From c73ea6ac918952fbe0fd37b426a3e957afd6ddc3 Mon Sep 17 00:00:00 2001
From: sunkaixuan <610262374@qq.com>
Date: Thu, 11 Sep 2025 16:25:16 +0800
Subject: [PATCH] Update mongodb

---
 .../SqlBuilder/MongoDbExpressionContext.cs    | 22 +++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/Src/Asp.NetCore2/SqlSugar.MongoDbCore/MongoDb/SqlBuilder/MongoDbExpressionContext.cs b/Src/Asp.NetCore2/SqlSugar.MongoDbCore/MongoDb/SqlBuilder/MongoDbExpressionContext.cs
index 7dc5f023b..7d8e69eb9 100644
--- a/Src/Asp.NetCore2/SqlSugar.MongoDbCore/MongoDb/SqlBuilder/MongoDbExpressionContext.cs
+++ b/Src/Asp.NetCore2/SqlSugar.MongoDbCore/MongoDb/SqlBuilder/MongoDbExpressionContext.cs
@@ -339,7 +339,7 @@ namespace SqlSugar.MongoDb
             context.queryBuilder.LambdaExpressions.Index++;
             return name;
         } 
-        public override string Contains(MethodCallExpressionModel model)
+      public override string Contains(MethodCallExpressionModel model)
         {
             var item = model.Args.First().MemberValue;
             BsonValue right = new ExpressionVisitor(context).Visit(item as Expression);
@@ -349,12 +349,26 @@ namespace SqlSugar.MongoDb
             {
                 { "$regex", right },        // right 是普通字符串值，例如 "a"
                 { "$options", "i" }         // 忽略大小写
-            }; 
-            var match=new BsonDocument
+            };
+            if (left is BsonDocument bsonDoc)
+            {
+                // left 是复杂表达式（如聚合管道中的表达式），需要嵌套 $expr
+                var exprDoc = new BsonDocument("$expr", new BsonDocument("$regexMatch", new BsonDocument
+                {
+                    { "input", bsonDoc },
+                    { "regex", right },
+                    { "options", "i" }
+                }));
+                return exprDoc.ToJson(UtilMethods.GetJsonWriterSettings());
+            }
+            else
+            {
+                var match = new BsonDocument
                 {
                     { left.ToString(), regexDoc }
                 };
-            return match.ToJson(UtilMethods.GetJsonWriterSettings());
+                return match.ToJson(UtilMethods.GetJsonWriterSettings());
+            }
         }
         public override string StartsWith(MethodCallExpressionModel model)
         {