Checks whether Microsoft Outlook is installed on a Windows system.

Check whether Outlook is installed via C#

private bool IsOutlookInstalled()
{
	Type requestType = Type.GetTypeFromProgID("Outlook.Application", false);
	if (requestType == null)
	{
		RegistryKey key = null;
		try
		{
			key = Registry.CurrentUser.OpenSubKey("Software\\Microsoft\\Office", false);
			if (key != null)
			{
				double version = 0.0, temp = 0.0;
				string[] valueNames = key.GetSubKeyNames();
				for (int i = 0; i < valueNames.Length; i++)
				{
					temp = 0.0;
					try
					{
						temp = Convert.ToDouble(valueNames[i],
						CultureInfo.CreateSpecificCulture("en-US").NumberFormat);
					}
					catch
					{
					}
					if (temp > version) version = temp;
				}
				key.Close();
				if (version != 0.0)
					requestType = Type.GetTypeFromProgID("Outlook.Application." + version.ToString().Replace(",", "."), false);
			}
		}
		catch
		{
			if (key != null) key.Close();
		}
	}
	return (requestType != null);
}

private int GetOfficeVersion()
{
	RegistryKey key = null;
	try
	{
		key = Registry.ClassesRoot.OpenSubKey("Outlook.Application\\CurVer", false);
		if (key != null)
		{
			string version = key.GetValue("", "Outlook.Application.9").ToString(); key.Close();
			int pos = version.LastIndexOf(".");
			if (pos >= 0)
			{
				version = version.Remove(0, pos + 1);
				return Convert.ToInt32(version);
			}
		}
	}
	catch (Exception e)
	{
		if (key != null) key.Close();
		module.DoError(e);
	}
	return 9;
}