How do I read last column of a text file and compare it with windows

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Hi,
I did a program where I can read last line of a text file selected with a button using open file dialog.
Now I have another problem.. The text file is something like that:
20/05/2020 10:46:00 --- ;another info; another info; another info
How is the code for:
- When I press the button that read the last line of the text file in the rich text box he also read the first column, that contains data and hour, and compare it with the windows data and if it not mach he give me an allarm?

Is that possible? How should the code come out?

Thank you.

What I have tried:

This is what I did at moment for read the last line of the text file:

private async void OpenFileBtn_ClickAsync(object sender, EventArgs e)
{
using(OpenFileDialog ofd = new OpenFileDialog() { Filter = "Text File|*.txt", Multiselect = false })
{

if (ofd.ShowDialog() == DialogResult.OK)
{
using (StreamReader rd = new StreamReader(ofd.FileName))
{
//ReaderRichTxtBox.Text = await rd.ReadToEndAsync();
string[] lines = rd.ReadToEnd().Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
ReaderRichTxtBox.Text = lines[lines.Length - 1];
}
}
}

}

Posted 19-May-20 22:54pm

Member 14786879

Updated 19-May-20 23:19pm

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2 solutions

Solution 1

Use the various functions of the string class to find the space characters and split the string into its separate parts. You can then convert the date string to a date/time type and do your comparison.

Posted 19-May-20 23:12pm

Richard MacCutchan

Updated 19-May-20 23:54pm

v2

Comments

Member 14786879 20-May-20 5:37am

Can you explain me better please? As a code example

Richard MacCutchan 20-May-20 5:52am

OriginalGriff has given that in his solution above.

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OriginalGriff · Accepted Answer · 2020-05-19T23:20:00

The problem is twofold: text files don't have "lines", and they certainly don't have "columns".

While that may seem wrong - and the File.ReadAllLines method would imply it is - it's actually true: textfiles have no intrinsic format, and "lines" are only accessible because the text file contains "end of line" characters which can be interpreted as separating lines. But you can't "replace a line", "insert a line", "delete a line", or "move to the last line" with a text file easily, because they don't have real "lines".
Similarly, nothing in a text file enforces columns, although it is possible to interpret "special characters" as column delimiters, they still have the same problems as lines do!

So to read the "last line" you need to read all the others first, and discard them.
The simplest way to do that is:

C#

string[] lines = File.ReadAllLines(pathToFile);
if (lines.Length > 0)
   {
   string lastLine = lines[lines.Length - 1];
   ...
   }

And then identify a "column separator" that is unique to yoru file - your data implies that ';' might be being used, but you will need to check properly to be sure. When you have the column separator character, you can break the last line into seperate "columns":

C#

string[] lines = File.ReadAllLines(pathToFile);
if (lines.Length > 0)
   {
   string lastLine = lines[lines.Length - 1];
   string[] columns = lastLine.Split(';');
   if (columns.Length > 0)
      {
      string lastColumn = columns[columns.Length - 1];
      ...
      }
   }