DtoGenerator.cs

[Generator]
public class DtoGenerator : ISourceGenerator
{
    public void Execute(GeneratorExecutionContext context)
    {
        var targetTypeTracker = context.SyntaxContextReceiver as TargetTypeTracker;
        var codeBuilder = new StringBuilder();

        foreach (var typeNode in targetTypeTracker.TypesNeedingDtoGening)
        {
	    // Use the semantic model to get the symbol for this type
	    var typeNodeSymbol = context.Compilation
	    .GetSemanticModel(typeNode.SyntaxTree)
	    .GetDeclaredSymbol(typeNode);
	    
	    // get the namespace of the entity class
  	    var entityClassNamespace = typeNodeSymbol.ContainingNamespace?.ToDisplayString() ?? "NoNamespace";

	    // give each DTO a name, just suffix the entity class name with "Dto"
	    var generatedDtoClassName = $"{typeNodeSymbol.Name}Dto";
			
	    // Add usings
            codeBuilder.AppendLine("using System;");
            codeBuilder.AppendLine("using System.Collections.Generic;");
            codeBuilder.AppendLine("using System.Linq;");
			
	    // Add target namespace
            codeBuilder.AppendLine($"namespace {entityClassNamespace}.Dtos");
            codeBuilder.AppendLine("{");
			
	    // Start class
            codeBuilder.AppendLine($"\tpublic class {generatedDtoClassName}");
            codeBuilder.AppendLine("\t{");
	    
	    // get all the properties defined in this class
	    var allProperties = typeNode.Members.OfType<PropertyDeclarationSyntax>();
	    
	    // for each property in the domain entity, create a corresponding property 
	    // in the DTO with the same type
            foreach (var property in allProperties)                
                    codeBuilder.AppendLine($"\t\t{property.BuildDtoProperty(context.Compilation)}");
			
	    // Add closing braces
            codeBuilder.AppendLine("\t}");
            codeBuilder.AppendLine("}");
			
	    // add the code for this DTO class to the context so it can be added to the build
            context.AddSource(generatedDtoClassName,
                SourceText.From(codeBuilder.ToString(), Encoding.UTF8));
            codeBuilder.Clear();
        }
    }

    public void Initialize(GeneratorInitializationContext context)
    {
        context.RegisterForSyntaxNotifications(() => new TargetTypeTracker());
    }
}

internal static class SourceGenExtns
{
    internal static string BuildDtoProperty(
        this PropertyDeclarationSyntax pds, Compilation compilation)
    {
	// get the symbol for this property from the semantic model
	var symbol = compilation
                .GetSemanticModel(pds.SyntaxTree)
                .GetDeclaredSymbol(pds);

        var property = (symbol as IPropertySymbol);	    
        // use the same type and name for the DTO properties as on the entity
        return $"public {property.Type.Name()} {property.Name} {{get; set;}}";
    }
    // instead of returning "System.Collections.Generic.IList<>", just condense it to "IList<>"
    // the namespace is already added in the usings block
    internal static string Name(this ITypeSymbol typeSymbol) =>
	    typeSymbol.ToDisplayString(SymbolDisplayFormat.MinimallyQualifiedFormat);
}

I have one suggestion on the code. The parameter property of the BuildDtoProperty method should be named pds, otherwise it will conflict with the property variable (row nr. 70).

I have one suggestion on the code. The parameter property of the BuildDtoProperty method should be named pds, otherwise it will conflict with the property variable (row nr. 70).

// bump @explorer14

I have one suggestion on the code. The parameter property of the BuildDtoProperty method should be named pds, otherwise it will conflict with the property variable (row nr. 70).

// bump @explorer14

Done! I didn't realise Thomas had commented on a gist! Thanks for the bump!🙂