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POBinding DataGridView to database with EF5 classes not sending changes to database
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  1. POBinding DataGridView to database with EF5 classes not sending changes to database
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    copied!<p>I am using Entity Framework 5.0 + .NET 4.5</p> <p>I have created database using EF Model first approach and I want to bind <code>DataGridView</code> to database using EF classes so that any changes to database or in the <code>DataGridView</code> are synchronized automatically.</p> <p><strong>This is my code:</strong></p> <pre><code>//form level fields private BindingList&lt;Product&gt; _products; private BindingSource _productSource = new BindingSource(); ... in the form load event //load the data from database using EF classes var tmp = _context.BaseCategorySet.OfType&lt;Product&gt;().ToList(); //converting to IBindingList _products = new BindingList&lt;Product&gt;(tmp); _products.AllowEdit = true; _products.AllowNew = true; _productSource.DataSource = _products; //setting GridControl's data source ProductGrid.DataSource = _productSource; </code></pre> <p>I can add new rows or change data, but those changes are not sent to the database - what am I missing?</p> <p><strong>Additional things I did in hope to find a solution...</strong></p> <p>1) I added a Save button to call updating the grid control's data to database explicitly, with code:</p> <pre><code>_productSource.EndEdit(); _context.SaveChanges(); </code></pre> <p>->this did not result in storing the new record into the database</p> <p>2) I added a code to add new records with a bunch of controls for individual record properties (Textboxes, DatePickers)</p> <pre><code>var x = _context.BaseCategorySet.Create&lt;Product&gt;(); //settting all the x properties with values //that are set in aforementioned individual controls _context.BaseCategorySet.Add(x); _context.SaveChanges(); </code></pre> <p>-->when I add new records using this technique - it IS stored in the database, but once more a strange behavior - this new record is not automatically loaded in the grid control (but should be, since I am databinding grid to the corresponding EF DbSet...)</p> <p>And one more strangeness - updates that I have made in the <code>DataGridView</code> control to the records that were loaded to database - those updates ARE sent to database...</p> <p>3) I switched from DevExpress <code>XtraGrid</code> to stadard <code>DataGridView</code> control, but that did not help...</p> <p>I have searched through tons of topics regarding EF databinding with no success...</p> <p>Don't know if this matters, but I am using inheritance in my Entity model: <code>Product</code> derives from <code>UnifOfSales</code> and <code>UnitOfSales</code> derives from <code>BaseCategory</code> class.</p> <p><strong>One more thing i tried</strong></p> <p>I tried the (..).Local.ToBindingList that was suggested by Ladislav Mrnka in this post <a href="https://stackoverflow.com/questions/12736958/how-to-make-two-way-databinding-using-ef-in-winforms">How to make two way-databinding using EF in winforms?</a></p> <p>well it did send changes back to the database, but the changes were stored only in the base class table (BaseCategory), but there is a table for derived class as well. This is the code i used for binding</p> <pre><code>_context.BaseCategorySet.OfType&lt;Product&gt;.Load(); //i tried to use derived class with OfType&lt;Product&gt; to ensure that compiler //knows that this is instance of derived class (Product), //not the base class BaseCategory, //but I can not get "Local" working with OfType... ProductGridView.DataSource = _context.BaseCategorySet.Local.ToBindingList(); </code></pre>
 

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