ShrlAlgoToolkit/ShrlAlgo.Toolkit.Mvvm/Attributes/NotNullOrEmptyAttribute.cs

using System.ComponentModel.DataAnnotations;

namespace ShrlAlgo.Toolkit.Mvvm.Attributes;

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter)]
public sealed class NotNullOrEmptyAttribute : ValidationAttribute
{
    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        var b = value != null || (value is string str && !string.IsNullOrEmpty(str));
        return b ? ValidationResult.Success : new("输入内容不是数值。");
    }
}