Structural Patterns – Private Class Data

Private Class Data – Restricts accessor/mutator access. Control write access to object attributes and separate data from function to use it. Encapsulate class data initialization.

From Design Pattern – Structural Patterns

Structure

Applicability

This design pattern applies to any class in many object oriented languages, or any situation.

Pros and Cons

How to Implement

#1 Basic Sample

public class CircleData
{
 public CircleData(double radius, Color color, Point origin)
 {
  this.Radius = radius;
  this.Color = color;
  this.Origin = origin;
 }

 public double Radius { get; }

 public Color Color { get; }

 public Point Origin { get; }
}

public class Circle {
 private CircleData circleData;

 public Circle(double radius, Color color, Point origin)
 {
  this.circleData = new CircleData(radius, color, origin);
 }

 public double Circumference {
  get { return this.circleData.Radius * Math.PI; }
 }

 public double Diameter {
  get { return this.circleData.Radius * 2;  }
 }

 public void Draw(Graphics graphics)
 {
  Image newImage = Image.FromFile("SampImage.jpg");
  PointF ulCorner = new PointF((float)this.circleData.Radius, (float)this.circleData.Radius);

  graphics.DrawImage(newImage,ulCorner);

 }
}

#2 Web Application Project

Step 1 Create the data transfer object(DTO) file for the private data class file that is in the Core project.

Step 2 Create the service class file then implement the generic type repository interface class.

Step 3 Create the Controller file and the Index page in the web project.

Step 4 Register the service class file of the private data class pattern.

// Private Data Class
services.AddScoped(typeof(PrivateDataClassServices));

• GitHub

Reference

• Source Marking – Private data class
• Wikipedia – Private class data pattern