Article purpose
This article details how to read Image files from the file system, create thumbnails and then encoding thumbnails images to Base64 strings.
Sample source code
This article is accompanied by a sample source code Visual Studio project which is available for download here.
Images as Base64 strings
From Wikipedia:
Base64 is a group of similar encoding schemes that represent binary data in an ASCII string format by translating it into a radix-64 representation. The Base64 term originates from a specific MIME content transfer encoding.
Base64 encoding schemes are commonly used when there is a need to encode binary data that need to be stored and transferred over media that are designed to deal with textual data. This is to ensure that the data remain intact without modification during transport. Base64 is commonly used in a number of applications including email via MIME, and storing complex data in XML.
From the definition quoted above the need for base64 encoding becomes more clear. From MSDN documentation:
The base-64 digits in ascending order from zero are the uppercase characters "A" to "Z", the lowercase characters "a" to "z", the numerals "0" to "9", and the symbols "+" and "/". The valueless character, "=", is used for trailing padding.
Base64 encoding allows developers to expose binary data without potentially encountering conflicts in regards to the transfer medium. Base64 encoded binary data serves ideally when performing data transfer operations using platforms such as html, xml, email.
A common implementation of Base64 encoding can be found when transferring image data. This article details how to convert/encode Image object thumbnails to Base64 strings.
Base64 Image encoding implemented as an extension method
The code snippet listed below details the ToBase64String extension method targeting the Image class.
public static string ToBase64String(this Image bmp) { string base64String = string.Empty; MemoryStream memoryStream = null;
try { memoryStream = new MemoryStream(); bmp.Save(memoryStream, ImageFormat.Png); } catch (Exception exc) { return String.Empty; }
memoryStream.Position = 0; byte[] byteBuffer = memoryStream.ToArray();
memoryStream.Close();
base64String = Convert.ToBase64String(byteBuffer, Base64FormattingOptions.InsertLineBreaks); byteBuffer = null;
return base64String; }
The ToBase64String method writes the targeted Image object’s pixel data to a MemoryStream object using the Png ImageFormat. Next a byte array is extracted and passed to the method Convert.ToBase64String, which is responsible for implementing the Base64 encoding.
Creating an Image tag implementing a Base64 string
The sample source code in addition also defines an extension method to generate html image tags to display a Base64 string encoded image.
public static string ToBase64ImageTag(this Image bmp) { string imgTag = string.Empty; string base64String = string.Empty;
base64String = bmp.ToBase64String();
imgTag = "<img src=\\"data:image/" + "png" + ";base64,"; imgTag += base64String + "\\" "; imgTag += "width=\\"" + bmp.Width.ToString() + "\\" "; imgTag += "height=\\"" + bmp.Height.ToString() + "\\" />";
return imgTag; }
The ToBase64ImageTag extension method invokes the ToBase64String extension method in order to retrieve encoded the data. The Html image tag has only to be slightly modified from the norm in order to accommodate Base64 encoded strings.
Creating Image thumbnails
The Image class conveniently provides the method GetThumbnailImage, which we’ll be using to create thumbnails from existing Image objects. The sample source code defines the method ToBase64Thumbnail, as listed below:
public static string ToBase64Thumbnail(this Image bmp, int width, int height, bool wrapImageTag) { Image.GetThumbnailImageAbort callback = new Image.GetThumbnailImageAbort(ThumbnailCallback);
Image thumbnailImage = bmp.GetThumbnailImage(width, height, callback, new IntPtr());
string base64String = String.Empty;
if (wrapImageTag == true) { base64String = thumbnailImage.ToBase64ImageTag(); } else { base64String = thumbnailImage.ToBase64String(); }
thumbnailImage.Dispose();
return base64String; }
private static bool ThumbnailCallback() { return true; }
The ToBase64Thumbnail is defined as an extension method targeting the Image class. The calling code is required to specify the width and height of the output thumbnails and in addition whether to wrap the Base64 encoded string in an Html <img> tag.
Note the definition of ThumnailCallback, the GetThumbnailImage method requires calling code to specify a callback delegate.
Based on the value of the parameter wrapImageTag, we next invoke either ToBase64ImageTag or ToBase64String, as defined/discussed earlier.
Reading Image files from the file system
The starting point in creating Base64 encoded thumbnails would be to read the local file system, searching for image files. The ToBase64Thumbnails method is defined as an extension method targeting the string class. When invoking the ToBase64Thumbnails method users are expected to provide a directory path, width and height of output thumbnails, whether to add Html <img> tags and which file types to process. The code snippet below details the implementation of the ToBase64Thumbnails method.
public static List<string> ToBase64Thumbnails(this string path, int width, int height, bool wrapImageTag, params string[] fileTypes) { List<string> base64Thumbnails = new List<string>();
string searchFilter = String.Empty;
if (fileTypes != null) { for (int k = 0; k < fileTypes.Length; k++) { searchFilter += "*." + fileTypes[k];
if (k < fileTypes.Length - 1) { searchFilter += "|"; } } } else { searchFilter = "*.*"; }
string[] files = Directory.GetFiles(path, searchFilter);
for (int k = 0; k < files.Length; k++) { StreamReader streamReader = new StreamReader(files[k]); Image img = Image.FromStream(streamReader.BaseStream); streamReader.Close();
base64Thumbnails.Add(img.ToBase64Thumbnail(width, height, wrapImageTag));
img.Dispose(); }
return base64Thumbnails; }
The ToBase64Thumbnails method implements the static method Directory.GetFiles in order to search a specified directory path. When invoking the ToBase64Thumbnails method the calling code can optionally specify a number of file extensions, which results in only files having file extensions conforming to the specified extensions being encoded.
Once an array of file paths have been determined the sample code iterates the array creating an Image object of each file specified. The final step required is to invoke the extension method ToBase64Thumbnail.
The implementation
The sample source code defines a console based application, used to test/illustrate creating Base64 encoded thumbnails based on a specified directory path. Included in the sample code is a template html file. The Main method generates a list of Base64 encoded thumbnails by invoking ToBase64Thumbnails, defined as an extension method targeting the String class. The resulting Base64 encoded thumbnails are defined as Html <img> tags, added to a copy of the html template file. The Console application’s definition:
static void Main(string[] args) { string path = "Images";
List<string> thumbnailTags = path.ToBase64Thumbnails(100, 100, true, null);
StreamReader streamreader = new StreamReader("HtmlTemplate.htm"); StringBuilder htmlPage = new StringBuilder(streamreader.ReadToEnd()); streamreader.Close();
StringBuilder imageTags = new StringBuilder();
for (int k = 0; k < thumbnailTags.Count; k++) { imageTags.AppendLine("<p>"); imageTags.AppendLine(thumbnailTags[k]); imageTags.AppendLine("</p>"); }
htmlPage.Replace("<!--Tags_Placeholder-->", imageTags.ToString());
StreamWriter streamwriter = new StreamWriter("TempPage.htm", false, Encoding.UTF8); streamwriter.Write(htmlPage.ToString()); streamwriter.Close();
Process.Start("TempPage.htm");
Console.ReadKey(); }
The resulting Base64 encoded image thumbnails viewed as html <img> tags forming part of an html file, as viewed in Microsoft Internet Explorer 9:
Web Service Definition Language (WSDL)
I’ve often found myself in a scenario where I have to interface with third parties via web services. It is often the case that third party service are proprietary, usually I find that I have very little control over the web services I’m required to interface to. Countless hours are wasted because of out dated test environments, missing/incorrect security certificates or even just trying to get hold of log files.
Time spent on development and testing can be significantly reduced in most cases if I had a local copy of a web service available to me. Having access to source code would be even more beneficial, being able to manipulate the data returned, testing timeouts etc. After surprisingly little effort I manage to develop a utility application capable of generating web method stubs and custom defined types in C# source code. The only required input in generating a web service is the WSDL of an existing web service.
This article is accompanied by sample source code in a Visual Studio project which is available for download 
The sample source accompanying this article defines a very simplistic web service, consisting of one web method HelloWorld(). The source code is listed below:
The crux of this article revolves around the Generate method defined in the associated sample source code. The method makes use of the 
After importing the service descriptions as defined by the specified WSDL and if no errors occurred we generate C# source code based on the service descriptions imported. The resulting source code generated is then saved to the file system based on the file path passed as method parameter.
Notice the use of the 
The code generated comes in the form of abstract classes and methods. The snippet below illustrates the raw generated code:
The code generated compiles without issue, but being declared 
The TestWebService class and HelloWorld method is now no longer defined as 
Software by Default 