Help change single file lzma maker to multiple in c#

[raminr63]

guys i use this code to create my files for App updater.
with this code i can just select one files every time and also the output copied to clipboard and zipped files crated in same directory near unzipped files.
BUT:
i need to edit this code for:

1)possible to select multiple files (all files with files in folders and sub folders) or i think its better give a folder address to add all files also the files in sub folders.
2)put output data on a file named "info.xml" except clipboard in somewhere.(each data for each files in per line)
an example for output data on clipboard is:

CSHARP Code

<ContentFile Name="logo.bmp" Size="109976" SHA1Hash="280EFF2ADD6557E90C542263B1C7971F8EBF19A8" CompressedSize="8625" />

3) at last put zipped files (lzma format) on the other place with same files names and folders and sub folders with included files.

Guys i need full code.
Thank you for Help

this is my code:

CSHARP Code

namespace UpdateBuilder
    {
    public partial class MainFrm : Form
    {
 
        public string fileName = "";
        public string output = "";
 
        public MainFrm()
        {
            InitializeComponent();
        }
 
        private void browseBtn_Click(object sender, EventArgs e)
        {
            // Show a file browsing dialog
            OpenFileDialog dialog = new OpenFileDialog();
            dialog.Filter = "All files (*.*)|*.*";
            dialog.InitialDirectory = Directory.GetCurrentDirectory();
            dialog.Title = "Select a file to build";
            if (dialog.ShowDialog() == DialogResult.OK)
            {
                // Place the selected file's path in the input textbox
                inBox.Text = dialog.FileName;
                fileName = dialog.SafeFileName;
            }
        }
 
        private void buildBtn_Click(object sender, EventArgs e)
        {
            if (inBox.Text != "")
            {
                // Disable all controls
                inBox.Enabled = false;
                browseBtn.Enabled = false;
                buildBtn.Enabled = false;
 
                // Start the converion utility
                ProcessStartInfo startInfo = new ProcessStartInfo();
                startInfo.FileName = "lzma.exe";
                startInfo.Arguments = "e " + inBox.Text + " " + inBox.Text + ".lzma -d21";
                startInfo.CreateNoWindow = true;
                startInfo.WindowStyle = ProcessWindowStyle.Hidden;
 
                using (Process p = Process.Start(startInfo))
                {
                    // And wait for it to finish
                    while (!p.HasExited)
                    {
                        Thread.Sleep(100);
                    }
                }
 
                // Generate that final string
                FileInfo inFile = new FileInfo(inBox.Text);
                FileInfo outFile = new FileInfo(inBox.Text + ".lzma");
                output = "<ContentFile Name=\"" + fileName + "\" Size=\"" + inFile.Length.ToString() + "\" SHA1Hash=\"" + HashCalc.GetSHA1Hash(inBox.Text) + "\" CompressedSize=\"" + outFile.Length.ToString() + "\" />";
 
                // Re-enable the controls
                inBox.Enabled = true;
                browseBtn.Enabled = true;
                buildBtn.Enabled = true;
 
                // Show notice and copy output to clipboard
                Clipboard.SetText(output);
                MessageBox.Show("Build succeeded.\nCopied output to clipboard.");
            }
            else
            {
                MessageBox.Show("Please select a file to build.");
            }
        }
 
    }
    }

[raminr63]

pleas some one help me