网站建设与制作企业,用wordpress插件推荐,关于建设网站的图片,正规网站建设推荐efcore 新特性 SaveChanges EventsIntro昨天早上看到之前关注的一个 efcore 的 issue 被 closed #xff0c;于是看了一眼#xff0c; ef core 新合并了一个 PR#xff0c;在 DbContext 中增加了 SaveChanges 相关的几个事件#xff0c;具体的变更可以参数 PR https://gith… efcore 新特性 SaveChanges EventsIntro昨天早上看到之前关注的一个 efcore 的 issue 被 closed 于是看了一眼 ef core 新合并了一个 PR在 DbContext 中增加了 SaveChanges 相关的几个事件具体的变更可以参数 PR https://github.com/dotnet/efcore/pull/21862Events之前写过两篇关于 EF Core 做自动审计的文章第一次的实现需要显式继承一个 AuditDbContext 在有些需要没办法修改 DbContext 或者原有 DbContext 已经有继承某一个类就没有办法用了可以参考 EF Core 数据变更自动审计设计后面结合 AOP 改进了一版通过一个审计切面逻辑完成自动审计但是需要引入 AOP 组件支持对于不想引入额外组件的项目来说也并非特别友好可以参考 打造更好用的 EF 自动审计在这个 PR 合并之后我们可以通过 SavingChanges 事件获取保存之前 DbContext 的状态通过 SavedChanges 事件来获取保存成功后的 DbContext 信息SaveChangesFailed 事件获取保存失败信息事件定义如下
/// summary
/// An event fired at the beginning of a call to see crefM:SaveChanges/ or see crefM:SaveChangesAsync/
/// /summary
public event EventHandlerSavingChangesEventArgs SavingChanges;/// summary
/// An event fired at the end of a call to see crefM:SaveChanges/ or see crefM:SaveChangesAsync/
/// /summary
public event EventHandlerSavedChangesEventArgs SavedChanges;/// summary
/// An event fired if a call to see crefM:SaveChanges/ or see crefM:SaveChangesAsync/ fails with an exception.
/// /summary
public event EventHandlerSaveChangesFailedEventArgs SaveChangesFailed;
事件参数定义如下/// summary
/// Base event arguments for the see crefM:DbContext.SaveChanges / and see crefM:DbContext.SaveChangesAsync / events.
/// /summary
public abstract class SaveChangesEventArgs : EventArgs
{/// summary/// Creates a base event arguments instance for see crefM:DbContext.SaveChanges //// or see crefM:DbContext.SaveChangesAsync / events./// /summary/// param nameacceptAllChangesOnSuccess The value passed to SaveChanges. /paramprotected SaveChangesEventArgs(bool acceptAllChangesOnSuccess){AcceptAllChangesOnSuccess acceptAllChangesOnSuccess;}/// summary/// The value passed to see crefM:DbContext.SaveChanges / or see crefM:DbContext.SaveChangesAsync /./// /summarypublic virtual bool AcceptAllChangesOnSuccess { get; }
}/// summary
/// Event arguments for the see crefDbContext.SavingChanges / event.
/// /summary
public class SavingChangesEventArgs : SaveChangesEventArgs
{/// summary/// Creates event arguments for the see crefM:DbContext.SavingChanges / event./// /summary/// param nameacceptAllChangesOnSuccess The value passed to SaveChanges. /parampublic SavingChangesEventArgs(bool acceptAllChangesOnSuccess): base(acceptAllChangesOnSuccess){}
}/// summary
/// Event arguments for the see crefDbContext.SavedChanges / event.
/// /summary
public class SavedChangesEventArgs : SaveChangesEventArgs
{/// summary/// Creates a new see crefSavedChangesEventArgs / instance with the given number of entities saved./// /summary/// param nameacceptAllChangesOnSuccess The value passed to SaveChanges. /param/// param nameentitiesSavedCount The number of entities saved. /parampublic SavedChangesEventArgs(bool acceptAllChangesOnSuccess, int entitiesSavedCount) : base(acceptAllChangesOnSuccess){EntitiesSavedCount entitiesSavedCount;}/// summary/// The number of entities saved./// /summarypublic virtual int EntitiesSavedCount { get; }
}/// summary
/// Event arguments for the see crefDbContext.SaveChangesFailed / event.
/// /summary
public class SaveChangesFailedEventArgs : SaveChangesEventArgs
{/// summary/// Creates a new see crefSaveChangesFailedEventArgs/ instance with the exception that was thrown./// /summary/// param nameacceptAllChangesOnSuccess The value passed to SaveChanges. /param/// param nameexception The exception thrown. /parampublic SaveChangesFailedEventArgs(bool acceptAllChangesOnSuccess, [NotNull] Exception exception): base(acceptAllChangesOnSuccess){Exception exception;}/// summary/// The exception thrown duringsee crefM:DbContext.SaveChanges/ or see crefM:DbContext.SaveChangesAsync/./// /summarypublic virtual Exception Exception { get; }
}
More除了上面的审计你也可以使用通过这些事件实现保存之前的自动更新数据库字段的值比如 Add 或 Update 操作数据时自动设置更新时间等信息本文提到的特性还未正式发布预计会在 .net5 下一个预览版中发布如果想现在要尝试请使用 efcore 的 daily build 的包可以参考 https://github.com/dotnet/aspnetcore/blob/master/docs/DailyBuilds.mdReferencehttps://github.com/dotnet/efcore/issues/15910https://github.com/dotnet/efcore/pull/21862
