# System.InvalidOperationException: LINQ 表达式 'DbSet<X>.Where(x => x.Property.Contains("value") || x.OtherProperty.Contains("other"))' 无法翻译。请以可翻译的形式重写查询，或通过插入对 'AsEnumerable'、'AsAsyncEnumerable'、'ToList' 或 'ToListAsync' 的调用来显式切换到客户端评估。

- **ID:** `dotnet/ef-core-query-cannot-be-translated-into-a-sql-expression`
- **领域:** dotnet
- **类别:** data_error
- **验证级别:** ai_generated
- **修复率:** 85%

## 根因

当 LINQ 表达式使用数据库提供程序不支持的某些字符串方法、自定义函数或复杂逻辑等构造时，Entity Framework Core 无法将其翻译为 SQL。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| Entity Framework Core 7.0 | active | — | — |
| Entity Framework Core 8.0 | active | — | — |
| Microsoft.EntityFrameworkCore.SqlServer 8.0.0 | active | — | — |

## 解决方案

1. ```
   仅使用数据库支持的构造重写 LINQ 表达式。例如，将 'x.Property.Contains("value") || x.OtherProperty.Contains("other")' 替换为 'EF.Functions.Like(x.Property, "%value%") || EF.Functions.Like(x.OtherProperty, "%other%")'，这会翻译为 SQL LIKE。
   ```
2. ```
   如果无法重写查询，则显式使用客户端评估，但首先在服务器端尽可能过滤。例如：'var filtered = await context.Orders.Where(o => o.Status == "Active").ToListAsync(); var result = filtered.Where(o => o.Description.Contains("keyword")).ToList();'
   ```

## 无效尝试

- **** — Calling 'ToList()' before the filter forces client evaluation but loads all data into memory, causing performance issues and potential out-of-memory errors. (75% 失败率)
- **** — Adding 'AsEnumerable()' at the start of the query chain also forces full client evaluation, defeating the purpose of database filtering. (80% 失败率)
- **** — Ignoring the error and assuming the query works on a different database provider (e.g., SQLite vs SQL Server) leads to runtime failures when deploying. (90% 失败率)