Desarrollo WEB

C# Services Create Scope and Generate Seeds

2025-11-17T18:21:32.960-05:00

using (var scope = app.Services.CreateScope())

{

var context = scope.ServiceProvider.GetRequiredService<ApplicationDbContext>();

await context.Database.EnsureCreatedAsync();

await Api.Seeds.SeedsGenerate.ApplicationSeeds(scope, context);

}

public static class SeedsGenerate

{

public static async Task ApplicationSeeds(IServiceScope scope, ApplicationDbContext context)

{

var roleManager = scope.ServiceProvider.GetRequiredService<RoleManager<IdentityRole>>();

var roleClaimManager = scope.ServiceProvider.GetRequiredService<RoleManager<IdentityRole>>();

var userManager = scope.ServiceProvider.GetRequiredService<UserManager<ApplicationUser>>();

// Seed Permissions

DbSet<Permission> dbsetpermission = context.Set<Permission>();

foreach (var actionType in Enum.GetValues<ActionType>())

{

string permissionName = $"{actionType}_Permission";

if (!await dbsetpermission.AnyAsync(p => p.Name == permissionName))

{

await dbsetpermission.AddAsync(new Permission

{

Name = permissionName,

Description = $"Permission to {actionType.ToString().ToLower()}",

ActionType = actionType

});

}

var assemblies = new[] { typeof(Product).Assembly, typeof(BaseEntity).Assembly };

var entityTypes = assemblies.SelectMany(assembly => assembly.GetTypes()).Where(type =>

type.IsClass && !type.IsAbstract &&

typeof(IBaseEntity).IsAssignableFrom(type)).ToList();

// Seed Permissions

foreach (var role in DataSeed.RolesSeed)

{

if (!await roleManager.RoleExistsAsync(role.Name))

{

await roleManager.CreateAsync(new IdentityRole

{ Id = role.RoleId, Name = role.Name, NormalizedName = role.Name.ToUpper() });

}

foreach (var entityType in entityTypes)

{

foreach (var rolegrant in DataSeed.RolesGrantsSeed)

{

var rol = DataSeed.RolesSeed.FirstOrDefault(x => x.Id == rolegrant.RoleId);

var grt = DataSeed.GrantsSeed.FirstOrDefault(x => x.Id == rolegrant.PermissionId);

roleClaimManager.AddClaimAsync(new IdentityRole { Id = rol!.RoleId },

new Claim("PERMISSION", $"PERMISSION.{entityType.Name}.{grt!.Name}")).Wait();

}

// Seed users

foreach (var role in DataSeed.RolesSeed)

{

string rolelower = role.Name.ToLower();

string monthname = CultureInfo.CurrentCulture.DateTimeFormat.GetMonthName(role.Id);

if (await roleManager.RoleExistsAsync(role.Name) && await userManager.FindByNameAsync(rolelower) is null)

{

var newuser = new ApplicationUser

{

UserName = rolelower,

Email = $"{rolelower}@devinline.com",

FirstName = role.Name,

LastName = $"{monthname} {role.Name}",

PhoneNumber = $"30{role.Id}600900{role.Id}",

Id = role.RoleId

};

await userManager.CreateAsync(newuser, $"{role.Name}..456");

await userManager.AddToRoleAsync(newuser, role.Name);

}

public class SystemRoles

{

public required int Id { get; set; }

public required string RoleId { get; set; }

public required string Name { get; set; }

}

public class SystemPermissions

{

public required int Id { get; set; }

public required string Name { get; set; }

}

public class SystemRolesPermissions

{

public required int RoleId { get; set; }

public required int PermissionId { get; set; }

}

public static class DataSeed

{

public static List<SystemRoles> RolesSeed =>

[

new() { Id = 1, RoleId = "00000000-0000-0000-0000-000000000001", Name = "Admin" },

new() { Id = 2, RoleId = "00000000-0000-0000-0000-000000000002", Name = "Approver" },

new() { Id = 3, RoleId = "00000000-0000-0000-0000-000000000003", Name = "BasicUser" },

new() { Id = 4, RoleId = "00000000-0000-0000-0000-000000000004", Name = "User" },

new() { Id = 5, RoleId = "00000000-0000-0000-0000-000000000005", Name = "Viewer" },

new() { Id = 6, RoleId = "00000000-0000-0000-0000-000000000006", Name = "Reports" },

new() { Id = 7, RoleId = "00000000-0000-0000-0000-000000000007", Name = "Guest" }

];

public static List<SystemPermissions> GrantsSeed =>

[

new() { Id = 1, Name = "Index" },

new() { Id = 2, Name = "Viewer" },

new() { Id = 3, Name = "Creation" },

new() { Id = 4, Name = "Edition" },

new() { Id = 5, Name = "Activation" },

new() { Id = 6, Name = "Deletion" },

new() { Id = 7, Name = "Exporting" },

new() { Id = 8, Name = "Importing" },

new() { Id = 9, Name = "Assign" },

new() { Id = 10, Name = "Reviewer" },

new() { Id = 11, Name = "Approver" },

new() { Id = 12, Name = "Rejecter" }

];

public static List<SystemRolesPermissions> RolesGrantsSeed =>

[

new (){ RoleId = 1, PermissionId = 1}, new (){ RoleId = 1,PermissionId = 2 }, new (){ RoleId = 1, PermissionId = 3},

new (){ RoleId = 1, PermissionId = 4}, new (){ RoleId = 1,PermissionId = 5 }, new (){ RoleId = 1, PermissionId = 6},

new (){ RoleId = 1, PermissionId = 7}, new (){ RoleId = 1,PermissionId = 8 }, new (){ RoleId = 1, PermissionId = 9},

new (){ RoleId = 1, PermissionId = 10}, new (){ RoleId = 1,PermissionId = 11 }, new (){ RoleId = 1, PermissionId = 12},

new (){ RoleId = 2, PermissionId = 1}, new (){ RoleId = 2,PermissionId = 2 }, new (){ RoleId = 2, PermissionId = 5},

new (){ RoleId = 2, PermissionId = 9}, new (){ RoleId = 2,PermissionId = 11 }, new (){ RoleId = 2, PermissionId = 12},

new (){ RoleId = 3, PermissionId = 1}, new (){ RoleId = 3,PermissionId = 2 }, new (){ RoleId = 3, PermissionId = 3},

new (){ RoleId = 3, PermissionId = 4}, new (){ RoleId = 3,PermissionId = 5 }, new (){ RoleId = 3, PermissionId = 6},

new (){ RoleId = 4, PermissionId = 1}, new (){ RoleId = 4,PermissionId = 2 }, new (){ RoleId = 4, PermissionId = 3},

new (){ RoleId = 4, PermissionId = 4}, new (){ RoleId = 4,PermissionId = 5 }, new (){ RoleId = 4, PermissionId = 6},

new (){ RoleId = 4, PermissionId = 7}, new (){ RoleId = 4,PermissionId = 8 }, new (){ RoleId = 4, PermissionId = 9},

new (){ RoleId = 4, PermissionId = 10}, new (){ RoleId = 5,PermissionId = 1 }, new (){ RoleId = 5, PermissionId = 2},

new (){ RoleId = 5, PermissionId = 7}, new (){ RoleId = 5,PermissionId = 10 }, new (){ RoleId = 6, PermissionId = 1},

new (){ RoleId = 6, PermissionId = 2}, new (){ RoleId = 6,PermissionId = 7 }, new (){ RoleId = 7, PermissionId = 1}

];

}

C# DataAnnotations

2025-06-03T14:43:00.001-05:00

/// <summary>
/// Token class
/// </summary>
[Index(nameof(AccessToken), IsUnique = true, Name = "Uk_DataModel_AccessToken")]
[Index(nameof(Status), Name = "Ix_DataModel_Status")]
[Index("Descripcion", Name = "UK_DataModel_Descripcion", IsUnique = true)]
public class DataModel
{
    /// <summary>
    /// Defgult constructor
    /// </summary>
    public DataModel()
    {
        UsernameChangeLimit = 10;
        Id = Guid.NewGuid();
        CreatedDate = DateTimeOffset.UtcNow.AddHours(-5);
        Status = Status.Active;
        ProfilePicture = Convert.FromBase64String("iVBORw0KGgo...");
    }

    /// <summary>
    /// Expire Minutes property
    /// </summary>
    [Required]
    [Range(1, 1440)]
    public int ExpireMinutes { get; set; }

    /// <summary>
    /// Symmetric Security Key property
    /// </summary>
    [Required]
    [ProtectedPersonalData]
    public string SymmetricSecurityKey { get; set; }

    /// <summary>
    /// Id property 
    /// </summary>
    [Key]
    [Required]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }

    /// <summary>
    /// Profile Picture
    /// </summary>
    [Comment("ProfilePicture")]
    [Display(Name = "Imagen usuario")]
    [Required(ErrorMessage = "{0} requerido")]
    public byte[] ProfilePicture { get; set; }

    /// <summary>
    /// First Name
    /// </summary>
    [PersonalData]
    [Comment("Nombre")]
    [Display(Name = "Nombre")]
    [Required(ErrorMessage = "{0} requerido")]
    [StringLength(50)]
    [MinLength(3, ErrorMessage = "{0} mínimo {1} caracteres")]
    [MaxLength(50, ErrorMessage = "{0} máximo {1} caracteres")]
    public string FirstName { get; set; }

    /// <summary>
    /// Username Change Limit
    /// </summary>
    [Comment("UsernameChangeLimit")]
    [Display(Name = "Límite cambio usuario")]
    [Range(1, 20, ErrorMessage = "{0} rango entre {1} y {2}")]
    public int UsernameChangeLimit { get; set; }

    /// <summary>
    /// Created Date property
    /// </summary>
    [Comment("CreatedDate")]
    [Display(Name = "Fecha creación")]
    [Required(ErrorMessage = "{0} requerido")]
    [DataType(DataType.DateTime, ErrorMessage = "{0} formato fecha incorrecto")]
    public DateTimeOffset CreatedDate { get; set; }

    /// <summary>
    /// Descripcion
    /// </summary>
    public string Descripcion { get; set; }

    [Comment("Price")]
    [Display(Name = "Precio")]
    [Range(0.1, 999999999, ErrorMessage = "{0} rango entre {1} y {2}")]
    public decimal Precio { get; set; }
}

C# Enum description

2025-06-03T14:04:00.001-05:00

using System.ComponentModel;
using System.Reflection;

#nullable disable

namespace Tools.Domain.Helpers;

/// <summary>
/// Proporciona métodos auxiliares para trabajar con enumeradores.
/// </summary>
public static class EnumHelper
{
    /// <summary>
    /// Obtiene la descripción asociada a un valor de enumerador utilizando el atributo <see cref="DescriptionAttribute"/>.
    /// Si no se encuentra el atributo <see cref="DescriptionAttribute"/>, devuelve el nombre del valor del enumerador.
    /// </summary>
    /// <param name="value">El valor del enumerador del cual se desea obtener la descripción.</param>
    /// <returns>
    /// La descripción del valor del enumerador si existe el atributo <see cref="DescriptionAttribute"/>;
    /// de lo contrario, el nombre del valor del enumerador.
    /// </returns>
    /// <example>
    /// Ejemplo de uso:
    /// <code>
    /// public enum Status
    /// {
    ///     [Description("Activo")]
    ///     Active = 1,
    ///     [Description("Inactivo")]
    ///     Inactive = 2,
    ///     [Description("Eliminado")]
    ///     Deleted = 3
    /// }
    /// 
    /// Console.WriteLine(EnumHelper.GetDescription(Status.Active)); // Salida: "Activo"
    /// </code>
    /// </example>
    public static string GetDescription(Enum value)
    {
        FieldInfo field = value.GetType().GetField(value.ToString());
        DescriptionAttribute attribute = field.GetCustomAttribute<DescriptionAttribute>();

        if (attribute == null) { return value.ToString(); }

        return attribute?.Description ?? value.ToString();
    }
}

/// <summary>
/// Representa los estados de un elemento en el sistema.
/// </summary>
public enum Status
{
    /// <summary>
    /// Estado Activo.
    /// Indica que el elemento está disponible y en uso.
    /// </summary>
    [Description("Activo")]
    Active = 1,

    /// <summary>
    /// Estado Inactivo.
    /// Indica que el elemento no está disponible temporalmente.
    /// </summary>
    [Description("Inactivo")]
    Inactive = 2,

    /// <summary>
    /// Estado Eliminado.
    /// Indica que el elemento ha sido marcado como eliminado
    /// y no debe mostrarse en las operaciones normales del sistema.
    /// </summary>
    [Description("Eliminado")]
    Deleted = 3
} 

HTML Plantilla favicon base64

2025-06-03T13:37:00.003-05:00

<!DOCTYPE html>
<html lang="es">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Página de inicio del proyecto" />
    <meta name="keywords" content="inicio, proyecto, ejemplo" />
    <meta name="author" content="Proyecto Global" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <title>Página de Inicio</title>
    <!-- Favicon -->
    <link href="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAMAAABEp
IrGAAAAn1BMVEUAAADCAAAAAAA3yDfUAAA3yDfUAAA8PDzr6+sAAAD4+Pg3yDeQkJDTAADt7e3V1dU3
yDdCQkIAAADbMTHUAABBykHUAAA2yDY3yDfr6+vTAAB3diDR0dGYcHDUAAAjhiPSAAA3yDeuAADUAAA
3yDf////OCALg9+BLzktBuzRelimzKgv87+/dNTVflSn1/PWz6rO126g5yDlYniy0KgwjJ0TyAAAAI3
RSTlMABAj0WD6rJcsN7X1HzMqUJyYW+/X08+bltqSeaVRBOy0cE+citBEAAADBSURBVDjLlczXEoIwF
IThJPYGiL0XiL3r+z+bBOJs9JDMuLffP8v+Gxfc6aIyDQVjQcnqnvRDEQwLJYtXpZT+YhDHKIjLbS+O
UeT4TjkKi6OwOArq+yeKXD9uDqQQbcOjyCy0e6bTojZSftX+U6zUQ7OuittDu1k0WHqRFfdXQijgjKf
F6ZwAikvmKD6OQjmKWUcDigkztm5FZN05nMON9ZcoinlBmTNnAUdBnRbUUbgdBZwWbkcBpwXcVsBtxf
jb31j1QB5qeebOAAAAAElFTkSuQmCC" rel="icon" type="image/x-icon" />
  </head>
  <body></body>
</html>

MS SQL Server - Cursor Index AVG Fragmentation in Percent

2025-05-18T21:04:00.001-05:00

DECLARE @MyTableVar TABLE ([schema_name] nvarchar(256),[object_name] nvarchar(256),index_name nvarchar(256),index_type nvarchar(120), avg_fragmentation_in_percent float(8),page_count bigint,alloc_unit_type_desc nvarchar(120));

DECLARE @Reg VARCHAR(255);

DECLARE MY_CURSOR CURSOR LOCAL STATIC READ_ONLY FORWARD_ONLY FOR SELECT [name] FROM sys.tables;

OPEN MY_CURSOR;

FETCH NEXT FROM MY_CURSOR INTO @Reg;

WHILE @@FETCH_STATUS = 0

BEGIN

INSERT INTO @MyTableVar SELECT OBJECT_SCHEMA_NAME(ips.object_id) AS schema_name, OBJECT_NAME(ips.object_id) AS object_name, i.name AS index_name, i.type_desc AS index_type, ips.avg_fragmentation_in_percent, ips.page_count, ips.alloc_unit_type_desc FROM sys.dm_db_index_physical_stats(DB_ID(), (SELECT st.object_id FROM SYS.tables st WHERE st.[name] = @Reg), default, default, 'LIMITED') AS ips INNER JOIN sys.indexes AS i ON ips.object_id = i.object_id AND ips.index_id = i.index_id ORDER BY page_count DESC;

FETCH NEXT FROM MY_CURSOR INTO @Reg;

END

CLOSE MY_CURSOR;

DEALLOCATE MY_CURSOR;

SELECT * FROM @MyTableVar WHERE index_type NOT IN ('HEAP') AND object_name NOT IN ('sysdiagrams') AND avg_fragmentation_in_percent > 0 ORDER BY 2;

C# LinQ

2024-07-13T17:44:00.002-05:00

Syntax and Usage

Query Syntax: Resembles SQL and is more readable for those familiar with SQL.

var query = from student in students

where student.Age > 18
select student;

Method Syntax: Uses lambda expressions and extension methods, offering more flexibility.

var query = students.Where(student => student.Age > 18).Select(student => student);

Key Components

Deferred Execution: LINQ queries are not executed until the query variable is iterated over. This can lead to performance optimizations.
Extension Methods: LINQ heavily relies on extension methods to extend the capabilities of existing .NET types.
Lambda Expressions: Used to write inline functions for LINQ methods.

Types of LINQ

LINQ to Objects: Queries in-memory collections like arrays, lists, and other IEnumerable<T> types.
LINQ to SQL: Queries relational databases using SQL-like syntax, leveraging ADO.NET under the hood.
LINQ to XML: Simplifies querying and manipulating XML data.
LINQ to Entities: Used with Entity Framework to query databases in an object-oriented manner.
Parallel LINQ (PLINQ): Enhances LINQ with parallel processing capabilities for better performance on multi-core processors.

Common LINQ Operations

Filtering: Using where or Where to filter elements based on a condition.
Projection: Using select or Select to transform elements.
Joining: Using join to combine elements from different data sources.
Grouping: Using group by or GroupBy to group elements.
Aggregating: Using methods like Sum, Average, Min, Max, and Count to perform calculations on collections.

Advantages

Readability: More readable and maintainable code, especially for those familiar with SQL.
Type Safety: Provides compile-time checking of queries, reducing runtime errors.
Versatility: Can be used with various data sources, making it a versatile tool for data manipulation.

Considerations

Performance: While LINQ offers readability and simplicity, it may introduce performance overhead in some scenarios. Profiling and optimization may be necessary.
Learning Curve: Requires learning new syntax and concepts, especially for those unfamiliar with functional programming paradigms.

Filtering and searching LINQ Examples

var resultwithAnyAndWhere = courses.Where(c => c.StudentIds.Any(id => id == 4)).ToList();
var resultAny = courses.Any(c => c.StudentIds.Any(id => id == 4));
var resultWhere = courses.Where(c => c.CourseId == 4).ToList();
var resultWithFirstOrDefault = courses.Where(c => c.CourseId == 4).ToList().FirstOrDefault();
var resultFirst = courses.First(c => c.StudentIds.Any(id => id == 4));
var resultSingle = courses.Single(c => c.StudentIds.Any(id => id == 4));
var resultAll = Students.All(s => s.Age > 15);

//Find is a method available on lists (List<T>) and is not part of the LINQ extension methods.
//It is similar to FirstOrDefault but is specific to List<T>.
var resultFind = courses.Find(c => c.StudentIds.Any(id => id == 4));

01. Any vs Where

The Any and Where methods in LINQ are used for different purposes, although they are often used together in queries.

Where

Purpose: Filters a collection based on a specified condition.
Return Type: Returns a collection of elements that satisfy the condition.
Use Case: When you need to retrieve all elements that meet a certain criteria.

Any

Purpose: Checks if any elements in a collection satisfy a specified condition.
Return Type: Returns a Boolean value (true or false).
Use Case: When you need to determine if there is at least one element in the collection that meets a certain criteria.

02. First vs FirstOrDefault

First and FirstOrDefault are both used to return the first element in a sequence that satisfies a specified condition, but they differ in their behavior when no such element is found.

First

Behavior: Returns the first element that satisfies the specified condition.
Exception Handling: Throws an exception (InvalidOperationException) if no elements satisfy the condition or if the sequence is empty.
Use Case: Use when you are sure that there is at least one element that satisfies the condition.

FirstOrDeafult

Behavior: Returns the first element that satisfies the specified condition, or a default value if no such element is found.
Exception Handling: Does not throw an exception if no elements satisfy the condition or if the sequence is empty. Instead, it returns the default value for the type (null for reference types, 0 for integers, etc.).
Use Case: Use when it is possible that no elements satisfy the condition, and you want to handle that case without exceptions.

03. Single vs SingleOrDefault

Single and SingleOrDefault are both LINQ methods used to retrieve a single element from a sequence that satisfies a specified condition. However, they differ in behavior when no or multiple elements match the condition.

Single

Purpose: Returns the only element that satisfies the specified condition.
Exception Handling: Throws an InvalidOperationException if either no elements or more than one element satisfy the condition.
Use Case: Use Single when you expect exactly one element to match the condition, and you want to ensure that only one such element exists.

SingleOrDefault

Purpose: Returns the only element that satisfies the specified condition, or a default value if no such element exists.
Exception Handling: Does not throw an exception if no elements satisfy the condition or if the sequence is empty. Instead, it returns the default value (null for reference types, 0 for integers, etc.).
Use Case: Use SingleOrDefault when it's possible that no elements will match the condition, and you want to handle that case gracefully without exceptions.

04. Any vs All

The Any() method checks if there are any elements in a sequence that satisfy a specified condition. It returns true if at least one element matches the condition, otherwise false. It short-circuits and stops iterating through the collection as soon as it finds the first matching element.
The All() method checks if all elements in a sequence satisfy a specified condition. It returns true if every element in the collection matches the condition, otherwise false. Similar to Any(), it also short-circuits and stops iterating through the collection as soon as it finds the first element that does not match the condition.

Projection LINQ Examples

In LINQ (Language Integrated Query), projection refers to the process of transforming the elements of a sequence into a new form or extracting a subset of data that contains only the information you need. This is typically done using the select clause in LINQ queries.

01. Selecting Entire Objects: You can project entire objects from a sequence. For example, if you have a collection of Person objects and you want to create a new sequence containing just their names, you can do:

var names = people.Select(person => person.Name);

02. Anonymous Types: LINQ also allows you to create anonymous types on-the-fly using projection. This is useful when you want to combine multiple properties from an object into a new structure:

var result = people.Select(person => new { person.Name, person.Age });

03. Transformations: You can apply transformations to the elements in the sequence using projection. For example, converting all names to uppercase:

var uppercaseNames = people.Select(person => person.Name.ToUpper());

04. Index-Based Projection: If you need to access elements with their index while projecting, you can use the Select overload that provides an index.

Here, person is the element of the sequence, and index is its position.

var indexedNames = people.Select((person, index) => new { Index = index, Name = person.Name });

05. Flattening Hierarchies: If your data includes nested collections or hierarchies, you can flatten them using projection. For example, flattening a list of lists.

This example flattens listOfLists into a single sequence of elements.

var flattened = listOfLists.SelectMany(list => list);

Joining LINQ Examples

Joining in LINQ refers to combining data from two or more sources based on a related key. LINQ (Language Integrated Query) provides powerful capabilities for querying data in C# or .NET languages. Here’s a basic overview of how joining works in LINQ.

01. Inner Join: This method performs an inner join between two sequences based on a key selector and projects the result using a result selector function.

var query = collection1.Join(
                collection2,
                item1 => item1.Key,
                item2 => item2.Key,
                (item1, item2) => new { item1, item2 });

02. Group Join: Performs a group join where each element from the first sequence is matched with a sequence of matching elements from the second sequence.

var query = collection1.GroupJoin(
                collection2,
                item1 => item1.Key,
                item2 => item2.Key,
                (item1, grouped) => new { item1, grouped });

03.SelectMany: Although not a traditional join, SelectMany can be used to flatten nested collections, often used in scenarios where you need to join sequences in a nested manner.

var query = collection1.SelectMany(
item1 => item1.Collection2,
(item1, item2) => new { Item1 = item1, Item2 = item2 });

Grouping LINQ Examples

Grouping in LINQ is a powerful feature that allows you to organize data into groups based on one or more keys or criteria. It’s particularly useful when you want to aggregate data, perform calculations within groups, or simply organize data for easier manipulation or presentation.

In LINQ, grouping is typically done using the group by clause in query syntax or the GroupBy() method in method syntax. Here’s how each looks.

public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
}

// Example data
List<Person> people = new List<Person>
{
    new Person { Name = "Alice", Age = 30 },
    new Person { Name = "Bob", Age = 25 },
    new Person { Name = "Charlie", Age = 30 },
    new Person { Name = "David", Age = 25 }
};

// Grouping by Age using LINQ query syntax
var groupedByAge = from person in people
                   group person by person.Age;

// Output each group
foreach (var ageGroup in groupedByAge)
{
    Console.WriteLine($"Age Group: {ageGroup.Key}");

    foreach (var person in ageGroup)
    {
        Console.WriteLine($" {person.Name}");
    }
}

output for the above grouping query

Age Group: 30
Alice
Charlie
Age Group: 25
Bob
David

Aggregation LINQ Examples

Aggregation in LINQ refers to the process of computing a single value from a collection of elements. This could involve calculating a sum, average, count, minimum, maximum, or performing other types of aggregate operations on data. LINQ provides several methods and techniques to perform aggregation seamlessly.

int count = collection.Count();
int total = collection.Sum(item => item.Property);
double average = collection.Average(item => item.Property);
int min = collection.Min(item => item.Property);
int max = collection.Max(item => item.Property);

Query Syntax vs Method Syntax

In LINQ, most keywords and functionalities can be used in both query syntax (using LINQ query expressions) and method syntax (using LINQ extension methods). However, there are a few keywords and operations that are more commonly associated with one syntax over the other due to how they are structured or used.

Join: While join can be used in method syntax (Join() method), it's more commonly seen and perhaps more intuitive in query syntax for joining data from multiple sources based on specified keys.
Group By: group by is extensively used in query syntax for grouping elements based on a key.
Method Syntax specific keywords: Any, All, ToDictionary, ToList, ToArray.

LINQ simplifies data querying and manipulation in C#, offering powerful, readable syntax for operations like filtering, sorting, and aggregation, enhancing developer productivity and code clarity across diverse applications. Mastering LINQ empowers efficient, maintainable data-driven solutions in .NET environments.

C# Consejos y trucos

2024-02-14T17:24:00.001-05:00

Combinar declaraciones If

Combinar dos declaraciones if en una sola

if (chips.Stock == 0)

{

if (chips.Status == Status.Ordered)

{

chips.Available = false;

}

Ahora:

if(chips is { Stock: 0, Status: Status.Ordered })

{

chips.Available = false;

}

Operador de asignación de fusión nula

Verificar si Apple es nulo, por lo que debemos inicializarlo y asignar un valor a la propiedad Título:

Product apple = null;

if (apple == null)

apple = new() { Title = "Green apple" };

Console.WriteLine(apple.Title);

Ahora:

Product apple = null;

apple ??= new() { Title = "Green apple" };

Console.WriteLine(apple.Title);

Constructor de cuerpos de expresión

Disponible desde C# 7, la versión actual es 11. Como la mayoría de nosotros sabemos, un objeto o clase se puede inicializar mediante parámetros:

public class Product

{

public int Id { get; set; }

public string Title { get; set; }

public int Stock { get; set; }

public Status Status { get; set; }

public bool Available { get; set; }

public Product(string title, int stock, Status status)

{

Title = title;

Stock = stock;

Status = status;

}

Ahora:

public class Product(string title, int stock, Status status)

{

public int Id { get; set; }

public string Title { get; set; } = title;

public int Stock { get; set; } = stock;

public Status Status { get; set; } = status;

public bool Available { get; set; }

}

SQL While

2023-11-13T11:12:00.001-05:00

DECLARE @counter INT;

SET @counter = 0;

WHILE @counter < 10

BEGIN

PRINT NEWID();

SET @counter += 1;

END;

C# Constructores con expresiones lambda

2023-06-12T19:41:00.001-05:00

Constructores con cuerpo versión clásica

public class Person

{

public string Name { get; }

public int Age { get; }

public Person(string name, int age)

{

Name = name;

Age = age;

}

Constructores con cuerpo de expresión

Expresiones lambda

Constructores con cuerpo de expresión utilizando las diferentes características introducidas por las tuplas:

public class Person

{

public string Name { get; }

public int Age { get; }

public Person(string name, int age) => (Name, Age) = (name, age);

}

Referencia https://www.linkedin.com/feed/update/urn:li:activity:6952198212967419905/

Seguridad de redes y sistemas defensivos

2023-04-25T10:12:00.001-05:00

Seguridad de redes y sistemas defensivos

Imagen tomada de ucsp.edu.pe

La seguridad de redes se refiere a la protección de las redes informáticas contra amenazas y vulnerabilidades que pueden afectar la confidencialidad, integridad y disponibilidad de la información que se transmite a través de ellas.

Esto incluye la implementación de medidas de seguridad tales como cortafuegos, sistemas de detección de intrusiones, autenticación y control de acceso, cifrado de datos y medidas de prevención de malware, entre otros.

La seguridad de redes también implica la gestión de riesgos y la elaboración de planes de contingencia en caso de fallas de seguridad o desastres, así como la educación y capacitación de los usuarios para prevenir vulnerabilidades como la ingeniería social o el phishing.

MS SQL Server - Reducir Log file BD

2019-07-16T19:44:00.000-05:00

USE [DataBaseName]

DBCC SHRINKFILE (N'DataBaseName_log' , EMPTYFILE)

PHP - Pasar variables entre páginas de forma segura (codificadas)

2019-07-16T19:39:00.000-05:00

FUNCION 1: Codificar antes de enviar

function encode_this($string)

{

$control = "extra";

$tmp_string = $string;

$string = $control . $tmp_string . $control;

$string = base64_encode($string);

return ($string);

}

FUNCION 2: Decodificar al recibir

function decode_this($string)

{

$string = base64_decode($string);

$control = "extra";

$string = str_replace($control, "", "$string");

return $string;

}

Esta última función:

1. Decodifica en base64 el string entero (la abominación)

2. Corta del string el string de control que había DELANTE y DETRAS

3. Retorna el valor verdadero que se intentaba enviar

Forma de uso

Página 1 (indice.php)

$id = encode_this($id);

echo "<a href='/abrir_pagina.php?id_secreto=" . $id . "'>Cargar pagina 234</a>";

Página 2 (abrir_pagina.php)

if ($_GET['id_secreto']) {

if (($id = decode_this(['id_secreto'])) != $date_hbd) {

echo "Please wait...<br>";

exit();

} else {

header("location: www.goo.gov/secretfile.php?id=" . $id);

}

} else {

echo "¿A dónde crees que vas sin tu ID super secreto?<br>";

exit();

}

MS SQL Server - Ejecutar comando DOS

2019-07-16T18:21:00.002-05:00

EXEC sp_configure 'show advanced options', 1

-- To update the currently configured value for advanced options.

RECONFIGURE

-- To enable the feature.

EXEC sp_configure 'xp_cmdshell', 1

-- To update the currently configured value for this feature.

RECONFIGURE

EXEC MASTER.dbo.xp_cmdshell 'DEL D:\MsSQL\file.bak';

MS SQL Server - Cambiar password sa

2019-07-16T18:15:00.000-05:00

USE master;

ALTER LOGIN sa WITH PASSWORD = 'tu-nuevo-password-sa';

MS SQL Server - Cursor Template

2019-06-19T06:47:00.001-05:00

DECLARE @Reg VARCHAR(255)

DECLARE MY_CURSOR CURSOR LOCAL STATIC READ_ONLY FORWARD_ONLY

FOR

SELECT Reg_NombreCorto FROM REGIONAL

OPEN MY_CURSOR

FETCH NEXT FROM MY_CURSOR INTO @Reg

WHILE @@FETCH_STATUS = 0

BEGIN

--mi code ini

PRINT @Reg

--mi code fin

FETCH NEXT FROM MY_CURSOR INTO @Reg

END

CLOSE MY_CURSOR

DEALLOCATE MY_CURSOR

C# - Generics and Delegates

2018-05-21T16:57:00.000-05:00

C# - Generics and Delegates

Método para generar archivo de texto con Generics y Delegates

public class Bo

{

public static void GenBo()

{

#region List Data

List<Informations> bines = new List<Informations>

{

new Informations(1,"604237"),

new Informations(2,"604238"),

new Informations(3,"604239"),

new Informations(4,"604240")

};

#endregion

#region Create Directory

DirectoryInfo directoryInfo = new DirectoryInfo("C:/PR/");

if (!directoryInfo.Exists) directoryInfo.Create();

#endregion

#region Write File

bines.ForEach(delegate (Informations t)

{

string filename = directoryInfo + t.Id.ToString() + t.Name + ".txt";

using (FileStream fileStream = new FileStream(filename,

FileMode.Create, FileAccess.Write, FileShare.None))

{

using (StreamWriter p = new StreamWriter(fileStream))

{

p.WriteLine(t.Id.ToString() + t.Name);

}

});

#endregion

}

public class Informations

{

public int Id { get; set; }

public string Name { get; set; }

public Informations(int Id, string Name)

{

this.Id = Id;

this.Name = Name;

}

MS SQL Server - Conteo total de registros por DB

2018-04-24T11:36:00.001-05:00

MS SQL Server - Conteo total de registros por DB

Script SQL para realizar el conteo total de registros por table de una base de datos de MS SQL Server.

SELECT

X.[name],

REPLACE(CONVERT(varchar, CONVERT(money, X.[rows]), 1), '.00', '') AS [rows],

REPLACE(CONVERT(varchar, CONVERT(money, X.[reserved]), 1), '.00', '') AS [reserved],

REPLACE(CONVERT(varchar, CONVERT(money, X.[data]), 1), '.00', '') AS [data],

REPLACE(CONVERT(varchar, CONVERT(money, X.[index_size]), 1), '.00', '') AS [index_size],

REPLACE(CONVERT(varchar, CONVERT(money, X.[unused]), 1), '.00', '') AS [unused]

FROM

(

SELECT

CAST(object_name(id) AS varchar(50)) AS [name],

SUM(CASE WHEN indid < 2 THEN CONVERT(bigint, [rows]) END) AS [rows],

SUM(CONVERT(bigint, reserved)) * 8 AS reserved,

SUM(CONVERT(bigint, dpages)) * 8 AS data,

SUM(CONVERT(bigint, used) - CONVERT(bigint, dpages)) * 8 AS index_size,

SUM(CONVERT(bigint, reserved) - CONVERT(bigint, used)) * 8 AS unused

FROM sysindexes WITH (NOLOCK)

WHERE sysindexes.indid IN (0, 1, 255)

AND sysindexes.id > 100

AND object_name(sysindexes.id) <> 'dtproperties'

GROUP BY sysindexes.id WITH ROLLUP

) AS X

WHERE X.[name] is not null

ORDER BY X.[rows] DESC

C# Leer XML y Serialización XMLNode a ArrayList

2014-12-23T12:12:00.001-05:00

Archivo Filexml.xml

<?xml version="1.0" encoding="UTF-8"?>

<urlhost>sitio.pagina.com</urlhost>

<urlhost>gmail.com</urlhost>

</referrer>

Carga de XML y tratamiento de nodos

// Carga de xml y tratamiento de nodos

XmlDocument xmldoc = new XmlDocument();

xmldoc.Load(Server.MapPath("Filexml.xml"));

XmlNodeList HostList = xmldoc.SelectNodes("//urlhost");

// Seteo del ArrayList

ArrayList arrHosts = new ArrayList();

// Serialización XMLNode a ArrayList

foreach (XmlNode item in HostList)

arrHosts.Add(item.InnerText);