How To Get A Stream Object From A Resource File (Console App/Windows Service Project)
I'm creating a Windows service and am trying to access some files I added to a resource file, but I'm stuck because I don't know how to access the individual files. Just for some background info, here's what I've done so far:
This is a C# Windows Service application running in debug mode as a console app, which helps me step into the code.
I added a resource file to the root called "Resources.resx".
In my resource file, I added a few jpg images and html files using the visual designer/editor.
After I added the images and html files to the resource file, a new folder in my project appeared named "Resources" with all the files I added.
In this new folder, I went to the properties of each file and changed the Build Action to Embedded Resource. (I don't know if this is necessary. Some blog I searched said to try it.)
The project's namespace is called "MicroSecurity.EmailService".
In order to get the name of the resource file, I used
GetType().Assembly.GetManifestResourceNames()
and I get the following
GetType().Assembly.GetManifestResourceNames() {string[2]} string[] [0] "MicroSecurity.EmailService.Services.EmailService.resources" string [1] "MicroSecurity.EmailService.Resources.resources" string
From this I identified that "MicroSecurity.EmailService.Resources.resources" is the string I want to use (index 1).
I used the this code to get a stream object.
var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream("MicroSecurity.EmailService.Resources.resources");
When I add a watch to this variable during debugging, I can see things such as metadata for my images and etc.
Here is where I'm stuck. I would like to access the image called "logo.jpg". This is what I'm doing to get at the image, but it's not working.
var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream("MicroSecurity.EmailService.Resources.resources.logo.jpg");
How can I get a stream from my logo.jpg file?
UPDATE:
Thanks to Andrew, I was able to figure it out. Below is some code I wrote for a demo project in order to study how the resource file works vs. embedding files directly. I hope this helps others to clarify the differences.
using System;
using System.Drawing;
using System.IO;
using System.Reflection;
namespace UsingResourceFiles
{
public class Program
{
/// <summary>
/// Enum to indicate what type of file a resource is.
/// </summary>
public enum FileType
{
/// <summary>
/// The resource is an image.
/// </summary>
Image,
/// <summary>
/// The resource is something other than an image or text file.
/// </summary>
Other,
/// <summary>
/// The resource is a text file.
/// </summary>
Text,
}
public static void Main(string[] args)
{
// There are two ways to reference resource files:
// 1. Use embedded objects.
// 2. Use a resource file.
// Get the embedded resource files in the Images and Text folders.
UseEmbeddedObjects();
// Get the embedded resource files in the Images and Text folders. This allows for dynamic typing
// so the resource file can be returned either as a stream or an object in its native format.
UseEmbeddedObjectsViaGetResource();
// Use the zombie.gif and TextFile.txt in the Resources.resx file.
UseResourceFile();
}
public static void UseEmbeddedObjects()
{
// =============================================================================================================================
//
// -=[ Embedded Objects ]=-
//
// This way is the easiest to accomplish. You simply add a file to your project in the directory of your choice and then
// right-click the file and change the "Build Action" to "Embedded Resource". When you reference the file, it will be as an
// unmanaged stream. In order to access the stream, you'll need to use the GetManifestResourceStream() method. This method needs
// the name of the file in order to open it. The name is in the following format:
//
// Namespace + Folder Path + File Name
//
// For example, in this project the namespace is "UsingResourceFiles", the folder path is "Images" and the file name is
// "zombie.gif". The string is "UsingResourceFiles.Images.zombie.gif".
//
// For images, once the image is in a stream, you'll have to convert it into a Bitmap object in order to use it as an Image
// object. For text, you'll need to use a StreamReader to get the text file's text.
// =============================================================================================================================
var imageStream = Assembly.GetExecutingAssembly().GetManifestResourceStream("UsingResourceFiles.Images.zombie.gif");
var image = new Bitmap(imageStream);
var textStream = Assembly.GetExecutingAssembly().GetManifestResourceStream("UsingResourceFiles.Text.TextFile.txt");
var text = new StreamReader(textStream).ReadToEnd();
}
public static void UseEmbeddedObjectsViaGetResource()
{
// =============================================================================================================================
//
// -=[ Embedded Objects Using GetResource() ]=-
//
// Using the overloaded GetResource() method, you can easily obtain an embedded resource file by specifying the dot file path
// and type. If you need the stream version of the file, pass in false to the useNativeFormat argument. If you use the
// GetResource() method outside of this file and are getting a null value back, make sure you set the resource's "Build Action"
// to "Embedded Resource".
// =============================================================================================================================
// Use the GetResource() methods to obtain the Images\zombie.gif file and the text from the Text\TextFile.txt file.
Bitmap image = GetResource("Images.zombie.gif", FileType.Image);
Stream imageStream = GetResource("Images.zombie.gif", FileType.Image, false);
string text = GetResource("Text.TextFile.txt", FileType.Text);
Stream textStream = GetResource("Text.TextFile.txt", FileType.Text, false);
}
public static void UseResourceFile()
{
// =============================================================================================================================
//
// -=[ Resource File ]=-
//
// This way takes more upfront work, but referencing the files is easier in the code-behind. One drawback to this approach is
// that there is no way to organize your files in a folder structure; everything is stuffed into a single resource blob.
// Another drawback is that once you create the resource file and add any files to it, a folder with the same name as your
// resource file is created, creating clutter in your project. A final drawback is that the properties of the Resources object
// may not follow proper C# naming conventions (e.g. "Resources.funny_man" instead of "Resources.FunnyMan"). A plus for using
// resource files is that they allow for localization. However, if you're only going to use the resource file for storing files,
// using the files as embedded objects is a better approach in my opinion.
// =============================================================================================================================
// The Resources object references the resource file called "Resources.resx".
// Images come back as Bitmap objects and text files come back as string objects.
var image = Resources.zombie;
var text = Resources.TextFile;
}
/// <summary>
/// This method allows you to specify the dot file path and type of the resource file and return it in its native format.
/// </summary>
/// <param name="dotFilePath">The file path with dots instead of backslashes. e.g. Images.zombie.gif instead of Images\zombie.gif</param>
/// <param name="fileType">The type of file the resource is.</param>
/// <returns>Returns the resource in its native format.</returns>
public static dynamic GetResource(string dotFilePath, FileType fileType)
{
try
{
var assembly = Assembly.GetExecutingAssembly();
var assemblyName = assembly.GetName().Name;
var stream = assembly.GetManifestResourceStream(assemblyName + "." + dotFilePath);
switch (fileType)
{
case FileType.Image:
return new Bitmap(stream);
case FileType.Text:
return new StreamReader(stream).ReadToEnd();
default:
return stream;
}
}
catch (Exception e)
{
Console.WriteLine(e);
return null;
}
}
/// <summary>
/// This method allows you to specify the dot file path and type of the resource file and return it in its native format.
/// </summary>
/// <param name="dotFilePath">The file path with dots instead of backslashes. e.g. Images.zombie.gif instead of Images\zombie.gif</param>
/// <param name="fileType">The type of file the resource is.</param>
/// <param name="useNativeFormat">Indicates that the resource is to be returned as resource's native format or as a stream.</param>
/// <returns>When "useNativeFormat" is true, returns the resource in its native format. Otherwise it returns the resource as a stream.</returns>
public static dynamic GetResource(string dotFilePath, FileType fileType, bool useNativeFormat)
{
try
{
if (useNativeFormat)
{
return GetResource(dotFilePath, fileType);
}
var assembly = Assembly.GetExecutingAssembly();
var assemblyName = assembly.GetName().Name;
return assembly.GetManifestResourceStream(assemblyName + "." + dotFilePath);
}
catch (Exception e)
{
Console.WriteLine(e);
return null;
}
}
}
}
Answer
If you set the files in the Resources folder to Embedded Resource then you should have seen it listed in the GetManifestResourceNames() call. You could try
var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream("MicroSecurity.EmailService.Resources.logo.jpg");
The name should be "MicroSecurity.EmailService.Resources.logo.jpg" if it is in the Resources folder. However, marking the file itself as an Embedded Resource defeats the purpose of the Resources file (the image itself would be embedded twice).
You can remove the resources file entirely and set each file as an Embedded Resource. At that point, there should be separate manifest resources for each file. In a C# project, each file name will be prefixed by the project namespace + the sub folder. Eg. if you add a "logo.jpg" file in a Resources/Embedded folder, the resource name will be "MicroSecurity.EmailService.Resources.Embedded.logo.jpg".
Alternatively, get the bitmap from the Resources file and convert it to a stream. You can find an example of converting a Bitmap to a MemoryStream in How do I convert a Bitmap to byte[]?