I have an report, in which I like to show reports about some Employees. The Employee Class contains the following attributes :
public class Employee {
public string name;
public Branch branch;
}
I have an list of employees, and I bind them to the report columns. It is showing employee name without any problem in the first column of the report table, but in the second column it is showing the Branch object's assembly, namespace etc etc. (It is obvious, of course, since I am binding the whole Branch object to that column).
My question is : how can I show employee name in one column and corresponding branch name in another column?
My Branch Class has the following definition :
public class Branch{
public int branchId;
public string name;
}
I am adding an data source to the report class from the tool box, creating an XtraReport object, and simply assigning an Employee list as follows :
XtraReport1.DataSource = EmployeeList;
XtraReport objects can do sub-property binding. Give your label the text "[branch.name]" (rather than picking the data source with the designer drop-down).
your binding probably looks like:
....DataBindings.Add(new Binding("Text", employee, "branch"));
change it to
....DataBindings.Add(new Binding("Text", employee.branch, "name"));
Related
I've been searching for an answer on how to delete ALL records from a table using LINQ method syntax but all answers do it based on an attribute.
I want to delete every single record from the databse.
The table looks like so:
public class Inventory
{
public int InventoryId { get; set; }
public string InventoryName { get; set; }
}
I'm not looking to delete records based on a specific name or id.
I want to delete ALL recods.
LINQ method syntax isn't a must, bt I do prefer it since it's easier to read.
To delete all data from DB table I recommend to use SQL:
Trancate Table <tableName>
Linq is not meant to change the source. There are no LINQ methods to delete or update any element from your input.
The only method to change you input, is to select the (identifiers of the )data that you want to delete in some collection, and then delete the items one by one in a foreach. It might be that your interface with the source collection already has a DeleteRange, in that case you don't have to do the foreach.
Alas you didn't mention what your table was: Is it a System.Data.DataTable? Or maybe an Entity Framework DbSet<...>? Any other commonly used class that represents a Table?
If you table class is a System.Data.DataTable, or implements ICollection, it should have a method Clear.
If your tabls is an entity framework DbSet<...>, then it depends on your Provider (the database management system that you use) whether you can use `Clear'. Usually you need to do the following:
using (var dbContext = new MyDbContext(...))
{
List<...> itemsToDelete = dbContext.MyTable.Where(...).ToList();
dbContext.MyTable.RemoveRange(itemsToDelete);
dbContext.SaveChanges();
}
class Person {
#PropertyName("detail.change")
Detail detail
}
class Detail {
String name;
String age;
}
I have a class named Person.
and it has a field named detail which is also an object
now i want to compare two Person
and no matter what the changes are, i want it returns me "detail.change" as the property name
for now if the name or age is different. javers returns me name or age
do you have any idea that i can do this?
really appreciate your help!
You can do it only if you map Detail to ValueType (https://javers.org/documentation/domain-configuration/#ValueType). ValueType is treated by Javers as atomic value. When Detail is mapped to ValueObject, Javers reports concrete properties of Detail as changed.
I am using ServiceStack.Ormlite, and also make heavy use of the automatic handling of enums whereby they are stored in the db as strings but retrieved and parsed nicely back into Enums on retrieval, so I can do easy type-comparison - say, for a property "UserRole" in the db/table class "User" of enum type "UserRoleEnum" (just for demonstration).
This works great.. until I want to use the enum property to define a multi-column unique constraint
CompositeIndexAttribute(bool unique, params string[] fieldNames);
like:
[CompositeIndex(true, nameof(UserId), nameof(UserRole)]
public class User
{
public long UserId {get;set;}
public UserRoleEnum UserRole {get;set;
}
(as per :
How to Create Unique Constraint with Multiple Columns using ServiceStack.OrmLite? ).
At which time i get:
System.Data.SqlClient.SqlException
Column 'UserRole' in table 'User' is of a type that is invalid for use as a key column in an index.
I currently see options as:
a) Define UserRole as a string (isntead of UserRoleEnum ) in the table entity class and lose the Enum use.... having to manually test the value each time to confirm that the db value is one that i expect in my business logic later
b) Continue to use UserRoleEnum but lose the ability to declare multicolumn uniqueconstraints using the class attribute, and probably have to create these manually using a subsequent db migration script?
Is there any way to make the enums and the multicolumn constraint play nicely, out of the box?
This issue was because enum properties were using the default string definition fallback of VARCHAR(MAX) which SQL Server doesn't let you create indexes on whereas the column definition of a string property is VARCHAR(8000).
This issue is now resolved from this commit which now uses the VARCHAR(255) string definition of the EnumConverter Type Converter. This change is available from v4.5.5 that's now available on MyGet.
Otherwise you can also change the size of the column definition to match a string property by adding a [StringLength] attribute, e.g:
[CompositeIndex(true, nameof(UserId), nameof(UserRole))]
public class User
{
public long UserId { get; set; }
[StringLength(8000)]
public string UserRole { get; set; }
}
I am using Entity Framework code first with a generic repository pattern with ASP.NET MVC. I have two tables Category and Product.
My model class of product is like this
Public class Product
{
public int ProductID{get;set;}
Public int CategoryID{get;set;}
[ForeignKey("CategoryID")]
public virtual Category Category{get;set;}
[NotMapped]
public string CategoryName{get;set;}
}
The model is binding correctly as long as I am getting data using DBContext.
But I am having a problem when I am getting list of products from stored procedure mapped to Product object. So it is not mapping the Category property of Product object and hence I cannot able to get Category.CategoryName.
So I added a new property with [NotMapped] attribute in product class as CategoryName. But it is also not binding from stored procedure.
And if I remove the [NotMapped] attribute then it is correctly binding from stored procedure but error occurs again when getting product by DbContext (Linq).
Please help me in this regards.
You don't need to add an extra property, use the DbSet.SqlQuery method for queries that return entity types. The returned objects must be of the type expected by the DbSet object, and they are automatically tracked by the database context unless you turn tracking off.
var products= _context.Products.SqlQuery("storedProcedureName",params);
The columns returned by SP should match the properties of your entity type otherwise, it will throw an exception.
After execute your SP, you should be able of get the CategoryName through your Category navigation property:
var catName=someProduct.Category.CategoryName;
On the other hand, the returned data by the Database.SqlQuery isn't tracked by the database context, even if you use this method to retrieve entity types. If you want to track the entities that you get after execute your SP using this method, you can try this:
//Attach the entity to the DbContext
_context.Product.Attach(someProduct);
//The Category navigation property will be lazy loaded
var catName=someProduct.Category.CategoryName;
If you have disabled lazy loading you can load explicitly your navigation property:
//Load the Category navigation property explicitly
_context.Entry(someProduct).Reference(c => c.Category).Load();
I am trying to extend my Linq-to-Sql entity with a few extra properties. These are "calculated" properties based on data from the underlying SQL View. For example, think of having a Date of Birth field, which is used to calculate an extended Age field.
I tried to extend my entity class by extending the OnLoaded() method.
I get a compile time error however stating that I cannot create it. I checked the designer code for my LTS entity class, and it doesn't have a partial definition for any of the expected extension points.
I checked a few of my other LTS entity classes and they do have these extension points. The only difference I see is that the one without is loaded from a SQL View, rather than a table. Is there a way to hook into a "Loaded" event when loading from a SQL View?
TIA!
I found that I did not have a PrimaryKey specified for my Linq-to-Sql entity class. I believe without a Primary Key specified, no extension methods generated in the entity class. Once I specified a Primary Key on my LTS entity class definition (through the designer), I was able to extend the OnLoaded() event.
You can do this by means of a property. Just create a partial class with the same name as your entity. Any properties or methods that you add will automatically be part of the entity and allow to use any of its members.
Here's an example of the pattern:
public partial class [The Name of the Entity]
{
public int Age
{
get
{
return CalculateAge(this.DateOfBirth);
}
}
}
Here's some logic on how to calculate the Age (Source: Geekpedia)
public static int CalculateAge(DateTime BirthDate)
{
int YearsPassed = DateTime.Now.Year - BirthDate.Year;
// Are we before the birth date this year? If so subtract one year from the mix
if (DateTime.Now.Month < BirthDate.Month ||
(DateTime.Now.Month == BirthDate.Month && DateTime.Now.Day < BirthDate.Day))
{
YearsPassed--;
}
return YearsPassed;
}