Skip to content

upd XPO readme #10

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
LanaDX merged 4 commits into from
Mar 10, 2026
Merged

upd XPO readme #10

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
a2a3ebe
upd XPO readme
LanaDX Feb 26, 2026
4683b77
README auto update [skip ci]
DevExpressExampleBot Feb 26, 2026
2b5338c
upd
LanaDX Feb 26, 2026
0212567
Merge branch 'update-readme' of https://github.com/DevExpress-Example…
LanaDX Feb 26, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
83 changes: 49 additions & 34 deletions CS/XPO/Readme.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,27 +4,18 @@ This example illustrates how to implement a business object with an identifier f

<img width="890" height="447" alt="sequential-number" src="https://github.com/user-attachments/assets/440955ce-ee90-43b2-b2ae-f63e25fac796" />

## Implementation Details

## Scenario

This is a variation of the [How to generate a sequential number for a business object within a database transaction](https://www.devexpress.com/Support/Center/p/E2620) XPO example, which was specially adapted for XAF applications.

In particular, for better reusability and smoother integration with standard XAF CRUD Controllers, all required operations to generate sequences are managed within the base persistent class automatically when a persistent object is being saved. This solution consists of several key parts:

* [Sequence](SequenceGenerator/SequenceGenerator.Module/SequenceClasses/SequenceGenerator.cs) and [SequenceGenerator](SequenceGenerator/SequenceGenerator.Module/SequenceClasses/SequenceGenerator.cs) are auxiliary classes that are primarily responsible for generating user-friendly identifiers. 
* [UserFriendlyIdPersistentObject](SequenceGenerator/SequenceGenerator.Module/SequenceClasses/UserFriendlyIdPersistentObject.cs) is a base persistent class that subscribes to XPO's Session events and delegates calls to the core classes above. To get the described functionality in your project, inherit your own business classes from this base class.

Check the original example description first for more information on the demonstrated scenarios and functionality.
Follow the steps below to add this functionality to your project:

## Implementation Details
1. Copy the following files to your project:

1. Copy the [SequenceGenerator](SequenceGenerator/SequenceGenerator.Module/SequenceClasses/SequenceGenerator.cs) and [UserFriendlyIdPersistentObject](SequenceGenerator/SequenceGenerator.Module/SequenceClasses/UserFriendlyIdPersistentObject.cs) files to your project.
* [SequenceGenerator.cs](SequenceGenerator/SequenceGenerator.Module/SequenceClasses/SequenceGenerator.cs) contains classes responsible for generating user-friendly identifiers.
* [UserFriendlyIdPersistentObject.cs](SequenceGenerator/SequenceGenerator.Module/SequenceClasses/UserFriendlyIdPersistentObject.cs) is a base persistent class that subscribes to XPO's Session events and delegates calls to the core classes above. To get the described functionality in your project, inherit your own business classes from this base class.

2. Register the `SequenceGeneratorProvider` scoped service, configure `SequenceGeneratorOptions`, and specify the method that will be used to retrieve the Connection String from the database:

For applications without multi-tenancy:

* ASP.NET Core Blazor (`YourSolutionName\YourSolutionName.Blazor.Server\Startup.cs`)
* **ASP.NET Core Blazor without multi-tenancy** (`YourSolutionName\YourSolutionName.Blazor.Server\Startup.cs`)

```cs{7-12}
public class Startup {
Expand All @@ -41,7 +32,7 @@ Check the original example description first for more information on the demonst
});
```

* WinForms (`YourSolutionName\YourSolutionName.Win\Startup.cs`)
* **WinForms without multi-tenancy** (`YourSolutionName\YourSolutionName.Win\Startup.cs`)

```cs{7-12}
//...
Expand All @@ -57,10 +48,23 @@ Check the original example description first for more information on the demonst
};
});
```

For multi-tenant applications:

* ASP.NET Core Blazor (`YourSolutionName\YourSolutionName.Blazor.Server\Startup.cs`)
* **Applications with Middle Tier Security without multi-tenancy** (`YourSolutionName.MiddleTier\Startup.cs`):

```cs{4-10}
public class Startup
//...
public void ConfigureServices(IServiceCollection services) {
services.AddScoped<SequenceGeneratorProvider>();
services.Configure<SequenceGeneratorOptions>(opt => {
opt.GetConnectionString = (serviceProvider) => {
var options = serviceProvider.GetRequiredService<IOptions<DataServerSecurityOptions>>();
return options.Value.ConnectionString;
};
});
```

* **ASP.NET Core Blazor multi-tenant applications** (`YourSolutionName\YourSolutionName.Blazor.Server\Startup.cs`)

```cs{7-12}
public class Startup {
Expand All @@ -77,7 +81,7 @@ Check the original example description first for more information on the demonst
});
```

* WinForms (`YourSolutionName\YourSolutionName.Win\Startup.cs`)
* **WinForms multi-tenant applications** (`YourSolutionName\YourSolutionName.Win\Startup.cs`)

```cs{7-12}
//...
Expand All @@ -94,9 +98,7 @@ Check the original example description first for more information on the demonst
});
```

For applications with Middle Tier Security:

* Middle Tier project (`YourSolutionName.MiddleTier\Startup.cs`):
* **Multi-tenant applications with Middle Tier Security** (`YourSolutionName.MiddleTier\Startup.cs`):

```cs{4-10}
public class Startup
Expand All @@ -105,14 +107,13 @@ Check the original example description first for more information on the demonst
services.AddScoped<SequenceGeneratorProvider>();
services.Configure<SequenceGeneratorOptions>(opt => {
opt.GetConnectionString = (serviceProvider) => {
var options = serviceProvider.GetRequiredService<IOptions<DataServerSecurityOptions>>();
return options.Value.ConnectionString;
return serviceProvider.GetRequiredService<IConnectionStringProvider>().GetConnectionString();
};
});
```

3. Inherit your business classes to which you want to add sequential numbers from the module's `UserFriendlyIdPersistentObject` class. Declare a calculated property that uses the `SequenceNumber` property of the base class to produce a string identifier according to the required format:
3. To add sequential numbers to your business class, inherit it from the `UserFriendlyIdPersistentObject` class. Declare a calculated property that utilizes the base class's `SequenceNumber` to generate a string identifier in the desired format.

```cs
public class Contact : GenerateUserFriendlyId.Module.BusinessObjects.UserFriendlyIdPersistentObject {
[PersistentAlias("Concat('C',PadLeft(ToStr(SequentialNumber),6,'0'))")]
Expand All @@ -122,8 +123,8 @@ Check the original example description first for more information on the demonst

```

4. Separate sequences are generated for each business object type. If you need to create multiple sequences for the same type, based on values of other object properties, override the `GetSequenceName` method and return the constructed sequence name. The `Address` class in this example uses separate sequences for each `Province` as follows:
4. Separate sequences are created for each business object type. To generate multiple sequences for the same type based on other properties, override `GetSequenceName` to return a custom sequence name. In this example, the `Address` class uses different sequences for each `Province`.

```cs
protected override string GetSequenceName() {
return string.Concat(ClassInfo.FullName, "-", Province.Replace(" ", "_"));
Expand All @@ -132,8 +133,12 @@ Check the original example description first for more information on the demonst

## Additional Information

1. In application with the Security System, the newly generated sequence number will appear in the Detail View only after a manual refresh (in other words, it will be empty right after saving a new record), because the sequence is generated on the server side only and is not passed to the client. See the following section of the **Auto-Generate Unique Number Sequence** KB article: [Refresh the Identifier field value in UI](https://docs.devexpress.com/eXpressAppFramework/403605/business-model-design-orm/unique-auto-increment-number-generation#refresh-the-identifier-field-value-in-the-ui).
2. You can specify the initial sequence value manually. For this purpose, either edit the **Sequence** table in the database or use the [standard XPO/XAF](https://docs.devexpress.com/eXpressAppFramework/113711/data-manipulation-and-business-logic/create-read-update-and-delete-data) techniques to manipulate the `Sequence` objects. For example, you can use the following code:



1. In applications with the Security System, a new sequence number appears in the Detail View only after a manual refresh because it is generated server-side and not immediately sent to the client. For more details, see the following help topic: [Refresh the Identifier Field Value in the UI](https://docs.devexpress.com/eXpressAppFramework/403605/business-model-design-orm/unique-auto-increment-number-generation#refresh-the-identifier-field-value-in-the-ui).

2. You can manually set the initial sequence value by editing the `Sequence` table in the database or using [standard XPO/XAF](https://docs.devexpress.com/eXpressAppFramework/113711/data-manipulation-and-business-logic/create-read-update-and-delete-data) methods to modify `Sequence` objects. For instance, you can use the following code:

```cs
using(IObjectSpace os = Application.CreateObjectSpace(typeof(Sequence))) {
Expand All @@ -142,8 +147,18 @@ Check the original example description first for more information on the demonst
os.CommitChanges();
}
```


## Files to Review

* [SequenceGenerator.cs](SequenceGenerator/SequenceGenerator.Module/SequenceClasses/SequenceGenerator.cs)
* [UserFriendlyIdPersistentObject.cs](SequenceGenerator/SequenceGenerator.Module/SequenceClasses/UserFriendlyIdPersistentObject.cs)
* [SequenceGenerator.Blazor.Server/Startup.cs](SequenceGenerator/SequenceGenerator.Blazor.Server/Startup.cs)
* [SequenceGenerator.Win/Startup.cs](SequenceGenerator/SequenceGenerator.Win/Startup.cs)

## Documentation

* [Auto-Generate Unique Number Sequence](https://www.devexpress.com/Support/Center/p/T567184)

* [Auto-Generate Unique Number Sequence](https://docs.devexpress.com/eXpressAppFramework/403605/business-model-design-orm/unique-auto-increment-number-generation)

## More Examples

* [How to generate a sequential number for a business object within a database transaction](https://supportcenter.devexpress.com/ticket/details/e2620/how-to-generate-a-sequential-number-for-a-business-object-within-a-database-transaction)
1 change: 0 additions & 1 deletion Readme.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,11 +1,10 @@
<!-- default badges list -->
![](https://img.shields.io/endpoint?url=https://codecentral.devexpress.com/api/v1/VersionRange/128590685/25.2.1%2B)
[![](https://img.shields.io/badge/Open_in_DevExpress_Support_Center-FF7200?style=flat-square&logo=DevExpress&logoColor=white)](https://supportcenter.devexpress.com/ticket/details/E2829)
[![](https://img.shields.io/badge/📖_How_to_use_DevExpress_Examples-e9f6fc?style=flat-square)](https://docs.devexpress.com/GeneralInformation/403183)
[![](https://img.shields.io/badge/💬_Leave_Feedback-feecdd?style=flat-square)](#does-this-example-address-your-development-requirementsobjectives)
<!-- default badges end -->

# XAF - How to generate a sequential number for a persistent object within a database transaction with Entity Framework Core

Check warning on line 7 in Readme.md

View workflow job for this annotation

GitHub Actions / vale

[vale] Readme.md#L7 

[DX.HeadingCapitalization] 'XAF - How to generate a sequential number for a persistent object within a database transaction' doesn't match our guidelines for title case. See tw wiki for details.
Raw output 
{"message": "[DX.HeadingCapitalization] 'XAF - How to generate a sequential number for a persistent object within a database transaction' doesn't match our guidelines for title case. See tw wiki for details.", "location": {"path": "Readme.md", "range": {"start": {"line": 7, "column": 3}}}, "severity": "WARNING"}

This example illustrates how to implement a business object with an identifier field with autogenerated sequential values.

Expand Down