VisualStudioFileOpening.cs

using System.Diagnostics;
using System.Globalization;
using System.IO;

using UnityEngine;
using UnityEditor;
using UnityEditor.Callbacks;

public static class VisualStudioFileOpening
{
	[OnOpenAsset]
	public static bool OpenFile(int instanceID, int line)
	{
		var assetPath = AssetDatabase.GetAssetPath(instanceID);

		return CanBeOpened(assetPath)
			&& OpenAsset(assetPath, line);
	}

	private static bool CanBeOpened(string assetPath)
	{
		var asset = AssetDatabase.LoadAssetAtPath(assetPath, typeof(UnityEngine.Object));

		return asset is TextAsset || asset is ComputeShader;
	}

	private static bool OpenAsset(string file, int line)
	{
		const string openerKey = "kScriptsDefaultApp";
		const string openerExe = "UnityVS.OpenFile.exe";

		var openFile = EditorPrefs.GetString(openerKey);

		if (!File.Exists(FullPathTo(file)) || !openFile.EndsWith(openerExe))
			return false;

		Process.Start(new ProcessStartInfo
		{
			UseShellExecute = false,
			CreateNoWindow = true,
			Arguments = QuoteIfNeeded(FullPathTo(file)) + " " + (line - 1).ToString(CultureInfo.InvariantCulture),
			FileName = NormalizePath(openFile),
		});

		return true;
	}

	private static string FullPathTo(string file)
	{
		return Path.GetFullPath(Path.Combine(ProjectDirectory(), NormalizePath(file)));
	}

	private static string NormalizePath(string path)
	{
		return path.Replace('/', '\\');
	}

	public static string ProjectDirectory()
	{
		return Path.GetFullPath(Path.Combine(Application.dataPath, ".."));
	}

	public static string QuoteIfNeeded(string str)
	{
		return str.Contains(" ") ? "\"" + str + "\"" : str;
	}
}