无法从C＃运行PowerShell：在模块“ Dism”中找到“ Get-WindowsOptionalFeature”命令，但无法加载该模块

Question

I tried to execute the following PowerShell command from my c# application.

$check = Get-WindowsOptionalFeature -Online -FeatureName WCF-HTTP-Activation45
if ($check.Installed -eq 'False') {
    Enable-WindowsOptionalFeature -Online -FeatureName WCF-HTTP-Activation45
}

But when I run this, the PowerShell raises the following exception:

The 'Get-WindowsOptionalFeature' command was found in the module 'Dism', but the module could not be loaded. For more information, run 'Import-Module Dism'

However, when I run the same script from the PowerShell window, it works just fine. What is the root of my problem? My operating system is Windows 10.

PowerShell version: 5 - 1 - 14393 - 953

C# Code:

const string psScript = @"$check = Get-WindowsOptionalFeature -Online -FeatureName WCF-HTTP-Activation45
if ($check.Installed -eq 'False') {
    Enable-WindowsOptionalFeature -Online -FeatureName WCF-HTTP-Activation45
}";

using (var PowerShellInstance = PowerShell.Create())
{
    PowerShellInstance.AddScript(psScript);
    var PSOutput = PowerShellInstance.Invoke();

    if (PowerShellInstance.Streams.Error.Count > 0)
    {                       
        foreach (var err in PowerShellInstance.Streams.Error)
            logger.LogError(err.ToString());
    }

    foreach (var outputItem in PSOutput)
    {            
        if (outputItem != null)
            logger.LogInfo(outputItem.ToString());
    }
}

Answer 1

尝试在脚本中包含“导入模块Dism”，如下所示：

const string psScript = @"Import-Module Dism; $check = Get-WindowsOptionalFeature -Online -FeatureName WCF-HTTP-Activation45 if ($check.Installed -eq 'False') { Enable-WindowsOptionalFeature -Online -FeatureName WCF-HTTP-Activation45 };";