我正在使用带有DataAnnotations的ASP.NET MVC.我创建了以下自定义ValidationAttribute,它可以正常工作.
public class StringRangeAttribute : ValidationAttribute
{
public int MinLength { get; set; }
public int MaxLength { get; set; }
public StringRangeAttribute(int minLength,int maxLength)
{
this.MinLength = (minLength < 0) ? 0 : minLength;
this.MaxLength = (maxLength < 0) ? 0 : maxLength;
}
public override bool IsValid(object value)
{
//null or empty is <em>not</em> invalid
string str = (string)value;
if (string.IsNullOrEmpty(str))
return true;
return (str.Length >= this.MinLength && str.Length <= this.MaxLength);
}
}
但是,出现的错误消息是标准的“字段*无效”.我想将其更改为：“[DisplayName]必须介于[minlength]和[maxlength]之间”,但我无法弄清楚如何从此类中获取DisplayName甚至字段的名称.
谁知道？
解决方法
稍微修改过的StringLengthAttribute：
public class StringRangeAttribute : ValidationAttribute
{
// Methods
public StringRangeAttribute(int minimumLength,int maximumLength)
: base(() => "The {0} must be between {1} and {2} chars long.")
{
MaximumLength = maximumLength;
MinimumLength = minimumLength;
}
public override string FormatErrorMessage(string name)
{
return string.Format(CultureInfo.CurrentCulture,ErrorMessageString,new object[] { name,MinimumLength,MaximumLength });
}
public override bool IsValid(object value)
{
if (value != null)
{
return (((string)value).Length <= MaximumLength) && (((string)value).Length >= MinimumLength);
}
return true;
}
public int MaximumLength { get; set; }
public int MinimumLength { get; set; }
}
