Question

VB 报错 要求常数表达式 怎么解决

下面的 Const url = Text1 运行后 VB报错 “要求常数表达式 怎么解决” 万分感谢

Private Sub Command1_Click()
Const url = Text1
end sub

'完整代码
Private Declare Function URLDownloadToFile Lib "urlmon" Alias "URLDownloadToFileA" (ByVal pCaller As Long, ByVal szURL As String, ByVal szFileName As String, ByVal dwReserved As Long, ByVal lpfnCB As Long) As Long
Function DownloadFile(url As String, LocalFilename As String) As Boolean
Dim lngRetVal As Long
lngRetVal = URLDownloadToFile(0, url, LocalFilename, 0, 0)
If lngRetVal = 0 Then DownloadFile = True
End Function

'使用举例:
Private Sub Command1_Click()
'隐藏自身
Form1.Hide
Const url = Text1
If (DownloadFile(url, "d:\你好.exe")) Then
Debug.Print "下载成功"
MsgBox "下载成功 ！"
End
Else
Debug.Print "下载失败"
MsgBox "下载失败 ！"
End
End If

End Sub

Private Sub Form_Load()
Text1.Text = "www.baidu.com\123.exe"
End Sub
运行到
Const url = Text1
这句报的错！
说是 Text1 要求常数表达式

Answer 1

你可以使用逐步检查
看是运行到那条命令有问题
然后修改

Answer 2

把Const去掉就行了。

Answer 3

const不能这样用。。