I Create a web-site and I have a problem. When I'm tring to get datas from mongodb and convert it to list, I have an error "Cannot apply indexing with [] to an expression of type 'CategoryModel'"
this is classes
public class CategoryModel
{
[BsonId]
public ObjectId id { get; set; }
[BsonElement("title")]
[JsonProperty("title")]
public string Name { get; set; }
[BsonElement("slug")]
public string slug { get; set; }
[BsonElement("__v")]
public int __v { get; set; }
}
public class ProductsModel
{
[BsonId]
public ObjectId id { get; set; }
[BsonElement("title")]
public string Name { get; set; }
[BsonElement("desc")]
public string Desc { get; set; }
[BsonElement("price")]
public int price { get; set; }
[BsonElement("category")]
public CategoryModel category { get; set; }
[BsonElement("image")]
public string ImageURL { get; set; }
}
this is my conntroller
public class ProductsController:Controller
{
private readonly IConfiguration _configuration;
List<CategoryModel> categoriesList = new List<CategoryModel>();
List<ProductsModel> productsList = new List<ProductsModel>();
[HttpGet("products")]
public async Task<IActionResult> Product()
{
var client = new MongoClient("mongodb://localhost:27017/");
var database = client.GetDatabase("cmscart");
var collection = database.GetCollection<CategoryModel>("categories");
var result = await collection.Find(new BsonDocument()).ToListAsync();
foreach (var item in result)
{
categoriesList.Add(new CategoryModel() { Name = (string)item["[title]"] }); //here I have an error
}
//products
var client2 = new MongoClient("mongodb://localhost:27017");
var database2 = client2.GetDatabase("cmscart");
var collection2 = database2.GetCollection<ProductsModel>("products");
var result2 = await collection2.Find(new BsonDocument()).ToListAsync();
foreach (var item2 in result2)
{
productsList.Add(new ProductsModel() { Name = (string)item2["title"], Desc = (string)item2["desc"], price = (int)item2["price"], ImageURL = (string)item2["image"] }); // and here I have an error
}
return View(categoryProduct);
}
}
I found a lot of solutions but I don't understand why this error is appear, because if this trick do with SQL then I don't have this error
You should be able to use the deserialized object directly:
var client = new MongoClient("mongodb://localhost:27017/");
var database = client.GetDatabase("cmscart");
var collection = database.GetCollection<CategoryModel>("categories");
List<CategoryModel> categoriesList = await collection.Find(new BsonDocument()).ToListAsync();
//products
var collection2 = database2.GetCollection<ProductsModel>("products");
List<ProductsModel> products = await collection2.Find(new BsonDocument()).ToListAsync();
Also, don't use class properties for local variables, declare everything in the innermost scope possible (in general). Ideally the MongoClient or Database would be injected into the class constructor too. You don't want to be instantiating them in an action method and you definitely don't want configuration values in there.
Related
I`m having simple method which builds IQueryable and returns it.
public IQueryable<ClassDTO> ReportByNestedProperty()
{
IQueryable<Class> query = this.dbSet;
IQueryable<ClassDTO> groupedQuery =
from opportunity in query
group new
{
ItemGroup = opportunity.OpportunityStage.Name,
EstimatedRevenue = opportunity.EstimatedRevenue,
CostOfLead = opportunity.CostOfLead
}
by new
{
opportunity.OpportunityStage.Name,
opportunity.OpportunityStage.Id
}
into item
select new ClassDTO()
{
ItemGroup = string.IsNullOrEmpty(item.Key.Name) ? "[Not Assigned]" : item.Key.Name,
Count = item.Select(z => z.ItemGroup.Name).Count(), // int
Commission = item.Sum(z => z.EstimatedRevenue), // decimal
Cost = item.Sum(z => z.CostOfLead), // decimal?
};
return groupedQuery;
}
This is fine. The thing i need is to create method with same return type, but groupby by different prperties dynamically. So from the above code I want to have 3 dynamic parts which will be passed as params:
ItemGroup = opportunity.OpportunityStage.Name
and
by new
{
opportunity.OpportunityStage.Name,
opportunity.OpportunityStage.Id
}
So the new method should be like this
public IQueryable<ClassDTO> ReportByNestedProperty(string firstNestedGroupByProperty, string secondNestedGroupByProperty)
{
// TODO: ExpressionTree
}
And call it like this:
ReportByNestedProperty("OpportunityStage.Name","OpportunityStage.Id")
ReportByNestedProperty("OtherNestedProperty.Name","OtherNestedProperty.Id")
ReportByNestedProperty("OpportunityStage.Name","OpportunityStage.Price")
So the main thing is to create expressions with these two selects:
opportunity.OpportunityStage.Name,
opportunity.OpportunityStage.Id
I have tried toe create the select expressions, groupby, the creation of Anonomoys classes and the DTO Class but I just cant get it right.
EDIT:
Here are the classes involved:
public class ClassDTO
{
public ClassDTO() { }
[Key]
public string ItemGroup { get; set; }
public decimal Commission { get; set; }
public decimal? Cost { get; set; }
public int Count { get; set; }
}
Class obj is a pretty big one so i`m posting just part of it
public partial class Class
{
public Class() { }
[Key]
public Guid Id { get; set; }
public Guid? OpportunityStageId { get; set; }
[ForeignKey(nameof(OpportunityStageId))]
[InverseProperty(nameof(Entities.OpportunityStage.Class))]
public virtual OpportunityStage OpportunityStage { get; set; }
}
public partial class OpportunityStage
{
public OpportunityStage()
{
this.Classes = new HashSet<Class>();
}
[Key]
public Guid Id { get; set; }
public string Name { get; set; }
[InverseProperty(nameof(Class.OpportunityStage))]
public virtual ICollection<TruckingCompanyOpportunity> Classes{ get; set; }
}
I have simplified your Grouping query and introduced private class IdName which should replace anonymous class usage:
class IdName
{
public int Id { get; set; }
public string Name { get; set; } = null!;
}
static Expression MakePropPath(Expression objExpression, string path)
{
return path.Split('.').Aggregate(objExpression, Expression.PropertyOrField);
}
IQueryable<ClassDTO> ReportByNestedProperty(IQueryable<Class> query, string nameProperty, string idProperty)
{
// Let compiler to do half of the work
Expression<Func<Class, string, int, IdName>> keySelectorTemplate = (opportunity, name, id) =>
new IdName { Name = name, Id = id };
var param = keySelectorTemplate.Parameters[0];
// generating expressions from prop path
var nameExpr = MakePropPath(param, nameProperty);
var idExpr = MakePropPath(param, idProperty);
var body = keySelectorTemplate.Body;
// substitute parameters
body = ReplacingExpressionVisitor.Replace(keySelectorTemplate.Parameters[1], nameExpr, body);
body = ReplacingExpressionVisitor.Replace(keySelectorTemplate.Parameters[2], idExpr, body);
var keySelectorLambda = Expression.Lambda<Func<Class, IdName>>(body, param);
// finalize query
IQueryable<ClassDTO> groupedQuery = query
.GroupBy(keySelectorLambda)
.Select(item => new ClassDTO()
{
ItemGroup = string.IsNullOrEmpty(item.Key.Name) ? "[Not Assigned]" : item.Key.Name,
Count = item.Count(x => x.Name), // int
Commission = item.Sum(x => x.EstimatedRevenue), // decimal
Cost = item.Sum(x => x.CostOfLead), // decimal?
});
return groupedQuery;
}
How can i make filter and add/update third, fourth level child of a mongodb document using C#.
I can add/Update till second level but not further. Please provide me a solution or any kind reference from where can get help. Is there any other way to do it except builders..Elemmatch.
Here is my classes and code:
namespace CrudWithMultilvelNestedDoc
{
public class Channel
{
[BsonId]
[BsonRepresentation(BsonType.String)]
public string Id { get; set; }
public string Name { get; set; }
public Episode[] Episodes { get; set; }
}
public class Episode
{
[BsonId]
[BsonRepresentation(BsonType.String)]
public string Id { get; set; }
public string Name { get; set; }
public Track[] Tracks { get; set; }
}
public class Track
{
[BsonId]
[BsonRepresentation(BsonType.String)]
public string Id { get; set; }
public string Name { get; set; }
public Like[] Likes { get; set; }
}
public class Like
{
[BsonId]
[BsonRepresentation(BsonType.String)]
public string Id { get; set; }
public string Name { get; set; }
}
}
//First Method
//var filter = Builders<Channel>.Filter.And(Builders<Channel>
// .Filter.Where(x => x.Id == "5e4606e6ae7b090688671416"), // OR &
// Builders<Channel>.Filter.ElemMatch(e => e.Episodes, Builders<Episode>
// .Filter.Eq(e => e.Id, "5e460851d29c1b3df4d27b7d")));
//Second Method
//var filter = Builders<Channel>.Filter.Eq(e => e.Id, "5e4606e6ae7b090688671416")
// & Builders<Channel>.Filter.ElemMatch(e => e.Episodes, Builders<Episode>.Filter.Eq(e => e.Id, "5e46071d385a672b0cea0f86"));
//Third Method
var filter = channelFilter.ElemMatch(e => e.Episodes, episodeFilter.ElemMatch(e=> e.Tracks, trackFilter.Eq(e => e.Id, "5e460dbe2bc5e70c9cfeac21")));
var data = collection.Find(filter);
//Update Filter
var update = Builders<Channel>.Update.Push("Episodes[-1].Tracks[-1].Likes", like);
var result = collection.UpdateOne(filter, update);
//Data
{"_id":"5e4606e6ae7b090688671416","Name":"Channel 1","Episodes":[{"_id":"5e46071d385a672b0cea0f86","Name":"Episode 1","Tracks":[{"_id":"5e460dbe2bc5e70c9cfeac21","Name":"Trak 1","Likes":[]},{"_id":"5e4612d60747a2121870c815","Name":"Trak 2","Likes":[]}]},{"_id":"5e460851d29c1b3df4d27b7d","Name":"Episode 2","Tracks":[{"_id":"5e460e307ca6843758ce814e","Name":"Trak 1","Likes":[]}]}]}
As per documentation:
The positional $ operator cannot be used for queries which traverse more than one array
So using -1 is not a way forward here. The approach you should take is the $ positional filtered operator.
There's no strongly-typed representation in C# so your code can look like below:
var filter = Builders<Channel>.Filter.Eq(x => x.Id, "5e4606e6ae7b090688671416");
var like = new Like() {Name = "new like", Id = "1"};
var episodeId = "5e46071d385a672b0cea0f86";
var trackId = "5e460dbe2bc5e70c9cfeac21";
var update = Builders<Channel>.Update.Push("Episodes.$[e].Tracks.$[t].Likes", like);
var arrayFilters = new List<ArrayFilterDefinition>();
ArrayFilterDefinition<BsonDocument> episodesFilter = new BsonDocument("e._id", new BsonDocument("$eq", episodeId));
ArrayFilterDefinition<BsonDocument> tracksFilter = new BsonDocument("t._id", new BsonDocument("$eq", trackId));
arrayFilters.Add(episodesFilter);
arrayFilters.Add(tracksFilter);
var updateOptions = new UpdateOptions { ArrayFilters = arrayFilters };
var result = mongoDBCollection.UpdateOne(filter, update, updateOptions);
How can I return fieldList from an IQueryable object?
// fieldList="Code,Name";
var result = from Activity in query
select new
{
Code = Activity.Code,
Name = Activity.Name,
StatusCode = Activity.ClaimStatus.Name
};
DTO
public class CustomDto
{
public string Code { get; set; }
public string Name { get; set; }
public string StatusCode { get; set; }
}
Convert To Dto
var result = items.AsQueryable().Select(x => new CustomDto()
{
Code = x.Code,
Name = x.Name,
StatusCode = x.ClaimStatus
}).ToList();
I am a beginner in MongoDB. Please see my models below.
public class Technology
{
public Technology()
{
ProductGroups = new List<ProductGroup>();
}
[BsonRepresentation(BsonType.ObjectId)]
public ObjectId _id { get; set; }
public string Name { get; set; }
public IEnumerable<ProductGroup> ProductGroups { get; set; }
}
public class ProductGroup
{
[BsonRepresentation(BsonType.ObjectId)]
public ObjectId _id { get; set; }
public string Name { get; set; }
}
Now the data shows like below.
I am try to add the ProductGroup ( it's a BsonDocument Collection) collection in Technology.
Use generic types where you can. Because this code parent["ProductGroups"] is dangerous place for any refactoring.
Your task can be done in one query
var productGroup = new ProductGroup { Id = ObjectId.GenerateNewId(), Name = model.Name };
var collection = database.GetCollection<Technology>("Technology");
var update = Builders<Technology>.Update.AddToSet(x => x.ProductGroups, productGroup);
await collection.FindOneAndUpdateAsync(x => x.Id == model._id, update);
Change your Model of Technology as
[BsonElementAttribute("productgroups")]
public IList<ProductGroup> ProductGroups{ get; set; }
Then,
var productGroup = new BsonDocument().Add("_id", productGroup_id).Add("Name", name);
var technologies = database.GetCollection("technology");
var technology = technologies.FindOneById(ObjectId.Parse(technology_id));
technology["productgroups"] = new BsonArray().Add(BsonValue.Create(productGroup));
technologies.Save(technology);
#CodingDefined I change my code as per the v2.0.1.27
Please see my code below. Thank you very much for your help.
var productGroup = new BsonDocument()
.Add("_id", ObjectId.GenerateNewId())
.Add("Name", model.Name);
BsonDocument parent = null;
var _parent = Collection.FindOneByIdAs(typeof(BsonDocument), model._id);
if (_parent != null)
{
parent = _parent.ToBsonDocument();
parent["ProductGroups"] = new BsonArray().Add(BsonValue.Create(productGroup));
Collection.Save(parent);
}
Please make sure, the new child record is not clearing the existing records
parent["ProductGroups"] = parent["ProductGroups"].AsBsonArray.Add(productGroup);
I have returned some odata data to a c# client using:
Uri uri = new Uri("testserver/WebApi/odata");
var container = new CourseService.Container(uri);
How do I convert the data into a list?
The returned data is a list of courses:
public partial class Course
{
public string Name { get; set; }
public string Description { get; set; }
public string Guid { get; set; }
}
here's a sample code for you.
List<Course> CourseList = new List<Course>();
foreach (var item in container)
{
Course obj = new Course();
obj.Name = item.Name;
obj.Description = item.Description;
obj.Guid = item.Guid;
CourseList.Add(obj);
}