添加项目文件。

Szmedi.RevitToolkit.Approval/Extensions/Extension.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+
+namespace Szmedi.RevitToolkit.Approval.Extensions
+{
+    internal static class Extension
+    {
+        /// <summary>
+        /// 提取字符串中所有中文字符
+        /// </summary>
+        public static string ExtractChinese(this string text)
+        {
+            if (string.IsNullOrEmpty(text)) return string.Empty;
+
+            // 先将非中文替换为空格，再将连续空格替换为单个空格，最后去除首尾空格
+            var result = Regex.Replace(text, @"[^\u4e00-\u9fa5]", " ");
+            result = Regex.Replace(result, @"\s+", " ").Trim();
+            return result;
+        }
+    }
+}