组件(Table)中表单维护，用 EF Core + MS Sql Server 作为数据源后，编辑功能无法正常使用。

[sundows]

BootstrapBlazor + Server 用 EF Core + MS Sql Server 作为数据源后，本人小白在实战过程中发现有些问题，不知哪位大佬可以解疑？
1、

按以上的 Table 设置后，添加、删除、过滤等功能都可以正常使用，数据库里的实际数据也发现变化，但是编辑功能无法正常使用，点击“取消/保存”按钮出现如下异常。
warn: Microsoft.AspNetCore.Components.Server.Circuits.RemoteRenderer[100]
Unhandled exception rendering component: The instance of entity type 'Customer' cannot be tracked because another instance with the key value '{CustomerId: 19}' is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached.
System.InvalidOperationException: The instance of entity type 'Customer' cannot be tracked because another instance with the key value '{CustomerId: 19}' is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached.
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap1.ThrowIdentityConflict(InternalEntityEntry entry) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap1.Add(TKey key, InternalEntityEntry entry, Boolean updateDuplicate)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap1.Add(TKey key, InternalEntityEntry entry) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap1.Add(InternalEntityEntry entry)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.StartTracking(InternalEntityEntry entry)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.InternalEntityEntry.SetEntityState(EntityState oldState, EntityState newState, Boolean acceptChanges, Boolean modifyProperties)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.InternalEntityEntry.SetEntityState(EntityState entityState, Boolean acceptChanges, Boolean modifyProperties, Nullable1 forceStateWhenUnknownKey, Nullable1 fallbackState)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.EntityGraphAttacher.PaintAction(EntityEntryGraphNode1 node) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.EntityEntryGraphIterator.TraverseGraph[TState](EntityEntryGraphNode1 node, Func2 handleNode) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.EntityGraphAttacher.AttachGraph(InternalEntityEntry rootEntry, EntityState targetState, EntityState storeGeneratedWithKeySetTargetState, Boolean forceStateWhenUnknownKey) at Microsoft.EntityFrameworkCore.DbContext.SetEntityState(InternalEntityEntry entry, EntityState entityState) at Microsoft.EntityFrameworkCore.DbContext.SetEntityState[TEntity](TEntity entity, EntityState entityState) at Microsoft.EntityFrameworkCore.DbContext.Update[TEntity](TEntity entity) at BootstrapBlazor.DataAccess.EntityFrameworkCore.DefaultDataService1.SaveAsync(TModel model, ItemChangedType changedType)
at BootstrapBlazor.Components.Table1.InternalOnSaveAsync(TItem item, ItemChangedType changedType) at BootstrapBlazor.Components.Table1.SaveModelAsync(EditContext context, ItemChangedType changedType)
at BootstrapBlazor.Components.Table1.OnSaveEditCallbackAsync(EditContext context, ItemChangedType changedType) at BootstrapBlazor.Components.Table1.<>c__DisplayClass1517_0.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at BootstrapBlazor.Components.TableEditDialogOptionExtensions.<>c__DisplayClass0_01.<<ToParameter>b__1>d.MoveNext() --- End of stack trace from previous location --- at BootstrapBlazor.Components.EditDialog1.OnValidSubmitAsync(EditContext context)
at BootstrapBlazor.Components.ValidateForm.OnValidSubmitForm(EditContext context)
at BootstrapBlazor.Components.BootstrapComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
at BootstrapBlazor.Components.BootstrapComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
at Microsoft.AspNetCore.Components.Forms.EditForm.HandleSubmitAsync()
at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)
fail: Microsoft.AspNetCore.Components.Server.Circuits.CircuitHost[111]
Unhandled exception in circuit '67Snb4hvPuhDymBZ0W4pMC1sMShVy4Z4r_faoZS8zro'.
System.InvalidOperationException: The instance of entity type 'Customer' cannot be tracked because another instance with the key value '{CustomerId: 19}' is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached.
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap1.ThrowIdentityConflict(InternalEntityEntry entry) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap1.Add(TKey key, InternalEntityEntry entry, Boolean updateDuplicate)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap1.Add(TKey key, InternalEntityEntry entry) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap1.Add(InternalEntityEntry entry)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.StartTracking(InternalEntityEntry entry)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.InternalEntityEntry.SetEntityState(EntityState oldState, EntityState newState, Boolean acceptChanges, Boolean modifyProperties)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.InternalEntityEntry.SetEntityState(EntityState entityState, Boolean acceptChanges, Boolean modifyProperties, Nullable1 forceStateWhenUnknownKey, Nullable1 fallbackState)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.EntityGraphAttacher.PaintAction(EntityEntryGraphNode1 node) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.EntityEntryGraphIterator.TraverseGraph[TState](EntityEntryGraphNode1 node, Func2 handleNode) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.EntityGraphAttacher.AttachGraph(InternalEntityEntry rootEntry, EntityState targetState, EntityState storeGeneratedWithKeySetTargetState, Boolean forceStateWhenUnknownKey) at Microsoft.EntityFrameworkCore.DbContext.SetEntityState(InternalEntityEntry entry, EntityState entityState) at Microsoft.EntityFrameworkCore.DbContext.SetEntityState[TEntity](TEntity entity, EntityState entityState) at Microsoft.EntityFrameworkCore.DbContext.Update[TEntity](TEntity entity) at BootstrapBlazor.DataAccess.EntityFrameworkCore.DefaultDataService1.SaveAsync(TModel model, ItemChangedType changedType)
at BootstrapBlazor.Components.Table1.InternalOnSaveAsync(TItem item, ItemChangedType changedType) at BootstrapBlazor.Components.Table1.SaveModelAsync(EditContext context, ItemChangedType changedType)
at BootstrapBlazor.Components.Table1.OnSaveEditCallbackAsync(EditContext context, ItemChangedType changedType) at BootstrapBlazor.Components.Table1.<>c__DisplayClass1517_0.<b__1>d.MoveNext()
--- End of stack trace from previous location ---
at BootstrapBlazor.Components.TableEditDialogOptionExtensions.<>c__DisplayClass0_01.<<ToParameter>b__1>d.MoveNext() --- End of stack trace from previous location --- at BootstrapBlazor.Components.EditDialog1.OnValidSubmitAsync(EditContext context)
at BootstrapBlazor.Components.ValidateForm.OnValidSubmitForm(EditContext context)
at BootstrapBlazor.Components.BootstrapComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
at BootstrapBlazor.Components.BootstrapComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
at Microsoft.AspNetCore.Components.Forms.EditForm.HandleSubmitAsync()
at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)
2、

按以上的 Table 设置后，添加、删除、修改等功能都可以使用，但是只是页面的数据发现变化，数据库里的实现数据没有变化。
Program.cs 里面的数据库设置如下：

不知有没有遇到同样问题的大佬，请不胜指点！

[Vision-Zhang]

步骤一，在查询数据时加上 AsNoTracking
步骤二， Bind-Items 修改的是内存数据源

[sundows]

步骤一，在查询数据时加上 AsNoTracking 步骤二， Bind-Items 修改的是内存数据源

@Vision-Zhang 感谢大佬的指点，按照你的步骤，查询时已加上 AsNoTracking，问题依然存在。

如果步骤二中，修改是内存数据源，那是不是需要用代码手动更新数据库，需要重载 SaveAsync、DeleteAsync、QueryAsync 等方法？

[Vision-Zhang]

去b站看看入门视频吧