.Net Core 2.1 IFormCollection模型错误

如何解决.Net Core 2.1 IFormCollection模型错误

我正在使用控件帮助程序将MVC 5转换为.Net Core 2.1。

  public static class ControllerHelpers
    {
        public static void AddRuleViolation(this ModelStateDictionary modelState,RuleViolation error,FormCollection collection)
        {
            modelState.AddModelError(error.PropertyName,error.ErrorMessage);
            modelState.SetModelValue(error.PropertyName,collection.TovalueProvider().GetValue(error.PropertyName));
        }

        public static void AddRuleViolations(this ModelStateDictionary modelState,IEnumerable errors,FormCollection collection)
        {
            foreach (RuleViolation issue in errors)
            {
                modelState.AddModelError(issue.PropertyName,issue.ErrorMessage);
                modelState.SetModelValue(issue.PropertyName,collection.TovalueProvider().GetValue(issue.PropertyName));
            }
        }
    }

我遇到错误

FormCollection does not have a deFinition for TovalueProvider

我也尝试过IFormCollection。