C# search all files in a directory that contain a string, then return that string

Question

Using user input into a textbox, I want to search for which file in the directory contains that text. I would then like to parse out the information

but I can't seem to find the string or at least return the information. Any help would be greatly appreciated.

My current code:

private void btnSearchSerial_Click(object sender, EventArgs e)
{
    dynamic dirScanner = @"\\mypath\";
    string strSerial;
    string strSID;
    string strInputLine;
    string strOutput;

    strSerial = Convert.ToString(txtSerialSearch);
    strSID = Convert.ToString(txtSID);

    if (txtSerialSearch.Text != "" && txtSID.Text != "")
    {
         try
         {                    
              string[] allFiles = Directory.GetFiles(dirScanner);

              foreach (string file in allFiles)
              {
                   if (file.EndsWith(".txt"))                            
                   {  
                        using (StreamReader sr = new StreamReader(file))
                        {
                              while (sr.Peek() >= 0)
                              {
                                   strInputLine = sr.ReadLine();

                                   if (strInputLine.Contains(strSerial))
                                   {
                                        strOutput = Convert.ToString(strInputLine);
                                        lblOutput.Text = Convert.ToString(strOutput);
                                   }
                              }
                        }
                   }
              }
         }
    }
}

Answer 1

You seem quite lost. Why are you using a dynamic when a string is all that you need? Your code has too many unnecessary variables and convertions. Here's a much simpler way to do it. I don't know what you want the label to have if there are many matching lines, here I'm only placing the first one there:

string dirScanner = @"\\mypath\";

if (string.IsNullOrWhiteSpace(txtSerialSearch.Text) || string.IsNullOrWhiteSpace(txtSID.Text))
    return;

string[] allFiles = Directory.GetFiles(dirScanner, "*.txt");

foreach (string file in allFiles)
{
    string[] lines = File.ReadAllLines(file);
    string firstOccurrence = lines.FirstOrDefault(l => l.Contains(txtSerialSearch.Text));
    if (firstOccurrence != null)
    {
        lblOutput.Text = firstOccurrence;
        break;
    }
}