Syntax to Call API through C# code

[DllImport("advapi32.dll", CharSet = CharSet.Unicode, EntryPoint = "RegQueryValueExW", SetLastError = true)]
static extern int RegQueryValueEx(
IntPtr hKey,
string lpValueName,
int lpReserved,
out uint lpType,
System.Text.StringBuilder lpData,
ref uint lpcbData);

Syntex to use:

uint pvSize = 1024;
System.Text.StringBuilder pvData = new System.Text.StringBuilder(1024);
uint pdwType = 0;
int success = RegQueryValueEx(regKey, "AKeyName", 0, out pdwType, pvData, ref pvSize);


[DllImport("advapi32.dll", SetLastError=true)]
static extern int RegCloseKey(
IntPtr hKey);
Syntex to use:

Microsoft.Win32.RegistryKey.Close() Method.


DllImport("advapi32.dll", SetLastError=true)]
static extern int RegCreateKeyEx(
int hKey,
string lpSubKey,
int Reserved,
string lpClass,
RegOption dwOptions,
RegSAM samDesired,
SECURITY_ATTRIBUTES lpSecurityAttributes,
out int phkResult,
out RegResult lpdwDisposition);


[Flags]
public enum RegOption
{
NonVolatile = 0x0,
Volatile = 0x1,
CreateLink = 0x2,
BackupRestore = 0x4,
OpenLink = 0x8
}

[Flags]
public enum RegSAM
{
QueryValue = 0x0001,
SetValue = 0x0002,
CreateSubKey = 0x0004,
EnumerateSubKeys = 0x0008,
Notify = 0x0010,
CreateLink = 0x0020,
WOW64_32Key = 0x0200,
WOW64_64Key = 0x0100,
WOW64_Res = 0x0300,
Read = 0x00020019,
Write = 0x00020006,
Execute = 0x00020019,
AllAccess = 0x000f003f
}

public enum RegResult
{
CreatedNewKey = 0x00000001,
OpenedExistingKey = 0x00000002
}

use :-

Microsoft.Win32.RegistryKey.CreateSubKey


[DllImport("advapi32.dll", SetLastError = true)]
static extern int RegSetValueEx(
IntPtr hKey,
[MarshalAs(UnmanagedType.LPStr)] string lpValueName,
int Reserved,
Microsoft.Win32.RegistryValueKind dwType,
[MarshalAs(UnmanagedType.LPStr)] string lpData,
int cbData);

use it :-
My.Computer.Registry.SetValue(KeyName, valueName, value, valueKind)
with signature:
keyName As String
valueName As String
value As Object
valueKind as RegistryValueKind

http://pinvoke.net/default.aspx/advapi32.RegSetValueEx#