下面是我写的读"G:\copy\boot.ini"的程序：（rootvalue（2）As string数组是我在模块里定义的，所有相关的api也声明过）
Private Sub Command3_Click()
Dim s As String, ret As Long
s = Space(1024)
ret = GetPrivateProfileString("boot loader", "default", "", s, 1024, "G:\copy\boot.ini")
If Dir("G:\copy\boot.ini") = "" Then
MsgBox "boot.ini文件不存在或已更改路径！", vbOKOnly + vbCritical, "提示"
ElseIf ret = 0 Then
MsgBox "default键值为零，读取文件出错!", vbOKOnly + vbCritical, "提示"
Else: rootvalue(0) = s
End If
s = Space(1024)
ret = GetPrivateProfileString("operating systems", rootvalue1, "", s, 1024, "G:\copy\boot.ini")
If ret = 0 Then
MsgBox "operating systems键值为零，读取文件出错!", vbOKOnly + vbCritical, "提示"
Else: rootvalue(1) = s
End If
rootvalue(1)=rootvalue(1) & "abcde"
text1.text=rootvalue(1)
End Sub
程序运行后，text1只显示"Microsoft Windows XP Professional" /execute /fastdetect并没有加上"abcde"
字符串连接应该没有错吧，具体是哪里的问题？各位帮个忙！

总之这个错有点奇怪……建议LZ设置一下缓冲

s = Space(1024)

它用了这个……

但是最后一位还是存在Vbnullchar (就是Chr(0),文本显示不了这个符号，而且会断开=.=)

Option Explicit

Private Declare Function GetPrivateProfileString Lib "kernel32" Alias "GetPrivateProfileStringA" (ByVal lpApplicationName As String, ByVal lpKeyName As Any, ByVal lpDefault As String, ByVal lpReturnedString As String, ByVal nSize As Long, ByVal lpFileName As String) As Long
Private Sub Command1_Click()
Dim rootvalue(2) As String
Dim s As String, ret As Long
s = Space(1024)
ret = GetPrivateProfileString("boot loader", "default", "", s, 1024, "G:\copy\boot.ini")
If Dir("G:\copy\boot.ini") = "" Then
MsgBox "boot.ini文件不存在或已更改路径！", vbOKOnly + vbCritical, "提示"
ElseIf ret = 0 Then
MsgBox "default键值为零，读取文件出错!", vbOKOnly + vbCritical, "提示"
Else: rootvalue(0) = s
End If
s = Space(1024) '这里应该用rootvalue(0)吧?
ret = GetPrivateProfileString("operating systems", rootvalue1, "", s, 1024, "G:\copy\boot.ini")
If ret = 0 Then
MsgBox "operating systems键值为零，读取文件出错!", vbOKOnly + vbCritical, "提示"
Else: rootvalue(1) = s
End If
rootvalue(1) = Left(rootvalue(1), InStr(rootvalue(1), vbNullChar) - 1)
rootvalue(1) = rootvalue(1) & "abcde"
Text1 = rootvalue(1)
End Sub

预置了1024个字符长度，你那样处理就多了N多空格……

chr(0)?为什么不直接用常量～汗

再一次谢谢slore版主！你太强了！问题又解决了！

不过能帮我解释一下：
rootvalue(1) = Left(rootvalue(1), InStr(rootvalue(1), vbNullChar) - 1)
rootvalue(1) = rootvalue(1) & "abcde"
是怎么回事吗？

自已注意看第二条加色的代码