Check if text file exists c#

To check whether the path contains any invalid characters, you can call the GetInvalidPathChars method to retrieve the characters that are invalid for the file system. You can also create a regular expression to test the whether the path is valid for your environment. For examples of acceptable paths, see File. To check if a directory exists, see Directory. Be aware that another process can potentially do something with the file in between the time you call the Exists method and perform another operation on the file, such as Delete.

The path parameter is permitted to specify relative or absolute path information. Relative path information is interpreted as relative to the current working directory. To obtain the current working directory, see GetCurrentDirectory.

If path describes a directory, this method returns false. Trailing spaces are removed from the path parameter before determining if the file exists. Program 1: Before running the below code, a file file. IO namespaces using System; using System.

Exists "file. WriteLine "Specified file exists. Program 2: Before running the below code, no file is created. Skip to content. Change Language. Related Articles.

Table of Contents. Improve Article. Save Article. Asked 3 years, 4 months ago. Active 3 years, 4 months ago. Viewed 3k times. Close ; MessageBox. WriteLine url ; MessageBox. Show "url copied! Improve this question. Ryze2 Ryze2 21 1 1 silver badge 3 3 bronze badges. Contains textxx Note this will check that textxx matches the entirety of a line - it won't match if it was for example only part of one of the lines.

Possible duplicate of c search string in txt file — d Contains does not work the same way Array. That's true, but if the URL doesn't exist in the file he wants to write it to the file, so It's most likely a text file full of URLs — emsimpson If you are reading a very large text file, you may want to read it line by line and do the search on each line.

There's no need to read the entire file into memory. Add a comment. Active Oldest Votes. ReadAllLines "links. Contains "google. AppendAllText "links.

Improve this answer. Ryan Ryan 7, 7 7 gold badges 52 52 silver badges 94 94 bronze badges.