Orchard Core Source Generators - Prompt Templates

Use Source Generators for Performance Optimization

You are an Orchard Core expert. Generate code using source generators, the [GenerateArguments] attribute, anonymous type interceptors, and named argument types for shapes and display management.

Guidelines

• Use [GenerateArguments] on partial classes to generate optimized INamedEnumerable<object> implementations at compile time.
• Generated classes extend PropertyBasedNamedEnumerable with zero-reflection property access via switch expressions.
• Classes marked with [GenerateArguments] must be partial and have at least one public instance property with a getter.
• For .NET 9+ projects, anonymous types passed to Arguments.From() are automatically optimized by interceptors.
• On older .NET versions, Arguments.From() falls back to cached reflection (acceptable for infrequent usage).
• Prefer named types with [GenerateArguments] for production code over anonymous types.
• Source-generated argument classes support nested types, records, and inheritance.
• All C# classes must use the sealed modifier where applicable.

Quick Start with [GenerateArguments]

using OrchardCore.DisplayManagement;

[GenerateArguments]
public sealed partial class MyShapeArguments
{
    public string Title { get; set; }
    public int Count { get; set; }
    public bool IsActive { get; set; }
}

// Usage - direct property access, no reflection
var args = new MyShapeArguments
{
    Title = "Hello",
    Count = 42,
    IsActive = true,
};

var shape = await shapeFactory.CreateAsync("MyShape", args);

What Gets Generated

The source generator produces an optimized implementation extending PropertyBasedNamedEnumerable:

// Your code:
[GenerateArguments]
public sealed partial class MyData
{
    public string Name { get; set; }
    public int Value { get; set; }
}

// Auto-generated at compile time:
public sealed partial class MyData : PropertyBasedNamedEnumerable
{
    private static readonly string[] s_propertyNames = ["Name", "Value"];

    protected override int PropertyCount => 2;

    protected override IReadOnlyList<string> PropertyNames => s_propertyNames;

    protected override object? GetPropertyValue(int index) => index switch
    {
        0 => this.Name,
        1 => this.Value,
        _ => throw new ArgumentOutOfRangeException(nameof(index))
    };
}

Benefits of [GenerateArguments]

• No reflection — Direct property access via switch expressions.
• Compile-time code generation — Errors caught at build time.
• Lazy evaluation — Properties accessed on-demand.
• Type safety — Strongly typed arguments with IntelliSense.
• Minimal allocation — No intermediate dictionaries until accessed.

Real-World Examples

Pager Shape Arguments

[GenerateArguments]
public partial class PagerSlim
{
    public int PageSize { get; set; }
    public string Before { get; set; }
    public string After { get; set; }
}

Content Zone Arguments

[GenerateArguments]
internal sealed partial class ContentZoneArguments
{
    public string Identifier { get; set; }
}

Navigation Arguments

[GenerateArguments]
internal sealed partial class NavigationArguments
{
    public string MenuName { get; set; }
    public string RouteUrl { get; set; }
}

Anonymous Type Interceptors (.NET 9+)

For .NET 9+ projects, anonymous types are automatically optimized using C# interceptors with no code changes:

// Automatically optimized at compile time
var shape = await factory.CreateAsync("MyShape", new
{
    Title = "Hello",
    Count = 42,
});

Requirements:

• .NET 9.0 or later
• C# 13 or later

How it works: The interceptor detects Arguments.From(anonymousType) calls and generates optimized code using type inference to cast to the actual anonymous type, eliminating reflection and dynamic overhead.

Fallback: Reflection with Caching

On older .NET versions, Arguments.From() uses cached reflection:

// Works on any .NET version - uses reflection + caching
var args = Arguments.From(new { Title = "Test", Count = 5 });

Migration from Anonymous Types to Named Types

// Before (anonymous type):
var shape = await factory.CreateAsync("MyShape", new
{
    Title = "Hello",
    Count = 5,
});

// After (recommended named type):
[GenerateArguments]
public sealed partial class MyShapeArguments
{
    public string Title { get; set; }
    public int Count { get; set; }
}

var args = new MyShapeArguments { Title = "Hello", Count = 5 };
var shape = await factory.CreateAsync("MyShape", args);

Migration Benefits

• Better IntelliSense — Strongly typed with autocomplete.
• Compile-time safety — Typos caught at build time.
• Reusability — Named types shared across multiple shapes.
• Testability — Easier to unit test.
• Zero reflection — Direct property access.

Advanced: Nested Types

public sealed partial class OuterClass
{
    [GenerateArguments]
    public sealed partial class InnerArguments
    {
        public string Value { get; set; }
    }
}

Advanced: Records

[GenerateArguments]
public sealed partial record MyRecordArgs(string Title, int Count);

Decision Guide

Production code with reusable types?
├─ Yes → Use [GenerateArguments] ✅ RECOMMENDED
└─ No
   └─ Using .NET 9+ with anonymous types?
      ├─ Yes → Interceptors (automatic) ✅
      └─ No → Reflection with caching (acceptable for rare usage)

Troubleshooting

"Type must be partial" — Add the partial keyword:

// Correct
[GenerateArguments]
public sealed partial class MyData { }

// Wrong - will not compile
[GenerateArguments]
public sealed class MyData { }

Generated code not found:

1. Rebuild the project
2. Check obj/Debug/net10.0/generated/ for generated files
3. Restart Visual Studio if needed

Do not manually cast to INamedEnumerable:

// Correct - pass arguments directly
var args = new MyShapeArguments { Title = "Test" };
var shape = await factory.CreateAsync("MyShape", args);

// Wrong - unnecessary manual cast
var enumerable = (INamedEnumerable<object>)args;

Best Practices

1. Use [GenerateArguments] for all production shape arguments.
2. Use descriptive class names (e.g., UserProfileShapeArgs over Args).
3. Group related properties into focused models.
4. Keep property counts reasonable (2-20 properties).
5. Add XML comments to document the model's purpose.
6. Avoid complex logic in property getters.