Windows Form Project c#, checking if Key exist in Registry

Question

Hi, I tried various things does not seem to work if key does not exist it gives exceptional error, but if it does it works.

Here Code:

private void Form1_Load(object sender, EventArgs e)

{

  

    RegistryKey Key = Registry.CurrentUser.OpenSubKey(@"SOFTWARE\MyApp") ;

   

 if (Key == null) Activated_Bool = false;  //key exist

    

    else Activated_Bool = true;

    

Key.Close();

}

Anyone has any idea, thanks in advance.

Answer 1

Hi @Gennady Gurin , Welcome to Microsoft Q&A,

You're trying to call Key.Close() regardless of whether Key is null.

If the registry key doesn't exist (Key == null), attempting to call Key.Close() will result in a NullReferenceException.

private void Form1_Load(object sender, EventArgs e)
{
    // Attempt to open the registry key
    using (RegistryKey key = Registry.CurrentUser.OpenSubKey(@"SOFTWARE\MyApp"))
    {
        // Check if the key exists
        if (key == null)
        {
            Activated_Bool = false; // Key does not exist
        }
        else
        {
            Activated_Bool = true; // Key exists
        }
    } // The 'using' statement ensures the key is properly closed
}

Best Regards,

Jiale

---

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". 

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.