如何刷新DbContext
如何刷新DbContext
提问于 2013-08-11 16:03:46
我想刷新我的DbContext的所有实体而不重新创建它，我尝试了以下方法，但没有一个有意义：
var context = ((IObjectContextAdapter)myDbContext).ObjectContext;
var refreshableObjects = (from entry in context.ObjectStateManager.GetObjectStateEntries(
EntityState.Added
| EntityState.Deleted
| EntityState.Modified
| EntityState.Unchanged)
where entry.EntityKey != null
select entry.Entity);
context.Refresh(RefreshMode.StoreWins, refreshableObjects);
//.......................................................................
foreach (var entry in this.Orm.ChangeTracker.Entries())
{
entry.State = EntityState.Unchanged;
}
this.Orm.ChangeTracker.DetectChanges();唯一能刷新我的DbContext的
foreach (var i in this.Orm.ChangeTracker.Entries())
i.Reload();但它太慢了。你能帮我选一条正确的路吗？
回答 4
Stack Overflow用户
发布于 2013-08-11 17:34:50
我检查了一下，id运行得很好：
//Search
Box box = dbContext.Boxes.FirstOrDefault(x => x.BoxId == 45);
//breakpoint here, change Name of Box by sql management studio
//Refresh
var context = ((IObjectContextAdapter)dbContext).ObjectContext;
context.Refresh(System.Data.Entity.Core.Objects.RefreshMode.StoreWins, box);
//Check refresh and if it is in context
box = dbContext.Boxes.FirstOrDefault(x => x.BoxId == 45);您确定它是相同的db-context吗？
Stack Overflow用户
发布于 2015-10-06 00:24:39
在某些情况下，如果集合已由第三方应用程序更新，则在刷新集合的对象时可能不会重新加载该集合。
在这种情况下，我有一个对象A，它与对象B有一对多的关系。
应用程序1加载一个A.ListB为空的对象A。应用程序2填充A.ListB集合。应用程序1重新加载对象A。
使用上面的解决方案，A.ListB仍然是空的。我必须显式地重新加载集合A.ListB。
下面是重新加载所有集合的通用方法：
var context = ((IObjectContextAdapter)this).ObjectContext;
// detach all added entities
ChangeTracker.Entries().Where(e => e.State == EntityState.Added).ToList().ForEach(e => e.State = EntityState.Detached);
// select entities
var refreshableObjects = ChangeTracker.Entries().Select(e => e.Entity).ToList();
// refresh each refreshable object
foreach (var @object in refreshableObjects)
{
// refresh each collection of the object
context.ObjectStateManager.GetRelationshipManager(@object).GetAllRelatedEnds().Where( r => r.IsLoaded).ToList().ForEach( c => c.Load() );
// refresh the object
context.Refresh(RefreshMode.StoreWins, @object);
}Stack Overflow用户
发布于 2015-03-14 03:23:39
using System.Data.Entity.Core.Objects;
using System.Data.Entity.Infrastructure;
using System.Linq;
namespace System.Data.Entity
{
public static class DbContextExtensions
{
/// <summary>
/// Refresh non-detached entities
/// </summary>
/// <param name="dbContext">context of the entities</param>
/// <param name="refreshMode">store or client wins</param>
/// <param name="entityType">when specified only entities of that type are refreshed. when null all non-detached entities are modified</param>
/// <returns></returns>
public static DbContext RefreshEntites(this DbContext dbContext, RefreshMode refreshMode, Type entityType)
{
//https://christianarg.wordpress.com/2013/06/13/entityframework-refreshall-loaded-entities-from-database/
var objectContext = ((IObjectContextAdapter)dbContext).ObjectContext;
var refreshableObjects = objectContext.ObjectStateManager
.GetObjectStateEntries(EntityState.Added | EntityState.Deleted | EntityState.Modified | EntityState.Unchanged)
.Where(x => entityType == null || x.Entity.GetType() == entityType)
.Where(entry => entry.EntityKey != null)
.Select(e => e.Entity)
.ToArray();
objectContext.Refresh(RefreshMode.StoreWins, refreshableObjects);
return dbContext;
}
public static DbContext RefreshAllEntites(this DbContext dbContext, RefreshMode refreshMode)
{
return RefreshEntites(dbContext: dbContext, refreshMode: refreshMode, entityType: null); //null entityType is a wild card
}
public static DbContext RefreshEntites<TEntity>(this DbContext dbContext, RefreshMode refreshMode)
{
return RefreshEntites(dbContext: dbContext, refreshMode: refreshMode, entityType: typeof(TEntity));
}
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/18169970
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