Vb net text file append

I want to be able to type in the host name in a textbox, save it to a text file, and append the text file every time I type in a new host name only if the host name doesn't already exist. Thank you for your help. The coed that you've all provided me with works but for some reason my output to the text file is still the same as you will notice below:.

Unfortunately it didn't work I get the following error: System. The code works fine for the first line. It's when I try to append the text file I get the funky output.

Here is the actual code:. Dim sw As New System. WriteLine Me. Text sw. What I'm trying to do is create the text file and append the file with machine names from textbox1. Also,I would like to append with the host name only if the name doesn't already exist in the text file.

It turns out that the code you've provided was helpful. I've just used the StreamReader class instead. StreamReader If File.

ReadToEnd sr. Close End If Else. Text 'Close the file. Close End If. We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, learning, and sharing knowledge.

Open "D:TempTest. The while loop below iterates through all the lines in the origianl text file and adds the data to the variable strData :. The line below concatenates the current line in the original text file with the string in strData. It also concatenates a vbCrLf to the end of the line so a new line is created.

Then The file is opened again, and a second line is appended to it. The text file contents are shown in the final comment.

NET program that uses StreamWriter to append. Here we use a For-loop with StreamWriter. When you have to loop and add text to a file, you should reuse a single StreamWriter—this improves performance. For Each, For. Write The file is opened, and one Windows file handle is created. Then, that same system resource is used to write ten numbers to the file.

Format The Write call in the For-loop specifies a format string. The format string prints the Integer with one decimal place. Creates a StreamWriter that appends UTF-8 encoded text to an existing file, or to a new file if the specified file does not exist. NET Framework and. NET Core versions older than 2. You can query for invalid characters by using the GetInvalidPathChars method. The specified path is invalid for example, the directory doesn't exist or it is on an unmapped drive.

The following example appends text to a file. The method creates a new file if the file doesn't exist.