C# FileAssociation Class

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Introduction

My small library here allows you to set File Associations. File Associations are a group of multiple keys in your registry that set what program a file type opens with, the description of the file type that's shown in the file properties dialog, the icon that's shown on a file type, and even what programs are displayed in the dialog that opens when Windows can't find the program that opens with a file type (Open with list).

Background

I've been using C# for about a year now... I previously ran into the problem of File Associations when I was working on a big word processor project with never-before-seen features. So I did some research and figured out how to do this.

Using the Code

The download at the top contains a CS file and a DLL file. The CS file contains my library's code so you can learn how it all works, and the DLL is for adding a reference to in your programs. The code block below shows how you use the library after referencing it.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using AF_Lib.IO.Associations;

public class AFFileAssociations_Example
{
    public static void Main()
    {
        // Initializes a new AF_FileAssociator to associate the .ABC file extension.
        AF_FileAssociator assoc = new AF_FileAssociator(".abc");

        // Creates a new file association for the .ABC file extension. 
        // Data is overwritten if it already exists.
        assoc.Create("My_App",
            "My application's file association",
            new ProgramIcon(@"C:\Program Files\My_App\icon.ico"),
            new ExecApplication(@"C:\Program Files\My_App\myapp.exe"),
            new OpenWithList(new string[] { "My_App" }));

        // Gets each piece of association info individually, all as strings.
        string id = assoc.ID;
        string description = assoc.Description;
        string icon = assoc.DefaultIcon.IconPath;
        string execApp = assoc.Executable.Path;
        string[] openWithList = assoc.OpenWith.List;

        // Sets each piece of association info individually.
        ProgramIcon newDefIcon = new ProgramIcon(@"C:\Program Files\My_App\icon2.ico");
        ExecApplication newExecApp = 
		new ExecApplication(@"C:\Program Files\My_App\myapp2.exe");
        OpenWithList newOpenWith = new OpenWithList(new string[] { "myapp2.exe" });

        assoc.ID = "My_App_2";
        assoc.Description = "My application's file association #2";
        assoc.DefaultIcon = newDefIcon;
        assoc.Executable = newExecApp;
        assoc.OpenWith = newOpenWith;

        // Gets the extension of the associator that was set when initializing it.
        string extension = assoc.Extension;

        // Deletes any keys that were associated with the .ABC file extension.
        assoc.Delete();
    }
} 

Points of Interest

This library should be very helpful. The attachment on this project contains my code file, and the DLL to reference it. Please leave any questions or comments below. Thanks for reading my article!

History

• 10^th November, 2009: Initial post
• 11^th November, 2009: Updated source code