EF扩展 更新指定字段

using System.Data.Entity.Infrastructure;
using System.Threading.Tasks;

/// <summary>
/// EF扩展
/// </summary>
public static class EFExtensions
{
/// <summary>
/// 更新实体根据字段
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="db">数据库上下文</param>
/// <param name="entity">实体</param>
/// <param name="fields">更新的字段列表</param>
public static int UpdateEntityFields<T>(this ApplicationDbContext db, T entity, IList<string> fields) where T : class
{
if (entity == null || fields == null || fields.Count == 0)
{
return 0;
}
db.Set<T>().Attach(entity);
var SetEntry = ((IObjectContextAdapter)db).ObjectContext.
ObjectStateManager.GetObjectStateEntry(entity);
foreach (var item in fields)
{
SetEntry.SetModifiedProperty(item);
}
return db.SaveChanges();
}

/// <summary>
/// 异步更新实体根据字段
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="db">数据库上下文</param>
/// <param name="entity">实体</param>
/// <param name="fields">更新字段列表</param>
/// <returns>受影响的行数</returns>
public static async Task<int> UpdateEntityFieldsAsync<T>(this ApplicationDbContext db, T entity, IList<string> fields) where T : class
{
if (entity == null || fields == null || fields.Count == 0)
{
return 0;
}
db.Set<T>().Attach(entity);
var SetEntry = ((IObjectContextAdapter)db).ObjectContext.
ObjectStateManager.GetObjectStateEntry(entity);
foreach (var item in fields)
{
SetEntry.SetModifiedProperty(item);
}
int result = await db.SaveChangesAsync();
return result;
}
}