How to programmatically install a NuGet package?

Question

I want to programmatically install a NuGet package to a project, and update the .csproj file, and the packages.config file.

I am using the

Answer 1

Thanks to @MattWard and @bashis, i've written my own code generator:

So, to add properly a reference into a given .csproj here's what I do:

var CsprojDoc = new XmlDocument();
CsprojDoc.LoadXml("*your_csproj_content*");
var Nsmgr = new XmlNamespaceManager(CsprojDoc.NameTable);
Nsmgr.AddNamespace("x", "http://schemas.microsoft.com/developer/msbuild/2003");

IPackage packageInfos = GetNugetPackage(packageId, packageRepositoryUri);

XmlNode referenceNode = CsprojDoc.CreateNode(XmlNodeType.Element, "Reference", XmlNamespaceValue);
XmlAttribute includeAttribute = CsprojDoc.CreateAttribute("Include");

var targetFwProfile = CsprojDoc.SelectSingleNode("//x:TargetFrameworkProfile", Nsmgr);
string targetFrameworkProfile = string.Empty;
if (!string.IsNullOrEmpty(targetFwProfile?.InnerXml))
{
    targetFrameworkProfile = targetFwProfile.InnerXml;
}

var targetFwAttribute = GetTargetFrameworkFromCsproj();
Regex p = new Regex(@"\d+(\.\d+)+");
Match m = p.Match(targetFwAttribute.FrameworkName);
Version targetFwVersion = Version.Parse(m.Value);

// Get the package's assembly reference matching the target framework from the given '.csproj'.
var assemblyReference =
    packageInfos.AssemblyReferences
        .Where(a => a.TargetFramework.Identifier.Equals(targetFwAttribute.FrameworkName.Split(',').First()))
        .Where(a => a.TargetFramework.Profile.Equals(targetFrameworkProfile))
        .Last(a => (a.TargetFramework.Version.Major.Equals(targetFwVersion.Major) && a.TargetFramework.Version.Minor.Equals(targetFwVersion.Minor)) ||
        a.TargetFramework.Version.Major.Equals(targetFwVersion.Major));

DownloadNugetPackage(packageInfos.Id, packageRepositoryUri, packagesFolderPath, packageInfos.Version.ToFullString());

string dllAbsolutePath = Path.GetFullPath($"{packagesFolderPath}\\{packageInfos.GetFullName().Replace(' ', '.')}\\{assemblyReference.Path}");
var assemblyInfos = Assembly.LoadFile(dllAbsolutePath);

includeAttribute.Value = $"{assemblyInfos.FullName}, processorArchitecture=MSIL";

referenceNode.Attributes.Append(includeAttribute);

XmlNode hintPathNode = CsprojDoc.CreateNode(XmlNodeType.Element, "HintPath", XmlNamespaceValue);
XmlNode privateNode = CsprojDoc.CreateNode(XmlNodeType.Element, "Private", XmlNamespaceValue);

hintPathNode.InnerXml = $"$(SolutionDir)\\packages\\{assemblyReference.Path}";
privateNode.InnerXml = "True";

referenceNode.AppendChild(hintPathNode);
referenceNode.AppendChild(privateNode);
var itemGroupNode = CsprojDoc.SelectSingleNode("//x:Project/x:ItemGroup/x:Reference", Nsmgr).ParentNode;
itemGroupNode.AppendChild(referenceNode);

Here's my DownloadNugetPackage method:

private static void DownloadNugetPackage(string packageId, Uri repoUri, string packagesFolderPath, string version)
{
    IPackageRepository packageRepository = PackageRepositoryFactory.Default.CreateRepository(repoUri.ToString());
    PackageManager packageManager = new PackageManager(packageRepository, packagesFolderPath);

    packageManager.InstallPackage(packageId, SemanticVersion.Parse(version));
}

My GetTargetFrameworkFromCsproj

    public static TargetFrameworkAttribute GetTargetFrameworkFromCsproj()
    {
        XmlNode targetFrameworkNode = CsprojDoc.SelectSingleNode("//x:TargetFrameworkVersion", Nsmgr);
        return new TargetFrameworkAttribute($".NETFramework, Version={targetFrameworkNode.InnerXml}");
    }

And my GetNugetPackage method:

public static IPackage GetNugetPackage(string packageId, Uri repoUri, string version = null)
{
    IPackageRepository packageRepository = PackageRepositoryFactory.Default.CreateRepository(repoUri.ToString());
    IPackage package;

    if (!string.IsNullOrEmpty(version))
    {
        package = packageRepository.FindPackagesById(packageId).SingleOrDefault(p => p.Version.ToFullString().Equals(version));
    }
    else
    {
        package = packageRepository.FindPackagesById(packageId).SingleOrDefault(p => p.IsLatestVersion);
    }

    return package;
}

Note: This time, i'm using the official NuGet package: Nuget.core 2.14: https://www.nuget.org/packages/NuGet.Core/

Note 2: When I add a new Reference node, in the processorArchitecture attribute, I've hard coded the value: MSIL

If you want to test it, you might tweak it a bit.

This work fine for me.

Answer 2

(Assuming you are writing the code generator on your own)

I am not sure this is the best solution but you could try something like this:

var assembly = Assembly.LoadFile("path_to_dll");
string info = assembly.FullName; // contains something like "AssemblyName, Version=0.0.0.0, Culture=neutral, PublicKeyToken=foobar"

which will add some overhead by loading the assembly, but will presumably do the job.