As I have mentioned in a previous article, improper association/nesting of form’s Class file (.vb), Designer file (.Designer.vb) and Resource file (.resx), could occur when adding existing files from another project, as shown below:

Incorrect Nesting in Solution Explorer

You may not be able to reproduce the problem when adding multiple files, it happens automatically. However, as VS is a computer program, there must be some reason (may be a bug in VS) for this problem. I don’t know the reason, but I know the solution at-least.

The list of files in a project is stored in its corresponding “.vbproj” file. “.vbproj” file is internally actually a pure XML file. Following is the content of the “.vbproj” file which was automatically created when a VB.NET Windows Application project was created:

<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="Build" xmlns="https://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
    <ProductVersion>8.0.50727</ProductVersion>
    <SchemaVersion>2.0</SchemaVersion>
    <ProjectGuid>{C70F5285-0F5C-493C-96FB-FC311C404D55}</ProjectGuid>
    <OutputType>WinExe</OutputType>
    <StartupObject>Incorrect_Nesting.My.MyApplication</StartupObject>
    <RootNamespace>Incorrect_Nesting</RootNamespace>
    <AssemblyName>Incorrect Nesting</AssemblyName>
    <MyType>WindowsForms</MyType>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
    <DebugSymbols>true</DebugSymbols>
    <DebugType>full</DebugType>
    <DefineDebug>true</DefineDebug>
    <DefineTrace>true</DefineTrace>
    <OutputPath>bin\Debug\</OutputPath>
    <DocumentationFile>Incorrect Nesting.xml</DocumentationFile>
    <NoWarn>42016,41999,42017,42018,42019,42032,42036,42020,42021,42022</NoWarn>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
    <DebugType>pdbonly</DebugType>
    <DefineDebug>false</DefineDebug>
    <DefineTrace>true</DefineTrace>
    <Optimize>true</Optimize>
    <OutputPath>bin\Release\</OutputPath>
    <DocumentationFile>Incorrect Nesting.xml</DocumentationFile>
    <NoWarn>42016,41999,42017,42018,42019,42032,42036,42020,42021,42022</NoWarn>
  </PropertyGroup>
  <ItemGroup>
    <Reference Include="System" />
    <Reference Include="System.Data" />
    <Reference Include="System.Deployment" />
    <Reference Include="System.Drawing" />
    <Reference Include="System.Windows.Forms" />
    <Reference Include="System.Xml" />
  </ItemGroup>
  <ItemGroup>
    <Import Include="Microsoft.VisualBasic" />
    <Import Include="System" />
    <Import Include="System.Collections" />
    <Import Include="System.Collections.Generic" />
    <Import Include="System.Data" />
    <Import Include="System.Drawing" />
    <Import Include="System.Diagnostics" />
    <Import Include="System.Windows.Forms" />
  </ItemGroup>
  <ItemGroup>
    <Compile Include="Form1.vb">
      <SubType>Form</SubType>
    </Compile>
    <Compile Include="Form1.Designer.vb">
      <DependentUpon>Form1.vb</DependentUpon>
      <SubType>Form</SubType>
    </Compile>
    <Compile Include="My Project\AssemblyInfo.vb" />
    <Compile Include="My Project\Application.Designer.vb">
      <AutoGen>True</AutoGen>
      <DependentUpon>Application.myapp</DependentUpon>
    </Compile>
    <Compile Include="My Project\Resources.Designer.vb">
      <AutoGen>True</AutoGen>
      <DesignTime>True</DesignTime>
      <DependentUpon>Resources.resx</DependentUpon>
    </Compile>
    <Compile Include="My Project\Settings.Designer.vb">
      <AutoGen>True</AutoGen>
      <DependentUpon>Settings.settings</DependentUpon>
      <DesignTimeSharedInput>True</DesignTimeSharedInput>
    </Compile>
  </ItemGroup>
  <ItemGroup>
    <EmbeddedResource Include="My Project\Resources.resx">
      <Generator>VbMyResourcesResXFileCodeGenerator</Generator>
      <LastGenOutput>Resources.Designer.vb</LastGenOutput>
      <CustomToolNamespace>My.Resources</CustomToolNamespace>
      <SubType>Designer</SubType>
    </EmbeddedResource>
  </ItemGroup>
  <ItemGroup>
    <None Include="My Project\Application.myapp">
      <Generator>MyApplicationCodeGenerator</Generator>
      <LastGenOutput>Application.Designer.vb</LastGenOutput>
    </None>
    <None Include="My Project\Settings.settings">
      <Generator>SettingsSingleFileGenerator</Generator>
      <CustomToolNamespace>My</CustomToolNamespace>
      <LastGenOutput>Settings.Designer.vb</LastGenOutput>
    </None>
  </ItemGroup>
  <Import Project="$(MSBuildBinPath)\Microsoft.VisualBasic.targets" />
  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
       Other similar extension points exist, see Microsoft.Common.targets.
  <Target Name="BeforeBuild">
  </Target>
  <Target Name="AfterBuild">
  </Target>
  -->
</Project>

The “.vbproj” file can be opened/edited in any text editor like Notepad, Notepad++, WordPad, Ms Office Word etc.

This file contains much information about the project but our primary focuses are the 3^rd and 4^th ItemGroup tags. The first ItemGroup is of References, second is of Imports, third is of project code files (highlighted with light-blue background) and fourth is of Resources (highlighted with light-yellow background). Now the above file is perfect. (Form’s “.resx” file is not created initially; it is created only after a resource (icon, image etc.) is added to a form.) Now look at the following table which should clear your doubt about improper nesting:

<Compile Include="Form1.Designer.vb">
  <DependentUpon>Form1.vb</DependentUpon>
  <SubType>Form</SubType>
</Compile>
			

<Compile Include="Form1.Designer.vb" />
<Compile Include="Form1.vb">
  <SubType>Form</SubType>
</Compile>
			

<EmbeddedResource Include="Form1.resx">
  <DependentUpon>Form1.vb</DependentUpon>
  <SubType>Designer</SubType>
</EmbeddedResource>
			

<EmbeddedResource Include="Form1.resx">
  <SubType>Designer</SubType>
</EmbeddedResource>
			

Even if the files are nested improperly, if project is run, the compiler will not display any error because there is no error in project, no reference is missing; it is just the project’s file which is just displaying incorrect nesting.

If a form’s “.Designer.vb” file is opened, only designer code is showed for editing instead of form’s design/window; and if “.vb” file is opened, the form’s design/window is showed! As VB code is not shown directly, you can access it by going to design view, right clicking on the form and selecting “View Code” option from popup menu OR by selecting “.vb” file in Solution Explorer and clicking the “View Code” button OR right-clicking on the “.vb” file in Solution Explorer and clicking the “View Code” option from popup menu.