/// <summary>
/// Receives our own property change events to update IsValid.
/// </summary>
void StandaloneTargetView_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
Debug.Assert(sender == this);
if (e.PropertyName != "IsValid")
{
IsValid = ScriptPath.IndexOfAny(Path.GetInvalidPathChars()) == -1 &&
WorkingDirectory.IndexOfAny(Path.GetInvalidPathChars()) == -1 &&
(Path.IsPathRooted(ScriptPath) || Path.IsPathRooted(WorkingDirectory)) &&
File.Exists(Path.Combine(WorkingDirectory, ScriptPath)) &&
(WorkingDirectory == string.Empty || Directory.Exists(WorkingDirectory)) &&
(File.Exists(InterpreterPath));
}
}