Overview:

The Template Method Pattern in C# turns your code into a cooking show script—providing a recipe with room for customization. Let's uncover the secrets of this culinary coding technique:

Implementation in C#:

In C#, the Template Method Pattern involves defining the skeleton of an algorithm in the base class but letting subclasses override specific steps. Imagine a recipe scenario:

// Abstract Class (Cooking Show Script)
public abstract class CookingShowScript
{
    public void MakeRecipe()
    {
        // Common steps for all recipes
        PrepareIngredients();
        MixIngredients();
        Cook();
        Serve();
    }

    protected abstract void PrepareIngredients();
    protected abstract void MixIngredients();
    protected abstract void Cook();
    protected abstract void Serve();
}

// Concrete Class (Specific Recipe)
public class ChocolateCakeRecipe : CookingShowScript
{
    protected override void PrepareIngredients()
    {
        // Ingredients for chocolate cake
    }

    protected override void MixIngredients()
    {
        // Mix chocolate cake ingredients
    }

    protected override void Cook()
    {
        // Bake the chocolate cake
    }

    protected override void Serve()
    {
        // Present the delicious chocolate cake
    }
}

Pros:

1. Code Reusability: Common steps are defined in the base class, promoting code reuse.

2. Customization: Subclasses can override specific steps for customization.

3. Consistent Structure: Ensures a consistent structure across multiple implementations.

Cons:

1. Rigidity: Changes to the template may affect all subclasses.

2. Limited Runtime Flexibility: Limited flexibility at runtime compared to more dynamic patterns.

When to Use and When Not:

• Use: When multiple algorithms share a common structure but have variations in certain steps or when you want to avoid code duplication.

• Avoid: In scenarios where dynamic runtime behavior is crucial or when changes in one part of the algorithm should not affect others.

Usage in .NET Core Framework:

While not explicitly present in the .NET Core framework, the Template Method Pattern's principles can be observed in various areas. For instance, the Dispose method in the IDisposable interface provides a template method for cleaning up resources.

Real-Life Example:

Consider a document processing application where different document types follow a similar export process. The Template Method Pattern is applied:

// Document exporter template
public abstract class DocumentExporter
{
    public void ExportDocument()
    {
        // Common export steps
        ValidateDocument();
        ConvertToCommonFormat();
        SaveToFile();
    }

    protected abstract void ValidateDocument();
    protected abstract void ConvertToCommonFormat();
    protected abstract void SaveToFile();
}

// Concrete exporter for PDF documents
public class PdfDocumentExporter : DocumentExporter
{
    protected override void ValidateDocument()
    {
        // Validate PDF document
    }

    protected override void ConvertToCommonFormat()
    {
        // Convert PDF to common format
    }

    protected override void SaveToFile()
    {
        // Save common format to a file
    }
}

Here, different document exporters follow the template, ensuring a consistent export process.

In conclusion, the Template Method Pattern in C# turns your code into a cooking show script—providing a recipe with room for customization. While fostering code reusability and a consistent structure, developers should be aware of potential rigidity and limited runtime flexibility. Its influence in the .NET Core framework demonstrates its versatility, making it a flavorful choice for scenarios where code becomes a culinary maestro, orchestrating a recipe with a balance of structure and customization.