/// <summary>
/// Opens entity utility functions. This opens an entity translation file
/// referred to via the Backsight property <see cref="PropertyNaming.EntityFile"/>
/// (if there is such a definition). It then reads the file into an
/// <see cref="EntityFile"/> object for later use.
/// <para/>
/// Also opens a style file referred to via the property
/// <see cref="PropertyNaming.StyleFile"/> (if there is such a definition).
/// It then reads the file into a <see cref="StyleFile"/> object for later use.
/// </summary>
/// <returns>True if an entity file and/or style file was loaded.</returns>
/// <remarks>
/// This function should be called near the start of the application. To release
/// the resources, a subsequent call to <see cref="Close"/> should be made.
/// </remarks>
internal bool Open()
{
// Ensure any files previously loaded have been released.
Close();
s_EntityFile = OpenEntityFile();
s_StyleFile = OpenStyleFile();
return (s_EntityFile!=null || s_StyleFile!=null);
}
/// <summary>
/// Also opens a style file referred to via the property
/// <see cref="PropertyNaming.StyleFile"/> (if there is such a definition).
/// It then reads the file into a <see cref="StyleFile"/> object for later use.
/// </summary>
/// <returns>The loaded style file (or null if no such file, or it could
/// not be loaded). If the environment variable is undefined, you get back
/// an object that represents an empty style file.</returns>
StyleFile OpenStyleFile()
{
// Get the translation (if any) of the property
// that refers to the standard style file.
IProperty prop = EnvironmentContainer.FindPropertyByName(PropertyNaming.StyleFile);
string stdfile = (prop == null ? null : prop.Value);
if (String.IsNullOrEmpty(stdfile))
return new StyleFile();
// Create a new style file object, and ask it to load the file.
StyleFile file = new StyleFile();
int nStyle = file.Create(stdfile);
// Return the file if it loaded ok
return (nStyle > 0 ? file : null);
}
/// <summary>
/// Releases any resources that were allocated via a prior
/// call to <see cref="Open"/>
/// </summary>
internal void Close()
{
s_EntityFile = null;
s_StyleFile = null;
}
