This article was written in 2020. Versions, tools and recommendations may have changed since then. Newer posts are collected under .NET.
Often you want to duplicate entities or their values in order to save an entity with a new ID. But what is the best way to do this?
There are many examples in the vastness of the Internet based on Object.Clone() or Reflection.
But this is not necessary. Entity Framework has inherent methods to copy values.
DbContext Clone
To simply copy values from an existing entity to a new entity, you have two stable ways.
Copy values to a local var first:
1var values = db.Entry(oldEntity).CurrentValues.Clone();
2var newEntity = ...
3db.Entry(newEntity ).CurrentValues.SetValues(values);
4newEntity.Id = 0;Directly copy values from old entity to new entity.
1db.Entry(newEntity).CurrentValues.SetValues(oldEntity);
2newEntity.Id = 0;These methods are stable and not based on any Reflection tinkering.
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BEN ABT
Ben is Chief Engineering Officer and Principal Software Engineer at Medialesson.de, with a strong focus on .NET and Microsoft Azure. In his professional role, he designs and builds highly scalable platforms for hybrid and cloud-based scenarios. He also advises companies and C-levels on migrating to the sovereign cloud.
He runs myCSharp.de, the largest and most active German-speaking C# community forum, actively contributes to both his own and external open-source projects and regularly shares his knowledge through his blog, at community events, conferences and as a writer for technical magazines.
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