c# - 如何从DataAnnotations获取StringLength

更新建议后，我仍然出现错误

尝试过.SingleOrDefault()或FirstOrDefault()
我需要检索StringLength批注值，这是我的代码，但是出现以下错误。

我尝试从here实现几乎相同的代码，但收到错误:

    public static class DataAnnotation
    {
        public static int GetMaxLengthFromStringLengthAttribute(Type modelClass, string propertyName)
        {
            int maxLength = 0;
            var attribute = modelClass.GetProperties()
                            .Where(p => p.Name == propertyName)
                            .Single()
                            .GetCustomAttributes(typeof(StringLengthAttribute), true)
                            .Single() as StringLengthAttribute;

            if (attribute != null)
                maxLength = attribute.MaximumLength;

            return 0;
        }
    }

//调用:

int length = DataAnnotation.GetMaxLengthFromStringLengthAttribute(typeof(EmployeeViewModel), "Name");


public class EmployeeViewModel
{
    [StringLength(20, ErrorMessage = "Name cannot be longer than 20 characters.")]
    public string Name{ get; set; }
}

最佳答案

我能够弄清楚，进行测试并且可以很好地工作，以防万一其他人正在寻找!

  StringLengthAttribute strLenAttr = typeof(EmployeeViewModel).GetProperty(name).GetCustomAttributes(typeof(StringLengthAttribute), false).Cast<StringLengthAttribute>().SingleOrDefault();
  if (strLenAttr != null)
  {
     int maxLen = strLenAttr.MaximumLength;
  }

关于c# - 如何从DataAnnotations获取StringLength，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/29824779/