将powershell cmdlet输出写入文件，而不是从c＃写入管道

Question

I am trying to implement a powershell cmdlet in C#.

I have an object in the code something like.

class A{
    string Title_p;
    string Title_q;
    int Title_r;
    string[] Title_s;
}

So, in the cmdlet implementation, when I give this.WriteObject(A_obj) , it converts the object data into beautiful readable table format with column titles as object names. Something like below:

Title_p   Title_q  Title_r  Title_s
=======   =======  =======  =======
Hello      Bolo     12     {RR,TT,YY}

But all this output is redirected to the pipeline where the final cmdlet will be fired from.

But I also want to log all this output to a file (besides printing to pipeline)

I am aware that I can give CmdLet-Sud | out-file c:/data.txt CmdLet-Sud | out-file c:/data.txt . But I don't want this. I want to just fire the command CmdLet-Sud , and it should print the data to pipeline as well as to a file.

So, how to convert the object into such a printable table format?

Answer 1

You can create a "Powershell" in your C# code (using System.Management.Automation.Powershell). Your "Powershell" (bad choice of class names IMO, I'll call it SMA.Powershell in this answer for clarity) can invoke tee-object (or append-content or set-content ). You can then pass your class instance(s) as arguments to the SMA.Powershell.

Alternatively you can just use classes under the System.IO file space and write the file directly. You can separately write the same output via write-object.

BTW, writing the output to a file doesn't make sense unless you have support for serialization and deserialization in your class. Unless, what you really want is to write your class instance as a textual table. In which case your SMA.Powershell can be something like % { $_ | ft | set-content c:\\data.txt; $_} % { $_ | ft | set-content c:\\data.txt; $_} % { $_ | ft | set-content c:\\data.txt; $_} .

Answer 2

Tee-Object did the work for me.

PowerShell powerShellInstance = PowerShell.Create();
powerShellInstance.AddCommand("Tee-Object");
powerShellInstance.AddParameter("FilePath", filePath);
powerShellInstance.AddParameter("InputObject", obj_A);
powerShellInstance.AddParameter("Append");
powerShellInstance.Invoke();

But, when the above code is invoked multiple times, the file is written as

Title_p   Title_q  Title_r  Title_s
=======   =======  =======  =======
Hello      Bolo     12     {RR,TT,YY}

Title_p   Title_q  Title_r  Title_s
=======   =======  =======  =======
Aaaao      Colo     13     {EE,YY}

Title_p   Title_q  Title_r  Title_s
=======   =======  =======  =======
HHSAR      Dolo     14     {QQ,XX}

But in cmdlet implementation, even though you call this.WriteObject() multiple times with multiple objects, the result would be as

Title_p   Title_q  Title_r  Title_s
=======   =======  =======  =======
Hello      Bolo     12     {RR,TT,YY}
Aaaao      Colo     13     {EE,YY}
HHSAR      Dolo     14     {QQ,XX}

I am trying to see if I can tweak the code such that even the invoke() command is called multiple times in a program, the output file would still have only only one column header instead of one column header for each object (in the final output file)

Answer 3

Finally done, with want I wanted:

// When this method is called for the first time, it creates a table header too.
// The following is the PowerShell line that will be run in the runspace.
// Write-Output -InputObject <object_A> | Format-Table | Out-String

// For the next time, when this routine is called, the following gets executed.
// Write-Output -InputObject <object_A> | Format-Table -HideTableHeaders | Out-String

Runspace runspace = RunspaceFactory.CreateRunspace();
runspace.Open();
Pipeline pipeLine = runspace.CreatePipeline();

Command command1 = new Command("Write-Output");
command1.Parameters.Add("InputObject", object_A);

Command command2 = new Command("Format-Table");
if (this.filePath != null)
{
    // If this is not the first row, hide the table headers
    command2.Parameters.Add("HideTableHeaders");
}
Command command3 = new Command("Out-String");

pipeLine.Commands.Add(command1);
pipeLine.Commands.Add(command2);
pipeLine.Commands.Add(command3);
var results = pipeLine.Invoke();

// The resultant text from the command will have a lot of white spaces/carriage returns.
// So, let us trim the content before adding it to file.
foreach (var result in results)
{
    string data = null;
    data = string.Concat(result);
    data = data.Trim();

    // For the first time, we need to create a log file too.
    if (filePath == null)
    {
        // Call custom routine CreateLogFile() which creates a file and returns the file path as string for you
        filePath = CreateLogFile();
    }

    // Write the object row into the file.
    using (StreamWriter writer = System.IO.File.AppendText(this.filePath))
    {
        writer.WriteLine(data);
    }
}

runspace.Close();