Core自定义View查找位置

    public class ThemeViewLocationExpander : IViewLocationExpander
    {
        public IEnumerable<string> ExpandViewLocations(ViewLocationExpanderContext context, IEnumerable<string> viewLocations)
        {
            string theme = context.Values["theme"];
            if (string.IsNullOrWhiteSpace(theme))
            {
                theme = "default";
            }
            string[] newLocation = { $"Views/{theme}/{{1}}/{{0}}.cshtml"};
            return viewLocations.Union(newLocation);
        }

        public void PopulateValues(ViewLocationExpanderContext context)
        {
            context.Values["theme"] = context.ActionContext.HttpContext.Request.Query["theme"].ToString();
        }
    }

//配置模版视图路径
            services.Configure<RazorViewEngineOptions>(options =>
            {
                options.ViewLocationExpanders.Add(new ThemeViewLocationExpander());
            });