C#

<pre lang="c#">using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.IO; 
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            // Create a DirectoryInfo class and point it to the 
            // directory you want to search in
            DirectoryInfo dirInf = new DirectoryInfo(@"C:\Program Files\Temp");

            // Create a FileInfo array and get the file information 
            // of all the TXT files in the directory
            FileInfo[] files = dirInf.GetFiles("*.txt");

            // Loop though all the files found
            foreach (FileInfo currentFile in files)
            {
                // Create a files stream
                FileStream fs = new FileStream(currentFile.FullName, FileMode.Open);

                //create a stream reader
                StreamReader reader = new StreamReader(fs);

                //read the text in the file
                string fileContent = reader.ReadToEnd();

                if (fileContent.Contains("Failed"))
                {
                    MessageBox.Show("The File " + currentFile.FullName +
                                    " Contains the text your searching for");
                }

                // flush and close the IO objects
                fs.Flush();
                reader.Close();
                fs.Close();
            }
        }
    }
}