vb.Net编程简介之四

"GetUserNameA" (ByVal lpBuffer As String, ByRef nSize As

Long) As Long

Function GetUser()

Dim Ret As Long

Dim UserName As String

Dim Buffer As String * 25

Ret = GetUserName(Buffer, 25)

UserName = Left$(Buffer, InStr(Buffer, Chr(0)) - 1)

MsgBox (UserName)

End Function

上面的代码出现了固定长度字符串，最好更改为：

Dim Buffer As String

Buffer = String$(25, " ")

升级到Visual Basic.NET后会称为下面的样子：

Declare Function GetUserName Lib "advapi32.dll" Alias _

"GetUserNameA" (ByVal lpBuffer As String, ByRef nSize As

Integer) As Integer

Function GetUser()

Dim Ret As Integer

Dim UserName As String

Dim Buffer As String

Buffer = New String(CChar(" "), 25)

Ret = GetUserName(Buffer, 25)

UserName = Left(Buffer, InStr(Buffer, Chr(0)) - 1)