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    <p>The most obvious thing you can do is to profile your application and find the bottlenecks in start up time. It sounds like the most likely culprit will be the loading of data from your database.</p> <p>One lesson I've learnt is that if you're using an ORM, when loading large datasets if you favour POCO (Plain Old CLR/C# Objects) over ORM-generated database entities (see example below), the load time will be a lot faster and RAM usage will be significantly decreased too. The reason for this is that EF will try to load the entire entity (i.e. all of it's fields) and possibly a whole load of data related to your entities, most of which you won't even need. The only time you really need to work directly with entities is when you're doing insert/update/delete operations. When reading data you should <em>only</em> get fields that your application needs to display and/or validate.</p> <p>If you follow the MVVM pattern, the above architecture isn't hard to implement.</p> <p>Example of loading data into POCOs with EF:</p> <pre><code>var query = from entity in context.Entities select new EntityPoco { ID = entity.ID, Name = entity.Name }; return query.ToList(); </code></pre> <p>POCOs are very simple classes with autoproperties for each field.</p> <p>We usually have repositories for each entity in our applications and each repository is responsible for getting/updating data related to that entity. The view models have references to the repositories they need so they don't use EF directly. When users make changes that need to be persisted, we use other methods in the repository that then load only a subset of entities (i.e. the ones the user changed) and apply the necessary updates - with some validation done by the viewmodel and possibly other validation going on in the DB via constraints/triggers, etc.</p>
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    1. POImprove perceived WPF app startup time
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    1. CO+1 for your recommendations. I did profile the application. It's really more or less 3s app (and framework) initialization which I won't be able to improve. The other 3s are coming from the creation of the user control and the data loading. I also thought about using basic ADO.NET data readers to improve performance.
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    2. CODo you have any good links to MVVM examples which are showing how they handle the data loading in background? What are they doing with the view during the loading?
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    3. COSorry, I don't have any online examples at hand; it's mostly stuff I learnt from a colleague. I've added my own example and elaborated a bit on my original answer. I can personally vouch that it works, because the application we're currently working on originally took over one and a half minutes to load. It's now down to less than 10 seconds. We're doing between 300k and 400k reads from a SQL Server DB at start up...
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