I’ve created a class that extends DbConnection in a brand new project. public class

Question

Asked: June 9, 20262026-06-09T13:30:32+00:00 2026-06-09T13:30:32+00:00

I’ve created a class that extends DbConnection in a brand new project.

public class FakeDbConnection : DbConnection { ... }

In the Solution Explorer the class looks like this: enter image description here

And when double-clicking it wants to open it in design mode which won’t work. Opening up the .csproj-file reveals the problem

<ItemGroup>
  <Compile Include="FakeADO\FakeDbConnection.cs">
    <SubType>Component</SubType>
  </Compile>
</ItemGroup>

Even if I remove the SubType tag VS2010 immediately re-adds it. Very annoying.

How can I stop VS2010 from opening up my .cs file in designer mode and just open it up as a regular code file?

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Editorial Team · Answer 1 · 2026-06-09T13:30:34+00:00

Editorial Team

As described in an answer to this question you can do this:

[System.ComponentModel.DesignerCategory("Code")]
class FakeDbConnection: DbConnection { ... }

Important: The attribute needs to be fully qualified otherwise VS2010 will ignore this.

Important (thanks to jmbpiano): The attribute only applies to the first class in the file.

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