replace v6 with experimental v7 code

src/MpvNet.Windows/WPF/HandyControl/Tools/Extension/StringExtension.cs

@@ -0,0 +1,33 @@
+
+
+using System.ComponentModel;
+
+namespace HandyControl.Tools.Extension
+{
+    public static class StringExtension
+    {
+        public static T Value<T>(this string input)
+        {
+            try
+            {
+                return (T) TypeDescriptor.GetConverter(typeof(T)).ConvertFromString(input);
+            }
+            catch
+            {
+                return default;
+            }
+        }
+
+        public static object Value(this string input, Type type)
+        {
+            try
+            {
+                return TypeDescriptor.GetConverter(type).ConvertFromString(input);
+            }
+            catch
+            {
+                return null;
+            }
+        }
+    }
+}