Note To read a file a single line of text at a time, use the method of the My.Computer.FileSystem object. The OpenTextFileReader method returns a object. You can use the method of the StreamReader object to read a file one line at a time. You can test for the end of the file using the method of the StreamReader object. To read from a text file • Use the ReadAllText method of the My.Computer.FileSystem object to read the contents of a text file into a string, supplying the path. The following example reads the contents of test.txt into a string and then displays it in a message box. Dim fileReader As String fileReader = My.Computer.FileSystem.ReadAllText('C: test.txt') MsgBox(fileReader) To read from a text file that is encoded • Use the ReadAllText method of the My.Computer.FileSystem object to read the contents of a text file into a string, supplying the path and file encoding type.

Mar 04, 2010  Hello, I am new to vb.net and am trying to do something really simple. I want to search a text file for 'abc123' and replace that one string with 'abc456'. The search string will only occur once in the file. This demonstrates a faster way to search any file and pull a full line from that file given a search string, than the string buffer way. Uses an API method to open a file and store it in a buffer then instr'gs though the buffer to find a match, also compares this to the ordinary string buffer method, API wins by a factor of about 3.5 for a 1.

The following example reads the contents of the UTF32 file test.txt into a string and then displays it in a message box. Dim fileReader As String fileReader = My.Computer.FileSystem.ReadAllText('C: test.txt', System.Text.Encoding.UTF32) MsgBox(fileReader) Robust Programming The following conditions may cause an exception: • The path is not valid for one of the following reasons: it is a zero-length string, it contains only white space, it contains invalid characters, or it is a device path (). • The path is not valid because it is Nothing (). • The file does not exist (). • The file is in use by another process or an I/O error occurs (). • The path exceeds the system-defined maximum length ().

• A file or directory name in the path contains a colon (:) or is in an invalid format (). • There is not enough memory to write the string to buffer (). • The user lacks necessary permissions to view the path (). Do not make decisions about the contents of the file based on the name of the file.

For example, the file Form1.vb may not be a Visual Basic source file. Verify all inputs before using the data in your application. The contents of the file may not be what is expected, and methods to read from the file may fail. Krunker io mod files downloads. See Also Feedback.