初步添加用户头像支持，仍需要完善

CommonLibrary/PortraitSupport/PortraitSupport.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.IO;
+
+namespace CommonLibrary
+{
+    public class PortraitSupport
+    {
+        /// <summary>
+        /// 小尺寸头像
+        /// </summary>
+        public const string SmallPortraitHead = "Size_32_";
+        /// <summary>
+        /// 大尺寸头像
+        /// </summary>
+        public const string LargePortraitHead = "Size_300_";
+
+
+        public static string GetSmallPortraitFileName(string dirPath)
+        {
+            string[] files = Directory.GetFiles(dirPath);
+            foreach(var m in files)
+            {
+                if(m.Contains(SmallPortraitHead))
+                {
+                    return m;
+                }
+            }
+            return string.Empty;
+        }
+        public static string GetLargePortraitFileName(string dirPath)
+        {
+            string[] files = Directory.GetFiles(dirPath);
+            foreach (var m in files)
+            {
+                if (m.Contains(LargePortraitHead))
+                {
+                    return m;
+                }
+            }
+            return string.Empty;
+        }
+    }
+}