VB6 code explanation

Question

I need to convert some of the legacy code which is currently in VB6 into C#. I am not able to understand this piece of code. Especially the InStr function, could someone please help me out with this and suggest me it's C# equivalent.

For i = 1 To Len(sString)
sChar = Mid$(sString, i, 1)
iPos = InStr(1, "0123456789", sChar, vbBinaryCompare)
If iPos > 0 Then
sRetStr = sRetStr & sChar
End If
Next i

[InStr Function (Visual Basic)](https://msdn.microsoft.com/en-us/library/8460tsh1(v=vs.90).aspx) — Ňɏssa Pøngjǣrdenlarp, Jun 02 '15 at 17:27
If you have access to Microsoft Office, then in something like Excel, Word, or Access, you can use VBA to help figure out VB6 code. (See http://stackoverflow.com/questions/993300/difference-between-visual-basic-and-vba) — rskar, Jun 02 '15 at 18:35

score 4 · Accepted Answer · answered Jun 02 '15 at 17:42

The InStr finds the (one-based) index of a string in another string. The closest equivalent in the modern .Net string methods is .IndexOf. However, I would replace the code you have with this C# statement.

string sRetStr = (sString.Where((c) => char.IsDigit(c)).ToArray()).ToString();

Joel Coehoorn · Answer 2 · 2015-06-02T19:05:57.757

4

I'd pare that code down to this:

sRetStr = Regex.Replace(sSTring, "[^0-9]", "");

edited Jun 02 '15 at 19:05

answered Jun 02 '15 at 18:19

Joel Coehoorn

399,467
113
570
794

VB6 code explanation

2 Answers2