如何在C#中通过反射更新数据库

Question

我想通过反射更新一个 table 实例

这是我试过的

var type = Assembly.GetExecutingAssembly().GetTypes()
    .FirstOrDefault(t => t.Name == TableName);


object instance = Activator.CreateInstance(type);

foreach (var item in dic)
{

    PropertyInfo information = type.GetProperties()
        .SingleOrDefault(x => x.Name == item.Key);

    information.SetValue(instance, item.Value.ToString(), null);

}
var fx = db.Set(instance.GetType());
fx.Add(instance);
result= db.SaveChanges();

它给了我以下异常

   InnerException = {"Violation of PRIMARY KEY constraint
 'PK_primryKeyName. Cannot insert duplicate key in object 'tableName'.
 The duplicate key value is (39).
\r\nThe statement has been terminated."}

它似乎 Entity framework 将其视为插入而不是更新

Answer 1

这就是我们如何处理未附加的东西而无需返回并通过手动获取它select。

   var type = Assembly.GetExecutingAssembly().GetTypes()
   .FirstOrDefault(t => t.Name == "");


            object instance = Activator.CreateInstance(type);

            foreach (var item in new Dictionary<string, string>())
            {

                PropertyInfo information = type.GetProperties()
    .SingleOrDefault(x => x.Name == item.Key);

                information.SetValue(instance, item.Value.ToString(), null);

            }               

            db.Entry(instance).State = EntityState.Modified;
            db.SaveChanges();

如何在C#中通过反射更新数据库

How to update db by reflection in c#

c#

.net

reflection

system.reflection