C# 如何从C中使用的对象中获取TableName和Key字段值#

我有一个类似的类，我使用它作为我的一个表的实体框架核心的模型。 保存后，我将传递对象以进行某种缓存工作。 如何获取表名和标记为键的字段的值（我使用单个字段作为键）

TableName来自System.ComponentModel.DataAnnotations.Schema 密钥来自System.ComponentModel.DataAnnotations

我已经使用了我自己的自定义属性，但这里想检查是否有一些buildin方法可以访问这些值。

---

我必须传递对象并获取键的表名和值

根据您的需要调整此测试代码：

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.IO;
using System.Linq;
using System.Reflection;


class Program
{
    [Table("audit_log")]
    public class AuditLog
    {
        [Key] public long auditlog_id { get; set; }

        [Required]
        public string appname { get; set; }
    }
    static void Main(string[] args)
    {

        GetClassAttributes(typeof(AuditLog ));
    }

    public static void GetClassAttributes(System.Type item)
    {
        var tableName=string.Empty;
        
        var tableAttr=item.GetCustomAttributes().FirstOrDefault() as TableAttribute;
        
        if (tableAttr != null) tableName = tableAttr.Name;
        Console.WriteLine("");
        Console.WriteLine("Table Name .... {0}", tableName);

        var properties = item.GetProperties();
        

        if (HasEFDataAnnotaion(properties))
        {
            Console.WriteLine("");
            Console.WriteLine("Found Data Annotations attributes at {0} ...", item.FullName);
            foreach (var property in properties)
            {
                var attributes = property.GetCustomAttributes(false);

                // Using reflection.  
                Attribute[] attrs = System.Attribute.GetCustomAttributes(property);
            

                // Displaying output.  
                foreach (Attribute attr in attrs)
                {

                    if (attr is KeyAttribute)
                    {
                        KeyAttribute a = (KeyAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                    }

                    if (attr is ForeignKeyAttribute)
                    {
                        ForeignKeyAttribute a = (ForeignKeyAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                    }

                    //if (attr is IndexAttribute)
                    //{
                    //  IndexAttribute a = (IndexAttribute)attr;
                    //  Console.WriteLine("attribute {0} on {1} ", a.GetType().FullName + a.ToString(), property.Name);
                    //}

                    if (attr is RequiredAttribute)
                    {
                        RequiredAttribute a = (RequiredAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                    }

                    if (attr is TimestampAttribute)
                    {
                        TimestampAttribute a = (TimestampAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                    }

                    if (attr is ConcurrencyCheckAttribute)
                    {
                        ConcurrencyCheckAttribute a = (ConcurrencyCheckAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                    }

                    if (attr is MinLengthAttribute)
                    {
                        MinLengthAttribute a = (MinLengthAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                    }

                    if (attr is MaxLengthAttribute)
                    {
                        MaxLengthAttribute a = (MaxLengthAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                    }

                    if (attr is StringLengthAttribute)
                    {
                        StringLengthAttribute a = (StringLengthAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                    }

                    if (attr is TableAttribute)
                    {
                        TableAttribute a = (TableAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                    }

                    if (attr is ColumnAttribute)
                    {
                        ColumnAttribute a = (ColumnAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                    }

                    if (attr is DatabaseGeneratedAttribute)
                    {
                        DatabaseGeneratedAttribute a = (DatabaseGeneratedAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                    }

                    if (attr is ComplexTypeAttribute)
                    {
                        ComplexTypeAttribute a = (ComplexTypeAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                    }
                }
            }
        }
    }

}
    private static bool HasEFDataAnnotaion(PropertyInfo[] properties)
    {
        return properties.ToList().Any((property) =>
        {
            var attributes = property.GetCustomAttributes(false);
            Attribute[] attrs = System.Attribute.GetCustomAttributes(property);
            return attrs.Any((attr) =>
            {
                return attr is KeyAttribute || attr is ForeignKeyAttribute || attr is RequiredAttribute || attr is TimestampAttribute //||  attr is IndexAttribute 
                || attr is ConcurrencyCheckAttribute || attr is MinLengthAttribute || attr is MinLengthAttribute
                || attr is MaxLengthAttribute || attr is StringLengthAttribute || attr is TableAttribute || attr is ColumnAttribute
                || attr is DatabaseGeneratedAttribute || attr is ComplexTypeAttribute;
            });
        });
    }
    

更新

如果需要键属性值，请将“我的代码”的开头更改为：

static void Main(string[] args)
    {
        var auditLog = new AuditLog {auditlog_id=1, appname="first log"};

     GetObjectAttributes(auditLog);
    }
    public static void GetObjectAttributes(object item)
    {
        
      var itemType= item.GetType()  ;
    
        var tableName=string.Empty;
        
        var tableAttr=itemType.GetCustomAttributes().FirstOrDefault() as TableAttribute;

        if (tableAttr != null) tableName = tableAttr.Name;
        Console.WriteLine("");
        Console.WriteLine("Table Name .... {0}", tableName);

        var properties = itemType.GetProperties();


        if (HasEFDataAnnotaion(properties))
        {
            Console.WriteLine("");
            Console.WriteLine("Found Data Annotations attributes at {0} ...", tableName);
            foreach (var property in properties)
            {
                var attributes = property.GetCustomAttributes(false);

                // Using reflection.  
                Attribute[] attrs = System.Attribute.GetCustomAttributes(property);
        

                // Displaying output.  
                foreach (Attribute attr in attrs)
                {

                    if (attr is KeyAttribute)
                    {
                        KeyAttribute a = (KeyAttribute)attr;
                        Console.WriteLine("attribute {0} on {1} ", a.ToString(), property.Name);
                        Console.WriteLine("property value on {1} is {0}  ", property.GetValue(item ), property.Name);
                    }
......Continue code above if you need another attributes

非常感谢，谢尔盖。 下面是我目前的解决方案

public static Tuple<bool, string, string> GetDataAnotationDetail<T>(T item) where T : class
        {
            Tuple<bool, string, string> result = null;

            var tableName = string.Empty;
            var tableAttr = item.GetType().GetCustomAttributes().FirstOrDefault() as TableAttribute;

            if (tableAttr != null)
            {
                tableName = tableAttr.Name;
            }

            var properties = item.GetType().GetProperties();
            bool breakcondition = false;
            foreach (var property in properties)
            {
                Attribute[] attrs = Attribute.GetCustomAttributes(property);
                if (attrs != null)
                {
                    foreach (Attribute attr in attrs)
                    {

                        if (attr is KeyAttribute)
                        {
                            var a = (KeyAttribute)attr;
                            var obj = property.GetValue(item, null);
                            result = Tuple.Create(true, tableName, Convert.ToString(obj));
                            breakcondition = true;
                            break;
                        }

                    }
                }
                if (breakcondition)
                {
                    break;
                }
            }

            return result;
        }

公共静态元组GetDataAnotationDetail（T项），其中T:class
{
元组结果=null；
var tableName=string.Empty；
var tabletattr=item.GetType（）.GetCustomAttributes（）.FirstOrDefault（）作为tabletAttribute；
如果（tableAttr！=null）
{
tableName=tableAttr.Name；
}
var properties=item.GetType（）.GetProperties（）；
bool-breakcondition=false；
foreach（属性中的var属性）
{
Attribute[]attrs=Attribute.GetCustomAttributes（属性）；
如果（属性！=null）
{
foreach（attrs中的属性attr）
{
if（attr是KeyAttribute）
{
var a=（KeyAttribute）attr；
var obj=property.GetValue（项，空）；
结果=Tuple.Create（true，tableName，Convert.ToString（obj））；
breakcondition=true；
打破
}
}
}
如果（断开状态）
{
打破
}
}
返回结果；
}

非常好。但我想传递的是实际对象而不是类型，其次我想获取键属性所在属性的值我添加了一些更改以获取键属性值。请检查我的更新

public static Tuple<bool, string, string> GetDataAnotationDetail<T>(T item) where T : class
        {
            Tuple<bool, string, string> result = null;

            var tableName = string.Empty;
            var tableAttr = item.GetType().GetCustomAttributes().FirstOrDefault() as TableAttribute;

            if (tableAttr != null)
            {
                tableName = tableAttr.Name;
            }

            var properties = item.GetType().GetProperties();
            bool breakcondition = false;
            foreach (var property in properties)
            {
                Attribute[] attrs = Attribute.GetCustomAttributes(property);
                if (attrs != null)
                {
                    foreach (Attribute attr in attrs)
                    {

                        if (attr is KeyAttribute)
                        {
                            var a = (KeyAttribute)attr;
                            var obj = property.GetValue(item, null);
                            result = Tuple.Create(true, tableName, Convert.ToString(obj));
                            breakcondition = true;
                            break;
                        }

                    }
                }
                if (breakcondition)
                {
                    break;
                }
            }

            return result;
        }