VB6.FixedLengthString(100)是啥玩艺儿？

[cnming]

从这个网页中http://network.programming-in.net/articles/art7-3.asp

可以找到Dim lpszName As New VB6.FixedLengthString(100) ，这个语句有问题，我不懂得如何改，请帮忙

Sub MapWebcamToWindow(ByRef lWidth As Integer, ByRef lHeight As Integer, ByRef hWnd As Integer)
Dim lpszName As New VB6.FixedLengthString(100)

Dim bmp As BITMAPINFO
With bmp.bmiHeader
.biSize = Len(bmp.bmiHeader)
.biWidth = 320
.biHeight = 240
.biPlanes = 1
.biBitCount = 24
End With
capGetDriverDescriptionA(0, lpszName.Value, 100, Nothing, 100)
lwndC = capCreateCaptureWindowA(lpszName.Value, WS_VISIBLE Or WS_CHILD, 0, 0, lWidth, lHeight, hWnd, 0)

If capDriverConnect(lwndC, 0) Then
capPreviewRate(lwndC, 66)
capPreview(lwndC, True)
capSetVideoFormat(lwndC, bmp, Len(bmp))
SetWindowPos(lwndC, 0, 0, 0, bmp.bmiHeader.biWidth, bmp.bmiHeader.biHeight, SWP_NOMOVE Or SWP_NOZORDER)
End If

End Sub

[canyqf]

好像就是这个特性：MarshalAs(UnmanagedType.ByValTStr, SizeConst=100)
不过给lpszName加上特性后，好像不能在方法体内申明...

[cnming]

在这里该如何写啊？

[canyqf]

<MarshalAs(UnmanagedType.ByValTStr, SizeConst=100>
private lpszName As string

Sub MapWebcamToWindow ....

好像VB里面SizeConst那里要这样写：SizeConst:=100， 但记不清楚...

[cnming]

up

[cnming]

这样写也不行，在“〉”中提示需要表达式

capGetDriverDescriptionA(0, lpszName.Value, 100, Nothing, 100)
lpszName.Value提示不是string的成员

[cnming]

还是不行的

<MarshalAs(UnmanagedType.ByValTStr, SizeConst=100> _
private lpszName As string

private 提示“需要表达式”

[canyqf]

faint, 语法错误而已...

<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=100)> _
private lpszName As string

[hsn1982]

VB6.FixedLengthString(100)
就是等于VB中的dim ste as string * 100
定长字符串

[cnming]

up

[canyqf]

Imports System.Runtime.InteropServices

...

<MarshalAs(UnmanagedType.ByValTStr, SizeConst=100> _
private lpszName As string

...

capGetDriverDescriptionA(0, lpszName, 100, Nothing, 100)

...