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POEntity Framework - One application/One user/One simple use case ... seem simple but is not
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  1. POEntity Framework - One application/One user/One simple use case ... seem simple but is not
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    copied!<p>I have a simple time sheet application. It manages:</p> <ul> <li>Group of employees</li> <li>Employees</li> <li>A list of WorkEntry for each Employee</li> </ul> <p>The use case is the following:</p> <ol> <li>My user start the application and connect to a database.</li> <li>He looks at his WorkEntry for the day.</li> <li>He adds 2 new WorkEntries, but is <strong>NOT</strong> saving the data right now.</li> <li>He prints the WorkEntries, a dialog is showing him the progression of the operation which can take some time to complete.</li> </ol> <hr> <p>When I first started the application, I had a single ObjectContext created at the connection (in the UI thread) and disposed when the user closed the application. </p> <p>It was working quite well, but I faced a problem implementing the printing function because I was not able to use the ObjectContext in a background worker thread.</p> <p>Googling a little bit I found the concept of unit of work. </p> <ul> <li>Create the ObjectContext</li> <li>Do want you want to do</li> <li>Close it</li> </ul> <p>Also, my understanding is that entities are belonging to one ObjectContext. </p> <p>Let say ObjectContext#1 - Is used in the UI thread to retreive WorkEntries for the day - Contains the two new WorkEntries of the user. - Is not yet disposed because the user has not saved his changes</p> <p>Let say ObjectContext#2 - Is used in the background worker thread - Retreive WorkEntries for the day - Print the WorkEntries</p> <p>How can ObjectContext#2 be aware of the two new WorkEntries in ObjectContext#1?</p> <hr> <p><strong>EDIT</strong></p> <p>I know there is a flaw ... the user MUST save to get the two new entries in the printed report.</p> <p>But let say my application is presenting the data in a grid, like excel. The user will expect (<em>with good reasons</em>) the same behavior has excel. That is, in excel, I'm not forced to save to print my new rows ... I just want to print what I see on my sheet, no matter the persistence state of the data presented.</p>
 

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