How to change filetype association in the registry?

Question

first time posting in StackOverflow. :D I need my software to add a couple of things in the registry.

My program will use

Process.Start(@"blblabla.smc");

to launch a file, but the problem is that most likely the user will not have a program set as default application for the particular file extension.

How can I add file associations to the WindowsRegistry?

Answer 1

In addition to the answers already provided, you can accomplish this by calling the command line programs "ASSOC" and "FTYPE". FTYPE associates a file type with a program. ASSOC associates a file extension with the file type specified through FTYPE. For example:

FTYPE SMCFile="C:\some_path\SMCProgram.exe" -some_option %1 %*
ASSOC .smc=SMCFile

This will make the necessary entries in the registry. For more information, type ASSOC /? or FTYPE /? at the command prompt.

Answer 2

Use the Registry class in Microsoft.Win32.

Specifically, you want the ClassesRoot property of Registry to access the HKEY_CLASSES_ROOT key (cf. Understanding MS Windows File Associations and HKEY_CLASSES_ROOT: Core Services).

using Microsoft.Win32;
Registry
    .ClassesRoot
    .CreateSubKey(".smc")
    .SetValue("", "SMC", RegistryValueKind.String);
Registry
    .ClassesRoot
    .CreateSubKey("SMC\shell\open\command")
    .SetValue("", "SMCProcessor \"%1\"", RegistryValueKind.String);

Replace "SMCProcessor \"%1\"" with the command-line path and argument specification for the program that you wish to associate with files with extension .smc.

But, instead of messing with the registry, why not just say

Process.Start("SMCProcessor blblabla.smc");