Fix BuildMap() generating orphaned [Map] attribute when mapped table has no display field

XCode/Code/EntityBuilder.cs

@@ -1176,7 +1176,7 @@ protected virtual void BuildMap()
                 mapName ??= mapTable.Columns.FirstOrDefault(e => e.Master);
                 mapName ??= mapTable.GetColumn("Name");
             }
-            else
+            else if (ss.Length > 2)
             {
                 // 默认字符串类型
                 mapName = new XField { Name = ss[2], DataType = typeof(String) };
@@ -1205,8 +1205,12 @@ protected virtual void BuildMap()
                 if (mapName != null && mapName.Name != "$") myName += mapName.Name;
             }
 
-            // 扩展属性有可能恰巧跟已有字段同名
-            if (!myName.IsNullOrEmpty() && !Table.Columns.Any(e => e.Name.EqualIgnoreCase(myName)))
+            // $表示用ToString()替代显示字段
+            var useToString = ss.Length > 2 && ss[2] == "$";
+
+            // 扩展属性有可能恰巧跟已有字段同名，且需要有显示字段才能生成扩展属性
+            if (!myName.IsNullOrEmpty() && !Table.Columns.Any(e => e.Name.EqualIgnoreCase(myName))
+                && (mapName != null || useToString))
             {
                 var type = Option.Nullable ? "String?" : "String";
 
@@ -1215,7 +1219,7 @@ protected virtual void BuildMap()
                 WriteLine("[Map(nameof({0}), typeof({1}), \"{2}\")]", column.Name, fullName, mapIdName);
                 if (column.Properties.TryGetValue("Category", out var att) && !att.IsNullOrEmpty())
                     WriteLine("[Category(\"{0}\")]", att);
-                if (ss.Length > 2 && ss[2] == "$")
+                if (useToString)
                     WriteLine("public {2} {0} => {1}?.ToString();", myName, name, type);
                 else if (mapName != null)
                 {

XUnitTest.XCode/Code/EntityBuilderTests.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using NewLife.Log;
@@ -400,6 +401,71 @@ public void FixModelFile()
         Assert.Contains("Name", xml);
     }
 
+    /// <summary>
+    /// 验证：Map特性只有表@主键（无显示字段），且被映射表无Master/Name字段时，
+    /// 不应生成孤立的[Map(...)]特性（缺少属性声明）
+    /// </summary>
+    [Fact]
+    public void BuildMap_NoDisplayField_NoOrphanedMapAttribute()
+    {
+        // 构造 ProductRelease 表（无 Master 字段，无 Name 字段）
+        var releaseTable = new XTable("ProductRelease") { Description = "产品版本" };
+        var releaseId = (XField)releaseTable.CreateColumn();
+        releaseId.Name = "Id";
+        releaseId.DataType = typeof(Int32);
+        releaseId.Identity = true;
+        releaseId.PrimaryKey = true;
+        releaseTable.Columns.Add(releaseId);
+
+        var releaseVersion = (XField)releaseTable.CreateColumn();
+        releaseVersion.Name = "Version";
+        releaseVersion.DataType = typeof(String);
+        releaseTable.Columns.Add(releaseVersion);
+
+        // 构造 ProductPackage 表，ReleaseId 的 Map 只有 "ProductRelease@Id"（无显示字段）
+        var packageTable = new XTable("ProductPackage") { Description = "产品发布包" };
+        var pkgId = (XField)packageTable.CreateColumn();
+        pkgId.Name = "Id";
+        pkgId.DataType = typeof(Int32);
+        pkgId.Identity = true;
+        pkgId.PrimaryKey = true;
+        packageTable.Columns.Add(pkgId);
+
+        var releaseIdCol = (XField)packageTable.CreateColumn();
+        releaseIdCol.Name = "ReleaseId";
+        releaseIdCol.DataType = typeof(Int32);
+        releaseIdCol.Map = "ProductRelease@Id";
+        releaseIdCol.Description = "发布版本。所属发布版本";
+        packageTable.Columns.Add(releaseIdCol);
+
+        var allTables = new List<IDataTable> { releaseTable, packageTable };
+
+        var option = new EntityBuilderOption
+        {
+            ConnName = "Test",
+            Namespace = "Test",
+            Nullable = true,
+        };
+
+        var builder = new EntityBuilder
+        {
+            Table = packageTable,
+            AllTables = allTables,
+            Option = option,
+        };
+
+        builder.Execute();
+        var code = builder.ToString();
+
+        Assert.NotEmpty(code);
+
+        // 验证不存在孤立的[Map(...)]特性（即[Map后面紧跟空行或#endregion）
+        Assert.DoesNotContain("[Map(nameof(ReleaseId)", code);
+
+        // 验证仍然生成了对象引用属性（ProductRelease对象），且使用 Extends.Get 模式
+        Assert.Contains("public ProductRelease? Release => Extends.Get(nameof(Release), k => ProductRelease.FindById(ReleaseId));", code);
+    }
+
     [Fact(Skip = "跳过")]
     public void Merge()
     {