complete the branch

HandyControlDemo/Tools/Helper/AssemblyHelper.cs

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+using System;
+
+namespace HandyControlDemo.Tools
+{
+    public class AssemblyHelper
+    {
+        private static readonly string NameSpaceStr = typeof(AssemblyHelper).Assembly.GetName().Name;
+
+        public static object CreateInternalInstance(string className)
+        {
+            try
+            {
+                var type = Type.GetType($"{NameSpaceStr}.{className}");
+                return type == null ? null : Activator.CreateInstance(type);
+            }
+            catch
+            {
+                return null;
+            }
+        }
+    }
+}

HandyControlDemo/Tools/Helper/CommonHelper.cs

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+using System.Linq;
+using System.Management;
+using HandyControl.Data;
+
+namespace HandyControlDemo.Tools
+{
+    public class CommonHelper
+    {
+        public static SystemVersionInfo GetSystemVersionInfo()
+        {
+            var managementClass = new ManagementClass("Win32_OperatingSystem");
+            var instances = managementClass.GetInstances();
+            foreach (var instance in instances)
+            {
+                if (instance["Version"] is string version)
+                {
+                    var nums = version.Split('.').Select(int.Parse).ToList();
+                    var info = new SystemVersionInfo(nums[0], nums[1], nums[2]);
+                    return info;
+                }
+            }
+            return default(SystemVersionInfo);
+        }
+    }
+}

HandyControlDemo/Tools/Helper/ExternDllHelper.cs

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+using System.Runtime.InteropServices;
+
+namespace HandyControlDemo.Tools
+{
+    internal class ExternDllHelper
+    {
+        private const string Winmm = "winmm.dll";
+
+        [DllImport(Winmm, EntryPoint = "mciSendString", CharSet = CharSet.Auto)]
+        public static extern int MciSendString(string lpstrCommand, string lpstrReturnString, int uReturnLength, int hwndCallback);
+    }
+}