Using Resources for External Content - Page 1

Resources are used when dealing with external content. When you have an application with images, icons, external text files, etc., you can refer to the external content by accessing the file's path directly, for example: C:\Kirupa\title.gif. That approach works well, and your application will access the file from that location. There is a catch though!

When you decide to share your application with others, unless their computers have a title.gif in their C:\Kirupa folder, they won't be able to see the external content that you could see on your computer. Web developers are are all too familiar with this problem when they accidentally refer to a file that works on their local computer but not on the web server because they forget to upload that file to the server.

Resource files solve this problem by localizing external content to the currently running application. To look at it another way, think of your application's executable as a zip file that contains inside it other files such as your external content. When you run your application, since all of your external content is contained inside your executable, it does not matter how or where your application is run. As long as you know where your application is run, you know where your external content is.

While the example in the previous paragraph isn't representative of how an actual application works, it does give you an idea of how having external content stored in one file allows you to refer to the external content without referencing the exact location the file is stored on a user's file system.

While using resources may seem unnecessary because of the extra steps needed to access your external content, it makes it pain-free when deploying your application for other users.

Using Embedded Resources for WinForms Applications
To use resources, there are three steps you need to follow: getting the external file into your project, changing the external file's Build Action, and being using code to refer to that file. Note that the next section will discuss how to use Resources when accessing WPF-specific elements.

Importing a File
Before you can use resources, you need to first import the external file into your Project. To import a file, right click on your project icon from the Solution Explorer and go to Add | Existing Item:

[ import an item by going to Add | Existing Item ]

The Add Existing Item dialog window should appear, and you can browse for the file or files you want to import into your project. After you have imported your files, you should see it in our your Solution Explorer. For example, as shown in the following image, I inserted an image file called blue.png, and I can now see it in my Solution Explorer:

[ the imported blue.png file displayed in the Solution Explorer ]

In the next page, we will take a look at the remaining steps needed to use external content in our application.

Onwards to the next page!

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