How to conditionally compile a NuGet package on build in a WPF project?

Question

I'm using a NuGet package in the project. Is there a way to isolate or ignore that NuGet package and use another NuGet package using a compile switch or Macro?

Purpose: This NuGet Package is licensed per developer, So the intent is to disconnect it during the development from other developers.

I have looked into myproject.csproj

...
<ItemGroup>
    <PackageReference Include="nugetPackage2Exclude" Version="1.0.0.0">
        <ExcludeAssets>none</ExcludeAssets>
    </PackageReference>
...

But, I could not make it work using a compile switch or macro.

Answer 1

After a lot of tinkering. This is the final solution that turned out to satisfy all my requirements. It is a bit long and I have added all the findings relevant to this question.

Before I get into implementation, this is my setup #(.NET 6.0, C# 10, WPF Project, VS2022)

Steps involved!

1. Declaration of a compile switch
2. Prebuild conditional switch for compiling/ignoring the Nuget Package
3. Context switch in the XAML file.
4. Compile switches to isolate the package in the C# file.

Step1: Declaration of a compile switch (NUGET_ENABLE)

Project -> Proprties -> Conditional Compilation Symbols

$(DefineConstants);NUGET_ENABLE

(Note: A value cannot be assigned to the NUGET_ENABLE, The NUGET_ENABLE has to be renamed or removed for Removing this NuGet Usage.)

Step2: Prebuild conditional switch for compiling/ignoring the Nuget Package

Open the myproject.csproj (Project file). Use a regex expression to find the specific compile switch from $(DefineConstants), If NUGET_ENABLE exists compile the NuGet package.

(Reference: MS Docs)

    <Choose>
    <When Condition="$([System.Text.RegularExpressions.Regex]::IsMatch($(DefineConstants), '^(.*;)*NUGET_ENABLE(;.*)*$'))">
        <!-- When NUGET_ENABLE is defined. -->
        <ItemGroup>
            <PackageReference Include="nugetPackage2Exclude" Version=""/>
        </ItemGroup>
    </When>
    </Choose>

Step3: Context switch in the XAML file

(Fair Warning!: The <mc:AlternateContent> Tag may prevent the loading of the Design preview window (Xaml Designer) in VS or Blend.)

(Reference: this question)

Step3a: Edit the assembly file to add a XAML Switch

#if NUGET_ENABLE 
[assembly: XmlnsDefinition("nuget_enable", "NameSpace")]
#endif // NUGET_ENABLE

Step3b: Add the XAML file headers

    ...
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     xmlns:nuget="http://schemas.nugetPackage2Exclude.etc/"
     xmlns:nugetEnabled="nuget_enable"
    ...
     mc:Ignorable="d nuget" // d is optional!
    ...

Step3c: Add the XAML context switch

    <mc:AlternateContent>
        <mc:Choice Requires="nugetEnabled">
                <!--<code calling the nuget>-->
        </mc:Choice>
        <mc:Fallback>
        
        </mc:Fallback>
    </mc:AlternateContent>

Step4:Compile switches to isolate the package in the C# file.

#if NUGET_ENABLE 
// Code
#endif