CODEWITHSUNDEEP
c#file
cindywmiao
cindywmiao

Reputation: 947

How do I read in file and modify a file at the same time?

I want to program in c#, read a file like this:

...

cindy cindy0 cindy1 cindy2 cindy3

miao miao0 miao1 miao2 miao3

...

And I want to add something like "cindy4" and the end of the first line.

System.IO.StreamReader file = new System.IO.StreamReader(filename);
string line = file.ReadLine();
while(line != null)
{
    if (line.Contains("cindy"))
    {
         tmp = line.Split(' ');
         file.Close();

         //TO DO change in the file

         break;
     }
     line = file.ReadLine();
}

In the TODO part, I code like this:

System.IO.StreamWriter writer = new System.IO.StreamWriter(System.IO.File.Open(filename, System.IO.FileMode.Open));
writer.Write("cindy4");
writer.Flush();

But it does not work. Could somebody get me an example?

Upvotes: 3

Views: 114

Answers (1)

mark
mark

Reputation: 89

Try this code:

string[] new_text = System.IO.File.ReadAllLines("file_path");
new_text[line_number] += "text_to_add"; 
//the line number start from zero 
//Example: first line will be: new_text[0]
//the second line will be: new_text[1]
//Etc...
System.IO.File.WriteAllLines("file_path",new_text);

Upvotes: 2

Related Questions