VB.Net (2019) 文件 I/O 混合数据 请帮助？
VB.Net (2019) File I/O Mixed Data Help Please?
我老了，习惯了 Excel 中较旧的 VBA 和较旧的 VB 代码。现在我正尝试在 Visual Studio 社区与 VB 一起工作。我曾寻求帮助，但我为 .NET 找到的所有内容都带有我不遵循的 C++ 或 C# 代码。我什至找不到一本书来帮助转换为更新的代码格式。我习惯了;
Dim outpath as integer
Dim aString as String
Dim aDouble as Double
aString = "Some Text"
aDouble = 3.1429
outpath = FreeFile
Open "C:\afolder\somedata.dat" For Output As outpath
print #outpath, aString
print #outpath, aDouble
close #outpath
要读取数据，我习惯使用 aString = input #outpath 指令。
从我读到的内容来看，我似乎应该使用 IO.Stream 函数，但没有找到任何可以复制我在上面习惯的旧方法的方法。
谁能给我指点一些在 VB 中涵盖此内容的网页，而不是陷入我无法翻译成 VB 的 C 代码。
谢谢你。
当然，有多种方法可以做到这一点。我也是从 VB6 过来的，还有很多 VBA.
那么，要转换以上内容并写入文件？
好吧，一个方法（我们甚至在 VBA 中做到了这一点）是创建一个字符串，将值集中到字符串中，然后将字符串写入文件。
这很容易，但你必须在代码中折腾下一行字符。
所以，这会起作用：
Dim aString As String
Dim aDouble As Double
aString = "Some Text"
aDouble = 3.1429
Dim strPath As String = "C:\test\somedata.dat"
Dim strOutBuf As String = ""
strOutBuf = aString
strOutBuf = strOutBuf & vbCrLf & aDouble
File.WriteAllText(strPath, strOutBuf)
因此，对于几行简单的文本 - 非常简单。
但是，对于很多代码，逐行输出——类似于VBA?
然后你这样做：
Dim FILE_NAME As String = "C:\test\test2.txt"
Dim MyFileWriter As New StreamWriter(FILE_NAME)
Dim aString As String
Dim aDouble As Double
aString = "Some Text"
aDouble = 3.1429
MyFileWriter.WriteLine(aString)
MyFileWriter.WriteLine(aDouble)
For i = 1 To 10
MyFileWriter.WriteLine(i)
Next
MyFileWriter.Close()
请注意，在上面，文件不（不能）已经存在。
所以，你必须处理这个问题。
您可以在开始写入之前删除文件。
例如：
Dim FILE_NAME As String = "C:\test\test2.txt"
If File.Exists(FILE_NAME) Then
File.Delete(FILE_NAME)
End If
（接下来是您的其余代码。因此不再需要（或概念）FreeFile()。
输出：
Some Text
3.1429
1
2
3
4
5
6
7
8
9
10
编辑：-----------------------------
好吧，展示如何写出文件有点像拥抱，而不是亲吻。那么，现在，我们如何读取文件？
嗯，这真的取决于我们想用那个输入做什么。但是 .net 倾向于一次性阅读（或实际上是编写）整个内容。
但是，逐行读取将如下所示：
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Dim FILE_NAME As String = "C:\test\test2.txt"
Dim MyFileReader As New StreamReader(FILE_NAME)
Do While MyFileReader.EndOfStream = False
Debug.Print("one line of file = " & MyFileReader.ReadLine)
Loop
MyFileReader.Close()
End Sub
output:
one line of file = Some Text
one line of file = 3.1429
one line of file = 1
one line of file = 2
one line of file = 3
one line of file = 4
one line of file = 5
one line of file = 6
one line of file = 7
one line of file = 8
one line of file = 9
one line of file = 10
' vb.net has allowed declaration and assignment on the same line for more than 20yrs now
Dim aString as String = "Some Text"
Dim aDouble as Double = 3.1429
' New API methods do not use integers to track files.
' That was always kind of weird.
Dim outpath As String = "C:\afolder\somedata.dat"
' StreamReader/StreamWriter are great, and you should learn them,
' but you don't need them for this sample
System.IO.File.WriteAllText(outpath, $"{aString}{vbCrLf}{aDouble}")
' Interpolated strings (like above) are kind of fun, too
同样，没有评论并假设 System.IO 的 Imports 指令，以强调这可能是多么简单：
Dim aString as String = "Some Text"
Dim aDouble as Double = 3.1429
Dim outpath As String = "C:\afolder\somedata.dat"
File.WriteAllText(outpath, $"{aString}{vbCrLf}{aDouble}")
如果插入的字符串太混乱，这里还有一个选项：
Dim aString as String = "Some Text"
Dim aDouble as Double = 3.1429
Dim outpath As String = "C:\afolder\somedata.dat"
File.WriteAllText(outpath, aString)
File.AppendAllText(outpath, aDouble.ToString("r"))
但是，实际上打开、写入和关闭文件两次。这是额外的 I/O，这是您在计算机上可以执行的最慢的操作，所以我不推荐它。
相反，您可以通过连接来构建输出字符串，但我相信您知道这也可能很麻烦，所以这里是最后一个替代方法 System.IO.StreamWriter:
Dim aString as String = "Some Text"
Dim aDouble as Double = 3.1429
Dim outpath As String = "C:\afolder\somedata.dat"
'Using blocks (added way back in 2005) replace the need to Close the file
' Moreover, they promise to dispose of the file handle
' **even if there's an exception/error**,
' making your code safer and better.
Using writer As New StreamWriter(outpath)
writer.WriteLine(aString)
writer.WriteLine(aDouble)
End Using
然后读回值：
Dim filePath As String = "C:\afolder\somedata.dat"
Dim aString as String
Dim aDouble as Double
Using reader As New StreamReader(filePath)
aString = reader.ReadLine()
aDouble = Double.Parse(reader.ReadLine())
End Using
我老了，习惯了 Excel 中较旧的 VBA 和较旧的 VB 代码。现在我正尝试在 Visual Studio 社区与 VB 一起工作。我曾寻求帮助，但我为 .NET 找到的所有内容都带有我不遵循的 C++ 或 C# 代码。我什至找不到一本书来帮助转换为更新的代码格式。我习惯了;
Dim outpath as integer
Dim aString as String
Dim aDouble as Double
aString = "Some Text"
aDouble = 3.1429
outpath = FreeFile
Open "C:\afolder\somedata.dat" For Output As outpath
print #outpath, aString
print #outpath, aDouble
close #outpath
要读取数据，我习惯使用 aString = input #outpath 指令。 从我读到的内容来看，我似乎应该使用 IO.Stream 函数，但没有找到任何可以复制我在上面习惯的旧方法的方法。
谁能给我指点一些在 VB 中涵盖此内容的网页，而不是陷入我无法翻译成 VB 的 C 代码。
谢谢你。
当然，有多种方法可以做到这一点。我也是从 VB6 过来的，还有很多 VBA.
那么，要转换以上内容并写入文件？
好吧，一个方法（我们甚至在 VBA 中做到了这一点）是创建一个字符串，将值集中到字符串中，然后将字符串写入文件。
这很容易，但你必须在代码中折腾下一行字符。
所以，这会起作用：
Dim aString As String
Dim aDouble As Double
aString = "Some Text"
aDouble = 3.1429
Dim strPath As String = "C:\test\somedata.dat"
Dim strOutBuf As String = ""
strOutBuf = aString
strOutBuf = strOutBuf & vbCrLf & aDouble
File.WriteAllText(strPath, strOutBuf)
因此，对于几行简单的文本 - 非常简单。
但是，对于很多代码，逐行输出——类似于VBA?
然后你这样做：
Dim FILE_NAME As String = "C:\test\test2.txt"
Dim MyFileWriter As New StreamWriter(FILE_NAME)
Dim aString As String
Dim aDouble As Double
aString = "Some Text"
aDouble = 3.1429
MyFileWriter.WriteLine(aString)
MyFileWriter.WriteLine(aDouble)
For i = 1 To 10
MyFileWriter.WriteLine(i)
Next
MyFileWriter.Close()
请注意，在上面，文件不（不能）已经存在。
所以，你必须处理这个问题。
您可以在开始写入之前删除文件。
例如：
Dim FILE_NAME As String = "C:\test\test2.txt"
If File.Exists(FILE_NAME) Then
File.Delete(FILE_NAME)
End If
（接下来是您的其余代码。因此不再需要（或概念）FreeFile()。
输出：
Some Text
3.1429
1
2
3
4
5
6
7
8
9
10
编辑：-----------------------------
好吧，展示如何写出文件有点像拥抱，而不是亲吻。那么，现在，我们如何读取文件？
嗯，这真的取决于我们想用那个输入做什么。但是 .net 倾向于一次性阅读（或实际上是编写）整个内容。
但是，逐行读取将如下所示：
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Dim FILE_NAME As String = "C:\test\test2.txt"
Dim MyFileReader As New StreamReader(FILE_NAME)
Do While MyFileReader.EndOfStream = False
Debug.Print("one line of file = " & MyFileReader.ReadLine)
Loop
MyFileReader.Close()
End Sub
output:
one line of file = Some Text
one line of file = 3.1429
one line of file = 1
one line of file = 2
one line of file = 3
one line of file = 4
one line of file = 5
one line of file = 6
one line of file = 7
one line of file = 8
one line of file = 9
one line of file = 10
' vb.net has allowed declaration and assignment on the same line for more than 20yrs now
Dim aString as String = "Some Text"
Dim aDouble as Double = 3.1429
' New API methods do not use integers to track files.
' That was always kind of weird.
Dim outpath As String = "C:\afolder\somedata.dat"
' StreamReader/StreamWriter are great, and you should learn them,
' but you don't need them for this sample
System.IO.File.WriteAllText(outpath, $"{aString}{vbCrLf}{aDouble}")
' Interpolated strings (like above) are kind of fun, too
同样，没有评论并假设 System.IO 的 Imports 指令，以强调这可能是多么简单：
Dim aString as String = "Some Text"
Dim aDouble as Double = 3.1429
Dim outpath As String = "C:\afolder\somedata.dat"
File.WriteAllText(outpath, $"{aString}{vbCrLf}{aDouble}")
如果插入的字符串太混乱，这里还有一个选项：
Dim aString as String = "Some Text"
Dim aDouble as Double = 3.1429
Dim outpath As String = "C:\afolder\somedata.dat"
File.WriteAllText(outpath, aString)
File.AppendAllText(outpath, aDouble.ToString("r"))
但是，实际上打开、写入和关闭文件两次。这是额外的 I/O，这是您在计算机上可以执行的最慢的操作，所以我不推荐它。
相反，您可以通过连接来构建输出字符串，但我相信您知道这也可能很麻烦，所以这里是最后一个替代方法 System.IO.StreamWriter:
Dim aString as String = "Some Text"
Dim aDouble as Double = 3.1429
Dim outpath As String = "C:\afolder\somedata.dat"
'Using blocks (added way back in 2005) replace the need to Close the file
' Moreover, they promise to dispose of the file handle
' **even if there's an exception/error**,
' making your code safer and better.
Using writer As New StreamWriter(outpath)
writer.WriteLine(aString)
writer.WriteLine(aDouble)
End Using
然后读回值：
Dim filePath As String = "C:\afolder\somedata.dat"
Dim aString as String
Dim aDouble as Double
Using reader As New StreamReader(filePath)
aString = reader.ReadLine()
aDouble = Double.Parse(reader.ReadLine())
End Using