[英]How to I call a variable somewhere else in my code in VB?
所以,我有以下VB代码:
Try
Using verSR As New StreamReader(appDataVersionLoc)
Dim txtVern As String
txtVern = verSR.ReadToEnd()
End Using
Catch ex As Exception
Dim verFile As System.IO.FileStream
verFile = System.IO.File.Create(appDataVersionLoc)
My.Computer.FileSystem.WriteAllText("appDataVersionLoc", "0.0.0.0", True)
MessageBox.Show("Version file missing/corrupt, created a new one.")
End Try
看到那个名为“txtVern?”的变量。 我试图在Try-End Try块之外的代码中的其他地方使用它。 差不多这个:
Try
Using verSR As New StreamReader(appDataVersionLoc)
Dim txtVern As String
txtVern = verSR.ReadToEnd()
End Using
Catch ex As Exception
Dim verFile As System.IO.FileStream
verFile = System.IO.File.Create(appDataVersionLoc)
My.Computer.FileSystem.WriteAllText("appDataVersionLoc", "0.0.0.0", True)
MessageBox.Show("Version file missing/corrupt, created a new one.")
End Try
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Dim currentversion As String = txtVern
现在,我是一个完整的VB菜鸟,我收到了这个错误:
'txtVern'未声明。 由于其保护级别,它可能无法访问。
我怎样才能解决这个问题? 谢谢!
在任何块内声明的变量仅在该块内可见。 你必须在Try
块之前移动声明:
Dim txtVern As String = String.Empty
Try
Using verSR As New StreamReader(appDataVersionLoc)
txtVern = verSR.ReadToEnd()
End Using
Catch ex As Exception
Dim verFile As System.IO.FileStream
verFile = System.IO.File.Create(appDataVersionLoc)
My.Computer.FileSystem.WriteAllText("appDataVersionLoc", "0.0.0.0", True)
MessageBox.Show("Version file missing/corrupt, created a new one.")
End Try
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Dim currentversion As String = txtVern
在try块中声明变量txtVern时,您将其范围限制为try块。 尝试在子例程的开头声明它们。
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