I just started to make my first project with Codefirst-Approach with C#, Linq and MSSQLSERVER and run into an problem when trying to insert a new DB-entry that contains an reference to an already existing element from another table.
InnerException {"Violation of PRIMARY KEY constraint 'PK_dbo.Manufacturers'. Cannot insert duplicate key in object 'dbo.Manufacturers'. The duplicate key value is (1d262e43-b9b6-4752-9c79-95d955d460ab).\r\nThe statement has been terminated."} System.Exception {System.Data.SqlClient.SqlException}
I broke the problem down to a simple project that I will upload to a share.
My data structure contains a class.Product that links to a Manufacturer object and a List of possible Suppliers.
public class Product
{
[Key]
public Guid Id { get { return _id; } set { _id = value; } }
private Guid _id = Guid.NewGuid();
public string Name { get; set; }
public Manufacturer Manuf { get; set; }
public List<Supplier> PossibleSupplier { get { return _possibleSupplier; } set { _possibleSupplier = value; } }
private List<Supplier> _possibleSupplier = new List<Supplier>();
}
public class Supplier
{
[Key]
public Guid Id { get { return _id; } set { _id = value; } }
private Guid _id = Guid.NewGuid();
public string Name { get; set; }
}
public class Manufacturer
{
[Key]
public Guid Id { get { return _id; } set { _id = value; } }
private Guid _id = Guid.NewGuid();
public string Name { get; set; }
}
I now generate 2 products.
Both products are produced by the same manufacturer.
The List of PossibleSuppliers does also contain same suppliers
private void GenerateProducts()
{
Manufacturer manufactuer1 = new Manufacturer() { Name = "mainManuf 1" };
Supplier supplier1 = new Supplier() { Name = "first Supplier" };
Supplier supplier2 = new Supplier() { Name = "second Supplier" };
Product firstProduct = new Product() { Name = "Product 1", Manuf = manufactuer1, PossibleSupplier = new List<Supplier>() { supplier1, supplier2 } };
Product secondProduct = new Product() { Name = "Product 2", Manuf = manufactuer1, PossibleSupplier = new List<Supplier>() { supplier1 } };
productList_ = new List<Product>() { firstProduct, secondProduct };
}
The following method is used for storing/updating the DB entries
public static class DbHandler
{
public static bool StoreProduct(Product product)
{
using (ProductDbContext dbObject = new ProductDbContext())
{
try
{
dbObject.Products.AddOrUpdate(product);
dbObject.SaveChanges();
}
catch (Exception ex)
{
//
return false;
}
}
return true;
}
}
public class ProductDbContext : DbContext
{
public ProductDbContext()
{
Database.SetInitializer<ProductDbContext>(new DropCreateDatabaseAlways<ProductDbContext>());
this.Database.Connection.ConnectionString = sqlConnection.ConnectionString;
}
public DbSet<Product> Products { get; set; }
public DbSet<Supplier> Suppliers { get; set; }
public DbSet<Manufacturer> Manufacturers { get; set; }
private static SqlConnectionStringBuilder sqlConnection = new SqlConnectionStringBuilder()
{
DataSource = "localhost\\MSSQLSERVER2019", // update me
UserID = "", // update me
Password = "", // update me
InitialCatalog = "ProductDb",
IntegratedSecurity = true
};
}
The insertion of the first product can be done without problems.
Also inserting additional products that will have unique manufacturers and suppliers will work without problem.
**So I do not have the problem of uniqueness of my primary keys. **
I only receive this error, when I like to add a new entry that has a foreign key to an already existing entry.
Using dbObject.Products.AddOrUpdate(product); instead of dbObject.Products.Add(product); have not solved my problem.
I am also not able to remove the manufacturer entry before adding the second product, because this will violate the foreign key of my first product…
I found a possible solution for manufacturer by adding an additional property for ManufacturerId
public Guid? ManuId { get; set; }
[ForeignKey("ManuId")]
public Manufacturer Manuf { get; set; }
to my data object, but I would not have an idea how to do this with my List PossibleSupplier??
Can someone please push me into the right direction?
!!Many thanks for the fast replays!!
I have updated my DataStructure as following:
public class Product
{
[Key]
public Guid Id { get { return _id; } set { _id = value; } }
private Guid _id = Guid.NewGuid();
public string Name { get; set; }
public virtual Manufacturer Manufacturer { get; set; }
public virtual ICollection<Supplier> PossibleSupplier { get; set; }
}
public class Supplier
{
[Key]
public Guid Id { get { return _id; } set { _id = value; } }
private Guid _id = Guid.NewGuid();
public string Name { get; set; }
[ForeignKey("Product")]
public Guid ProductId { get; set; }
public virtual Product Product { get; set; }
}
public class Manufacturer
{
[Key]
public Guid Id { get { return _id; } set { _id = value; } }
private Guid _id = Guid.NewGuid();
public string Name { get; set; }
[ForeignKey("Product")]
public Guid ProductId { get; set; }
public virtual ICollection<Product> Product { get; set; }
}
But I still get the "Violation of PRIMARY KEY constraint 'PK_dbo.Manufacturers'. Cannot insert duplicate key..." error while trying to insert the second entry.
I have attached how the DB looks in SQL-Server
Okay so I believe I know what your issue is. It lies somewhat with this portion here:
private void GenerateProducts()
{
Manufacturer manufactuer1 = new Manufacturer() { Name = "mainManuf 1" };
Supplier supplier1 = new Supplier() { Name = "first Supplier" };
Supplier supplier2 = new Supplier() { Name = "second Supplier" };
Product firstProduct = new Product() { Name = "Product 1", Manuf = manufactuer1, PossibleSupplier = new List<Supplier>() { supplier1, supplier2 } };
Product secondProduct = new Product() { Name = "Product 2", Manuf = manufactuer1, PossibleSupplier = new List<Supplier>() { supplier1 } };
productList_ = new List<Product>() { firstProduct, secondProduct };
}
When you assign Manuf = manufacturer1 in both portions below it will work for the first insert because the manufacturer does not exist yet. Now the reason why on the second insert it does not work is because of your code below:
using (ProductDbContext dbObject = new ProductDbContext())
{
try
{
dbObject.Products.AddOrUpdate(product);
dbObject.SaveChanges();
}
catch (Exception ex)
{
//
return false;
}
}
Right now when you go to insert the second product, it will throw the duplicate key exception because you are not referencing the existing entity within your context. You should change it to something like the following:
using (ProductDbContext dbObject = new ProductDbContext())
{
try
{
//Need to check if the manufacturer already exists in the db, if it does
//make sure your project references the EXISTING entity within your context
var check = dbObjec.Manufacturer.Where(x => x.Id == product.Manufacturer.Id).FirstOrDefault();
if (check != null)
product.Manufacturer = check;
dbObject.Products.Add(product);
dbObject.SaveChanges();
}
catch (Exception ex)
{
//
return false;
}
}
If you don't reference the existing manufacturer within the context and then assign it, EF will assume you are trying to add a new one not reference the existing one.
as mentioned in the commands I'd like to share my updated and working project for further use....
MainWindow that generates the test data and executes read/write to DB
public partial class MainWindow : Window
{
private List<Product> productList_;
public MainWindow()
{
GenerateProducts();
InitializeComponent();
}
private void InsertFirst_Click(object sender, RoutedEventArgs e)
{
DbHandler.StoreProduct(productList_[0]);
}
private void InsertSecond_Click(object sender, RoutedEventArgs e)
{
DbHandler.StoreProduct(productList_[1]);
}
private void Read_Click(object sender, RoutedEventArgs e)
{
var productList = DbHandler.GetAllProducts();
}
private void GenerateProducts()
{
Manufacturer manufactuer1 = new Manufacturer() { Name = "mainManuf 1" };
Supplier supplier1 = new Supplier() { Name = "first Supplier" };
Supplier supplier2 = new Supplier() { Name = "second Supplier" };
Supplier supplier3 = new Supplier() { Name = "third Supplier" };
Product firstProduct = new Product() { Name = "Product 1", Manufacturer = manufactuer1, PossibleSupplier = new List<Supplier>() { supplier1, supplier2 } };
Product secondProduct = new Product() { Name = "Product 2", Manufacturer = manufactuer1, PossibleSupplier = new List<Supplier>() { supplier2, supplier3 } };
productList_ = new List<Product>() { firstProduct, secondProduct };
}
}
DataStructure: Because of the many to many relation ship between Product and Supplier I have to add
[ForeignKey("Product")]
public ICollection<Guid> ProductId { get; set; }
public virtual ICollection<Product> Product { get; set; }
to the Supplier class. I also decided to add a collection of Products to my manufacturer to make some query-calls more comfortable
public class Product
{
[Key]
public Guid Id { get { return _id; } set { _id = value; } }
private Guid _id = Guid.NewGuid();
public string Name { get; set; }
public virtual Manufacturer Manufacturer { get; set; }
public virtual ICollection<Supplier> PossibleSupplier { get; set; }
}
public class Supplier
{
[Key]
public Guid Id { get { return _id; } set { _id = value; } }
private Guid _id = Guid.NewGuid();
public string Name { get; set; }
[ForeignKey("Product")]
public ICollection<Guid> ProductId { get; set; }
public virtual ICollection<Product> Product { get; set; }
}
public class Manufacturer
{
[Key]
public Guid Id { get { return _id; } set { _id = value; } }
private Guid _id = Guid.NewGuid();
public string Name { get; set; }
//only nice for reverse object from Man --> Product
[ForeignKey("Product")]
public ICollection<Guid> ProductId { get; set; }
public virtual ICollection<Product> Product { get; set; }
}
Before adding a new product to the DB it is important to load possible Manufacturer/Suppliers from the DB and assign them to the current product.
Adding new products is now working fine but as you can see the loading and assigning of the possible suppliers is not really handsome. Therefore I will try to make some modifications on this process in the upcoming days.... I will come back if I have found a "solution".
public static class DbHandler
{
public static List<Product> GetAllProducts()
{
using (ProductDbContext dbObject = new ProductDbContext())
{
//loading with childs and their reverse objects to products
var productList = dbObject.Products.Include("Manufacturer").Include("Manufacturer.Product").Include("PossibleSupplier").Include("PossibleSupplier.Product").Where(i => i.Id != null).ToList();
//loding with childs but without reverse objects
//var productList = dbObject.Products.Include("Manufacturer").Include("PossibleSupplier").Where(i => i.Id != null).ToList();
return productList;
}
}
public static bool StoreProduct(Product product)
{
using (ProductDbContext dbObject = new ProductDbContext())
{
try
{
//this does not solve the loading problem, even when property _id is changed to "private Guid _id = new Guid();
//dbObject.Entry(product).State = product.Id == new Guid() ? EntityState.Added : EntityState.Modified;
//dbObject.Entry(product.Manufacturer).State = product.Manufacturer.Id == new Guid() ? EntityState.Added : EntityState.Modified;
//foreach (var supplier in product.PossibleSupplier)
//{
// dbObject.Entry(supplier).State = supplier.Id == new Guid() ? EntityState.Added : EntityState.Modified;
//}
//Therefore loading must be done manually
Guid manufacturerId = product.Manufacturer.Id;
//Need to check if the manufacturer already exists in the db, if it does
//make sure your project references the EXISTING entity within your context
var checkManuf = dbObject.Manufacturers.Where(x => x.Id == manufacturerId).FirstOrDefault();
if (checkManuf != null)
product.Manufacturer = checkManuf;
List<Supplier> dbSuppliers = new List<Supplier>();
foreach (var posSupplier in product.PossibleSupplier)
{
var checkSupplier = dbObject.Suppliers.FirstOrDefault(x => x.Id == posSupplier.Id);
if (checkSupplier != null)
{
dbSuppliers.Add(checkSupplier);
}
}
foreach (var dbSup in dbSuppliers)
{
product.PossibleSupplier.Remove(product.PossibleSupplier.Single(i => i.Id == dbSup.Id));
product.PossibleSupplier.Add(dbSup);
}
dbObject.Products.Add(product);
dbObject.SaveChanges();
}
catch (Exception ex)
{
//
return false;
}
}
return true;
}
}
public class ProductDbContext : DbContext
{
public ProductDbContext()
{
Database.SetInitializer<ProductDbContext>(new DropCreateDatabaseIfModelChanges<ProductDbContext>());
this.Database.Connection.ConnectionString = sqlConnection.ConnectionString;
}
public DbSet<Product> Products { get; set; }
public DbSet<Supplier> Suppliers { get; set; }
public DbSet<Manufacturer> Manufacturers { get; set; }
private static SqlConnectionStringBuilder sqlConnection = new SqlConnectionStringBuilder()
{
DataSource = "localhost\\MSSQLSERVER2019", // update me
UserID = "", // update me
Password = "", // update me
InitialCatalog = "ProductDb",
IntegratedSecurity = true
};
}
One way seams by using EntityStates but they do not work as expected --> I received duplicated entries in DB.
I have uploaded the current state of the project to the share - filename SqlTestporject_20200414_2027.zip
Br,
-------------------------- Update 2020-04-15 --------------------------
I ended up by writing methods that are handling the decision between update/insert for every single child on its own because I do not have found a way how to update possible offline-changes of already existing dbEntries by simultaneously adding not existing dbEntries.
The main problem was that I received duplicated entries in the DB during adding the second product. The strange thing was, that this duplicates event violates the PK-uniqueness without an error/exception....
So I do have to call down the AddOrUpdate() methods until I reach the last child for my complete data structure.
public static Product AddOrUpdateProduct(Product product)
{
using (ProductDbContext dbObject = new ProductDbContext())
{
try
{
product.Manufacturer = AddOrUpdateManufacturer(dbObject, product.Manufacturer);
List<Supplier> dbSupplierList = new List<Supplier>();
foreach (var supplier in product.PossibleSupplier)
{
dbSupplierList.Add(AddOrUpdateSupplier(dbObject, supplier));
}
product.PossibleSupplier.Clear();
product.PossibleSupplier = dbSupplierList;
if (product.Id == new Guid())
{
//add new product
dbObject.Products.Add(product);
dbObject.SaveChanges();
return product;
}
else
{
//update existing product
var dbProduct = dbObject.Products.Single(x => x.Id == product.Id);
dbProduct.Name = product.Name;
dbObject.SaveChanges();
return dbProduct;
}
}
catch (Exception)
{
throw;
}
}
}
private static Supplier AddOrUpdateSupplier(ProductDbContext dbObject, Supplier supplier)
{
supplier.Address = AddOrUpdateAdress(dbObject, supplier.Address);
if (supplier.Id == new Guid())
{
//add new product
dbObject.Suppliers.Add(supplier);
dbObject.SaveChanges();
return supplier;
}
else
{
//update existing product
var dbSupplier = dbObject.Suppliers.Single(x => x.Id == supplier.Id);
dbSupplier.Name = supplier.Name;
dbObject.SaveChanges();
return dbSupplier;
}
}
private static Manufacturer AddOrUpdateManufacturer(ProductDbContext dbObject, Manufacturer manufacturer)
{
manufacturer.Address = AddOrUpdateAdress(dbObject, manufacturer.Address);
if (manufacturer.Id == new Guid())
{
//add new product
dbObject.Manufacturers.Add(manufacturer);
dbObject.SaveChanges();
return manufacturer;
}
else
{
//update existing product
var dbManufacturer = dbObject.Manufacturers.Single(x => x.Id == manufacturer.Id);
dbManufacturer.Name = manufacturer.Name;
dbObject.SaveChanges();
return dbManufacturer;
}
}
private static Address AddOrUpdateAdress(ProductDbContext dbObject, Address address)
{
if (address.Id == new Guid())
{
//add new product
dbObject.Addresses.Add(address);
dbObject.SaveChanges();
return address;
}
else
{
//update existing product
var dbAddress = dbObject.Addresses.Single(x => x.Id == address.Id);
dbAddress.Street = address.Street;
dbAddress.HouseNumber = address.HouseNumber;
dbAddress.PLZ = address.PLZ;
dbAddress.City = address.City;
dbObject.SaveChanges();
return dbAddress;
}
}
This version can be found here - file SqlTestporject_20200415_1033.zip.
Additionally I'd like to share the following link. Maybe chapter Example 4.18: Creating a Generic Method That Can Apply State Through Any Graph can help others to implement a more comfortable solution.
Related
I have a Web API for OData services. I have a lot of table with many relations. Here is some of the table:
MSADDRESSCOUNTRY
public partial class MSADDRESSCOUNTRY
{
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage","CA2214:DoNotCallOverridableMethodsInConstructors")]
public MSADDRESSCOUNTRY()
{
this.MSADDRESSPROVINCEs = new HashSet<MSADDRESSPROVINCE>();
}
public int ID { get; set; }
public string CODE { get; set; }
public string COUNTRYNAME { get; set; }
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage","CA2227:CollectionPropertiesShouldBeReadOnly")]
public virtual ICollection<MSADDRESSPROVINCE> MSADDRESSPROVINCEs { get; set; }
}
MSADDRESSPROVINCE
public partial class MSADDRESSPROVINCE
{
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
public MSADDRESSPROVINCE()
{
this.MSADDRESSDISTRICTs = new HashSet<MSADDRESSDISTRICT>();
}
public int ID { get; set; }
public Nullable<int> COUNTRYID { get; set; }
public string PROVINCENAME { get; set; }
public virtual MSADDRESSCOUNTRY MSADDRESSCOUNTRY { get; set; }
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage","CA2227:CollectionPropertiesShouldBeReadOnly")]
public virtual ICollection<MSADDRESSDISTRICT> MSADDRESSDISTRICTs { get; set; }
}
MSADDRESSDISTRICT
public partial class MSADDRESSDISTRICT
{
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
public MSADDRESSDISTRICT()
{
this.MSADDRESSSUBDISTRICTs = new HashSet<MSADDRESSSUBDISTRICT>();
}
public int ID { get; set; }
public Nullable<int> PROVINCEID { get; set; }
public string DISTRICTNAME { get; set; }
public virtual MSADDRESSPROVINCE MSADDRESSPROVINCE { get; set; }
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
public virtual ICollection<MSADDRESSSUBDISTRICT> MSADDRESSSUBDISTRICTs { get; set; }
}
I create DTO object model for every table with the property is the same with Database object model.
I want the client can use $expand keyword to get child data and/or parent data.
For MSADDRESSCOUNTRY I need to write the code like this.
[EnableQuery(MaxExpansionDepth = 4)]
public IQueryable<MsAddressCountryObject> Get()
{
return db.MSADDRESSCOUNTRies.Select(c => new MsAddressCountryObject
{
ID = c.ID,
CODE = c.CODE,
COUNTRYNAME = c.COUNTRYNAME,
MSADDRESSPROVINCEs = c.MSADDRESSPROVINCEs.Select(data => new MsAddressProvinceObject()
{
ID = data.ID,
COUNTRYID = data.COUNTRYID,
PROVINCENAME = data.PROVINCENAME,
MSADDRESSCOUNTRY = new MsAddressCountryObject()
{
ID = data.MSADDRESSCOUNTRY.ID,
CODE = data.MSADDRESSCOUNTRY.CODE,
COUNTRYNAME = data.MSADDRESSCOUNTRY.COUNTRYNAME,
},
MSADDRESSDISTRICTs = data.MSADDRESSDISTRICTs.Select(dist => new MsAddressDistrictObject()
{
ID = dist.ID,
PROVINCEID = dist.PROVINCEID,
DISTRICTNAME = dist.DISTRICTNAME,
})
})
});
}
For MSADDRESSPROVINCE I need to write the code like this.
[EnableQuery(MaxExpansionDepth = 4)]
public IQueryable<MsAddressProvinceObject> Get()
{
return db.MSADDRESSPROVINCEs.Select(data => new MsAddressProvinceObject()
{
ID = data.ID,
COUNTRYID = data.COUNTRYID,
PROVINCENAME = data.PROVINCENAME,
MSADDRESSCOUNTRY = new MsAddressCountryObject()
{
ID = data.MSADDRESSCOUNTRY.ID,
CODE = data.MSADDRESSCOUNTRY.CODE,
COUNTRYNAME = data.MSADDRESSCOUNTRY.COUNTRYNAME,
},
MSADDRESSDISTRICTs = data.MSADDRESSDISTRICTs.Select(dist => new MsAddressDistrictObject()
{
ID = dist.ID,
PROVINCEID = dist.PROVINCEID,
DISTRICTNAME = dist.DISTRICTNAME
})
});
}
That code works fast. But if I add/change/remove column, I have to modify the controller manually, one by one for all controller. For example, if I want to add geological coordinate in MSADDRESSDISTRICT, I have to change the code in Country Controller, Province Controller and District Controller.
So I decide to create extension method like this.
public static MsAddressCountryObject ToDTO(this MSADDRESSCOUNTRY data)
{
return new MsAddressCountryObject()
{
ID = data.ID,
CODE = data.CODE,
COUNTRYNAME = data.COUNTRYNAME,
};
}
public static IQueryable<MsAddressCountryObject ToDTO(this IEnumerable<MSADDRESSCOUNTRY datas)
{
return datas.Select(country =
{
var obj = country?.ToDTO();
obj.MSADDRESSPROVINCEs = country.MSADDRESSPROVINCEs?.ToDTO();
return obj;
}).AsQueryable();
}
public static MsAddressProvinceObject ToDTO(this MSADDRESSPROVINCE data)
{
return new MsAddressProvinceObject()
{
ID = data.ID,
COUNTRYID = data.COUNTRYID,
PROVINCENAME = data.PROVINCENAME,
MSADDRESSCOUNTRY = data.MSADDRESSCOUNTRY?.ToDTO()
};
}
public static IQueryable<MsAddressProvinceObject ToDTO(this IEnumerable<MSADDRESSPROVINCE datas)
{
return datas.Select(province =
{
var obj = province?.ToDTO();
obj.MSADDRESSDISTRICTs = province.MSADDRESSDISTRICTs.ToDTO();
return obj;
}).AsQueryable();
}
public static MsAddressDistrictObject ToDTO(this MSADDRESSDISTRICT data)
{
return new MsAddressDistrictObject()
{
ID = data.ID,
PROVINCEID = data.PROVINCEID,
DISTRICTNAME = data.DISTRICTNAME,
MSADDRESSPROVINCE = data.MSADDRESSPROVINCE?.ToDTO()
};
}
public static IQueryable<MsAddressDistrictObject ToDTO(this IEnumerable<MSADDRESSDISTRICT datas)
{
return datas.Select(district =
{
var obj = district?.ToDTO();
obj.MSADDRESSSUBDISTRICTs = district.MSADDRESSSUBDISTRICTs?.ToDTO();
return obj;
}).AsQueryable();
}
And the controller just like this.
[EnableQuery(MaxExpansionDepth = 4)]
public IQueryable<MsAddressCountryObject Get()
{
return db.MSADDRESSCOUNTRies.ToDTO()
}
And that makes the performance really bad. I think the extension is making a lot of memory allocation or some thing that make the result not being delivered directly to the client.
My goal is to create the code easy to maintain, and the performance not drop significantly.
I have many relation in other table. I want the $expand works without write all parent/child Select statement manually and one by one.
I have try to not calling ToDTO() from all the extension method. The result is the performance is fast. But I lost all the relation or I need to write the parent/child Select statement for all method.
Any suggestion will help.
Thanks.
Im trying to access and display the value of a dictionary where the dictionary has no real name but is a property of a class.
Currently I have an enum "Roles" with three elements (fighter, rogue, and sorcerer), and:
public class Adventurer
{
public int ID { get; set; }
public string Name { get; set; }
public Roles Role { get; set; }
public List<Skill> Skills { get; set; }
public override string ToString()
{
return $"{ID}" + " - " + $"{Name}" + " - " + $"{Role}";
}
}
and:
public class Skill
{
public int ID { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public Dictionary<Roles, Skill> LinkedTo { get; set; }
}
and in another class I have:
private void CreateSkills()
{
Skill swordFighting = new Skill() { ID = 1, Name = "Sword fighting"};
Skill stealth = new Skill() { ID = 2, Name = "Stealth"};
Skill magic = new Skill() { ID = 3, Name = "Magic"};
swordFighting.LinkedTo = new Dictionary<Roles, Skill>
{
{ Roles.Fighter, swordFighting }
};
stealth.LinkedTo = new Dictionary<Roles, Skill>
{
{ Roles.Rogue, stealth }
};
magic.LinkedTo = new Dictionary<Roles, Skill>
{
{ Roles.Sorcerer, magic }
};
}
private void DisplaySkills(Adventurer adventurer)
{
adventurer.Skills = adventurer.Role.LinkedTo; // I WOULD LIKE SOMETHING LIKE THIS...
lstAdventurer.ItemsSource = adventurer.Skills;
}
Is there some way of accessing the values (skills) of the adventurer by knowing only the role (fighter/rogue/sorcerer)?
Best,
Dedoj
Would you mean something like this?
for known Roles like Roles.Fighter:
adventurer.Skills = adventurer.Skills
.Select(s => s.LinkedTo.ContainsKey(Roles.Fighter) ? s.LinkedTo[Roles.Fighter] : null)
.Where(s => s != null).ToList();
I have this class, a hierarchy of categories.
class Categories
{
public long Id { get; set; }
public long ParentId { get; set; }
public string Name { get; set; }
public bool IsActive { get; set; }
public List<Categories> ChildrenData { get; set; }
}
How can I recursively iterate through this class of unknown depth and return the path to get there?
All "Id" values are unique. Say I want to find Id = 23 and get the path to get there by concatenating "Name".
For example, in the image below searching for ID = 23 would return: Default Category/Books/Nonfiction/Best-sellers
Example Hierarchy
My suggestion is that you first build an index:
public static Dictionary<long, Category> IndexBuilder(Category c)
{
var index = new Dictionary<long, Category>();
IndexBuilder(c, index);
return index;
}
private static void IndexBuilder(Category c, Dictionary<long, Category> index)
{
if (index.ContainsKey(c.Id))
return;
index[c.Id] = c;
foreach(var child in c.ChildrenData)
IndexBuilder(child, index);
}
Now you have a lookup, and your path is then easy to produce:
static IEnumerable<Category> PathToRoot(long id, Dictionary<long, Category> index)
{
// Presumably the parent id of the top category is a sentinel.
long current = id
while (current != 0)
{
var category = index[current];
yield return category;
current = category.ParentId;
}
}
Or maybe we just go until we run out of index:
static IEnumerable<Category> PathToRoot(long id, Dictionary<long, Category> index)
{
long current = id
while (index.ContainsKey(current))
{
var category = index[current];
yield return category;
current = category.ParentId;
}
}
Now you have a tool you can use to make your string:
static string Slash<T>(this IEnumerable<T> items) =>
string.Join("/", items);
var s = PathToRoot(23, index)
.Reverse()
.Select(c => c.Name)
.Slash();
See what I am doing here? Make a bunch of helper methods each of which is about five lines long, that can be composed together to make powerful solutions.
I have provided 2 ways, the first way is recursive and the last is not.
Recursive way, add a reference to your parent. This way when you find a match you can easily traverse your way back up the chain to create your path.
class Categories
{
public Categories Parent { get; set; }
public long Id { get; set; }
public long ParentId { get; set; }
public string Name { get; set; }
public bool IsActive { get; set; }
public List<Categories> ChildrenData { get; set; }
}
Then add a Find() method:
public string Find(long id)
{
if( Id == id )
{
return GetPath(); //<-- we need to code this next.
}
else
{
foreach( var entry in Categories)
{
string path = entry.Find(id);
if( path != null )
{
return path;
}
}
return null;
}
}
And finally the GetPath(), the assumption here is that the highest level instances of Categories do not have a Parent:
public string GetPath()
{
System.Text.StringBuilder sb = new StringBuilder();
Categories current = this;
while( current != null)
{
sb.Insert(0,current.Name);
if( current != this)
{
sb.Insert(0,"/");
}
current = Parent;
}
return sb.ToString();
}
Now if recursion isn't what you want, then pass in the current path to the Find() method.
public string Find(long id, string pathSoFar)
{
if (pathSoFar == null)
{
pathSoFar = Name;
}
else
{
pathSoFar = pathSoFar + Name;
}
if ( Id == id)
{
return pathSoFar;
}
else
{
foreach( var entry in Categories)
{
string path = entry.Find(id, pathSoFar + "/");
if( path != null )
{
return path;
}
}
return null;
}
}
Usage:
var nonRecusive = cats.Find(23, null);
This will get what you are looking for using recursion:
void Main()
{
var data = GetData();
Console.WriteLine(GetPath(data, 23, ""));
}
public String GetPath(Categories c, Int32 id, String path)
{
if (c.Id == id)
{
return path + "/" + c.Name;
}
foreach (var cd in c.ChildrenData)
{
var p = GetPath(cd, id, path + "/" + c.Name);
if (!String.IsNullOrWhiteSpace(p))
{
return p;
}
}
return "";
}
public class Categories
{
public long Id { get; set; }
public long ParentId { get; set; }
public string Name { get; set; }
public bool IsActive { get; set; }
public List<Categories> ChildrenData { get; set; }
}
public Categories GetData()
{
return
new Categories
{
Id = 1,
Name = "Default Category",
ChildrenData = new List<Categories>
{
new Categories
{
Id = 2,
Name = "Magazines",
ChildrenData = new List<Categories> {}
},
new Categories
{
Id = 2,
Name = "Books",
ChildrenData = new List<Categories>
{
new Categories
{
Id = 20,
Name = "Fiction",
ChildrenData = new List<Categories> {}
},
new Categories
{
Id = 21,
Name = "Nonfiction",
ChildrenData = new List<Categories>
{
new Categories
{
Id = 22,
Name = "New",
ChildrenData = new List<Categories> {}
},
new Categories
{
Id = 23,
Name = "Best-Sellers",
ChildrenData = new List<Categories> {}
},
}
}
}
}
}
};
}
I try to update my Products table but i can't because throw an error.
This is my hardcode controller:
[HttpPost]
public ActionResult EditProduct(ProductsViewModel productViewModel)
{
TechStoreEntities context = new TechStoreEntities();
Product newProduct = new Product
{
ProductId = productViewModel.ProductId,
Name = productViewModel.Name,
Price = productViewModel.Price,
Discount = productViewModel.Discount,
Quantity = productViewModel.Quantity,
Size = productViewModel.Size,
Description = productViewModel.Description,
ProducerName = productViewModel.ProducerName,
PaymentMethods = productViewModel.PaymentMethods,
CategoryID = productViewModel.CategoryID,
SubcategoryID = productViewModel.SubcategoryID,
IsNew = productViewModel.IsNew,
IsEnable = productViewModel.IsEnable
};
context.Entry(newProduct).State = EntityState.Modified;
context.SaveChanges();
ViewBag.CategoryID = new SelectList(context.Categories.Where(c => c.SubCategoryID == null), "CategoryID", "Name");
ViewBag.SubcategoryID = new SelectList(context.Categories.Where(c => c.SubCategoryID != null), "CategoryID", "Name");
return RedirectToAction("Products");
}
This is a model:
public class ProductsViewModel
{
public int ProductId { get; set; }
public string Name { get; set; }
public int Price { get; set; }
public int Discount { get; set; }
public int Quantity { get; set; }
public string Size { get; set; }
public string Description { get; set; }
public string ProducerName { get; set; }
public string PaymentMethods { get; set; }
public bool IsNew { get; set; }
public bool IsEnable { get; set; }
public string Category { get; set; }
public int CategoryID { get; set; }
public string Subcategory { get; set; }
public int SubcategoryID { get; set; }
public DateTime? CreateDate { get; set; }
}
I use strongly typed view:
#model MyTechStore.Models.ProductsViewModel
I add in a view:
#Html.HiddenFor(model => model.ProductId)
When i start app and enter some data to update existing data and press save, throw me exception:
System.Data.Entity.Infrastructure.DbUpdateConcurrencyException
When i debugging i saw that only the ProductId was 0. Everything else is OK. I tested with scaffolding controller but there is OK. I want to use view model, not as scaffolding controller use the model from my database.
Can someone tell me where i'm wrong?
My GET method:
public ActionResult EditProduct(int? id)
{
TechStoreEntities context = new TechStoreEntities();
ProductsManipulate product = new ProductsManipulate();
ProductsViewModel editProduct = product.EditProduct(id);
ViewBag.CategoryID = new SelectList(context.Categories.Where(c => c.SubCategoryID == null), "CategoryID", "Name");
ViewBag.SubcategoryID = new SelectList(context.Categories.Where(c => c.SubCategoryID != null), "CategoryID", "Name");
return View(editProduct);
}
And my data access layer:
public ProductsViewModel EditProduct(int? id)
{
TechStoreEntities context = new TechStoreEntities();
Product dbProduct = context.Products.Find(id);
ProductsViewModel product new ProductsViewModel
{
Name = dbProduct.Name,
Price = dbProduct.Price,
Quantity = dbProduct.Quantity,
CategoryID = dbProduct.CategoryID,
SubcategoryID = dbProduct.SubcategoryID,
IsNew = dbProduct.IsNew
};
return product;
}
You need to populate ProductId in ProductsViewModel
public ProductsViewModel EditProduct(int? id)
{
TechStoreEntities context = new TechStoreEntities();
Product dbProduct = context.Products.Find(id);
ProductsViewModel product = new ProductsViewModel()
{
// You need this line to pass the value to View
ProductId = dbProduct.ProductId,
Name = dbProduct.Name,
Price = dbProduct.Price,
Quantity = dbProduct.Quantity,
CategoryID = dbProduct.CategoryID,
SubcategoryID = dbProduct.SubcategoryID,
IsNew = dbProduct.IsNew
};
return product;
}
What that error is saying, is that EF tried to update a Product with those fields, but the it returned 0 RowCount therefore it knows something went wrong.
As you have mentioned before, the ProductId is 0, meaning you probably don't have a Product with that ID, and therefore when EF tries to update it, the row count is 0, which causes EF to throw a DbUpdateConcurrencyException.
You need to make sure your Id is populated if you want to an update an existing product.
Otherwise if you want an upsert (Update or Insert) you first need to check if a record exists for your given ProductId and if it does, do update, otherwise do insert.
I am receiving the following error when trying to insert an object into a child collection after the model binder has created the model, children and grandchildren and then using context.SaveChanges();
Multiplicity constraint violated. The role 'OrderDetail_OrderDetailPricelistProductOptions_Source' of the relationship 'PPLib.Models.OrderDetail_OrderDetailPricelistProductOptions' has multiplicity 1 or 0..1.
My models are as follows (removed properties for brevity);
public class Order
{
public int OrderId { get; set; }
public virtual List<OrderDetail> OrderDetails { get; set; }
}
public class OrderDetail
{
public int OrderDetailId { get; set; }
public int OrderId { get; set; }
public int ProductId { get; set; }
public virtual Product Product { get; set; } //FK NAV
public int? PricelistProductId { get; set; } // if a subscriber order ...has the ProductId from a PriceList.
private decimal _Price = 0;
public decimal Price { get { return _Price; } set { _Price = value; } }
private int _Quantity = 1;
public int Quantity { get { return _Quantity; } set { _Quantity = value; } }
public virtual List<OrderDetailPricelistProductOption> OrderDetailPricelistProductOptions { get; set; }
}
public class OrderDetailPricelistProductOption
{
public int OrderDetailPricelistProductOptionId { get; set; }
public int OrderDetailId { get; set; }
public virtual List<OrderDetailPricelistProductOptionsDetail> OrderDetailPricelistProductOptionsDetails { get; set; }
}
public class OrderDetailPricelistProductOptionsDetail
{
public int OrderDetailPricelistProductOptionsDetailId { get; set; }
public int OrderDetailPricelistProductOptionId { get; set; }
public string Name { get; set; }
}
To be clearer:
If I submit a complete new Order, with a list of OrderDetails, its list of OrderDetailPricelistProductOptions and its list of OrderDetailPricelistProductOptionsDetails, the model binder does its job and I receive no error doing:
db.Orders.Add(order);
db.SaveChanges();
If I submit an Edit with and Existing Order and a NEW a list of OrderDetails, its list of OrderDetailPricelistProductOptions and its list of OrderDetailPricelistProductOptionsDetails, I get the Order from the DB context and then merge the OrderDetails from the view model, using:
order.OrderDetails.AddRange(pricelistProductVM.Order.OrderDetails);
and I receive no error doing:
db.Entry(order).State = EntityState.Modified;
db.SaveChanges();
I have a particular situation, where I have to instantiate a new OrderDetail called autoFillOd, and inject its values from one of the existing OrderDetails assembled by the Model Binder. I change its Quantity value and then add it to the collection of OrderDetails in the ViewModel, like so:
pricelistProductVM.Order.OrderDetails.Add(autoFillOd);
When I do db.SaveChanges(), I receive the error.
You'll notice that the error is on the child of the OrderDetails: OrderDetail_OrderDetailPricelistProductOptions_Source
Why can I not add an OrderDetail dynamically into the collection of OrderDetails? All the OrderDetails are new (to be inserted) so the values are the same between the copies, except for the Quantity property which should not be an issue.
The controller action is as follows:
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Add(pricelistProductVM pricelistProductVM)
{
OrderLogic ol = new OrderLogic();
//Auth is running on execute
int userId = WebSecurity.CurrentUserId;
int websiteId = (int)Session["websiteId"];
int? id = null; // mediaId
int productId = pricelistProductVM.Product.ProductId;
int? eventId = pricelistProductVM.eventId;
string err = "";
if (productId > 0)
{
//Set Pricelist
Pricelist pricelist = ol.setPricelist(websiteId, id, eventId);
if (pricelist.PricelistId != 0)
{
//get the pricelistproduct from the pricelist
PricelistProduct pp = await (from ppx in db.PricelistProducts
where ppx.ProductId == productId
&& ppx.PricelistId == pricelist.PricelistId
&& ppx.isAvailable == true
&& ppx.DiscontinuedDate == null
&& ppx.Product.isAvailable == true
&& ppx.Product.DiscontinuedDate == null
select ppx).SingleOrDefaultAsync();
if (pp != null)
{
Order order = new Order();
//set some default values for the Order entity
if (pricelistProductVM.Order.OrderId == 0)
{
pricelistProductVM.Order.WebsiteId = websiteId;
pricelistProductVM.Order.UserId = userId;
pricelistProductVM.Order.EventId = eventId;
pricelistProductVM.Order.StartedDate = DateTime.UtcNow;
order = pricelistProductVM.Order;
}
else
{
order = await db.Orders.FindAsync(pricelistProductVM.Order.OrderId);
}
//set some default values for the OrderDetails entity
pricelistProductVM.Order.OrderDetails.First().InjectFrom(pp);
pricelistProductVM.Order.OrderDetails.First().IsPackage = false;
//determine if this product should be automatically added to any packages in the order
OrderDetail autoFillOd = ol.packageCheck(ref pp, ref pricelistProductVM, ref order, websiteId, db);
if (autoFillOd != null)
{
if (autoFillOd.Quantity > 0)
{
//This is where the OrderDetail that causes a problem is added
pricelistProductVM.Order.OrderDetails.Add(autoFillOd);
}
}
if (pricelistProductVM.Order.OrderId == 0)
{
db.Orders.Add(order);
}
else
{
order.OrderDetails.AddRange(pricelistProductVM.Order.OrderDetails);
db.Entry(order).State = EntityState.Modified;
}
db.SaveChanges();
}
else
{
//return error
err = "The product was not found in the available pricelist. Please reload your browser and make sure you are signed-in.";
}
}
}
else
{
//return error
err = "A productId was not passed so no product could not be found. Please reload your browser and make sure you are signed-in.";
}
if (err == "")
{
ViewBag.data = JsonConvert.SerializeObject(new { Success = 1, Msg = "The product was successfully added to your cart." });
}
else
{
ViewBag.data = JsonConvert.SerializeObject(new { Success = 0, Msg = err });
}
return View();
}
I appreciate the help!
I think OrderDetailPricelistProductOption.OrderDetailId can't be single -> it should be a list because it can appear in many OrderDetails...