DiffPlex

DiffPlex is C# library to generate textual diffs. It targets netstandard1.0.

About the API

The DiffPlex library currently exposes two interfaces for generating diffs:

IDiffer (implemented by the Differ class) - This is the core diffing class. It exposes the low level functions to generate differences between texts.
ISidebySideDiffer (implemented by the SideBySideDiffer class) - This is a higher level interface. It consumes the IDiffer interface and generates a SideBySideDiffModel. This is a model which is suited for displaying the differences of two pieces of text in a side by side view.

Examples

For examples of how to use the API please see the the following projects contained in the DiffPlex solution.

For use of the IDiffer interface see:

SidebySideDiffer.cs contained in the DiffPlex Project.
UnidiffFormater.cs contained in the DiffPlex.ConsoleRunner project.

For use of the ISidebySideDiffer interface see:

DiffController.cs and associated MVC views in the WebDiffer project
TextBoxDiffRenderer.cs in the SilverlightDiffer project

Sample code

var diffBuilder = new InlineDiffBuilder(new Differ());
var diff = diffBuilder.BuildDiffModel(before, after);

foreach (var line in diff.Lines)
{
    switch (line.Type)
    {
        case ChangeType.Inserted:
            Console.ForegroundColor = ConsoleColor.Red;
            Console.Write("+ ");
            break;
        case ChangeType.Deleted:
            Console.ForegroundColor = ConsoleColor.Green;
            Console.Write("- ");
            break;
        default:
            Console.ForegroundColor = ConsoleColor.White;
            Console.Write("  ");
            break;
    }

    Console.WriteLine(line.Text);
}

IDiffer Interface

/// <summary>
/// Provides methods for generate differences between texts
/// </summary>
public interface IDiffer
{
    /// <summary>
    /// Create a diff by comparing text line by line
    /// </summary>
    /// <param name="oldText">The old text.</param>
    /// <param name="newText">The new text.</param>
    /// <param name="ignoreWhiteSpace">if set to <c>true</c> will ignore white space when determining if lines are the same.</param>
    /// <returns>A DiffResult object which details the differences</returns>
    DiffResult CreateLineDiffs(string oldText, string newText, bool ignoreWhiteSpace);

    /// <summary>
    /// Create a diff by comparing text character by character
    /// </summary>
    /// <param name="oldText">The old text.</param>
    /// <param name="newText">The new text.</param>
    /// <param name="ignoreWhitespace">if set to <c>true</c> will treat all whitespace characters are empty strings.</param>
    /// <returns>A DiffResult object which details the differences</returns>
    DiffResult CreateCharacterDiffs(string oldText, string newText, bool ignoreWhitespace);

    /// <summary>
    /// Create a diff by comparing text word by word
    /// </summary>
    /// <param name="oldText">The old text.</param>
    /// <param name="newText">The new text.</param>
    /// <param name="ignoreWhitespace">if set to <c>true</c> will ignore white space when determining if words are the same.</param>
    /// <param name="separators">The list of characters which define word separators.</param>
    /// <returns>A DiffResult object which details the differences</returns>
    DiffResult CreateWordDiffs(string oldText, string newText, bool ignoreWhitespace, char[] separators);

    /// <summary>
    /// Create a diff by comparing text in chunks determined by the supplied chunker function.
    /// </summary>
    /// <param name="oldText">The old text.</param>
    /// <param name="newText">The new text.</param>
    /// <param name="ignoreWhiteSpace">if set to <c>true</c> will ignore white space when determining if chunks are the same.</param>
    /// <param name="chunker">A function that will break the text into chunks.</param>
    /// <returns>A DiffResult object which details the differences</returns>
    DiffResult CreateCustomDiffs(string oldText, string newText, bool ignoreWhiteSpace, Func<string, string[]> chunker);
}

ISidebySideDiffer Interface

/// <summary>
/// Provides methods that generate differences between texts for displaying in a side by side view.
/// </summary>
public interface ISideBySideDiffBuilder
{
    /// <summary>
    /// Builds a diff model for  displaying diffs in a side by side view
    /// </summary>
    /// <param name="oldText">The old text.</param>
    /// <param name="newText">The new text.</param>
    /// <returns>The side by side diff model</returns>
    SideBySideDiffModel BuildDiffModel(string oldText, string newText);
}

Sample Website

DiffPlex also contains a sample website that shows how to create a basic side by side diff in an ASP MVC website.