I have a table named EFT_BANK_INFO. Due to reasons I won't get into, I had to split up the form into 2 separate forms. This means that half the fields for this table are edited from one view, and half from another.
Everything was working great, until I added form validation to the tables model .cs file. While the codes syntax is correct, all submissions from both forms are labeled as being invalid, preventing me from updating, deleting, and adding rows to the table. It is marked as invalid due to the separation; i.e; I have Required fields in the model for the second portion of the fields, so when I submit data for one half of the fields, the other fields not part of the view/submission are marked as being invalid because no data was received for them.
A potential workaround would be to artificially satisfy the validation for the unwanted fields by inserting values for those fields in the C# controller during the create process. I could also do this for the edit process.
I was wondering if there's a better alternative, given I must have it structured this way. I'd like it to only validate the relevant fields in the model, and not validate all of them for the submission, which is causing the error. No code is really necessary since I have no bugs and know what is wrong, this is more of a theory/solution identification problem. Thanks.
Use ViewModels.
A view model represents only the data that you want to display on your view/page, whether it be used for static text or for input values (like textboxes and dropdowns).
See the accepted answer on the question linked above.
Related
I'm currently trying to implement a table within my SQL database. I'm looking to create a table that can be used to check if a user on my website has liked a post. The idea is to have a table with one axes iterating the posts on the website and one axis with the userID values iterated. Then in each box hold a binary value as to whether they have liked it. I'm just wondering how I would implement this. I have been doing this in C# by creating classes and converting these into server side code using Entity Framework 6.4.0.
Any help would be great.
What you are suggesting is a normalized structure for your use case; it would, for example, require adding more columns to the table everytime a post is added to the database (or a user, depending on whether you use rows or columns).
A typical database solution would be a bridge table, that represents the many to many relationship between posts and users.
Say table user_like_posts, with the following columns:
user_id -- foreign key to the "users" table
post_id -- foreign key to the "posts" table
You may want to add additional columns to the bridge table, like the timestamp when the user liked the post, or the-like.
Will every user have an opinion on every post? If not then you don't have the data you described. If users and posts are not related one to one then you have a simple relation. For each post that a user likes (or dislikes?) there is an entry for that user:
Likes/Dislikes Table:
User identifier
Post identifier
The binary value that indicates like or dislike
If the table only indicates 'likes' then you don't need the last column.
A design like this would work even if every user and every post is in this table. The table might get large in a hurry and keep growing every time you introduced a new post. But if this table only includes actual 'likes' (and/or 'dislikes') it should be manageable.
For a class you just have an enumerable that has the posts 'liked' (and possibly another that indicates the posts 'disliked.')
Think about what you are trying to represent. Ask yourself questions. Don't just latch on to an idea and try to 'do' it.
Will every user have an opinion of every post?
Do you need to store both 'likes' and 'dislikes?'
Can there be a 'neutral' opinion on a post?
Can users change their opinions?
You can only discover the correct data structure by asking and answering all the questions that matter to your situation (my list is not exhaustive - it is only an example.)
I have a business object type representing customers which, when its .Save() method is called, attempts to retrieve (using LINQ) a matching entity from the database based on the object's ID property. If it does not find a matching entity, it creates a new one; if it does find a matching entity it updates that entity's properties and calls [my datacontext].SubmitChanges().
That last part is the problem. Much of the data for a user is stored in an XML field in the database, named content_xml. There is a bug in the code which is failing to retrieve two of those data items ("coordinates" and "sales_groups") when constructing the business object, and so when the .Save() method goes to update the entity, the XML it's sending is missing those elements.
For some reason this is throwing a ChangeConflictException, stating that "1 of 12" updates failed. In order to identify what was causing the problem, I used the code from http://msdn.microsoft.com/en-us/library/Bb386985%28v=vs.100%29.aspx to extract information about the change conflict.
From that, I see that [my datacontext].ChangeConflicts contains a single ObjectChangeConflict, which itself contains a single MemberChangeConflict representing the XML field.
The part I do not understand is that when checking the values of currVal, origVal and databaseVal, I see that XML data held in currVal is what I would expect based on the bug (it's missing the two elements), and the XML for origVal and databaseVal are identical. That shouldn't cause a conflict, should it?
Even more strange is that when I manually correct the bug by providing the correct (according to the database) values for the missing elements, just before the .SubmitChanges() call, it still causes a conflict, even though the XML from all three (currVal, origVal and databaseVal) all now look identical.
Can anyone suggest what might be causing the conflict?
Edit:
OK, this is a bit of a surprise, but even if I never set the content_xml property value of the retrieved entity before submitting changes, I still get a conflict on the XML field.
I would guess that the change conflict stems from L2S comparing old vs new value in an incorrect way for your xml field.
A possible workaround for this is to add a timestamp or rowversion column to the table and updating the L2S model. If a table contain rowversion/timestamp, only that column will be used for detecting change conflicts...
I have an ASP.Net form and I want to send an email when the user changes their data. The email should only include data that has changed, and there are about 15 data fields total.
I don't want to use an ORM since I am updating a website that a 3rd party built for us, and all their data access calls go through a custom library of theirs.
The only ways to do this I can think of is
Make another database call to get old values and compare the form values one-by-one. If they're different, append to the email.
Store original data somewhere when it's first loaded (hidden field, session, etc), and once again compare the data one field at a time and append the differences to an email
Have someone on SO tell me there's an easier and/or simpler way that I haven't thought of
All the text boxes will have a TextChanged event, you can have them mark themselves as modified. ComboBox's will have a SelectedIndexChanged event, and so on.
Edit: All changed events can check their initial values (even on reverted changes) and either mark themselves as still modified or on a revert, as un-modified.
Here are some suggestions that may / may not be useful:
Trigger on the database table and the trigger compares the old (using the DELETED table) and updated (using the INSERTED table) and then sends an email. This may or may not be viable and I am not a big advocate of triggers.
Like you have already said you could make another database call, which would be my reccommended approach.
From what you've said I think that the only way forward is to create a duplicate dataset on the form to store the old data and run a comparison at the point where you want to produce the email.
You can use Dataset.Copy to copy structure and data.
However, now that I think about it there's always the Datset.GetChanges() method and the Dataset.AcceptChanges() along with DataSet.HasChanges()
Example code from this link:
if(dataSet.HasChanges(DataRowState.Modified |
DataRowState.Added)&& dataSet.HasErrors)
{
// Use GetChanges to extract subset.
changesDataSet = dataSet.GetChanges(
DataRowState.Modified|DataRowState.Added);
PrintValues(changesDataSet, "Subset values");
// Insert code to reconcile errors. In this case, reject changes.
foreach(DataTable changesTable in changesDataSet.Tables)
{
if (changesTable.HasErrors)
{
foreach(DataRow changesRow in changesTable.Rows)
{
//Console.WriteLine(changesRow["Item"]);
if((int)changesRow["Item",DataRowVersion.Current ]> 100)
{
changesRow.RejectChanges();
changesRow.ClearErrors();
}
}
}
}
// Add a column to the changesDataSet.
changesDataSet.Tables["Items"].Columns.Add(
new DataColumn("newColumn"));
PrintValues(changesDataSet, "Reconciled subset values");
// Merge changes back to first DataSet.
dataSet.Merge(changesDataSet, false,
System.Data.MissingSchemaAction.Add);
}
PrintValues(dataSet, "Merged Values");
I'm creating a database where users can enter some Error Reports and we can view them. I'm making these database with C# in the ASP MVC 3 .NET framework (as the tags imply). Each Error Report has a unique ID, dubbed ReportId, thus none of them are stored under the same Id. However, whenever a User creates a new Error, I pass their User Name and store it in with the rest of the report (I use User.Identity.Name.ToString() to get their name and store it as a string). I know how to get a single item from the data using a lambda expression, like so:
db.DBSetName.Single(g => g.Name == genre)
The above code is based on an MVC 3 tutorial (The Movie Store one) provided by ASP. This was how they taught me how to do it.
My major question is: is there a member function like the .Single one that will parse through the whole database and only output database entries whose stored User Name matches that of the currently logged in user's? Then, I can use this to restrict User's to being only able to edit their own entries, since only their entries would be passed to the User's View.
What would be the best way to implement this? Since the ReportId will not be changed, a new data structure can be created to store the user's Errors and passed through to the Index (or Home) View of that particular controller. From there they should be able to click any edit link, which will pass the stored ReportId back to the Edit Action of this particular controller, which can then search the entire database for it. Am I right in assuming this would work? And would this be ideal, given that the other items in the database are NOT passed through to the Index in this method, meaning the User does not have access to the other items' ReportId's, which the user needs to pass into the Edit Action for it to work? If this is ideal, this is the method that requires me to know how to parse through a database and grab every element that fits a particular description (stored User Name matches User's current User Name).
Or would a better approach be to pass the whole database to the Index View and only output the database entries that have User Name values that match the current logged in user's? I guess this could be done in a foreach loop with a nested if loop, like so:
#foreach(var item in db.Reports)
{
if(item.UserName == User.Identity.Name.ToString())
{
...code to output table...
}
}
But this passes the whole database which gives the user a lot more info than they need. It also gives them potential access to info I don't want them to have. However, I don't have to make a new data structure or database, which should lower server memory usage and fetch time, right? Or are databases passed by copy? If so, this method seems kinda dumb. However, I don't know if the first method would fracture the database potentially, this one certainly would not. Also don't remember if I NEED an else statement in C#, I'm more familiar with C++, where you don't need one and you also don't need {}'s for single line if's, if I need one: please don't judge me too harshly on it!
Small note: I am using CRUD Controllers made with the Entity First Framework in order to edit my database. As such, all creation, reading, updating, and deletion code has been provided for me. I have chosen not to add such basic, common code. If it is needed, I can add it. I will add what the Edit Action looks like:
public ActionResult Edit(string id)
{
Report report = db.Reports.Find(id);
return View(report);
}
It accepts a string as an id, ReportId is the id used and it IS a string. It is a randomly generated GUID string made with the GUID.NewGuid().ToString() function. I will also be doing the comparison of names with:
Model.UserName == User.Identity.Name.ToString()
Which was shown earlier. Sorry if this is too much text, I wanted to provide as much info as possible and not make anyone mad. If more info is needed, it can certainly be provided. So at the end of the post, the major question actually comes down to: which of the above two methods is best? And, if it's the first one, how do I implement something like that?
Thanks for your help!
Unless I'm completely misunderstanding you, you just want .Where()
Like this:
var reports = db.Reports.Where(r => r.genre == inputGenre);
This would get you an IEnumerable of Report, which you could then use however you wish.
Scenario
I'm parsing emails and inserting them a database using an ORM (NHibernate to be exact). While my current approach does technically work I'm not very fond of it but can't of a better solution. The email contains 50~ fields and is sent from a third party and looks like this (obviously a very short dummy sample).
Field #1: Value 1 Field #2: Value 2
Field #3: Value 3 Field #4: Value 4 Field #5: Value 5
Problem
My problem is that with parsing this many fields the database table is an absolute monster. I can't create proper models employing any kind of relationships either AFAIK because each email sent is all static data and doesn't rely on any other sources.
The only idea I have is to find commonalities between each field and split them into more manageable chunks. Say 10~ fields per entity, so 5 entities total. However, I'm not terribly in love with that idea either seeing as all I'd be doing is create one-to-one relationships.
What is a good way of managing large number of properties that are out of your control?
Any thoughts?
Create 2 tables: 1 for the main object, and the other for the fields. That way you can programatically access each field as necessary, and the object model doesn't look to nasty.
But this is just off the top of my head; you have a weird problem.
If the data is coming back in a file that you can parse easily, then you might be able to get away with creating a command line application that will produce scripts and c# that you can then execute and copy, paste into your program. I've done that when creating properties out of tables from html pages (Like this one I had to do recently)
If the 50 properties are actually unique and discrete pieces of data regarding this one entity, I don't see a problem with having those 50 properties (even though that sounds like a lot) on one object. For example, the Type class has a large number of boolean properties relating to it's data (IsPublic, etc).
Alternatives:
Well, one option that comes to mind immediately is using dynamic object and overriding TryGetMember to lookup the 'property' name as a key in a dictionary of key value pairs (where your real set up of 50 key value pairs exists). Of course, figuring out how to map that from your ORM into your entity is the other problem and you'd lose intellisense support.
However, just throwing the idea out there.
Use a dictionary instead of separate fields. In the database, you just have a table for the field name and its value (and what object it belongs to).