Вы можете попробовать это (написано на C #):
C # релиз
List<string> newLines = new List<string>();
string[] lines = File.ReadAllLines(filename);
foreach (string line in lines)
{
string[] parts = line.Split(";".ToCharArray());
parts[3] = string_from_db;
newLines.Add(String.Join(";", parts));
}
File.WriteAllLines(filename, newLines.ToArray());
VB.NET выпуск
Dim newLines As List(Of String) = New List(Of String)
Dim lines As String() = File.ReadAllLines(filename)
For Each line As String In lines
Dim parts As String() = line.Split(";")
parts(3) = string_from_db
newLines.Add(String.Join(";", parts))
Next
File.WriteAllLines(filename, newLines.ToArray())