Unable to extract constants from static field accesses

[andrewlock]

I've been using this library without issue for some time, including in .NET Core 2.x apps, so thanks for that 🙂

However, I've just come across an issue with standard constants exposed as static fields like Guid.Empty and string.Empty. Basically, they are ignored during URL generation in ExpressionRouteHelper, in the MemberAccess branch:

AspNet.Mvc.TypedRouting/src/AspNet.Mvc.TypedRouting/LinkGeneration/ExpressionRouteHelper.cs

Lines 234 to 246 in 2994a60

	else if (expressionArgument.NodeType == ExpressionType.MemberAccess
	&& ((MemberExpression)expressionArgument).Member is FieldInfo)
	{
	// Expression of type c => c.Action(id)
	// Value can be extracted without compiling.
	var memberAccessExpr = (MemberExpression)expressionArgument;
	var constantExpression = (ConstantExpression)memberAccessExpr.Expression;
	if (constantExpression != null)
	{
	var innerMemberName = memberAccessExpr.Member.Name;
	var compiledLambdaScopeField = constantExpression.Value.GetType().GetField(innerMemberName);
	value = compiledLambdaScopeField.GetValue(constantExpression.Value);
	}

As they're not a ConstantExpression, that branch returns null, no value is generated for the parameter, and link generation completely fails.

[ivaylokenov]

Hi, thank you for your issue. Since I am overwhelmed with my other project https://github.com/ivaylokenov/MyTested.AspNetCore.Mvc, I did not have a lot of time to support this one. Will try to publish a new package during the weekend. Thank you for your patience!

[Piedone]

Would you be able to publish an updated package @ivaylokenov? Yours is a really great project and the best library for this purpose but not really usable with ASP.NET Core MVC 3.1.