Linq级联删除 CascadingDeleteOnSubmit
函数
用递归获取外键关联记录，从最外面一直删到最里面（本身）。
获取外键关联记录的办法是找有AssociationAttribute属性的Property，然后遍历，删除。
1 public static void CascadingDeleteOnSubmit(this DataContext context, object entity)
2 {
3 var entityType = entity.GetType();
4 var entityProperties = entityType.GetProperties();
5 //查找是否有“AssociationAttribute”标记的属性
6 //（Linq中有“AssociationAttribute”标记的属性代表外表）
7 var associationProperties = entityProperties.Where(
8 c => c.GetCustomAttributes(true).Any(
9 attrbute => attrbute.GetType().Name == "AssociationAttribute")
10 & c.PropertyType.IsGenericType);//该属性必需是泛型
11 //其他表有外键关联的记录
12 foreach (var associationProperty in associationProperties)
13 {
14 //获取Property值
15 object propertyValue = associationProperty.GetValue(entity, null);
16 //Property是EntitySet`1类型的值，如EntitySet<DataSetStructure>，
17 //而EntitySet`1有IEnumerable接口
18 IEnumerable enumerable = (IEnumerable)propertyValue;
19 foreach (object o in enumerable)
20 {
21 //递归
22 CascadingDeleteOnSubmit(context, o);
23 }
24 }
25
26 try
27 {
28 //删除没外键关联的记录
29 context.GetTable(entity.GetType()).DeleteOnSubmit(entity);
30 }
31 catch (Exception ex)
32 {
33 throw ex;
34 }
35 }
用法：
1 public virtual string CascadingDelete(string id)
2 {
3 TDataContext context = new TDataContext();
4 TEntity t = context.GetTable<TEntity>().Where(c => c.ID.Equals( id)).First();
5 context.CascadingDeleteOnSubmit(t);
6 context.SubmitChanges();
7 return Constances.ErrorMassage.SUCCEED;
8 }
