c# 写信息到指定文件的尾部

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using System.IO; string Filename =  Application.StartupPath +"\\"+ DateTime.Now.ToString("yyyyMMddHHmmss")+".txt";WriteInfo(Filename, "weidadezhonghuarenmingongheguowangshi"); public void WriteInfo(string MyfileName,string strInfo) {     if (!System.IO.File.Exists(MyfileName))     {  //没有则创建这个文件  FileStream fs1 = new FileStream(MyfileName, FileMode.Create, FileAccess.Write);//创建写入文件   System.IO.File.SetAttributes(@MyfileName, FileAttributes.Normal);  StreamWriter sw = new StreamWriter(fs1);    sw.WriteLine(strInfo);//开始写入值  sw.Close();  fs1.Close();}     else     {  FileStream fs = new FileStream(MyfileName, FileMode.Append);    //设置在文件尾部增加  System.IO.File.SetAttributes(@MyfileName, FileAttributes.Normal);  StreamWriter sr = new StreamWriter(fs);  sr.WriteLine(strInfo);//开始写入值  sr.Close();  fs.Close();     } }