VB.NET VS2010. Need help with streamreader. Reading all files in the folder one by one.

By the way I forgot to mention that the folder is on FTP server

Here is a tutorial on FTP

http://www.codeproject.com/KB/IP/FtpClient.aspx

FTP is not too important i can download files to the local computer. What I'm interested in is how to read those files one by one.

You will first need to download all files from FTP and then read these files and merge the files in one file and after that upload the result file on FTP.
So basically you will have to perform following steps.

1. Download files from FTP.
2. Read Files content (StreamReader)
3. Write Files content in a file (using StreamWriter)
4. Upload File on FTP (if Required)

For step 1 and 4, kindly have a look on here.

RTF files are formatted text. So what you can do is this

Dim RTF As New RichTextBox

Dim RTFFiles As String() = IO.Directory.GetFiles("path", "*.rtf")

For Each File in RTFFiles
   RTF.RTF = IO.File.ReadAllText(File)
   IO.File.AppendAllText("TargetFilePath", RTF.Text)
Next

before i use readers how can i do something like:

If file-extension = ".txt" then

elseif file-extension = "rtf then

end if

Also before i read a file I need to make sure that a string exists for example "SOMESTRING"

Did you try my example?

If you need to check the string content that it constains something and then want to append then you can try this code.

string[] files = System.IO.Directory.GetFiles("Path", "*.txt");
            foreach (string file in files)
            {
                System.IO.StreamReader reader = new System.IO.StreamReader(file);
                string fileContent = reader.ReadToEnd();
                reader.Close();
                if (fileContent.Contains("SOMETHING"))
                    System.IO.File.AppendAllText("destfilePath", fileContent);
            }

Select allOpen in new window

how to show progressbar while downloading files from the FTP server?

So it shows how many files in total are in that folder and % how much left.

Also would be good to know download speed