Firstly, think of how you would want to do it, write it down.
Work out some code that looks like it should do what you wanted.
try it, what does it do?
if it doesnt work, post it, explain what you're getting you didnt expect, and ask for assistance.

Dont post just asking for us to do it for you

Open the first file with FileMode.Append.
Open the file to append with FileMode.Open.
Read the file to append into a byte array.
Write the byte array to the first file.

hi
try using namespace System.IO;you will find two classes responsible for reading and writing from file with more options are :
- StreamReader ;
- StreamWriter ;
u can read ur file using StreamReader the write it using StreamWriter
but after using ur StreamReader and Writer close them EX :
StreamReader sr = new StreamReader(Strin Path);
TextBox1.Text=sr.ReadLine();
sr.close(); ------------> close reader;

and the same with Writer ;

there is another class File contains static members
File.ReadAllText();
File.WriteAllText();
File.open(string path , filemode.append);

all these depends on ur application if u wana preview ur text file and append with another file or u wanna do ur method during procesisng ur code ;

there is more but that easy ways u can append ur txt files

bye

ReadLine reads a file untill the next \n character, this line is then put into a textbox. Nice.
What's the relevancy with this question ?

yeah u right
but u can use method "ReadToEnd" for multiline controls

StreamReader sr = new StreamReader(---------);
TextBox1.text = sr.ReadToEnd();
so ur reader will return all readed data ......

That's very inventive BlackSun.
But if I drink wine I use a wineglass.
When I drink a coffee I use a coffeecup.
Do you drink wine from a coffeecup?
Don't use a textbox for this, but use a string.

LizR, the next time you have a question follow your own advice. I can't believe that anyone would be so arrogant as to respond with such a snobish answer. The poster, like I, likely knew how to logically handle such a task but was rather looking for a pre-existing method like, say, File.Merge(StringArrayOfPaths). If you don't have anything to contribute to a post other than ignorant statements, don't bother posting.

Actually nareitz what LizR did was the correct response. If you check the forum policy it clearly states that users should attempt to solve the problem themselves before posting. We are here to help troubleshoot, not to do all the work.
You may be right that they know how to do it themselves, if that is the case, they should post what they have and ask if there is a better way to do it.
next time you have something to say, perhaps you should read the forum rules before you lambaste a poster without good cause.