为什么在尝试删除单个对象时会出现此错误？

Question

当用户删除我的 Entity Framework 核心网站上的记录时出现此错误：

Microsoft.EntityFrameworkCore.DbUpdateConcurrencyException: The database operation was expected to affect 1 row(s), but actually affected 0 row(s);

这一行是错误发生的地方：await _context.SaveChangesAsync();

我按照此页面设置删除控制器：https://docs.microsoft.com/en-us/ef/core/saving/basic

代码如下：

public class GameWorldsController : ControllerBase
{
    private readonly actionGames_ProdContext _context;
    
    public GameWorldsController(actionGames_ProdContext context)
    {   
        _context = context;
        
    }
    
    [HttpDelete("{id}")]    
    public async Task<ActionResult<GameWorlds>> DeleteGameWorlds(string id)
    {
        var gameWorlds = await _context.GameWorlds.FindAsync(id);
        
        if (gameWorlds == null)
        {
            return NotFound("Game World does not exist.");
        }
        
        _context.GameWorlds.Remove(gameWorlds);
        await _context.SaveChangesAsync();
        
        return gameWorlds;
    }
}

我能做些什么来解决这个问题吗？

完整的错误状态：

 Microsoft.EntityFrameworkCore.DbUpdateConcurrencyException: The database operation was expected to affect 1 row(s), but actually affected 0 row(s); data may have been modified or deleted since entities were loaded. See http://go.microsoft.com/fwlink/?LinkId=527962 for information on understanding and handling optimistic concurrency exceptions.

   at Microsoft.EntityFrameworkCore.Update.AffectedCountModificationCommandBatch.ThrowAggregateUpdateConcurrencyException(Int32 commandIndex, Int32 expectedRowsAffected, Int32 rowsAffected)

   at Microsoft.EntityFrameworkCore.Update.AffectedCountModificationCommandBatch.ConsumeResultSetWithoutPropagationAsync(Int32 commandIndex, RelationalDataReader reader, CancellationToken cancellationToken)

   at Microsoft.EntityFrameworkCore.Update.AffectedCountModificationCommandBatch.ConsumeAsync(RelationalDataReader reader, CancellationToken cancellationToken)

   at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.ExecuteAsync(IRelationalConnection connection, CancellationToken cancellationToken)

   at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.ExecuteAsync(IRelationalConnection connection, CancellationToken cancellationToken)

   at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.ExecuteAsync(IEnumerable`1 commandBatches, IRelationalConnection connection, CancellationToken cancellationToken)

   at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.ExecuteAsync(IEnumerable`1 commandBatches, IRelationalConnection connection, CancellationToken cancellationToken)

   at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.ExecuteAsync(IEnumerable`1 commandBatches, IRelationalConnection connection, CancellationToken cancellationToken)

   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(IList`1 entriesToSave, CancellationToken cancellationToken)

   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(StateManager stateManager, Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)

   at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func`4 operation, Func`4 verifySucceeded, CancellationToken cancellationToken)

   at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)

   at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)

Answer 1

这看起来像是一个竞争条件，其中 EF 尝试删除在 SaveChangesAsync 之前已经删除的记录。你可以试试这个来验证是否是这样：

将断点放在 SaveChangesAsync。
开始调试。
调用 API 并等待调试器到达断点。
从数据库中删除记录
继续调试。

如果是这样，您将看到相同的错误。对此没有快速解决方法，您可以尝试捕获该特定异常并根据需要忽略它。

为什么在尝试删除单个对象时会出现此错误？

Why am I getting this error when trying to delete a single object?

c#

entity-framework-core