C#判断.NetFramework库是否安装

namespace env_monitor.Utils
{
    using Microsoft.Win32;
    using System.Diagnostics;

    /// <summary>
    /// 检测.Net环境
    /// </summary>
    public class EnvCheckUtil
    {
        /// <summary>
        /// 判断.Net Framework的Version是否符合需要 (.Net Framework 版本在2.0及以上)
        /// </summary>
        /// <param name="version">
        /// 需要的版本 version = 4.5
        /// </param>
        /// <returns>
        /// </returns>
        public static bool IsInstallDotNet(string version)
        {
            string oldname = "0";
            using (RegistryKey ndpKey = RegistryKey.OpenRemoteBaseKey(
                           RegistryHive.LocalMachine,
                           ""
                       )
                       .OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\"))
            {
                if (ndpKey != null)
                    foreach (string versionKeyName in ndpKey.GetSubKeyNames())
                    {
                        if (versionKeyName.StartsWith("v"))
                        {
                            RegistryKey versionKey = ndpKey.OpenSubKey(versionKeyName);
                            if (versionKey != null)
                            {
                                string newname = (string)versionKey.GetValue(
                                    "Version",
                                    ""
                                );
                                if (string.CompareOrdinal(
                                        newname,
                                        oldname
                                    ) >
                                    0)
                                {
                                    oldname = newname;
                                }
                                if (newname != "")
                                {
                                    continue;
                                }
                                foreach (string subKeyName in versionKey.GetSubKeyNames())
                                {
                                    RegistryKey subKey = versionKey.OpenSubKey(subKeyName);
                                    if (subKey != null)
                                        newname = (string)subKey.GetValue(
                                            "Version",
                                            ""
                                        );
                                    if (string.CompareOrdinal(
                                            newname,
                                            oldname
                                        ) >
                                        0)
                                    {
                                        oldname = newname;
                                    }
                                }
                            }
                        }
                    }
            }
            return string.CompareOrdinal(
                       oldname,
                       version
                   ) >
                   0;
        }

        /// <summary>
        /// 打开系统软件卸载页面
        /// </summary>
        public static void OpenAppUninstallPage()
        {
            Process.Start("appwiz.cpl");
        }
    }
}

var isInstallNet = EnvCheckUtil.IsInstallDotNet("4.5");
Console.WriteLine(@"是否安装.Net4.5:" + isInstallNet);