C# 动态数据中的多对多关系

我刚刚创建了一个动态数据项目，我的数据库项目中有很多多对多关系和元素。最大的问题是，当我想要编辑/插入一个元素时，因为每个多对多关系都会在复选框列表中“转换”。因此，对于我要插入/编辑的实体，它将导致一个高度约4000px的页面，其中充满了多对多元素

这样（假设产品和类别之间存在多对多关系）：

我现在想的是创建一个名为“GridViewCheckBox”的自定义字段，其中有一个GridView，我可以在其中加载实体，在实体名称前面有一个复选框（因为GridView也有分页功能）

我的问题是：

1） 可以跟随吗

2） 如何使gridview加载我的特定多对多关系

---

因为我有产品类别，但我也可以有汽车修理厂，我也可以有个人城市等等。

这就是我目前在我的许多编辑网站ascx.cs中的内容

public void Page_Load(object sender, EventArgs e) {
    // Register for the DataSource's updating event
    EntityDataSource ds = (EntityDataSource)this.FindDataSourceControl();

    // This field template is used both for Editing and Inserting
    ds.Updating += new EventHandler<EntityDataSourceChangingEventArgs>(DataSource_UpdatingOrInserting);
    ds.Inserting += new EventHandler<EntityDataSourceChangingEventArgs>(DataSource_UpdatingOrInserting);


}

void DataSource_UpdatingOrInserting(object sender, EntityDataSourceChangingEventArgs e) {
    MetaTable childTable = ChildrenColumn.ChildTable;

    // Comments assume employee/territory for illustration, but the code is generic

    // Get the collection of territories for this employee
    RelatedEnd entityCollection = (RelatedEnd)Column.EntityTypeProperty.GetValue(e.Entity, null);

    // In Edit mode, make sure it's loaded (doesn't make sense in Insert mode)
    if (Mode == DataBoundControlMode.Edit && !entityCollection.IsLoaded) {
        entityCollection.Load();
    }

    // Get an IList from it (i.e. the list of territories for the current employee)
    // REVIEW: we should be using EntityCollection directly, but EF doesn't have a
    // non generic type for it. They will add this in vnext
    IList entityList = ((IListSource)entityCollection).GetList();

    // Go through all the territories (not just those for this employee)
    foreach (object childEntity in childTable.GetQuery(e.Context)) {

        // Check if the employee currently has this territory
        bool isCurrentlyInList = entityList.Contains(childEntity);

        // Find the checkbox for this territory, which gives us the new state
        string pkString = childTable.GetPrimaryKeyString(childEntity);
        ListItem listItem = CheckBoxList1.Items.FindByValue(pkString);
        if (listItem == null)
            continue;

        // If the states differs, make the appropriate add/remove change
        if (listItem.Selected) {
            if (!isCurrentlyInList)
                entityList.Add(childEntity);
        }
        else {
            if (isCurrentlyInList)
                entityList.Remove(childEntity);
        }
    }
}

protected void gvMyGrid_DataBound(object sender, EventArgs e)
{




}

protected void CheckBoxList1_DataBound(object sender, EventArgs e) {
    MetaTable childTable = ChildrenColumn.ChildTable;

    // Comments assume employee/territory for illustration, but the code is generic

    IList entityList = null;
    ObjectContext objectContext = null;

    if (Mode == DataBoundControlMode.Edit) {
        object entity;
        ICustomTypeDescriptor rowDescriptor = Row as ICustomTypeDescriptor;
        if (rowDescriptor != null) {
            // Get the real entity from the wrapper
            entity = rowDescriptor.GetPropertyOwner(null);
        } else {
            entity = Row;
        }

        // Get the collection of territories for this employee and make sure it's loaded
        RelatedEnd entityCollection = Column.EntityTypeProperty.GetValue(entity, null) as RelatedEnd;
        if (entityCollection == null) {
            throw new InvalidOperationException(String.Format("The ManyToMany template does not support the collection type of the '{0}' column on the '{1}' table.", Column.Name, Table.Name));
        }
        if (!entityCollection.IsLoaded) {
            entityCollection.Load();
        }

        // Get an IList from it (i.e. the list of territories for the current employee)
        // REVIEW: we should be using EntityCollection directly, but EF doesn't have a
        // non generic type for it. They will add this in vnext
        entityList = ((IListSource)entityCollection).GetList();

        // Get the current ObjectContext
        // REVIEW: this is quite a dirty way of doing this. Look for better alternative
        ObjectQuery objectQuery = (ObjectQuery)entityCollection.GetType().GetMethod(
            "CreateSourceQuery").Invoke(entityCollection, null);
        objectContext = objectQuery.Context;
    }

    // Go through all the territories (not just those for this employee)
    foreach (object childEntity in childTable.GetQuery(objectContext)) {
        MetaTable actualTable = MetaTable.GetTable(childEntity.GetType());
        // Create a checkbox for it
        ListItem listItem = new ListItem(
            actualTable.GetDisplayString(childEntity),
            actualTable.GetPrimaryKeyString(childEntity));

        // Make it selected if the current employee has that territory
        if (Mode == DataBoundControlMode.Edit) {
            listItem.Selected = entityList.Contains(childEntity);
        }

        CheckBoxList1.Items.Add(listItem);
    }
}

public override Control DataControl {
    get {
        return gvMyGrid;
    }
}

public void页面加载（对象发送方，事件参数e）{
//注册数据源的更新事件
EntityDataSource ds=（EntityDataSource）this.FindDataSourceControl（）；
//此字段模板用于编辑和插入
ds.updateing+=新的EventHandler（DataSource\u UpdatengorInserting）；
ds.Inserting+=新的事件处理程序（DataSource\U UpdatingOrInserting）；
}
void DataSource_updatengorInserting（对象发送方，EntityDataSourceChangingEventArgs e）{
MetaTable childTable=ChildrenColumn.childTable；
//注释假设员工/地区用于说明，但代码是通用的
//获取此员工的区域集合
RelatedEnd entityCollection=（RelatedEnd）Column.EntityTypeProperty.GetValue（e.Entity，null）；
//在编辑模式下，确保已加载（在插入模式下没有意义）
if（Mode==DataBoundControlMode.Edit&！entityCollection.IsLoaded）{
entityCollection.Load（）；
}
//从中获取IList（即当前员工的区域列表）
//评论：我们应该直接使用EntityCollection，但EF没有
//它的非泛型类型。他们将在vnext中添加它
IList entityList=（（IListSource）entityCollection.GetList（）；
//检查所有区域（不仅仅是该员工的区域）
foreach（childTable.GetQuery（e.Context）中的对象childEntity）{
//检查员工当前是否拥有此区域
bool isCurrentlyInList=entityList.Contains（childEntity）；
//找到这个区域的复选框，它为我们提供了新的状态
字符串pkString=childTable.GetPrimaryKeyString（childEntity）；
ListItem ListItem=CheckBoxList1.Items.FindByValue（pkString）；
如果（listItem==null）
继续；
//如果状态不同，请进行适当的添加/删除更改
如果（listItem.Selected）{
如果（！isCurrentlyInList）
entityList.Add（子实体）；
}
否则{
如果（isCurrentlyInList）
entityList.Remove（子实体）；
}
}
}
受保护的void gvMyGrid_数据绑定（对象发送方，事件参数e）
{
}
受保护的void CheckBoxList1_数据绑定（对象发送方，事件参数e）{
MetaTable childTable=ChildrenColumn.childTable；
//注释假设员工/地区用于说明，但代码是通用的
IList entityList=null；
ObjectContext=null；
if（Mode==DataBoundControlMode.Edit）{
对象实体；
ICustomTypeDescriptor rowDescriptor=作为ICustomTypeDescriptor的行；
if（行描述符！=null）{
//从包装器中获取真实实体
entity=rowDescriptor.GetPropertyOwner（null）；
}否则{
实体=行；
}
//获取此员工的区域集合并确保已加载
RelatedEnd entityCollection=Column.EntityTypeProperty.GetValue（实体，null）作为RelatedEnd；
if（entityCollection==null）{
抛出新的InvalidOperationException（String.Format（“ManyToMany模板不支持{1}”表上的{0}列的集合类型。”，column.Name，table.Name））；
}
如果（！entityCollection.IsLoaded）{
entityCollection.Load（）；
}
//从中获取IList（即当前员工的区域列表）
//评论：我们应该直接使用EntityCollection，但EF没有
//它的非泛型类型。他们将在vnext中添加它
entityList=（（IListSource）entityCollection）.GetList（）；
//获取当前ObjectContext
//评论：这是一个相当肮脏的做法。寻找更好的替代方法
ObjectQuery ObjectQuery=（ObjectQuery）entityCollection.GetType（）.GetMethod(
“CreateSourceQuery”）.Invoke（entityCollection，null）；
objectContext=objectQuery.Context；
}
//检查所有区域（不仅仅是该员工的区域）
foreach（childTable.GetQuery（objectContext）中的对象childEntity）{
MetaTable actualTable=MetaTable.GetTable（childEntity.GetType（））；
//为它创建一个复选框
ListItem ListItem=新ListItem(
actualTable.GetDisplayString（childEntity），
GetPrimaryKeyString（childEntity））；
//如果当前员工拥有该区域，则将其选中
if（Mode==DataBoundControlMode.Edit）{
listItem.Selected=entityList.Contains（childEntity）；
}
CheckBoxList1.Items.Add（listItem）；
}
}
公共覆盖控制数据控制{
得到{
返回gvMyGrid；
}
}

我知道这是非常非常古老的，但它确实停止了好几天，可以看看为什么我的许多人总是无法获得现场数据：我使用DD的时间只有大约1-2周，比我以前的时间要长

public void Page_Load(object sender, EventArgs e) {
    // Register for the DataSource's updating event
    EntityDataSource ds = (EntityDataSource)this.FindDataSourceControl();

    // This field template is used both for Editing and Inserting
    ds.Updating += new EventHandler<EntityDataSourceChangingEventArgs>(DataSource_UpdatingOrInserting);
    ds.Inserting += new EventHandler<EntityDataSourceChangingEventArgs>(DataSource_UpdatingOrInserting);


}

void DataSource_UpdatingOrInserting(object sender, EntityDataSourceChangingEventArgs e) {
    MetaTable childTable = ChildrenColumn.ChildTable;

    // Comments assume employee/territory for illustration, but the code is generic

    // Get the collection of territories for this employee
    RelatedEnd entityCollection = (RelatedEnd)Column.EntityTypeProperty.GetValue(e.Entity, null);

    // In Edit mode, make sure it's loaded (doesn't make sense in Insert mode)
    if (Mode == DataBoundControlMode.Edit && !entityCollection.IsLoaded) {
        entityCollection.Load();
    }

    // Get an IList from it (i.e. the list of territories for the current employee)
    // REVIEW: we should be using EntityCollection directly, but EF doesn't have a
    // non generic type for it. They will add this in vnext
    IList entityList = ((IListSource)entityCollection).GetList();

    // Go through all the territories (not just those for this employee)
    foreach (object childEntity in childTable.GetQuery(e.Context)) {

        // Check if the employee currently has this territory
        bool isCurrentlyInList = entityList.Contains(childEntity);

        // Find the checkbox for this territory, which gives us the new state
        string pkString = childTable.GetPrimaryKeyString(childEntity);
        ListItem listItem = CheckBoxList1.Items.FindByValue(pkString);
        if (listItem == null)
            continue;

        // If the states differs, make the appropriate add/remove change
        if (listItem.Selected) {
            if (!isCurrentlyInList)
                entityList.Add(childEntity);
        }
        else {
            if (isCurrentlyInList)
                entityList.Remove(childEntity);
        }
    }
}

protected void gvMyGrid_DataBound(object sender, EventArgs e)
{




}

protected void CheckBoxList1_DataBound(object sender, EventArgs e) {
    MetaTable childTable = ChildrenColumn.ChildTable;

    // Comments assume employee/territory for illustration, but the code is generic

    IList entityList = null;
    ObjectContext objectContext = null;

    if (Mode == DataBoundControlMode.Edit) {
        object entity;
        ICustomTypeDescriptor rowDescriptor = Row as ICustomTypeDescriptor;
        if (rowDescriptor != null) {
            // Get the real entity from the wrapper
            entity = rowDescriptor.GetPropertyOwner(null);
        } else {
            entity = Row;
        }

        // Get the collection of territories for this employee and make sure it's loaded
        RelatedEnd entityCollection = Column.EntityTypeProperty.GetValue(entity, null) as RelatedEnd;
        if (entityCollection == null) {
            throw new InvalidOperationException(String.Format("The ManyToMany template does not support the collection type of the '{0}' column on the '{1}' table.", Column.Name, Table.Name));
        }
        if (!entityCollection.IsLoaded) {
            entityCollection.Load();
        }

        // Get an IList from it (i.e. the list of territories for the current employee)
        // REVIEW: we should be using EntityCollection directly, but EF doesn't have a
        // non generic type for it. They will add this in vnext
        entityList = ((IListSource)entityCollection).GetList();

        // Get the current ObjectContext
        // REVIEW: this is quite a dirty way of doing this. Look for better alternative
        ObjectQuery objectQuery = (ObjectQuery)entityCollection.GetType().GetMethod(
            "CreateSourceQuery").Invoke(entityCollection, null);
        objectContext = objectQuery.Context;
    }

    // Go through all the territories (not just those for this employee)
    foreach (object childEntity in childTable.GetQuery(objectContext)) {
        MetaTable actualTable = MetaTable.GetTable(childEntity.GetType());
        // Create a checkbox for it
        ListItem listItem = new ListItem(
            actualTable.GetDisplayString(childEntity),
            actualTable.GetPrimaryKeyString(childEntity));

        // Make it selected if the current employee has that territory
        if (Mode == DataBoundControlMode.Edit) {
            listItem.Selected = entityList.Contains(childEntity);
        }

        CheckBoxList1.Items.Add(listItem);
    }
}

public override Control DataControl {
    get {
        return gvMyGrid;
    }
}