将Feature/XP.Common和Feature/XP.Hardware分支合并至Develop/XP.forHardwareAndCommon，完善XPapp注册和相关硬件类库通用类库功能。

XP.Hardware.PLC.Sentry/Converters/NullOrEmptyToVisibilityConverter.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Globalization;
+using System.Windows;
+using System.Windows.Data;
+
+namespace XP.Hardware.PLC.Sentry.Converters
+{
+    /// <summary>
+    /// 将 null 或空字符串转换为 Collapsed，非空字符串转换为 Visible | Converts null/empty string to Collapsed, non-empty to Visible
+    /// </summary>
+    public class NullOrEmptyToVisibilityConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return string.IsNullOrEmpty(value as string) ? Visibility.Collapsed : Visibility.Visible;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            throw new NotSupportedException();
+        }
+    }
+}