fix: avoid SqlSugar invalid SQL from null/HasValue KB filters

Co-authored-by: Cursor <cursoragent@cursor.com>

src/Oms.Application/Services/Kb/KbArticleService.cs

@@ -209,33 +209,68 @@ public class KbArticleService : ApplicationService
 
     private static Expression<Func<KbArticle, bool>> BuildAdminPredicate(KbArticleListInput input)
     {
-        var keyword = input.Keyword?.Trim();
+        var keyword = NormalizeOptional(input.Keyword);
         var status = NormalizeOptional(input.Status);
         var audience = NormalizeOptional(input.Audience);
-        return x =>
+        var predicate = ExpressionPredicate.True<KbArticle>();
-            (!input.CategoryId.HasValue || x.CategoryId == input.CategoryId.Value)
+
-            && (status == null || x.Status == status)
+        if (input.CategoryId is int categoryId)
-            && (audience == null || x.Audience == audience)
+        {
-            && (!input.IsPinned.HasValue || x.IsPinned == input.IsPinned.Value)
+            predicate = ExpressionPredicate.AndAlso(predicate, x => x.CategoryId == categoryId);
-            && (keyword == null
+        }
-                || x.Title.Contains(keyword)
+
-                || (x.Summary != null && x.Summary.Contains(keyword))
+        if (status != null)
-                || (x.Tags != null && x.Tags.Contains(keyword)));
+        {
+            predicate = ExpressionPredicate.AndAlso(predicate, x => x.Status == status);
+        }
+
+        if (audience != null)
+        {
+            predicate = ExpressionPredicate.AndAlso(predicate, x => x.Audience == audience);
+        }
+
+        if (input.IsPinned is bool isPinned)
+        {
+            predicate = ExpressionPredicate.AndAlso(predicate, x => x.IsPinned == isPinned);
+        }
+
+        if (keyword != null)
+        {
+            predicate = ExpressionPredicate.AndAlso(
+                predicate,
+                x => x.Title.Contains(keyword)
+                    || (x.Summary != null && x.Summary.Contains(keyword))
+                    || (x.Tags != null && x.Tags.Contains(keyword)));
+        }
+
+        return predicate;
     }
 
     private static Expression<Func<KbArticle, bool>> BuildPortalPredicate(string? keyword, int? categoryId)
     {
         var kw = NormalizeOptional(keyword);
         var now = DateTime.Now;
-        return x =>
+        var predicate = ExpressionPredicate.AndAlso(
-            x.Status == KbArticleStatusCodes.Published
+            ExpressionPredicate.True<KbArticle>(),
-            && x.Audience == KbAudienceCodes.Customer
+            x => x.Status == KbArticleStatusCodes.Published
-            && (x.ExpireTime == null || x.ExpireTime > now)
+                && x.Audience == KbAudienceCodes.Customer
-            && (!categoryId.HasValue || x.CategoryId == categoryId.Value)
+                && (x.ExpireTime == null || x.ExpireTime > now));
-            && (kw == null
+
-                || x.Title.Contains(kw)
+        if (categoryId is int cid)
-                || (x.Summary != null && x.Summary.Contains(kw))
+        {
-                || (x.Tags != null && x.Tags.Contains(kw)));
+            predicate = ExpressionPredicate.AndAlso(predicate, x => x.CategoryId == cid);
+        }
+
+        if (kw != null)
+        {
+            predicate = ExpressionPredicate.AndAlso(
+                predicate,
+                x => x.Title.Contains(kw)
+                    || (x.Summary != null && x.Summary.Contains(kw))
+                    || (x.Tags != null && x.Tags.Contains(kw)));
+        }
+
+        return predicate;
     }
 
     private static void EnsurePortalVisible(KbArticle entity)

src/Oms.Application/Services/Kb/KbCategoryService.cs

@@ -1,8 +1,10 @@
+using System.Linq.Expressions;
 using Fake.Application;
 using Fake.Domain.Exceptions;
 using Microsoft.AspNetCore.Mvc;
 using Oms.Application.Dtos.Kb;
 using Oms.Application.Dtos.Shared;
+using Oms.Application.Shared;
 using Oms.Domain.KbAggregate.Entities;
 using Oms.Domain.KbAggregate.Repositories;
 
@@ -23,8 +25,13 @@ public class KbCategoryService : ApplicationService
     [HttpGet("/kb/admin/category/list")]
     public async Task<OmsItemsResult<KbCategoryOutput>> AdminListAsync([FromQuery] bool? enabledOnly = null)
     {
-        var items = await CategoryRepository.GetListAsync(x =>
+        Expression<Func<KbCategory, bool>> predicate = ExpressionPredicate.True<KbCategory>();
-            !enabledOnly.HasValue || x.Enabled == enabledOnly.Value);
+        if (enabledOnly is bool enabled)
+        {
+            predicate = ExpressionPredicate.AndAlso(predicate, x => x.Enabled == enabled);
+        }
+
+        var items = await CategoryRepository.GetListAsync(predicate);
         var ordered = items.OrderBy(x => x.SortOrder).ThenBy(x => x.Id).ToList();
         return new OmsItemsResult<KbCategoryOutput>
         {

src/Oms.Application/Shared/ExpressionPredicate.cs

@@ -0,0 +1,38 @@
+using System.Linq.Expressions;
+
+namespace Oms.Application.Shared;
+
+/// <summary>
+/// 组合 LINQ 谓词，避免把 `HasValue` / `== null` 写进表达式导致 SqlSugar 生成非法 SQL。
+/// </summary>
+public static class ExpressionPredicate
+{
+    public static Expression<Func<T, bool>> True<T>() => static _ => true;
+
+    public static Expression<Func<T, bool>> AndAlso<T>(
+        Expression<Func<T, bool>> left,
+        Expression<Func<T, bool>> right)
+    {
+        var parameter = Expression.Parameter(typeof(T), "x");
+        var leftBody = new ReplaceParameterVisitor(left.Parameters[0], parameter).Visit(left.Body)
+            ?? throw new InvalidOperationException("left predicate body is null");
+        var rightBody = new ReplaceParameterVisitor(right.Parameters[0], parameter).Visit(right.Body)
+            ?? throw new InvalidOperationException("right predicate body is null");
+        return Expression.Lambda<Func<T, bool>>(Expression.AndAlso(leftBody, rightBody), parameter);
+    }
+
+    private sealed class ReplaceParameterVisitor : ExpressionVisitor
+    {
+        private readonly ParameterExpression _from;
+        private readonly ParameterExpression _to;
+
+        public ReplaceParameterVisitor(ParameterExpression from, ParameterExpression to)
+        {
+            _from = from;
+            _to = to;
+        }
+
+        protected override Expression VisitParameter(ParameterExpression node) =>
+            ReferenceEquals(node, _from) ? _to : base.VisitParameter(node);
+    }
+}