Question

考虑：

Function ABC {
    [Object] $Connection = ((New-Object -TypeName System.IO.Ports.SerialPort -ArgumentList COM1, 11200, None, 8, one)
    $Connection.open()
}

现在我想在我需要的时候在外面使用$Connection。我怎样才能访问

$Connection.write("`r")  # Calling from outside
$Connection.Readexisting("`r")  # Calling from outside

Answer 1

您遇到的问题是范围。如果在函数内声明变量，则变量仅具有该函数的作用域，并在函数运行后消失。你需要做的是在函数之外声明$connection，将它传递给函数，在那里修改它，然后仍然可以访问函数之外的变量。

示例：

$connection
function MyFunction
{
     param([Parameter(Mandatory=$true)][AllowNull()]$connection)
     # do work here
}

另一种方法是将函数的返回值声明为变量

$myConnection = MyFunction

然后你可以在函数内部使用return来返回变量。

Answer 2

从函数中返回<body> <p>Note: Make sure the numbers are among the following: 4, 6, 8, 10, and 20.</p> <form id="diceForm" name="diceForm" action=""> <label>Enter your number here:</label> <input type="number" name="dicenum" required='required' placeholder="Enter a number among 4, 6, 8, 10, and 20..."> <br> <input type="submit" value="submit"> </form> <% if(request.getParameter("dicenum") != null) { // Opening curly braces for NPE guard %> <% int num = Integer.parseInt(request.getParameter("dicenum")); if (num == 4 || num == 6 || num == 10 || num == 20){ num = 1 + (Math.random()*num); } else { num = 0; } %> <%= (num == 0)? "The number you've entered is out of range.": num %> <% } %> // Closing curly braces for NPE guard </body>对象：

$connection

现在您可以使用它：

function New-COM1Connection
{
    $Connection = New-Object -TypeName System.IO.Ports.SerialPort -ArgumentList COM1, 11200, None, 8, One
    $Connection.Open()
    return $Connection
}

PowerShell可变范围串行端口

2 个答案: