VB总是弹出"变量未定义"

[a506556425]

我在vb输入:
Private Sub 打开_Click()
CommonDialog3.FileName = ""
CommonDialog3.Flags = 4096
CommonDialog3.ShowOpen
CommonDialog3.Filter = "all files|*.*|(*.TXT)|*.TXT|(*.DOC)|*.DOC"
CommonDialog3.FilterIndex = 3
CommonDialog3.DialogTitle = "打开"
CommonDialog3.Action = 1
If CommonDialog3 = "" Then
MsgBox "No file selectd", 37, "Checking"
Else
'对所选择的文件进行处理
Open CommonDialog3.FileName For Input As #1
Do While Not EOF(1)
Input #1, a$
Print a$
Loop
End If
End Sub
VB总是弹出"变量未定义",Input #1, a$
Print a$
变成了红色．这是为什么？我可是按照书上说的来做的．

[hskshk]

书上不一定都是对的
现在有好多垃圾书

[Alices]

Print a$ ????
请问一下你VB是什么版的啊?!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!N年前的书吧,记得是QBASIC时用过
现在都用console.writeline OR console.write了
还有打开文件:
//VB.NET 2008

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim strm As IO.StreamReader
        Dim strall As String = String.Empty

        If OpenFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
            strm = New IO.StreamReader(OpenFileDialog1.OpenFile(), System.Text.Encoding.GetEncoding("gb2312"))
            strall = strm.ReadToEnd
            console.writeline(strall)
        End If
End Sub

[qiu5208]

你用是的vb6吧，如果是用vb.net那这本书根本没用。

你的vb6中强制要求声明，

有两中方法解决，
1，在代码开头加入，dim a as string
然后把 Input #1, a$
Print a$
改成Input #1, a
Print a

2，把你程式码开头的Option Explicit 去掉。

[a506556425]

谢谢

[w237872018]

print a $
定义a为字符串，需要中间空格出来……