GetCustomAttributes 和 [DatabaseGenerated(DatabaseGeneratedOption.Computed)]答案

【问题标题】：GetCustomAttributes and [DatabaseGenerated(DatabaseGeneratedOption.Computed)]GetCustomAttributes 和 [DatabaseGenerated(DatabaseGeneratedOption.Computed)]
【发布时间】：2021-12-01 02:42:38
【问题描述】：

在获取此类属性时如何跳过计算列？我可以为 NotMapped 做，但不确定DatabaseGenerated(DatabaseGeneratedOption.Computed)？

  [DatabaseGenerated(DatabaseGeneratedOption.Computed)]
        public bool AAUProcessing { get; set; }

跳过未映射和计算的列

var props = typeof(TK).GetProperties()
                    .Where(propertyInfo => !propertyInfo.GetCustomAttributes(typeof(NotMappedAttribute)).Any())
                    .ToArray();

【问题讨论】：

标签： c# .net entity-framework reflection ef-code-first

【解决方案1】：

只需将其转换为正确的类型 (DatabaseGeneratedAttribute)，您就可以检查它是否具有您认为合适的任何属性。

以下示例将过滤掉计算和未映射的属性：

void Main()
{
    var props = typeof(TK).GetProperties()
                    .Where(IsNotMapped)
                    .Where(IsNotComputedColumn)
                    .ToArray();

    foreach (var property in props)
    {
        Console.WriteLine(property.Name);
    }
}

static bool IsNotMapped(PropertyInfo propertyInfo)
{
    return !propertyInfo
        .GetCustomAttributes(typeof(NotMappedAttribute))
        .Any();
}

static bool IsNotComputedColumn(PropertyInfo propertyInfo)
{
    return !propertyInfo
        .GetCustomAttributes(typeof(DatabaseGeneratedAttribute))
        .Cast<DatabaseGeneratedAttribute>()
        .Any(a => a.DatabaseGeneratedOption == DatabaseGeneratedOption.Computed);
}

public class TK
{
    [DatabaseGenerated(DatabaseGeneratedOption.Computed)]
    public bool IsComputed { get; set; }

    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public bool IsIdentity { get; set; }

    [NotMapped]
    public bool NotMapped { get; set; }

    public bool StandardColumn { get; set; }
}

输出是

IsIdentity
StandardColumn

【讨论】：