How do I use RedirectStandardInput when running a Process with administrator privileges in C#?

Question

I'm trying to run a process using diskpart, but to do that I need administrator privileges because I'm using a PC at my work. In order to run a Process as administrator I need Process.StartInfo.Verb = "runas" and I also need Process.StartInfo.UseShellExecute = true. With UseShellExecute set to true, I can't pass commands to standard input, but if I set it to false, I get an error saying "The requested operation requires elevation" (aka I need admin privileges). If I try passing a script to in Process.StartInfo.Arguments it doesn't seem to do anything. Here are a couple versions of the code I have tried out so far (none of them have worked):

Version 1:

Process p = new Process();
p.StartInfo.UseShellExecute = true;
p.StartInfo.FileName = @"C:\Windows\System32\diskpart.exe";
p.StartInfo.Verb = "runas";
p.StartInfo.Arguments = "vhdScript.txt";
p.Start();

Version 2:

Process p = new Process();
p.StartInfo.UseShellExecute = true;
p.StartInfo.FileName = @"C:\Windows\System32\diskpart.exe";
p.StartInfo.Verb = "runas";
p.StartInfo.Arguments = "/s vhdScript.txt";
p.Start();

Version 3:

Process p = new Process();
p.StartInfo.UseShellExecute = true;
p.StartInfo.FileName = @"C:\Windows\System32\cmd.exe";
p.StartInfo.Verb = "runas";
p.StartInfo.Arguments = "/c diskpart /s vhdScript.txt";
p.Start();

Version 4:

Process p = new Process();
p.StartInfo.UseShellExecute = false;
p.StartInfo.FileName = @"C:\Windows\System32\cmd.exe";
p.StartInfo.Verb = "runas";
p.StartInfo.Arguments = "/c diskpart";
p.StartInfo.RedirectStandardInput = true;
p.Start();
p.StandardInput.WriteLine("select vdisk 1");

Any thoughts? Thanks.

Answer 1

The following shows how to create a diskpart script and then use System.Diagnostics.Process to execute the script.

Create a new Windows Forms App (.NET Framework) project (name: ProcessDiskPartTest)

Add an Application Manifest to your project

Note: This is used to prompt the user to execute the program as Administrator.

• In VS menu, click Project
• Select Add New Item...
• Select Application Manifest File (Windows Only) (name: app.manifest)
• Click Add

In app.manifest, replace

<requestedExecutionLevel level="asInvoker" uiAccess="false" />

with

<requestedExecutionLevel  level="requireAdministrator" uiAccess="false" />

---

Add the following using statements:

• using System.IO;
• using System.Diagnostics;

The following code will use Process to execute diskpart script.

private void RunDiskPart(string arguments)
{
    string diskpartPath = Path.Combine(Environment.GetEnvironmentVariable("windir"), "System32", "diskpart.exe");

    if (!System.IO.File.Exists(diskpartPath))
        throw new Exception(String.Format("'{0}' doesn't exist.", diskpartPath));

    Debug.WriteLine("diskpartPath: " + diskpartPath);

    ProcessStartInfo psInfo = new ProcessStartInfo(diskpartPath);
    psInfo.Arguments = arguments;
    
    psInfo.CreateNoWindow = true;
    psInfo.RedirectStandardError = true; //redirect standard Error
    psInfo.RedirectStandardOutput = true; //redirect standard output
    psInfo.RedirectStandardInput = false;
    psInfo.UseShellExecute = false; //if True, uses 'ShellExecute'; if false, uses 'CreateProcess'
    psInfo.Verb = "runas"; //use elevated permissions
    psInfo.WindowStyle = ProcessWindowStyle.Hidden;
    
    //create new instance and set properties
    using (Process p = new Process() { EnableRaisingEvents = true, StartInfo = psInfo })
    {
        //subscribe to event and add event handler code
        p.ErrorDataReceived += (sender, e) =>
        {
            if (!String.IsNullOrEmpty(e.Data))
            {
                //ToDo: add desired code 
                Debug.WriteLine("Error: " + e.Data);
            }
        };

        //subscribe to event and add event handler code
        p.OutputDataReceived += (sender, e) =>
        {
            if (!String.IsNullOrEmpty(e.Data))
            {
                //ToDo: add desired code
                Debug.WriteLine("Output: " + e.Data);
            }
        };

        p.Start(); //start

        p.BeginErrorReadLine(); //begin async reading for standard error
        p.BeginOutputReadLine(); //begin async reading for standard output

        //waits until the process is finished before continuing
        p.WaitForExit();
    }
}

---

Below, shows how to add a diskpart script as an embedded resource.

Create a folder for your DiskPart script(s)

• In VS menu, click View
• Select Solution Explorer
• In Solution Explorer, right-click <project name>. Select Add. Select New Folder (name: DiskPartScripts)

Add DiskPart script to project

Note: The diskpart script below is only for testing purposes. Rename it to your desired name and replace the commands with your desired diskpart command(s).

• In Solution Explorer, right-click DiskPartScripts folder. Select Add. Select New Item....
• Select Text File (name: DiskPartListDisk.txt)

DiskPartListDisk.txt

list disk
list volume

Make text file an embedded resource

• In VS menu, click View
• Select Properties Window
• In Solution Explorer, click on "DiskpartListDisk.txt"
• In Properties Window, set Build Action: Embedded Resource

The following is used to read an embedded text file.

Create a class (name: HelperLoadResource.cs)

HelperLoadResource.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Reflection;
using System.Diagnostics;

namespace ProcessDiskPartTest
{
    public static class HelperLoadResource
    {
        public static string ReadResource(string filename)
        {
            //use UTF8 encoding as the default encoding
            return ReadResource(filename, Encoding.UTF8);
        }

        public static string ReadResource(string filename, Encoding fileEncoding)
        {
            string fqResourceName = string.Empty;
            string result = string.Empty;

            //get executing assembly
            Assembly execAssembly = Assembly.GetExecutingAssembly();

            //get resource names
            string[] resourceNames = execAssembly.GetManifestResourceNames();

            if (resourceNames != null && resourceNames.Length > 0)
            {
                foreach (string rName in resourceNames)
                {
                    if (rName.EndsWith(filename))
                    {

                        //set value to 1st match
                        //if the same filename exists in different folders,
                        //the filename can be specified as <folder name>.<filename>
                        //or <namespace>.<folder name>.<filename>
                        fqResourceName = rName;

                        //exit loop
                        break;
                    }
                }

                //if not found, throw exception
                if (String.IsNullOrEmpty(fqResourceName))
                {
                    throw new Exception($"Resource '{filename}' not found.");
                }

                //get file text
                using (Stream s = execAssembly.GetManifestResourceStream(fqResourceName))
                {
                    using (StreamReader reader = new StreamReader(s, fileEncoding))
                    {
                        //get text
                        result = reader.ReadToEnd();
                    }
                }
            }

            return result;
        }
    }
}

Note: The code for "ReadResource" is from here.

---

Usage:

//temp filename that we'll use for diskpart
string diskpartScriptFilename = Path.Combine(Path.GetTempPath(), String.Format("diskpart_{0}.txt", System.Reflection.Assembly.GetExecutingAssembly().GetName().Name));

//get embedded diskpart script
string diskpartScript = HelperLoadResource.ReadResource("DiskpartListDisk.txt");

//write script to file
File.WriteAllText(diskpartScriptFilename, diskpartScript);

//execute script
RunDiskPart("/s " + diskpartScriptFilename);

if (File.Exists(diskpartScriptFilename))
    File.Delete(diskpartScriptFilename); //delete file

Resources:

• diskpart
• System.Diagnostics.Process
• How to read embedded resource text file

Answer 2

I followed one of the suggestions in this article UseShellExecute=false and Raising Elevation

When I create an command line exe with the below code, and Run As Administrator, I get the results I expect. May or may not work for you. (the SELECT VDISK 1 syntax was incorrect from your example so I improvised). This might help

using (Process p = new())
{
    p.StartInfo.UseShellExecute = false;
    p.StartInfo.FileName = @"C:\Windows\System32\diskpart.exe";
    p.StartInfo.Verb = "runas";
    //p.StartInfo.Arguments = "/c diskpart";
    p.StartInfo.RedirectStandardInput = true;

    p.Start();

    StreamWriter myStreamWriter = p.StandardInput;
    myStreamWriter.WriteLine("LIST DISK");
    myStreamWriter.Close();
    p.WaitForExitAsync();

}