转换

Question

你好，我想显示一个错误，如果语句的一个是假的，但我得到一个错误：错误\ example.exe“从字符串转换‘’键入”布尔“是无效”

If My.Computer.Registry.GetValue("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\EXAMPLE", "InstallLocation", "") <> "" And 
     My.Computer.FileSystem.FileExists(My.Computer.Registry.GetValue("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\EXAMPLE", "InstallLocation", "ERROR")) & "\example.exe" Then 
    Else 
     System.Threading.Thread.Sleep(1000) 
     example_error.ShowDialog() 
    End If 

编辑：

Private Sub Form_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
    Dim ExecutablePath = IO.Path.Combine(CStr(My.Computer.Registry.GetValue("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\MYAPP", "InstallLocation", "ERROR")), "myapp.exe") 
    If Not String.IsNullOrEmpty(CStr(My.Computer.Registry.GetValue("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\MYAPP", "InstallLocation", ""))) _ 
     AndAlso My.Computer.FileSystem.FileExists(ExecutablePath) Then 
    Else 
     System.Threading.Thread.Sleep(1000) 
     GUI_Error.ShowDialog() 
    End If 
End Sub 

Answer 1

，因为要连接的路径与文件名，并使用你的第二个条件是不正确检查文件是否存在，但文件名不在方法调用内。而不将字符串创建的路径，你应该使用Path.Combine：

Dim filePath = Path.Combine(CStr(My.Computer.Registry.GetValue("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\EXAMPLE", "InstallLocation", "ERROR")), 
          "example.exe") 
If Not String.IsNullOrEmpty(CStr(My.Computer.Registry.GetValue("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\EXAMPLE", "InstallLocation", ""))) _ 
    AndAlso File.Exists(filePath) Then 
Else 
    System.Threading.Thread.Sleep(1000) 
    example_error.ShowDialog() 
End If