注册表键值明明存在OpenSubKey始终返回null，解决方案

先上代码及实例

RegistryKey rsg = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Macromedia\FlashPaper Printer\2\Installation\", false);
为什么返回值是NULL

L

原因其实是在64位电脑上跑32位程序，以上代码读取为空值，32位电脑读注册表使用OpenSubKey是正确的

解决方法：

I will show you how to get connecting string stored in registry. The code which I will show in this blog will work both on 32 and 64 bit machines. Let's say your connectingstring key name is "MyAppConnectionStringKey" and stored at following path "SOFTWARE\MyApp\Settings" with following value "Initial Catalog=mydb;Server=MY-PC;User ID=sa;Password=test"

Goal:
To get the "MyAppConnectionStringKey" value via code.

Solution:
First of all add the following "RegistryHelpers" class in your solution. I have added few methods in this class to get registrykey and value.

using System;
using Microsoft.Win32;

namespace TestConsole
{
    public class RegistryHelpers
    {

        public static RegistryKey GetRegistryKey()
        {
            return GetRegistryKey(null);
        }

        public static RegistryKey GetRegistryKey(string keyPath)
        {
            RegistryKey localMachineRegistry
                = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine,
                                          Environment.Is64BitOperatingSystem
                                              ? RegistryView.Registry64
                                              : RegistryView.Registry32);

            return string.IsNullOrEmpty(keyPath)
                ? localMachineRegistry
                : localMachineRegistry.OpenSubKey(keyPath);
        }

        public static object GetRegistryValue(string keyPath,string keyName)
        {
            RegistryKey registry = GetRegistryKey(keyPath);
            return registry.GetValue(keyName);
        }
    }
}

Let's test this code with a console program to fetch the value of key:

using System;

namespace TestConsole
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            string keyPath = @"SOFTWARE\MyApp\Settings";
            string keyName = "MyAppConnectionStringKey";

            object connectionString = RegistryHelpers.GetRegistryValue(keyPath, keyName);

            Console.WriteLine(connectionString);
            Console.ReadLine();
        }
    }
}

Output: