C # use Windows Registry to edit

Using Microsoft. Win32;

Creating subkeys in the Registry

We create a subkey by using the createsubkey method. We usually want to create a subkey in HKEY_CURRENT_USER/ Software That is why we use the following code:

 


RegistryKey reg = Registry.CurrentUser.CreateSubKey("SOFTWARE\\Geekpedia\\Test");


Adding Values to subkeys

Now we can add a value to the subkey by using the following piece of code:

 


reg.SetValue("URL", "http://www.geekpedia.com");


As you can see, the code is rather straightforward. We create a value with the name 'url' and the data 'HTTP: // www.geekpedia.com '.

Retrieving data

Further, we shall retrieve the value we just added and store it in a string variable:

 


string URL = (string)reg.GetValue("URL");


... And display the output:


Console.WriteLine("Before: " + URL);


Changing the values

We change the value of 'reg '. we specify the same path, but now we also add a 'true' Boolean at the end. that means we use the overloaded method and 'true' means we want the path in write mode.
The overloaded method prototype is:

 


public RegistryKey OpenSubKey(string name, bool writable);


And here is the code we use:


RegistryKey reg = Registry.CurrentUser.OpenSubKey("SOFTWARE\\Geekpedia\\Test", true);


Because we opened the subkey in write mode, we can modify the data:


reg.SetValue("URL", "about:blank");


And store it again in the same variable:


URL = (string)reg.GetValue("URL");


... And display the output:


Console.WriteLine("After: " + URL);


And finally close the opened connection with the registry subkey and flush:


reg.Close();


Finally, all the Code put together looks like this:


using System;
using Microsoft.Win32;
class Class1
{
    [STAThread]
    static void Main(string[] args)
    {
        // Create a new SubKey or open it if already exists
        RegistryKey reg = Registry.CurrentUser.CreateSubKey("SOFTWARE\\Geekpedia\\Test");
        // Add a new value to the SubKey
        reg.SetValue("URL", "http://www.geekpedia.com");
        // Store it in 'URL' variable
        string URL = (string)reg.GetValue("URL");
        // Display it
        Console.WriteLine("Before: " + URL);

        // Open the SubKey this time in write mode
        reg = Registry.CurrentUser.OpenSubKey("SOFTWARE\\Geekpedia\\Test", true);
        // Change the value 'URL'
        reg.SetValue("URL", "about:blank");
        // Store it in the earlier variable
        URL = (string)reg.GetValue("URL");
        // Display it
        Console.WriteLine("After: " + URL);
        // Close the registry SubKey and flush
        reg.Close();
    }
}

Deleting subkeys

For removing subkeys from the Registry you can use the method with the following prototype:

 


public void DeleteSubKey(string subkey);


And here is a hands-on example:


// Open SOFTWARE
RegistryKey reg = Registry.CurrentUser.OpenSubKey("SOFTWARE");
// Delete Geekpedia from SOFTWARE
reg.DeleteSubKeyTree("Geekpedia");
//Close the registry SubKey and flush
reg.Close();


If the key doesn't exist you will get a nasty exception. for ignoring the exception use the overloaded method:


public void DeleteSubKey(string subkey, bool throwOnMissingSubKey);


In our example this looks like this:


reg = Registry.CurrentUser.OpenSubKey("SOFTWARE", false);


Deleting values

Deleting a value is similar to deleting a subkey, it also has two prototypes:

 


public void DeleteValue(string name);
public void DeleteValue(string name, bool throwOnMissingValue);


Which act the same as in deletesubkey.