How to write your own registry accessing functions by using base class libraries in Visual C# .NET or in Visual C# 2005 (816163)

MORE INFORMATION

Using the Registry and RegistryKey Classes

To access the registry, use the Registry class and the RegistryKey class in the Microsoft.Win32 namespace.

• The Registry class supplies the base registry keys to access values and subkeys in the registry. It has static fields, such as CurrentUser, to represent the root registry key.
• The RegistryKey class represents a key level node in the Windows registry. The class is a registry encapsulation that enables read and write operations to the registry through the GetValue method and the SetValue method of the RegistryKey class.

To create a console project to read and write to the registry by using the Registry class and the RegistryKey class, follow these steps:

1. Start Microsoft Visual Studio .NET or Microsoft Visual Studio 2005.
2. On the File menu, point to New3, and then click Project.
3. Under Project Types, select Visual C# Projects. Under Templates, select Console Application, and then click OK.
   
   Note In Visual Studio 2005, click Visual C# under Project Types, click Console Application under Templates, and then click OK.
4. Add the following namespace to Class1.cs:
   
   Note In Visual Studio 2005, the default file is Program.cs.

   using Microsoft.Win32;

5. Add the following code to the Class1 class:
   
   Note In Visual Studio 2005, add the code to the Program class.

   static void WriteRegistry(RegistryKey parentKey, String subKey, String valueName, Object value)
   {
   	RegistryKey key;
   	try
   	{
   		key = parentKey.OpenSubKey(subKey, true);
   		if(key == null) //If the key doesn't exist.
   			key = parentKey.CreateSubKey(subKey);
   		
   		//Set the value.
   		key.SetValue(valueName, value);
   
   		Console.WriteLine("Value:{0} for {1} is successfully written.", value, valueName);
   	}
   	catch(Exception e)
   	{
   		Console.WriteLine("Error occurs in WriteRegistry" + e.Message);
   	}
   }
   
   static void ReadRegistry(RegistryKey parentKey, String subKey, String valueName, Object value)
   {
   	RegistryKey key;
   	
   	try
   	{
   		key = parentKey.OpenSubKey(subKey, true);
   		if(key == null) //If the key doesn't exist.
   			throw new Exception("The registry key doesn't exist");
   
   		//Get the value.
   		value = key.GetValue(valueName);
   
   		Console.WriteLine("Value:{0} for {1} is successfully retrieved.", value, valueName);
   	}
   	catch(Exception e)
   	{
   		Console.WriteLine("Error occurs in ReadRegistry" + e.Message);
   	}
   }
   

6. Copy and paste the following code to replace the code in Main that is generated by Visual C#:

   static void Main(string[] args)
   {
   	WriteRegistry(Registry.CurrentUser, "Software\\MySoftware", "Count", 123);
   
   	Object value = null;
   	ReadRegistry(Registry.CurrentUser, "Software\\MySoftware", "Count", value);
   
   	Console.ReadLine();
   }

7. Press F5 to run the application.
   
   Note This procedure creates a registry key that is named MySoftware under the subkey HKEY_CURRENT_USER\Software. This procedure also creates a DWORD value named Count with the value 123 under the MySoftware key.

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Complete Code Listing

using System;
using Microsoft.Win32;

class Class1
{
	[STAThread]
	static void Main(string[] args)
	{
		WriteRegistry(Registry.CurrentUser, "Software\\MySoftware", "Count", 123);

		Object value = null;
		ReadRegistry(Registry.CurrentUser, "Software\\MySoftware", "Count", value);

		Console.ReadLine();
	}

	static void WriteRegistry(RegistryKey parentKey, String subKey, String valueName, Object value)
	{
		RegistryKey key;
		try
		{
			key = parentKey.OpenSubKey(subKey, true);
			if(key == null) //If the key doesn't exist.
				key = parentKey.CreateSubKey(subKey);
	
			//Set the value.
			key.SetValue(valueName, value);

			Console.WriteLine("Value:{0} for {1} is successfully written.", value, valueName);
		}
		catch(Exception e)
		{
			Console.WriteLine("Error occurs in WriteRegistry" + e.Message);
		}
	}

	static void ReadRegistry(RegistryKey parentKey, String subKey, String valueName, Object value)
	{
		RegistryKey key;

		try
		{
			key = parentKey.OpenSubKey(subKey, true);
			if(key == null) //If the key doesn't exist.
				throw new Exception("The registry key doesn't exist");

			//Get the value.
			value = key.GetValue(valueName);

			Console.WriteLine("Value:{0} for {1} is successfully retrieved.", value, valueName);
		}
		catch(Exception e)
		{
			Console.WriteLine("Error occurs in ReadRegistry" + e.Message);
		}
	}
}

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