How do I search for a specific string and return the entire line containing that string? [closed]

Question

I have text file like this:

11/18/2012 test1

11/19/2012 test2

11/20/2012 test3

11/21/2012 test4

11/22/2012 test5

11/23/2012 test6

11/24/2012 test7

11/25/2012 test8

How do I search for the current date and return the entire line containing that date? For instance, if I run the program today, it should return

11/18/2012 test1

Code:

string searchKeyword = monthCalendar1.SelectionStart.ToShortDateString();
string[] textLines = File.ReadAllLines(@"c:\temp\test.txt");
List<string> results = new List<string>();

foreach (string line in textLines)
{
    if (line.Contains(searchKeyword))
    {
        results.Add(line);
        listBox2.Items.Add(line);
    }
}

Answer 1

First - split your text by lines. E.g. this way:

// string[] lines = File.ReadAllLines(@"c:\temp\test.txt");
string[] lines = text.Split(new string[] { Environment.NewLine }, StringSplitOptions.None);

Second - find lines which start with current date string in specified format:

string date = DateTime.Now.ToString("MM/dd/yyyy");    
IEnumerable<string> results = lines.Where(l => l.StartsWith(date));

If you completely sure that there could be only one such line, then use

string result = lines.SingleOrDefault(l => l.StartsWith(date));

---

Here is your code fixed and reafactored (you should use custom date string format and use StartsWith instead of Contains)

string searchKeyword = monthCalendar1.SelectionStart.ToString("MM/dd/yyyy"); 
string[] textLines = File.ReadAllLines(@"c:\temp\test.txt");

foreach (string line in textLines.Where(l => l.StartsWith(searchKeyword)))
    listBox2.Items.Add(line);

Answer 2

var matches = new List<string>();
var currentDate = DateTime.Now.ToString("dd/MM/yyyy");

using (StreamReader sr = new StreamReader("file.txt"))
{
    var line = sr.ReadLine();
    if(line.StartsWith(currentDate))
        matches.Add(line);
}

To add them to the listbox:

foreach (var match in matches)
    listBox.Items.Add(match);