Add project files.

UI/WPF/Extensions/EventArgsExtensions.cs

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+using System;
+using System.Globalization;
+using System.Windows.Data;
+
+namespace TheXamlGuy.UI.WPF;
+
+public static class EventArgsExtensions
+{
+    public static dynamic? GetEventArguments(this EventArgs args, string? path, IValueConverter? converter, object? converterParameter)
+    {
+        if (path is { Length: > 0 })
+        {
+            if (GetEventArgsPropertyPathValue(args, path) is object value)
+            {
+                if (converter is not null)
+                {
+                    return converter.Convert(value, typeof(object), converterParameter, CultureInfo.CurrentCulture);
+                }
+
+                return value;
+            }
+        }
+
+        return args;
+    }
+
+    private static object GetEventArgsPropertyPathValue(object args, string path)
+    {
+        object? value = args;
+        if (path is { })
+        {
+            value = PropertyPathHelper.GetValue(args, path);
+        }
+
+        return value;
+    }
+}