代码示例：

1. 创建验证程序类和验证结果类

public class MyCustomValidator { public static ValidationResult Validate(string value, int maxLength) { if (string.IsNullOrEmpty(value) || value.Length > maxLength) return new ValidationResult("输入不能为空且长度不超过 " + maxLength + "。"); else return ValidationResult.Success; } }

public class ValidationResult
{
    public bool IsValid { get; }
    public string ErrorMessage { get; }

    public ValidationResult(bool isValid, string errorMessage = null)
    {
        IsValid = isValid;
        ErrorMessage = errorMessage;
    }

    public static ValidationResult Success { get; } = new ValidationResult(true);
}

2. 在Razor组件中使用

@using System.ComponentModel.DataAnnotations @using MyApp.Shared

Blazor自定义验证程序

提交

@code { private readonly MyModel Model = new MyModel();

private class MyModel
{
    [MyCustomValidator]
    [Required]
    public string Email { get; set; }
}

}

3. 创建自定义的验证属性

public class MyCustomValidatorAttribute : ValidationAttribute { public override bool IsValid(object value) { return MyCustomValidator.Validate(value?.ToString(), 10).IsValid; }

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        return MyCustomValidator.Validate(value?.ToString(), 10);
    }
}

4. 在验证类中使用变量

public class MyCustomValidator { private int maxLength;

    public MyCustomValidator(int maxLength)
    {
        this.maxLength = maxLength;
    }

    public ValidationResult Validate(string value)
    {
        if (string.IsNullOrEmpty(value) || value.Length > maxLength)
            return new ValidationResult("输入不能为空且长度不超过 " + maxLength + "。");
        else
            return ValidationResult.Success;
    }
}

5. 在Razor组件中使用

@using MyApp.Shared

Blazor自