Comments on: Discard changes in LINQ to SQL DataContext

By: umair

umair — Tue, 01 May 2012 16:37:02 +0000

This works perfect for me. I hope in future, they will make this much simpler than this.

Thanks

By: Reza

Reza — Mon, 30 Jan 2012 08:33:21 +0000

Compelete code of my Datacontext:

using System;
using System.Collections;
using System.Collections.Generic;
using System.Data.Linq;
using System.Linq;

namespace DataContextDiscardChanges
{
partial class NorthwindDataContext
{
#region Public Members

public void DiscardChanges()
{
this.DiscardUpdates();
this.DiscardInserts();
this.DiscardDeletes();
}

public void DiscardInserts(Func predicate = null)
{
if (predicate != null)
discardInserts(this.GetChangeSet().Inserts.OfType().Where(predicate));
else
discardInserts(this.GetChangeSet().Inserts.OfType());
}

public void DiscardInserts()
{
discardInserts(this.GetChangeSet().Inserts);
}

public void DiscardDeletes(Func predicate = null)
{
if (predicate != null)
discardDeletes(this.GetChangeSet().Deletes.OfType().Where(predicate));
else
discardDeletes(this.GetChangeSet().Deletes.OfType());
}

public void DiscardDeletes()
{
discardDeletes(this.GetChangeSet().Deletes);
}

public void DiscardUpdates(Func predicate = null)
{
if (predicate != null)
discardUpdates(this.GetChangeSet().Updates.OfType().Where(predicate));
else
discardUpdates(this.GetChangeSet().Updates.OfType());
}

public void DiscardUpdates()
{
discardUpdates(this.GetChangeSet().Updates);
}

#endregion Public Members

#region Private Memebers

private void discardInserts(IEnumerable insertedEntities)
{
foreach (var insertedItem in insertedEntities)
{
this.GetTable(insertedItem.GetType()).DeleteOnSubmit(insertedItem);
}
}

private void discardDeletes(IEnumerable deletedEntities)
{
foreach (var deletedItem in deletedEntities)
{
this.GetTable(deletedItem.GetType()).InsertOnSubmit(deletedItem);
}
}

private void discardUpdates(IEnumerable updatedEntities)
{
foreach (var updatedItem in updatedEntities)
{
ModifiedMemberInfo[] modifiedMembers = this.GetTable(updatedItem.GetType()).GetModifiedMembers(updatedItem);

foreach (var modifiedMember in modifiedMembers)
{
updatedItem.GetType().GetProperty(modifiedMember.Member.Name).SetValue(updatedItem, modifiedMember.OriginalValue, null);
}
}
}

#endregion Private Memebers
}
}

By: Reza

Reza — Sun, 29 Jan 2012 12:07:42 +0000

hello every body

Discard Updated with Refresh method, reads orginal data from database and it’s not good way to Discard in-memory objects

i’m using reflection to solve this problem:

public void DiscardUpdates()
{
var changeSet = this.GetChangeSet();
foreach (var updatedItem in changeSet.Updates)
{
ModifiedMemberInfo[] modifiedMembers = this.GetTable(updatedItem.GetType()).GetModifiedMembers(updatedItem);

foreach (var modifiedMember in modifiedMembers)
{
updatedItem.GetType().GetProperty(modifiedMember.Member.Name).SetValue(updatedItem, modifiedMember.OriginalValue, null);
}
}
}

By: Andre

Andre — Fri, 13 Jan 2012 14:00:32 +0000

It’s an incredible article. It’s such a simple solution for all my problems with discarding data contexts.

Thanks so much!

By: Usman

Usman — Tue, 29 Nov 2011 23:00:43 +0000

Thanks! Good to know this exists! My small blogpost on this
http://usman-suglatwala.blogspot.com/2011/11/discarding-changes-in-linq-memory.html

By: Jimbo

Jimbo — Wed, 26 Oct 2011 14:55:57 +0000

Glad I found this, creating a new DataContext was just not an option for me - your code works great, thanks

By: John P.

John P. — Tue, 27 Sep 2011 20:15:28 +0000

I’d been working on this for hours before finding this post. Works Great! Thanks.

By: Daniel

Daniel — Fri, 11 Feb 2011 20:17:26 +0000

the data.GetTable(insertion.GetType()).DeleteOnSubmit(insertion);
works
but
data.GetTable(deletion.GetType()).InsertOnSubmit(deletion);
does not work for me
.net4.0
the data.getchangeset() will show the same number of deletes (1)
& of course at a subsequent SubmitChanges will operate on the database the pending delete
anybody could help?

By: Alex

Alex — Fri, 11 Feb 2011 19:48:27 +0000

fantastic article - thank you!

Question, is there a problem with the following code? it seemed to work in my testing

static void DiscardChanges()
{
var changes = data.GetChangeSet();

//insert the deletes
foreach (var insertion in changes.Inserts)
data.GetTable(insertion.GetType()).DeleteOnSubmit(insertion);

//delete the inserts
foreach (var deletion in changes.Deletes)
data.GetTable(deletion.GetType()).InsertOnSubmit(deletion);

//undo the updates
foreach (var update in changes.Updates)
data.Refresh(System.Data.Linq.RefreshMode.OverwriteCurrentValues, changes.Updates);
}

By: Shalu

Shalu — Fri, 22 Oct 2010 12:28:15 +0000

Awesome article. The c# code for discarding the changes helped me so much. Thanks for posting this article.