Creating A Hard Disk Partition Using C#

/// <summary>
/// Creates a partition on the hard disk.
/// </summary>
/// <param name="partitionSizeInGB">Partition size in gigabytes</param>
/// <returns>Exit code indicating the success or failure of the operation</returns>
private static int CreatePartition(int partitionSizeInGB)
{
    string sd = string.Empty;
    int result = 0;
    // Get all drives excluding CD drives and network drives.
    List<DriveInfo> allDrivesInfo = DriveInfo.GetDrives().Where(x => x.DriveType != DriveType.Network).OrderBy(c => c.Name).ToList();
    // Get a new drive name based on existing drives.
    char newDriveName = allDrivesInfo.LastOrDefault()?.Name.FirstOrDefault() ?? 'A';
    newDriveName = (char)(Convert.ToUInt16(newDriveName) + 1);
    // Get information about fixed drives.
    List<DriveInfo> allFixedDrives = DriveInfo.GetDrives().Where(c => c.DriveType == DriveType.Fixed).ToList();

    try
    {
        string scriptFilePath = System.IO.Path.GetTempPath() + @"\dpScript.txt";
        string driveName = allFixedDrives.FirstOrDefault()?.Name;
        if (File.Exists(scriptFilePath))
        {
            File.Delete(scriptFilePath); // Delete the script if it exists.
        }
        // Create the script to resize and format the partition.
        File.AppendAllText(scriptFilePath,
            string.Format(
                "SELECT DISK=0\n" +       // Select the first disk drive.
                "SELECT VOLUME={0}\n" +   // Select the drive.
                "SHRINK DESIRED={1} MINIMUM={1}\n" + // Shrink to half the original size.
                "CREATE PARTITION PRIMARY\n" +       // Make the drive partition.
                "ASSIGN LETTER={2}\n" +             // Assign its letter.
                "FORMAT FS=FAT32 QUICK\n" +         // Format it.
                "EXIT",
                driveName, partitionSizeInGB * 1000, newDriveName)); // Exit.
        int exitCode = 0;
        string resultStr = ExecuteCmdCommand("DiskPart.exe" + " /s " + scriptFilePath, ref exitCode);
        File.Delete(scriptFilePath); // Delete the script file.
        if (exitCode > 0)
        {
            result = exitCode;
        }
        return result;
    }
    catch (Exception ex)
    {
        throw ex;
    }
}

ExecuteCmdCommand

We will open a command prompt and run the script in a separate process using C#.

/// <summary>
/// Executes a command using the cmd.exe process.
/// </summary>
/// <param name="command">The command to execute</param>
/// <param name="exitCode">The exit code of the executed command</param>
/// <returns>The output of the command</returns>
private static string ExecuteCmdCommand(string command, ref int exitCode)
{
    ProcessStartInfo processInfo;
    Process process = new Process();
    string output = string.Empty;
    processInfo = new ProcessStartInfo("cmd.exe", "/C " + command);
    processInfo.CreateNoWindow = false;
    processInfo.WindowStyle = ProcessWindowStyle.Normal;
    processInfo.UseShellExecute = false;
    processInfo.RedirectStandardOutput = true;
    process.StartInfo = processInfo;
    process = Process.Start(processInfo);
    StreamReader streamReader = process.StandardOutput;
    output = streamReader.ReadToEnd();
    exitCode = process.ExitCode;
    process.Close();
    return output;
}

I was searching for a proper solution for creating a partition using C#, and after a long search, I found the following solution from an MSDN forum.

Shrink, create a partition in C# without DiskPart