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Reading Specific Line In Text File - C# App

Posted on 2006-10-30
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Last Modified: 2012-08-14
Hey everyone,

I am trying to create a program that will read a file, extract two lines and then act based on what those lines say.  

What I need help with is actually reading the two lines.  I am using the following code to read the first line which is www.yahoo.com but I am not sure how to read line number two, and write it to a text box.

            System.IO.StreamReader StreamReader3 =
            new System.IO.StreamReader("website.txt");
            txtWebsite.Text = StreamReader3.ReadToEnd();
            StreamReader3.Close();

What code can I get to read only line two which says "Yahoo!!!" into a text box called txtSiteName.Text
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Question by:angus_young_acdc
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7 Comments
 
LVL 8

Expert Comment

by:sabeesh
ID: 17833163
you can use regular expressoin to read the specified word
0
 
LVL 6

Expert Comment

by:dorothy2
ID: 17833330
string line;

 StreamReader reader = new StreamReader("website.txt");
 while((line = reader.ReadLine()) != null)
{
      if(line.IndexOf("Yahoo") != -1)
      {
            // Do something
      }
}
reader.Close();

Dorothy
0
 
LVL 15

Author Comment

by:angus_young_acdc
ID: 17833492
Hi Dorothy,

I have tried using your code but a little stumped.    I am unsure how to get it to read a specific line, paste that to the correct text box, and then do the same for the 2nd line.   This is the theory (using your code) of what I want it to do:

          string line;
           
            StreamReader reader = new StreamReader("website.txt");
            while ((line = reader.ReadLine()) != null)
            {
                if (line.IndexOf("Yahoo!!!") != -1)
                {
                    // read line one, put contents of line one into txtWebsite.Text
                    // read line two, out contents of line two into txtSiteName.Text
                }
            }
            reader.Close();


When I tried having just one line read and put into txtWebsite.Text I get this error:

I get the following error:
Error      2      Cannot convert method group 'ReadToEnd' to non-delegate type 'string'. Did you intend to invoke the method?      C:\Documents and Settings\xxx\My Documents\Visual Studio 2005\Projects\EasyAxs\EasyAxs\frmMainSystem.cs      178      37      EasyAxs

using this code:
            string line;
           
            StreamReader reader = new StreamReader("website.txt");
            while ((line = reader.ReadLine()) != null)
            {
                if (line.IndexOf("Yahoo!!!") != -1)
                {
                    txtWebsite.Text = reader.ReadToEnd;
                }
            }
            reader.Close();
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LVL 6

Accepted Solution

by:
dorothy2 earned 120 total points
ID: 17833574
To test, I wrote a console app rather than a Windows app. Just substitute populating your text box where I am writing the lines to the console. The code below reads the lines like my previous example. There is a flag to indicate when you find "Yahoo"". Then code loops one more time, but the second condition, foundIt == false, is no longer met (it's true now) so you break out of the loop. Line is already populated:

                        string line;
                  bool foundIt = false;
                  StreamReader reader = new StreamReader("C:\\Temp\\Yahoo.txt");
                  while((line = reader.ReadLine()) != null && !foundIt)
                  {
                        if(line.IndexOf("Yahoo") != -1)
                        {
                              Console.WriteLine("This is the first line:");
                              Console.WriteLine(line);
                              foundIt = true;
                              
                        }
                  }

                  if(foundIt)
                  {                        
                        Console.WriteLine("This is the second line:");
                        Console.WriteLine(line);
                  }
                  reader.Close();            
0
 
LVL 15

Author Comment

by:angus_young_acdc
ID: 17833684
Excellant thanks dorothy that worked brilliantly :)  

Last question on it (obviously I will increase the points).  To save multiple lines I thought it would be something like this:
                System.IO.StreamWriter StreamWriter1 =
                new System.IO.StreamWriter("alarm.txt");
                StreamWriter1.Write(txtWebsite.Text);
                StreamWriter1.NewLine;
                StreamWriteer1.Write(txtSiteName.Text);
                StreamWriter1.Close();

But that just brings up the following error:
Error      2      Only assignment, call, increment, decrement, and new object expressions can be used as a statement      C:\Documents and Settings\xxx\My Documents\Visual Studio 2005\Projects\EasyAxs\EasyAxs\frmMainSystem.cs      221      17      EasyAxs


How can I then get it to write the 2nd textbox (txtSiteName) to the 2nd line?  So that it will look like this in the file:
www.yahoo.com
Yahoo!!!
0
 
LVL 15

Author Comment

by:angus_young_acdc
ID: 17833696
Can't see an edit button but new System.IO.StreamWriter("alarm.txt") should be "website.txt"
0
 
LVL 15

Author Comment

by:angus_young_acdc
ID: 17833702
Never mind I got it sorted myself :)
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