C#: Get MimeType from a File Name

private string GetMimeType (string fileName)
{
string mimeType = "application/unknown";
string ext = System.IO.Path.GetExtension(fileName).ToLower();
Microsoft.Win32.RegistryKey regKey = Microsoft.Win32.Registry.ClassesRoot.OpenSubKey(ext);
if (regKey != null && regKey.GetValue("Content Type") != null)
mimeType = regKey.GetValue("Content Type").ToString();
return mimeType;
}

C#: Handle new line characters ("\n") while saving text to file

New line charactars as observed in multi line TextBox or RichTextBox controls ("\n") often cause invalid characters to be saved in the file when it is saved. In order to appropriately handle new line characters, the following code can be used in stead of WriteLine:

FileStream fs = new FileStream(saveFileDialog1.FileName, FileMode.OpenOrCreate,FileAccess.ReadWrite);
StreamWriter sw = new StreamWriter(fs, Encoding.UTF8);
sw.Write(txtReturn.Text.Replace("\n",Environment.NewLine)); // Environment.NewLine is the real trick ;-)
sw.Dispose(); sw = null;
fs.Dispose(); fs = null;

C#: Execute a windows batch script and wait for return

Unlike simply calling Process.Start("executable_name.exe","arguments") - which does not pause the parent C# process thread, use the below implementation for waiting for the batch script to finish executing before proceeding with the next set of instructions:

using System.Diagnostics;

Process proc = new Process();
proc.StartInfo.FileName = "C:\\myscript.bat";
proc.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
proc.Start();
proc.WaitForExit();
int exitCode = proc.ExitCode;
proc.Close();