从注册表检索值 [英] Retrieve value from Registry

问题描述

我有一个c#应用程序，其中包含用于检索注册表值并检查其值的代码.注册表值以以下方式存储:

MainKey:
名称:user123
已注册:否

但是，如果Isregistered返回否，它将显示相应的消息.
我收到这样的错误:---

对象引用未设置为对象的实例.

C#代码:

I have c# application which include code to retrieve registry values and check it''s values.registry values stored in following manner:

MainKey:
Name:user123
Isregistered:no

however if Isregistered returns no,it will display appropriate message.
i am getting error like this:---

Object reference not set to an instance of an object.

C# Code:

RegistryKey se =  Registry.CurrentUser.OpenSubKey(@"MainKey", true);
           string currentKey;
            currentKey = reg.GetValue("Isregistered", true).ToString();
           if (currentKey == "Yes")
           {
               Console.WriteLine(currentKey.ToString());

           }
           else
           {
               Console.WriteLine(currentKey.ToString());
    }

我在 currentKey = reg.GetValue("Isregistered"，true).ToString();

i am getting error on currentKey =reg.GetValue("Isregistered", true).ToString();

推荐答案

上遇到错误它可能是其中的一部分:

The problem is that it could be either part of that:

reg.GetValue("Isregistered", true)

reg可能为空-您不会显示它正在定义或初始化

reg could be null - you don''t show it being defined or initialised

reg.GetValue("Isregistered", true).ToString()

如果reg 正常，则GetValue 可能返回null.
或者，它可能在您的GetValue方法本身中.

将其分解，然后在调试器中进行以下操作:

If reg is ok, then GetValue could be returning null.
Or, it could be in your GetValue method itself.

Break it up, and single step throung in the debugger:

if (reg != null)
    {
    object o = reg.GetValue("Isregistered", true);
    currentKey = o.ToString();
    }

然后您就有机会解决导致问题的原因.

Then you stand a chance of working out which is causing the problem.

您可以在Read方法中将Isregistered值传递给Access注册表值，如

you can pass Isregistered value in Read method for access Registry value as

Read("Isregistered ");

看看方法声明

have a look at method declaration

public string Read(string KeyName)
{
    // Opening the registry key
      RegistryKey rk = baseRegistryKey ;
    // Open a subKey as read-only

    RegistryKey sk1 = rk.OpenSubKey(subKey);
    // If the RegistrySubKey doesn''t exist -> (null)

    if ( sk1 == null )
    {
        return null;
    }
    else
    {
        try 
        {
       // If the RegistryKey exists I get its value or null is returned.        
         return (string)sk1.GetValue(KeyName.ToUpper());
        }
        catch (Exception e)
        {
            ShowErrorMessage(e, "Reading registry " + KeyName.ToUpper());
            return null;
        }
    }
}

参考链接:-使用C#读取注册表 [

Reference Link :- Read Registry using C#[^]

我找到了解决方案.感谢您的帮助.

i got solution.Thanks for help.

RegistryKey reg =  Registry.CurrentUser.OpenSubKey(@"MainKey", true);
            string currentKey;
             
             if (reg != null)
             {
                 RegistryKey rKey = reg.OpenSubKey("Isregistered", true);
                 object o = rKey.GetValue("Isregistered");
                 currentKey = o.ToString();
                 
           
                Console.WriteLine(currentKey.ToString());
              }

这篇关于从注册表检索值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！