从C#调用powershell cmdlet

Question

我正在尝试学习如何从C#调用PS cmdlet,并且遇到了PowerShell类.它适用于基本用途,但现在我想执行此PS命令:

Get-ChildItem | where {$_.Length -gt 1000000}

我尝试通过powershell类来构建它,但我似乎无法做到这一点.到目前为止这是我的代码:

PowerShell ps = PowerShell.Create();
ps.AddCommand("Get-ChildItem");
ps.AddCommand("where-object");
ps.AddParameter("Length");
ps.AddParameter("-gt");
ps.AddParameter("10000");


// Call the PowerShell.Invoke() method to run the 
// commands of the pipeline.
foreach (PSObject result in ps.Invoke())
{
    Console.WriteLine(
        "{0,-24}{1}",
        result.Members["Length"].Value,
        result.Members["Name"].Value);
} // End foreach.

我跑这个时总是遇到异常.是否可以像这样运行Where-Object cmdlet？

Answer 1

Length,-gt而10000不是参数Where-Object.FilterScript在位置0 只有一个参数,其值为ScriptBlock包含表达式的类型.

PowerShell ps = PowerShell.Create();
ps.AddCommand("Get-ChildItem");
ps.AddCommand("where-object");
ScriptBlock filter = ScriptBlock.Create("$_.Length -gt 10000")
ps.AddParameter("FilterScript", filter)

如果您需要分解更复杂的语句,请考虑使用tokenizer(在v2或更高版本中可用)更好地理解结构:

    # use single quotes to allow $_ inside string
PS> $script = 'Get-ChildItem | where-object -filter {$_.Length -gt 1000000 }'
PS> $parser = [System.Management.Automation.PSParser]
PS> $parser::Tokenize($script, [ref]$null) | select content, type | ft -auto

这会丢弃以下信息.它不像v3中的AST解析器那么丰富,但它仍然有用:

    Content                   Type
    -------                   ----
    Get-ChildItem          Command
    |                     Operator
    where-object           Command
    -filter       CommandParameter
    {                   GroupStart
    _                     Variable
    .                     Operator
    Length                  Member
    -gt                   Operator
    1000000                 Number
    }                     GroupEnd

希望这可以帮助.