In the context of C#, a solution parser refers to a program or library that can parse and comprehend data from Visual Studio solution (.sln) files and its project (.csproj) files. These parsers enable developers to work with, adjust, and examine a solution's architecture and components, including its projects, dependencies, references, and build settings.

Benefits of a Solution Parser in C#

• Automated Analysis and Reporting: Solution parsers enable the automated extraction of information regarding the structure, dependencies, and configurations of a solution. This feature proves to be valuable in generating reports on code quality, dependencies, and build status.
• Dependency Management: Through the parsing of solution and project files, tools can analyze and visualize the dependencies between projects. This capability aids in identifying potential issues like circular dependencies or outdated packages.
• Build Automation: Integrating solution parsers into build automation scripts allows for dynamic modification of solution and project configurations. This proves to be beneficial in continuous integration (CI) pipelines where different build environments may require different settings.
• Refactoring Support: Developers can utilize solution parsers to automate refactoring tasks, such as renaming projects, updating namespaces, or restructuring solution folders.
• Custom Tooling: Solution parsers can be utilized to build custom development tools that cater to specific needs, such as custom linting rules, project templates, or automated code generation.

Popular Parsing Solutions for C#

• Microsoft Build (MSBuild): Visual Studio and.NET use MSBuild as their build platform. It provides developers with a variety of APIs to load, query, and edit project files. Solution files can be parsed indirectly using these APIs. Microsoft.Build.Evaluation and Microsoft.Build.Locator are the most often utilized namespaces for this kind of work.
• EnvDTE: An automation model that gives developers a way to communicate with the Visual Studio environment is called the Development Tools Environment. Developers can work with solution and project elements from Visual Studio extensions or automation scripts thanks to this access.
• NuGet Package Manager: The NuGet Package Manager offers tools such as NuGet.Protocol and NuGet.Packaging, which can be employed to manage dependencies specified in project files. When combined with other libraries, these tools can form an integral part of a comprehensive solution parsing and manipulation toolkit.

Implementation
Step 1. Xaml View
<Window x:Class="SolutionParserExample.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:SolutionParserExample"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*"/>
            <RowDefinition Height="*"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <GroupBox Header="WithDTE Result[First Approach]" Grid.Row="0">
            <DataGrid x:Name="DataridWithDTE"/>
        </GroupBox>

        <GroupBox Header="WithoutOutDTE Result[Second Approach]" Grid.Row="1">
            <DataGrid x:Name="DataridWithoutDTE"/>
        </GroupBox>

        <GroupBox Header="WithoutOutDTE Result[Third Approach]" Grid.Row="2">
            <DataGrid x:Name="DataridThirdApproach"/>
        </GroupBox>
    </Grid>

</Window>

Code behind(CS file)
using EnvDTE80;
using Microsoft.Build.Construction;
using System.Collections.ObjectModel;
using System.IO;
using System.Reflection;
using Window = System.Windows.Window;

namespace SolutionParserExample
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        Type? s_SolutionParserFromSolutionFile;
        PropertyInfo? s_SolutionParserReader;
        MethodInfo? s_SolutionParserSolution;
        PropertyInfo? s_SolutionParserProjects;
        public List<ProjectSolution> ProjectsList { get; set; }
        ProjectInSolution[] arrayOfProjects = null;

        // Change below path with your solution file
        string solutionFilePath = @"C:\Users\sanjay\Desktop\MediaElementSampleProject (3)\MediaElementSampleProject\MediaElementSampleProject.sln";
        private ObservableCollection<ProjectDetail> _ProjectsListWithoutDTE;

        public ObservableCollection<ProjectDetail> ProjectsListWithoutDTE
        {
            get { return _ProjectsListWithoutDTE; }
            set { _ProjectsListWithoutDTE = value; }
        }

        private ObservableCollection<ProjectDetail> _ProjectsListWithDTE;

        public ObservableCollection<ProjectDetail> ProjectsListWithDTE
        {
            get { return _ProjectsListWithDTE; }
            set { _ProjectsListWithDTE = value; }
        }

        private ObservableCollection<ProjectDetail> _ProjectsListThirdApproachExample;

        public ObservableCollection<ProjectDetail> ProjectsListThirdApproachExample
        {
            get { return _ProjectsListThirdApproachExample; }
            set { _ProjectsListThirdApproachExample = value; }
        }

        public MainWindow()
        {
            InitializeComponent();
            GetProjectDetailsWithDTE(); // First Approach
            GetProjectDetailsWithoutDTE(); // Second Approach
            GetProjectInformationByThirdApproach(); // Third Approach
            DataridWithoutDTE.ItemsSource = ProjectsListWithoutDTE;
            DataridWithDTE.ItemsSource = ProjectsListWithDTE;
            DataridThirdApproach.ItemsSource = ProjectsListThirdApproachExample;
        }

        private void GetProjectInformationByThirdApproach()
        {
            // Load the solution file
            SolutionFile solutionFile = SolutionFile.Parse(solutionFilePath);
            ProjectsListThirdApproachExample = new ObservableCollection<ProjectDetail>();

            // Iterate through each project in the solution
            foreach (var project in solutionFile.ProjectsInOrder)
            {
                string projectName = project.ProjectName;
                string projectRelativePath = project.RelativePath;
                string projectFullPath = System.IO.Path.Combine(System.IO.Path.GetDirectoryName(solutionFilePath), projectRelativePath);
                string projectGuid = project.ProjectGuid;
                string projectType = project.ProjectType.ToString();

                ProjectsListThirdApproachExample.Add(new ProjectDetail
                {
                    ProjectName = projectName,
                    ProjectGuid = projectGuid,
                    ProjectType = projectType,
                    RelativePath = projectRelativePath,
                });
            }
        }

        private string GetRelativePath(string basePath, string fullPath)
        {
            Uri baseUri = new Uri(basePath + Path.DirectorySeparatorChar);
            Uri fullUri = new Uri(fullPath);
            Uri relativeUri = baseUri.MakeRelativeUri(fullUri);
            string relativePath = Uri.UnescapeDataString(relativeUri.ToString());

            return relativePath.Replace('/', Path.DirectorySeparatorChar);
        }

        private void GetProjectDetailsWithDTE()
        {
            string solutionDirectory = Path.GetDirectoryName(solutionFilePath);
            var dte = GetDTE();
            dte.Solution.Open(solutionFilePath);
            ProjectsListWithDTE = new ObservableCollection<ProjectDetail>();

            foreach (EnvDTE.Project project in dte.Solution.Projects)
            {
                ProjectsListWithDTE.Add(new ProjectDetail
                {
                    ProjectName = project.Name,
                    RelativePath = GetRelativePath(solutionDirectory, project.FullName),
                });
            }
            dte.Solution.Close(false);
        }

        private DTE2 GetDTE()
        {
            Type dteType = Type.GetTypeFromProgID("VisualStudio.DTE.17.0", true);
            object obj = Activator.CreateInstance(dteType, true);
            return (DTE2)obj;
        }

        private void GetProjectDetailsWithoutDTE()
        {
            s_SolutionParserFromSolutionFile = Type.GetType("Microsoft.Build.Construction.SolutionFile, Microsoft.Build, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", false, true);

            if (s_SolutionParserFromSolutionFile != null)
            {
                s_SolutionParserReader = s_SolutionParserFromSolutionFile.GetProperty("SolutionReader", BindingFlags.NonPublic | BindingFlags.Instance);
                s_SolutionParserProjects = s_SolutionParserFromSolutionFile.GetProperty("ProjectsInOrder", BindingFlags.Public | BindingFlags.Instance);
                s_SolutionParserSolution = s_SolutionParserFromSolutionFile.GetMethod("ParseSolution", BindingFlags.NonPublic | BindingFlags.Instance);
            }

            if (s_SolutionParserFromSolutionFile != null)
            {
                var solutionResultParser = s_SolutionParserFromSolutionFile.GetConstructors(BindingFlags.Instance | BindingFlags.NonPublic).First().Invoke(null);

                using (var streamReader = new StreamReader(solutionFilePath))
                {
                    s_SolutionParserReader.SetValue(solutionResultParser, streamReader, null);
                    s_SolutionParserSolution.Invoke(solutionResultParser, null);
                }

                var projects = new List<ProjectSolution>();
                var projectsobj = s_SolutionParserProjects.GetValue(solutionResultParser, null) as IReadOnlyList<ProjectInSolution>;

                if (projectsobj != null)
                {
                    arrayOfProjects = projectsobj.ToArray();
                }

                for (int i = 0; i < arrayOfProjects.Length; i++)
                {
                    projects.Add(new ProjectSolution(arrayOfProjects.GetValue(i)));
                }

                this.ProjectsList = projects;
                ProjectsListWithoutDTE = new ObservableCollection<ProjectDetail>();

                foreach (var item in ProjectsList)
                {
                    ProjectsListWithoutDTE.Add(new ProjectDetail
                    {
                        ProjectName = item.ProjectName,
                        ProjectGuid = item.ProjectGuid,
                        ProjectType = item.ProjectType,
                        RelativePath = item.RelativePath,
                    });
                }
            }
        }
    }

    public class ProjectSolution
    {
        static readonly PropertyInfo? s_ProjectName;
        static readonly PropertyInfo? s_RelativePath;
        static readonly PropertyInfo? s_ProjectGuid;
        static readonly PropertyInfo? s_ProjectType;

        static ProjectSolution()
        {
            Type? ProjectInSolution = Type.GetType("Microsoft.Build.Construction.ProjectInSolution, Microsoft.Build, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", false, true);

            if (ProjectInSolution != null)
            {
                s_ProjectName = ProjectInSolution.GetProperty("ProjectName", BindingFlags.Public | BindingFlags.Instance);
                s_RelativePath = ProjectInSolution.GetProperty("RelativePath", BindingFlags.Public | BindingFlags.Instance);
                s_ProjectGuid = ProjectInSolution.GetProperty("ProjectGuid", BindingFlags.Public | BindingFlags.Instance);
                s_ProjectType = ProjectInSolution.GetProperty("ProjectType", BindingFlags.Public | BindingFlags.Instance);
            }
        }

        public string ProjectName { get; private set; }
        public string RelativePath { get; private set; }
        public string ProjectGuid { get; private set; }
        public string ProjectType { get; private set; }

        public ProjectSolution(object solutionProject)
        {
            this.ProjectName = (s_ProjectName == null ? "" : s_ProjectName.GetValue(solutionProject, null) as string);
            this.RelativePath = (s_RelativePath == null ? "" : s_RelativePath.GetValue(solutionProject, null) as string);
            this.ProjectGuid = (s_ProjectGuid == null ? "" : s_ProjectGuid.GetValue(solutionProject, null) as string);
            this.ProjectType = (s_ProjectType == null ? "" : s_ProjectType.GetValue(solutionProject, null).ToString());
        }
    }
}

Step 2. Result View