Check out example codes for "c# append text to file". It will help you in understanding the concepts better.
Code Example 1
File.AppendAllText(@"c:\path\file.txt", "text content" + Environment.NewLine);
Code Example 2
using (FileStream fs = new FileStream(fileName,FileMode.Append, FileAccess.Write))
using (StreamWriter sw = new StreamWriter(fs))
{
sw.WriteLine(something);
}
Code Example 3
File.AppendAllText(@"c:\path\file.txt", "text content" + Environment.NewLine);
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