C# 在Silverlight 4 RIA（实体框架）中从数据库中删除对象

我正在开发基于一对多关联的简单Silverlight4应用程序。 提出了关系模型

该页面由两个网格组成，一个直接从DomainDataSource（ExcelTemplate one）加载。选择ExcelTemplate后，第二个将加载ObservaleCollection中的ColumnValidationRules，该集合基于ExcelTemplate的列表填充。实体没有OnDelete操作。我在删除ColumnValidationRule对象族时遇到很多问题。基本上，我尝试了两种不同的方法：

• 使用仅删除ColumnValidationRule ColumnValidationRuleDomainDataSource（基于GetColumnValidationRule查询）：

XAML与my DomainDataSources:

                                <riaControls:DomainDataSource AutoLoad="True" d:DesignData="{d:DesignInstance my:ExcelTemplate, CreateList=true}" Height="0" LoadedData="ExcelTemplateDomainDataSource_LoadedData" Name="excelTemplatesForValidatiorsDDS" QueryName="GetExcelTemplatesQuery" Width="0">
                                    <riaControls:DomainDataSource.DomainContext>
                                        <my1:SRFDomainContext />
                                    </riaControls:DomainDataSource.DomainContext>
                                </riaControls:DomainDataSource>

                                <riaControls:DomainDataSource AutoLoad="True" d:DesignData="{d:DesignInstance my:ColumnValidationRule, CreateList=true}" Height="0" LoadedData="ExcelTemplateDomainDataSource_LoadedData" Name="columnValidationRulesDomainDataSource" QueryName="GetColumnValidationRulesQuery" Width="0">
                                    <riaControls:DomainDataSource.DomainContext>
                                        <my1:SRFDomainContext />
                                    </riaControls:DomainDataSource.DomainContext>
                                </riaControls:DomainDataSource>

w System.ServiceModel.DomainServices.Client.EntitySet.Remove(Entity entity)
   w System.Windows.Controls.PagedEntityCollectionView.RemoveCore(Entity item, Int32 index)
   w System.Windows.Controls.PagedEntityCollectionView.RemoveItem(Entity item)
   w System.Windows.Controls.EntityCollectionView.Remove(Object item)
   w System.Windows.Controls.DomainDataSourceView.Remove(Object item)
   w LANOS.UserManagement.DeleteRuleButton_Click(Object sender, RoutedEventArgs e)
   w System.Windows.Controls.Primitives.ButtonBase.OnClick()
   w System.Windows.Controls.Button.OnClick()
   w System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
   w System.Windows.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e)
   w MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventN

结果我得到一个错误： 指定的实体不包含在此EntitySet中。

错误详细信息：

                                <riaControls:DomainDataSource AutoLoad="True" d:DesignData="{d:DesignInstance my:ExcelTemplate, CreateList=true}" Height="0" LoadedData="ExcelTemplateDomainDataSource_LoadedData" Name="excelTemplatesForValidatiorsDDS" QueryName="GetExcelTemplatesQuery" Width="0">
                                    <riaControls:DomainDataSource.DomainContext>
                                        <my1:SRFDomainContext />
                                    </riaControls:DomainDataSource.DomainContext>
                                </riaControls:DomainDataSource>

                                <riaControls:DomainDataSource AutoLoad="True" d:DesignData="{d:DesignInstance my:ColumnValidationRule, CreateList=true}" Height="0" LoadedData="ExcelTemplateDomainDataSource_LoadedData" Name="columnValidationRulesDomainDataSource" QueryName="GetColumnValidationRulesQuery" Width="0">
                                    <riaControls:DomainDataSource.DomainContext>
                                        <my1:SRFDomainContext />
                                    </riaControls:DomainDataSource.DomainContext>
                                </riaControls:DomainDataSource>

w System.ServiceModel.DomainServices.Client.EntitySet.Remove(Entity entity)
   w System.Windows.Controls.PagedEntityCollectionView.RemoveCore(Entity item, Int32 index)
   w System.Windows.Controls.PagedEntityCollectionView.RemoveItem(Entity item)
   w System.Windows.Controls.EntityCollectionView.Remove(Object item)
   w System.Windows.Controls.DomainDataSourceView.Remove(Object item)
   w LANOS.UserManagement.DeleteRuleButton_Click(Object sender, RoutedEventArgs e)
   w System.Windows.Controls.Primitives.ButtonBase.OnClick()
   w System.Windows.Controls.Button.OnClick()
   w System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
   w System.Windows.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e)
   w MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventN

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• 为每个对象族创建不同的DomainDataSource： ColumnValidationRule，AssociatedColumn，ColumnValue。然后使用这些DomainDataSource删除它们并从 从头到尾。这种方法也失败了。我也有类似的错误 第一种方法中的方法。有时也会有一些 DomainDataSource的为空

我在谷歌上搜索一些可以解决这个问题的例子，但我没有找到任何。感谢任何提示、链接或帮助；）

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更新1:

                                <riaControls:DomainDataSource AutoLoad="True" d:DesignData="{d:DesignInstance my:ExcelTemplate, CreateList=true}" Height="0" LoadedData="ExcelTemplateDomainDataSource_LoadedData" Name="excelTemplatesForValidatiorsDDS" QueryName="GetExcelTemplatesQuery" Width="0">
                                    <riaControls:DomainDataSource.DomainContext>
                                        <my1:SRFDomainContext />
                                    </riaControls:DomainDataSource.DomainContext>
                                </riaControls:DomainDataSource>

                                <riaControls:DomainDataSource AutoLoad="True" d:DesignData="{d:DesignInstance my:ColumnValidationRule, CreateList=true}" Height="0" LoadedData="ExcelTemplateDomainDataSource_LoadedData" Name="columnValidationRulesDomainDataSource" QueryName="GetColumnValidationRulesQuery" Width="0">
                                    <riaControls:DomainDataSource.DomainContext>
                                        <my1:SRFDomainContext />
                                    </riaControls:DomainDataSource.DomainContext>
                                </riaControls:DomainDataSource>

w System.ServiceModel.DomainServices.Client.EntitySet.Remove(Entity entity)
   w System.Windows.Controls.PagedEntityCollectionView.RemoveCore(Entity item, Int32 index)
   w System.Windows.Controls.PagedEntityCollectionView.RemoveItem(Entity item)
   w System.Windows.Controls.EntityCollectionView.Remove(Object item)
   w System.Windows.Controls.DomainDataSourceView.Remove(Object item)
   w LANOS.UserManagement.DeleteRuleButton_Click(Object sender, RoutedEventArgs e)
   w System.Windows.Controls.Primitives.ButtonBase.OnClick()
   w System.Windows.Controls.Button.OnClick()
   w System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
   w System.Windows.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e)
   w MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventN

我采纳了你的建议：

    this.columnValidationRulesDomainDataSource.Load();
    ColumnValidationRule deletedObject = null;

    foreach (ColumnValidationRule cvr in this.columnValidationRulesDomainDataSource.DataView)
    {
        if (cvr.ID.Equals((this.srfValidatorsDataGrid.SelectedItem as ColumnValidationRule).ID))
        {
            deletedObject = cvr;
        }
    }
    this.columnValidationRulesDomainDataSource.DataView.Remove(deletedObject);
    this.columnValidationRulesDomainDataSource.SubmitChanges();

现在我收到了这个错误：提供的项不是Entity类型的实例：/

---

更新2:

                                <riaControls:DomainDataSource AutoLoad="True" d:DesignData="{d:DesignInstance my:ExcelTemplate, CreateList=true}" Height="0" LoadedData="ExcelTemplateDomainDataSource_LoadedData" Name="excelTemplatesForValidatiorsDDS" QueryName="GetExcelTemplatesQuery" Width="0">
                                    <riaControls:DomainDataSource.DomainContext>
                                        <my1:SRFDomainContext />
                                    </riaControls:DomainDataSource.DomainContext>
                                </riaControls:DomainDataSource>

                                <riaControls:DomainDataSource AutoLoad="True" d:DesignData="{d:DesignInstance my:ColumnValidationRule, CreateList=true}" Height="0" LoadedData="ExcelTemplateDomainDataSource_LoadedData" Name="columnValidationRulesDomainDataSource" QueryName="GetColumnValidationRulesQuery" Width="0">
                                    <riaControls:DomainDataSource.DomainContext>
                                        <my1:SRFDomainContext />
                                    </riaControls:DomainDataSource.DomainContext>
                                </riaControls:DomainDataSource>

w System.ServiceModel.DomainServices.Client.EntitySet.Remove(Entity entity)
   w System.Windows.Controls.PagedEntityCollectionView.RemoveCore(Entity item, Int32 index)
   w System.Windows.Controls.PagedEntityCollectionView.RemoveItem(Entity item)
   w System.Windows.Controls.EntityCollectionView.Remove(Object item)
   w System.Windows.Controls.DomainDataSourceView.Remove(Object item)
   w LANOS.UserManagement.DeleteRuleButton_Click(Object sender, RoutedEventArgs e)
   w System.Windows.Controls.Primitives.ButtonBase.OnClick()
   w System.Windows.Controls.Button.OnClick()
   w System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
   w System.Windows.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e)
   w MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventN

我添加了SubmitedChanges事件处理程序，正如我在文章开头所怀疑的，外键导致的删除存在问题：

e.Error.Message "Submit operation failed. An error occurred while updating the entries. See the inner exception for details. InnerException message: The DELETE statement conflicted with the REFERENCE constraint \"FK_AssociatedColumn_ColumnValidationRule\". The conflict occurred in database \"LANOS\", table \"dbo.AssociatedColumns\", column 'ColumnValidationRuleID'.\r\nThe statement has been terminated."

不幸的是，我无法设置模型以使用End-On-Delete-Cascade属性。 设置级联删除原因编译错误：

End 'ColumnValue' on relationship 'LANOSModel.FK_AssociatedColumnColumnValue' cannot have operation specified since its multiplicity is '*'. Operations cannot be specified on ends with multiplicity '*'.

“此EntitySet中不包含指定实体”的原因是。。。。等等。。。该实体的指定实例实际上不包含在EntitySet中

显然，您已从以前的数据上下文加载了数据网格，而

this.columnValidationRulesDomainDataSource.Load（）

正在创建一组新的实体，因此无法从新数据集中删除特定的旧对象。它们具有相同的值，但不是相同的对象

但是，您可以使用对象中的键，并在新上下文（id匹配的上下文）上执行删除操作。只需先找到匹配的实例并删除它

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如果你能提供更多的细节/代码，我也许能提供一个具体的例子，但你现在应该有足够的时间继续下去。

你是如何填写数据视图的？根据错误消息，您试图删除一个未附加到上下文的实体，因此您可能在某个地方创建了该实体的副本？请将这段代码发布在充装数据视图的充电器中。我已经添加了您要求的代码。虽然很痛苦，但我已设法解决了所有问题。你的提示非常有用，所以谢谢你的帮助。干杯