the class container the call to ReadNextFile(). Then you would always have reference to the current object with IEnumerator.Current, and MoveNext() will return the bool you are looking for to check for advancement. Something like this:
public class ObjectReader : IEnumerator<DataObject>
{
public bool MoveNext()
{
// try to read next file, return false if you can't
// if you can, set the Current to the returned DataObject
}
public DataObject Current
{
get;
private set;
}
}