VB6中的get语句的C#等效项是什么? [英] What is the C# equivalent of a get statement in VB6?

问题描述

一个简单的问题.在C#中，功能相同的转换是什么样的?

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

这是我在C#中的尝试(不会返回类似结果):

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);

推荐答案

在VB6中，字符串存储为Unicode.在内存中，VB6字符串存储4个字节的开销，每个字符加上2个字节，因此您的语句 Dim rec As String * 200 实际上分配了 4 + 200 * 2 个字节的内存，即404个字节.由于VB6字符串和C#字符串都是Unicode，因此您无需在此处进行任何更改.

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.

VB6中的 Get 命令从文件中检索字节.格式为获取[#]文件编号，[字节位置]，variableName .无论从 byte position 的偏移量开始，这将检索多少个 variableName 字节.在VB6中，字节位置从1开始.

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.

因此，现在，要翻译您的代码，它应类似于以下内容:

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);

请注意， SubString 是基于0的，而 Mid 是基于1的，所以我使用了 6 而不是 7 .另外， Read 方法中的偏移量是从0开始的. Get 在VB6中是基于1的，因此我们减去一个.

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.

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