read the first 5 characters of file

In my last example, note that the for loop to get the bytes
can be replaced with a ReadBytes(5) instruction:

'For index = 0 To 4  
'    bArray(index) = reader.ReadByte  
'Next  
bArray = reader.ReadBytes(5)  
  

• Wayne

user might select any file type, with or without extension,
need to get the 5 characters of file

It may depend on what you mean by "characters".

Do you mean one byte, as in a raw file dump?

Or do you really mean characters, such as 5 ASCII characters or
5 Unicode characters, etc.

For getting the first 5 bytes from any file, including binary
types such as .exe, .dll, etc. try this code.

NOTE: For brevity I have omitted all error checks. For robust
code you will need to add them. Such as file open failures,
files less than 5 bytes long, etc.

For testing in the IDE, the file test.exe will need to be in
the same folder as the program's .exe - such as ..\bin\debug

Imports System.IO  
Module Module1  
  
    Sub Main()  
        Dim bArray(4) As Byte  
        Dim filename As String = "test.exe"  
        Dim stream = File.Open(filename, FileMode.Open)  
        Dim reader = New BinaryReader(stream)  
        For index = 0 To 4  
            bArray(index) = reader.ReadByte  
        Next  
        For index = 0 To 4  
            Console.WriteLine("{0:X2}", bArray(index))  
        Next  
    End Sub  
  
End Module  
  

• Wayne

Try something like this:

Dim characters(4) As Char  
  
Using f = File.OpenText("C:\MyFile.txt")  
    f.Read(characters, 0, 5)  
End Using  

Dim text As String = String.Concat(characters).TrimEnd(Chr(0))