public class CustomValidationAttribute : ValidationAttribute
{
    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        // 使用validationContext获取服务或其他上下文信息
        var service = (IMyService)validationContext.GetService(typeof(IMyService));
        
        // 验证逻辑...
        if (/* 验证失败 */)
        {
            return new ValidationResult("错误消息", new[] { validationContext.MemberName });
        }
        
        return ValidationResult.Success;
    }
}

var model = new MyModel();
var context = new ValidationContext(model);
var results = new List<ValidationResult>();

bool isValid = Validator.TryValidateObject(model, context, results, true);

var propertyValue = model.PropertyToValidate;
var context = new ValidationContext(model) { MemberName = nameof(model.PropertyToValidate) };
var results = new List<ValidationResult>();

bool isValid = Validator.TryValidateProperty(propertyValue, context, results);

var serviceProvider = new ServiceCollection()
    .AddSingleton<IMyService, MyService>()
    .BuildServiceProvider();

var context = new ValidationContext(model, serviceProvider, null);

var context = new ValidationContext(model) 
{ 
    MemberName = nameof(model.PropertyName) 
};

Validator.TryValidateObject(model, context, results, validateAllProperties: true);

public class DateRangeAttribute : ValidationAttribute
{
    protected override ValidationResult IsValid(object value, ValidationContext context)
    {
        var model = (MyModel)context.ObjectInstance;
        
        if (model.StartDate >= model.EndDate)
        {
            return new ValidationResult("结束日期必须大于开始日期", 
                new[] { nameof(model.StartDate), nameof(model.EndDate) });
        }
        
        return ValidationResult.Success;
    }
}

var context = new ValidationContext(model)
{
    Items = { ["AdditionalData"] = "SomeValue" }
};