I'm getting an error on View
The model item passed into the dictionary is of type 'System.Collections.Generic.List'1[oneToOneRelationship.Student]', but this dictionary requires a model item of type 'System.Collections.Generic.IEnumerable'1[oneToOneRelationship.StudentDBContext]'.
While running the application, database is getting updated.
namespace oneToOneRelationship.Controllers
{
public class StudentController : Controller
{
StudentDBContext objContext;
public StudentController()
{
objContext = new StudentDBContext();
}
public ActionResult Index()
{
Student s = new Student
{
StudentId = 1,
StudentName = "Hitesh",
StudentAge = 24
};
StudentAccount sa = new StudentAccount {
StudentName = "Sports account",
StudentAmount = 300,
student = s
};
objContext.Students.Add(s);
objContext.StudentAccounts.Add(sa);
objContext.SaveChanges();
var result = from r in objContext.Students select r;
var data = objContext.Students.ToList();
return View(data);
}
}
}
Related
I have 20 Dbsets in my context which I want to get the row count for each dbset to make sure all dbset row count is 0. To get the count for one dbset, this is my code:
var person = context.Persons.Count();
Is there a way to loop through the context, get the count for each dbset dynamically?
There is solution. Usage is simple:
var tablesinfo = ctx.GetTablesInfo();
if (tablesinfo != null)
{
var withRecords = tablesinfo
.IgnoreQueryFilters()
.Where(ti => ti.RecordCount > 0)
.ToArray();
}
Extension returns IQueryable<TableInfo> and you can reuse this query later. Probably you will need to filter out Views, but I think you can handle that. Note that IgnoreQueryFilters can be important if you have Global Query Filters defined.
What extension do:
It scans Model for entity types registered for particular DbContext and generates big Concat of Count queries. Here we have to do that via grouping by constant value.
Schematically it will generate the following LINQ query:
var tablesinfo =
ctx.Set<Entity1>.GroupBy(e => 1).Select(g => new TableInfo { TableName = "Entity1", RecordCount = g.Count()})
.Concat(ctx.Set<Entity2>.GroupBy(e => 1).Select(g => new TableInfo { TableName = "Entity2", RecordCount = g.Count()}))
.Concat(ctx.Set<Entity3>.GroupBy(e => 1).Select(g => new TableInfo { TableName = "Entity3", RecordCount = g.Count()}))
...
Which wll be converted to the following SQL:
SELECT "Entity1" AS TableName, COUNT(*) AS RecordCount FROM Entity1
UNION ALL
SELECT "Entity2" AS TableName, COUNT(*) AS RecordCount FROM Entity2
UNION ALL
SELECT "Entity3" AS TableName, COUNT(*) AS RecordCount FROM Entity3
...
Implementation:
public static class QueryableExtensions
{
public class TableInfo
{
public string TableName { get; set; } = null!;
public int RecordCount { get; set; }
}
public static IQueryable<TableInfo> GetTablesInfo(this DbContext ctx)
{
Expression query = null;
IQueryProvider provider = null;
var ctxConst = Expression.Constant(ctx);
var groupingKey = Expression.Constant(1);
// gathering information for MemberInit creation
var newExpression = Expression.New(typeof(TableInfo).GetConstructor(Type.EmptyTypes));
var tableNameProperty = typeof(TableInfo).GetProperty(nameof(TableInfo.TableName));
var recordCountProperty = typeof(TableInfo).GetProperty(nameof(TableInfo.RecordCount));
foreach (var entityType in ctx.Model.GetEntityTypes())
{
var entityParam = Expression.Parameter(entityType.ClrType, "e");
var tableName = entityType.GetTableName();
// ctx.Set<entityType>()
var setQuery = Expression.Call(ctxConst, nameof(DbContext.Set), new[] {entityType.ClrType});
// here we initialize IQueryProvider, which is needed for creating final query
provider ??= ((IQueryable) Expression.Lambda(setQuery).Compile().DynamicInvoke()).Provider;
// grouping paraneter has generic type, we have to specify it
var groupingParameter = Expression.Parameter(typeof(IGrouping<,>).MakeGenericType(typeof(int), entityParam.Type), "g");
// g => new TableInfo { TableName = "tableName", RecordCount = g.Count() }
var selector = Expression.MemberInit(newExpression,
Expression.Bind(tableNameProperty, Expression.Constant(tableName)),
Expression.Bind(recordCountProperty,
Expression.Call(typeof(Enumerable), nameof(Enumerable.Count), new[] {entityParam.Type}, groupingParameter)));
// ctx.Set<entityType>.GroupBy(e => 1)
var groupByCall = Expression.Call(typeof(Queryable), nameof(Queryable.GroupBy), new[]
{
entityParam.Type,
typeof(int)
},
setQuery,
Expression.Lambda(groupingKey, entityParam)
);
// ctx.Set<entityType>.GroupBy(e => 1).Select(g => new TableInfo { TableName = "tableName", RecordCount = g.Count()}))
groupByCall = Expression.Call(typeof(Queryable), nameof(Queryable.Select),
new[] {groupingParameter.Type, typeof(TableInfo)},
groupByCall,
Expression.Lambda(selector, groupingParameter));
// generate Concat if needed
if (query != null)
query = Expression.Call(typeof(Queryable), nameof(Queryable.Concat), new[] {typeof(TableInfo)}, query,
groupByCall);
else
query = groupByCall;
}
// unusual situation, but Model can have no registered entities
if (query == null)
return null;
return provider.CreateQuery<TableInfo>(query);
}
}
My application is ASP.NET MVC 5 / SQL Server.
I am trying to select specific columns from a list based on an array:
First list has 200 columns: Age, Gender, .....
var list1 = _reportRepository.ShowMasteView().ToList();
Second list has 20 columns: Age, Gender, ......
From the view I select the items to be displayed:
string[] lits2 = showColumn.Where(c => c.Value == true).Select(c=> c.Key).ToArray();
I get
To get these two specific columns, I tried
var nList = list1.Select(t2 => lits2.Any(t1 => t2.Contains(t1)));
I get an error
Can not resolve symbol "Contains"
I was able to do it using the following
var keys = "Age,Gender";
var connection =
ConfigurationManager.ConnectionStrings["DALEntities"].ConnectionString;
using (var dataAdapter = new SqlDataAdapter("SELECT " + keys
+ " from dbo.vw_MasterView", connection))
{
var dataTable = new DataTable();
dataAdapter.Fill(dataTable);
dataAdapter.FillSchema(dataTable, SchemaType.Mapped);
return dataTable;
}
Is there a better way in linq?
From my understand it appears you are trying to extract/select a dynamic object that only has the desired properties/columns.
This can be achieved by building a dynamic expression/function to apply to the Select
The following builds an expression based on the model type and the provided properties
static class DynamicExtensions {
public static IQueryable<dynamic> SelectDynamic<TModel>(this IQueryable<TModel> query, ISet<string> propertyNames) {
var selector = query.BuildSelectorFor(propertyNames);
return query.Select(selector);
}
static Expression<Func<TModel, dynamic>> BuildSelectorFor<TModel>(this IQueryable<TModel> query, ISet<string> propertyNames) {
var modelType = typeof(TModel);
var properties = modelType.GetProperties().Where(p => propertyNames.Contains(p.Name));
// Manually build the expression tree for
// the lambda expression v => new { PropertyName = v.PropertyName, ... }
// (TModel v) =>
var parameter = Expression.Parameter(modelType, "v");
// v.PropertyName
var members = properties.Select(p => Expression.PropertyOrField(parameter, p.Name));
var addMethod = typeof(IDictionary<string, object>).GetMethod(
"Add", new Type[] { typeof(string), typeof(object) });
// { { "PropertyName", v.PropertyName}, ... }
var elementInits = members.Select(m =>
Expression.ElementInit(addMethod, Expression.Constant(m.Member.Name), Expression.Convert(m, typeof(object))));
// new ExpandoObject()
var newExpando = Expression.New(typeof(ExpandoObject));
// new ExpandoObject() { { "PropertyName", v.PropertyName}, ... }
var expando = Expression.ListInit(newExpando, elementInits);
// (TModel v) => new ExpandoObject() { { "PropertyName", v.PropertyName}, ... }
var lambdaExpression = Expression.Lambda<Func<TModel, dynamic>>(expando, parameter);
return lambdaExpression;
}
}
This takes advantage of ExpandoObject whose members can be dynamically added and removed at run time.
The following test was used as an example of how the above function is invoked.
[TestMethod]
public void DynamicList() {
var list1 = new List<Person>
{
new Person{ Gender = "Male", Age = 10, FirstName = "Nama1", SampleNumber = 12},
new Person{ Gender = "Male", Age = 12, FirstName = "Nama2", SampleNumber = 13},
new Person{ Gender = "Female", Age = 13, FirstName = "Nama3", SampleNumber = 14},
new Person{ Gender = "Male", Age = 14, FirstName = "Nama4", SampleNumber = 15},
};
var keys = new string[] { "Age", "Gender", };
var nList = list1.AsQueryable().SelectDynamic(new HashSet<string>(keys));
foreach (IDictionary<string, object> row in nList) {
var msg = $"{{ {keys[0]} = {row[keys[0]]}, {keys[1]} = {row[keys[1]]} }}";
Debug.WriteLine(msg);
}
}
and produces the following output
{ Age = 10, Gender = Male }
{ Age = 12, Gender = Male }
{ Age = 13, Gender = Female }
{ Age = 14, Gender = Male }
The dynamic objects can be used in the View and it is a simple matter of calling the desired members.
For example suppose you have a model as follows
public class MyViewModel {
public string MyProperty { get; set; }
public string[] Keys { get; set; }
public List<dynamic> MyDynamicProperty { get; set; }
}
that was populated with data and given to the view
var list1 = _reportRepository.ShowMasteView();
var keys = new string[] { "Age", "Gender", };
var nList = list1.AsQueryable().SelectDynamic(new HashSet<string>(keys));
var viewModel = new MyViewModel {
MyProperty = "Hello World",
MyDynamicProperty = nList.ToList(),
Keys = keys
};
return View(viewModel);
Then in the view you can use the model as desired, casting to get access to members in the expando object.
#model MyViewModel
...
<h2>#Model.MyProperty</h2>
<table>
<tr>
#foreach(string key in Model.Keys) {
<th>#key</th>
}
</tr>
#foreach (IDictionary<string, object> row in Model.MyDynamicProperty) {
<tr>
#foreach(string key in Model.Keys) {
<td>#row[#key]</td>
}
</tr>
}
</table>
I think you just need to use Contains on your list2.
var nList = list1.Where(t => lits2.Contains(t1));
Contains is a method for Lists. The code you had was trying to use it on a string.
If you have two list of a person's class
public class Person
{
public int id { get; set; }
public string name { get; set; }
}
If the lists are as below:
var list1 = new List<Person>
{
new Person{ id = 1, name = "Nama1"},
new Person{ id = 2, name = "Nama2"},
new Person{ id = 3, name = "Nama3"},
new Person{ id = 4, name = "Nama4"},
};
var list2 = new List<Person>
{
new Person{ id = 1, name = "Nama1"},
new Person{ id = 2, name = "Nama2"},
};
You can filter in the following ways
var keys = list2.Select(x => x.id).ToList();
var filter1= list1.Where(x => keys.Contains(x.id)).ToList();
var filter2= list1.Where(x => keys.Contains(x.id)).Select(x => new { x.name }).ToList();
var filter3= list1.Select(x => new
{
id = x.id,
name = x.name,
check = keys.Contains(x.id)
}).Where(x => x.check).ToList();
If you have array of string
you can use below code
array string same
var lis1 = new string[] {"name1", "name2","name3" };
var lis2 = new string[] { "name1" };
You can filter array of string in the following ways
var items1= lis1.Where(x=>lis2.Contains(x)).ToList();
var items= lis1.Select(x=> new { x, check= lis2.Contains(x) }).Where(x=>x.check == true).ToList();
Im working with a custom plugin for CRM online 2015 and every time I try to access the activityparty from the field "Email.To" I get
"base {System.SystemException} = {"Unable to cast object of type 'Microsoft.Xrm.Sdk.Entity' to type ...ActivityParty'."}"
Here is how my code looks like:
public class PreCreate : Plugin
{
public PreCreate()
: base(typeof(PreCreate))
{
base.RegisteredEvents.Add(new Tuple<int, string, string, Action<LocalPluginContext>>(20, "Create", "email", new Action<LocalPluginContext>(ExecutePreEntityCreate)));
}
public void ExecutePreEntityCreate(LocalPluginContext localContext)
{
var target = (Entity)localContext.PluginExecutionContext.InputParameters["Target"];
using (var context = new XrmServiceContext(localContext.OrganizationService))
{
var email = target.ToEntity<Email>(); //The entity has the right values
var activityPartyList=email.To // here I see the exception
//If I use the following code:
var activityParty = email.GetAttributeValue<EntityCollection>("to");
//I get an empty ActivityParty(empty Id)
}
}
}
Do I have to do some initialization for activityparty types?
There is no issue with the code, the field Email.To will return a EntityCollection and to obtain that you need to use:
var entityCollection = email.GetAttributeValue<EntityCollection>("to");
This will give you a collection of entities that need to be converted to ActivityParty(entityCollection.Entities).
To convert the Entities you need to:
foreach (var entityItem in entityCollection.Entities)
{
var ap = entityItem.ToEntity<ActivityParty>();
//Here you will get the LogicalName in this case Lead
// the Id and the name
var leadId = ap.PartyId.Id;
//To get the Lead
var lead=context.LeadSet.FirstOrDefault(l => l.Id == leadId);
}
I am trying to follow the guidelines provided http://msdn.microsoft.com/en-us/library/dn314429.aspx by Microsoft for Unittesting DbSets. All was going well - as they documented. Until I got to some code which works with a inheritance table. Since OfType() is an extension method, I cannot figure out how to create a Mock which will work to keep my code testable.
To clarify: I am trying to Test My Service Layer, which take a DBContext which is Injected, and which exposes several DbSets. In particular, I have an abstract History class, which has concrete derived types of StaffHistory, ContactHistory, etc. As a result, I only have 1 DbSet on my Dbcontext, which is of type History. I then use the Extension method OfType to set the discriminator and query the particular type.
When I create a Mock DbSet all usually works fine, except the OfType extension method fails, reporting NullReference Exception.
Any ideas or tips?
Service Layer:
public IEnumerable<ContactHistory> GetContactHistory(int ContactId, int AgeInDays)
{
var age = DateTimeOffset.Now.AddDays(-Math.Abs(AgeInDays));
return context.History.OfType<ContactHistory>()
.Where(h => h.ContactId == ContactId && h.CreatedAt >= age)
.AsEnumerable();
}
Unit Test Code:
[TestMethod]
public void History_Returns_Limited_Results()
{
var testData = new List<ContactHistory> {
new ContactHistory {
ContactId = 1,
CreatedAt = DateTimeOffset.Now,
UserName = "UserA",
Action = "Action",
},
new ContactHistory {
ContactId = 4,
CreatedAt = DateTimeOffset.Now.AddDays(-61),
UserName = "UserA",
Action = "Action",
},
new ContactHistory {
ContactId = 4,
CreatedAt = DateTimeOffset.Now.AddDays(-60),
UserName = "UserA",
Action = "Action",
},
new ContactHistory {
ContactId = 4,
CreatedAt = DateTimeOffset.Now,
UserName = "UserA",
Action = "Action",
}
}.AsQueryable();
// Setup
var mockContext = new Mock<IPEContext>();
var mockSet = new Mock<IDbSet<History>>();
mockSet.As<IQueryable<ContactHistory>>().Setup(m => m.Provider).Returns(testData.Provider);
mockSet.As<IQueryable<ContactHistory>>().Setup(m => m.Expression).Returns(testData.Expression);
mockSet.As<IQueryable<ContactHistory>>().Setup(m => m.ElementType).Returns(testData.ElementType);
mockSet.As<IQueryable<ContactHistory>>().Setup(m => m.GetEnumerator()).Returns(testData.GetEnumerator());
mockContext.Setup(c => c.History).Returns(mockSet.Object);
// Test
var service = new HistoryService(mockContext.Object);
var historyFound = service.GetContactHistory(4, 60);
// Verify
Assert.IsNotNull(historyFound);
Assert.AreEqual(2, historyFound.Count());
}
Is there something flawed in my approach? Is there something flawed in how I have setup my mock? This was following the Microsoft Article I mentioned above so that I could test service logic acting on a DbSet. The only flaw seems to be the Extension Method - not sure how I should work around that.
OK - I have figured this out. Of course there was a simple answer, but one which eluded me, because I had already mapped the Linq Provider and all in as the Type IQueryable. If you are using the .OfType() method, your mock must return on the Untyped Queryable method.
Here is the test code to allow the Method to work properly:
[TestMethod]
public void History_Returns_Limited_Results()
{
var today = new DateTimeOffset(DateTime.Today, DateTimeOffset.Now.Offset);
var testData = new List<ContactHistory> {
new ContactHistory {
ContactId = 1,
CreatedAt = today,
UserName = "UserA",
Action = "Action",
},
new ContactHistory {
ContactId = 4,
CreatedAt = today.AddDays(-61),
UserName = "UserA",
Action = "Action",
},
new ContactHistory {
ContactId = 4,
CreatedAt = today.AddDays(-60),
UserName = "UserA",
Action = "Action",
},
new ContactHistory {
ContactId = 4,
CreatedAt = today,
UserName = "UserA",
Action = "Action",
}
}.AsQueryable();
// Setup
var mockContext = new Mock<IPEContext>();
var mockSet = new Mock<IDbSet<History>>();
mockSet.As<IQueryable>().Setup(m => m.Provider).Returns(testData.Provider);
mockSet.As<IQueryable>().Setup(m => m.Expression).Returns(testData.Expression);
mockSet.As<IQueryable>().Setup(m => m.ElementType).Returns(testData.ElementType);
mockSet.As<IQueryable>().Setup(m => m.GetEnumerator()).Returns(testData.GetEnumerator());
mockContext.Setup(c => c.History).Returns(mockSet.Object);
// Test
var service = new HistoryService(mockContext.Object);
var contact = new Person { ContactId = 4 };
var historyFound = service.GetContactHistory(contact, 60);
// Verify
Assert.IsNotNull(historyFound);
Assert.AreEqual(2, historyFound.Count());
}
Graph of objects stored in the database and the same object graph is serialized into a binary package. Package is transmitted over the network to the client, then it is necessary to merge data from the package and data from the database.
Source code of merge:
//objList - data from package
var objectIds = objList.Select(row => row.ObjectId).ToArray();
//result - data from Database
var result = SomeService.Instance.LoadObjects(objectIds);
foreach (var OSobj in objList)
{
var obj = result.Objects.ContainsKey(OSobj.ObjectId)
? result.Objects[OSobj.ObjectId]
: result.Objects.CreateNew(OSobj.ObjectId);
var targetObject = result.DataObjects.Where(x => x.ObjectId == OSobj.ObjectId).FirstOrDefault();
targetObject.StopTracking();
var importedProperties = ImportProperties(targetObject.Properties, OSobj.Properties);
targetObject.Properties.Clear();
foreach (var property in importedProperties)
{
targetObject.Properties.Add(property);
}
targetObject.StartTracking();
}
return result;
And code of ImportProperties method:
static List<Properties> ImportProperties(
IEnumerable<Properties> targetProperties,
IEnumerable<Properties> sourceProperties)
{
Func<Guid, bool> hasElement = targetProperties
.ToDictionary(e => e.PropertyId, e => e)
.ContainsKey;
var tempTargetProperties = new List<Properties>();
foreach (var sourceProperty in sourceProperties)
{
if (!hasElement(sourceProperty.PropertyId))
{
sourceProperty.AcceptChanges();
tempTargetProperties.Add(sourceProperty.MarkAsAdded());
}
else
{
sourceProperty.AcceptChanges();
tempTargetProperties.Add(sourceProperty.MarkAsModified());
}
}
return tempTargetProperties;
}
Server save incoming changes like this :
_context.ApplyChanges("OSEntities.Objects", entity);
_context.SaveChanges(SaveOptions.DetectChangesBeforeSave);
When the server tries to save the changes occur exception:
AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges.
But if I change the code of ImportProperties method, the error does not occur and the changes are saved successfully:
static List<Properties> ImportProperties(
IEnumerable<Properties> targetProperties,
IEnumerable<Properties> sourceProperties)
{
Func<Guid, bool> hasElement = targetProperties.ToDictionary(e => e.PropertyId, e => e).ContainsKey;
var tempTargetProperties = new List<Properties>();
foreach (var sourceProperty in sourceProperties)
{
if (!hasElement(sourceProperty.PropertyId))
{
var newProp = new Properties
{
ElementId = sourceProperty.ElementId,
Name = sourceProperty.Name,
ObjectId = sourceProperty.ObjectId,
PropertyId = sourceProperty.PropertyId,
Value = sourceProperty.Value
};
tempTargetProperties.Add(newProp);
}
else
{
var modifiedProp = new Properties
{
ElementId = sourceProperty.ElementId,
Name = sourceProperty.Name,
ObjectId = sourceProperty.ObjectId,
PropertyId = sourceProperty.PropertyId,
Value = sourceProperty.Value
};
modifiedProp.MarkAsModified();
tempTargetProperties.Add(modifiedProp);
}
}
return tempTargetProperties;
}
Why is there an exception?
When you transport an object graph (Entity with n-level deep navigation properties) to a client application the entities will record any changes made in their respective change trackers. When entity (or object graph) is sent back to the server side of the application basically all you need to do is:
try
{
using(Entities context = new Entities())
{
context.ApplyChanges(someEntity);
context.SaveChanges();
}
}
catch
{
...
}
I don't see the need of all the code above you posted. What are you trying to achieve with that code?