CODEWITHSUNDEEP
c#
Jagrit Ojha
Jagrit Ojha

Reputation: 177

reading and querying a txt/log file using c#

i have created a log file example.txt that records events as

Button1 Click event happen ID=xyz DT:3/1/2015 9:27:32 AM
Button2 Click event happen ID=xyz DT:3/1/2015 9:28:32 AM
Button1 Click event happen ID=xyz DT:3/1/2015 9:29:32 AM
Button2 Click event happen ID=xyz DT:3/1/2015 9:30:32 AM

i can read those file but i will get everything written in the log file.\ i have used the following code 

    try
    {
      using(FileStream fileStream = new FileStream("c://temp1/example_logfile.txt",FileMode.Open,FileAccess.Read,FileShare.ReadWrite))
       {
            using(StreamReader streamReader = new StreamReader(fileStream))
            {
                this.txt.Text = streamReader.ReadToEnd();
            }
        }
     }

I want to read just the Button1 click event. how do you do that?

Upvotes: 2

Views: 13767

Answers (2)

Kavindu Dodanduwa
Kavindu Dodanduwa

Reputation: 13069

What about a solution with StreamReader.ReadLine() combined with String.Contains() 

   String line;

   while (!streamReader.EndOfStream)  // <= Check for end of file
   {
     line = streamReader.ReadLine(); // <=Get a single line
     if (line.Contains("Button1"))  // <= Check for condition ; line contains 'Button1'
        {
          this.txt.Text += line + "\n"; // <== Append text  with a newline 
        } 
     }

Upvotes: 3

Grant Winney
Grant Winney

Reputation: 66459

Use File.ReadLines and a bit of LINQ to get only the lines you're interested in:

var results = File.ReadLines(filePath).Where(x => x.StartsWith("Button1 Click"));

Now you've got a collection of strings representing the matching lines. If you want to display them in a single TextBox, you can flatten the list back out to a single string:

this.txt.Text = String.Join(", ", results);

Or modify the LINQ statement to get, say, the first match only: (assuming at least one match)

this.txt.Text = File.ReadLines(filePath).First(x => x.StartsWith("Button1 Click"));

Upvotes: 4

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