DifferenceEngine.DiffList_TextFile sourceFile  null;
DifferenceEngine.DiffList_TextFile destinationFile = null;

sourceFile = new DifferenceEngine.DiffList_TextFile("1.txt");
destinationFile = new DifferenceEngine.DiffList_TextFile("2.txt");

DifferenceEngine.DiffEngine engine = new DifferenceEngine.DiffEngine();
engine.ProcessDiff(sourceFile,destinationFile, DifferenceEngine.DiffEngineLevel.FastImperfect);
ArrayList diffLines = engine.DiffReport();
foreach (DifferenceEngine.DiffResultSpan span in diffLines)
 {  
   switch (span.Status)
    {
 case ifferenceEngine.DiffResultSpanStatus.NoChange:
    //没改变
      break;
 case DifferenceEngine.DiffResultSpanStatus.AddDestination:
//新增的
     break;
 case DifferenceEngine.DiffResultSpanStatus.DeleteSource:
//已删除的
     break;
case DifferenceEngine.DiffResultSpanStatus.Replace:
//修改的      
                break;
default:
 //  默认
                      break;

}

}

 

获取新增内容示例：

string str = ((DifferenceEngine.TextLine)(destinationFile.GetByIndex(span.DestIndex))).Line;

http://www.codeproject.com/KB/recipes/diffengine.aspx

 

3. htmldiff

简介：

HtmlDiff原本是Ruby版的HTML差异比较算法，后来有朋友做了个C#版本，特点是非常好用，过于简单
C#版：  http://htmldiff.codeplex.com/

Ruby版： http://github.com/myobie/htmldiff
http://www.rohland.co.za/index.php/2009/10/31/csharp-html-diff-algorithm/

---

4.NDiffDiff: A Diff Implementation for Lines and Chars in Text File

简介：

提供Winform Demo

http://www.codeproject.com/KB/recipes/NBDiffDiff.aspx