完善功能

电子展板/Utility/ContentTypeUtils.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace 电子展板.Utility
+{
+    public class ContentTypeUtils
+    {
+        public static string GetContentType(string fileName)
+        {
+            return System.Web.MimeMapping.GetMimeMapping(fileName);
+        }
+    }
+}