以下从‘读’‘写’‘删除’‘判断’四个事例实现对注册表的简单操作 
1.读取指定名称的注册表的值 
private string GetRegistData(string name) 
{ 
string registData; 
RegistryKey hkml = Registry.LocalMachine; 
RegistryKey software = hkml.OpenSubKey("SOFTWARE",true); 
RegistryKey aimdir = software.OpenSubKey("XXX",true); 
registData = aimdir.GetValue(name).ToString(); 
return registData; 
} 
以上是读取的注册表中HKEY_LOCAL_MACHINE\SOFTWARE目录下的XXX目录中名称为name的注册表值； 

2.向注册表中写数据 
private void WTRegedit(string name,string tovalue) 
{ 
RegistryKey hklm = Registry.LocalMachine; 
RegistryKey software = hklm.OpenSubKey("SOFTWARE",true); 
RegistryKey aimdir = software.CreateSubKey("XXX"); 
aimdir.SetValue(name,tovalue); 
} 
以上是在注册表中HKEY_LOCAL_MACHINE\SOFTWARE目录下新建XXX目录并在此目录下创建名称为name值为tovalue的注册表项； 

3.删除注册表中指定的注册表项 
private void DeleteRegist(string name) 
{ 
string[] aimnames; 
RegistryKey hkml = Registry.LocalMachine; 
RegistryKey software = hkml.OpenSubKey("SOFTWARE",true); 
RegistryKey aimdir = software.OpenSubKey("XXX",true); 
aimnames = aimdir.GetSubKeyNames(); 
foreach(string aimKey in aimnames) 
{ 
if(aimKey == name) 
aimdir.DeleteSubKeyTree(name); 
} 
} 
以上是在注册表中HKEY_LOCAL_MACHINE\SOFTWARE目录下XXX目录中删除名称为name注册表项； 

4.判断指定注册表项是否存在 
private bool IsRegeditExit(string name) 
{ 
bool _exit = false; 
string[] subkeyNames; 
RegistryKey hkml = Registry.LocalMachine; 
RegistryKey software = hkml.OpenSubKey("SOFTWARE",true); 
RegistryKey aimdir = software.OpenSubKey("XXX",true); 
subkeyNames = aimdir.GetSubKeyNames(); 
foreach(string keyName in subkeyNames) 
{ 
if(keyName == name) 
{ 
_exit = true; 
return _exit; 
} 
} 
return _exit; 
} 
以上是在注册表中HKEY_LOCAL_MACHINE\SOFTWARE目录下XXX目录中判断名称为name注册表项是否存在，这一方法在删除注册表时已经存在，在新建一注册表项时也应有相应判断

https://www.cnblogs.com/liuxinls/archive/2013/03/21/2974134.html