Can I create a file that sits next to a .Designer.cs file in Visual Studio?

Question

In Visual Studio, two files are created when you create a new Windows Form in your solution (e.g. if you create MyForm.cs, MyForm.Designer.cs and MyForm.resx are also create

Answer 1

You need to edit the csproj directly. There is a DependentUpon tag that you have to add as a child tag of the file you want to place under MyForm.cs.

Example:

<Compile Include="MyForm.MyCoolSubFile.cs">
  <DependentUpon>MyForm.cs</DependentUpon>
</Compile>

Answer 2

Yes, but it's a bit of a hassle - basically you need to edit the project file by hand.

Here's an example from a project that Marc Gravell and I both work on:

<Compile Include="Linq\Extensions\DataProducerExt.cs" />
<Compile Include="Linq\Extensions\DataProducerExt.SingleReturn.cs">
  <DependentUpon>DataProducerExt.cs</DependentUpon>
</Compile>
<Compile Include="Linq\Extensions\DataProducerExt.Grouping.cs">
  <DependentUpon>DataProducerExt.cs</DependentUpon>
</Compile>
<Compile Include="Linq\Extensions\DataProducerExt.Pipeline.cs">
  <DependentUpon>DataProducerExt.cs</DependentUpon>
</Compile>
<Compile Include="Linq\Extensions\DataProducerExt.Conversion.cs">
  <DependentUpon>DataProducerExt.cs</DependentUpon>
</Compile>
<Compile Include="Linq\Extensions\DataProducerExt.Math.cs">
  <DependentUpon>DataProducerExt.cs</DependentUpon>
</Compile>

Note the "DependentUpon" element in each of the dependencies. This displays appropriately in VS, with DataProducerExt.cs as the parent.

Answer 3

Open .csproj in edit mode, look for the file you want to be under another one, and add the DependentUpon element, like this:

<Compile Include="AlertDialog.xaml.cs">
  <DependentUpon>AlertDialog.xaml</DependentUpon>
</Compile>