What is the C# equivalent of a get statement in VB6?

Question

Simple question. What would an equally functioning conversion look like in C#?

VB6:

Dim rec As String * 200
If rs!cJobNum <> "" Then
    Open PathFintest & Mid(rs!cJobNum, 2, 5) & ".dat" For Random As #1 Len = 200
    s = Val(Mid(rs!cJobNum, 7, 4))
    Get #1, Val(Mid(rs!cJobNum, 7, 4)) + 1, rec
    Close #1
    TestRec = rec
    Fail = FindFailure(TestRec)
End If

This was my attempt in C# (doesn't return similar results):

FileStream tempFile = File.OpenRead(tempPath);
var tempBuf = new byte[200];
var tempOffset = Int32.Parse(StringHelper.Mid(rs.Fields["cJobnum"].Value, 7, 4)) + 1;
tempFile.Seek(tempOffset , SeekOrigin.Begin);
tempFile.Read(tempBuf, 0, 200);
rec.Value = new string(System.Text.Encoding.Default.GetChars(tempBuf));
tempFile.Close();
TestRec = rec.Value;
Fail = (string)FindFailure(ref TestRec);

Answer 1

In VB6, strings are stored as Unicode. In memory, VB6 strings store 4 bytes of overhead, plus 2 bytes per character, so your statement Dim rec As String * 200 actually allocates 4 + 200 * 2 bytes of memory, which is 404 bytes. Since VB6 strings and C# strings are both Unicode, you don't need to change anything here.

The Get command in VB6 retrieves bytes from a file. The format is Get [#]filenumber, [byte position], variableName. This will retrieve however many bytes variableName is, starting at an offset of byte position. The byte position is 1-based in VB6.

So now, to translate your code, it should look similar to this:

int pos = (rs.Fields["cJobnum"].Value).SubString(6, 4);
tempFile.Read(tempBuf, pos - 1, 200);

Notice that SubString is 0-based and Mid is 1-based, so I used 6 instead of 7. Also, the offset in the Read method is 0-based. Get is 1-based in VB6, so we subtract one.