OOP 和 C# 中的自引用答案

【问题标题】：Self-Reference in OOP & C#OOP 和 C# 中的自引用
【发布时间】：2016-04-27 09:36:59
【问题描述】：

考虑下表：

FkName            SchemaName    Table    Column     RefTable    RefColumn
FK_Factory_Person dbo           Factory  PersonId   Person      Id
FK_Car_Person     dbo           Car      PersonId   Person      Id
FK_Factory_Car    dbo           Factory  CarId      Car         Id

我想创建依赖类来保存依赖数据

所以我写了一个自引用类，任何依赖都可以有依赖。

public class Dependency
{
    public string TableName { get; set; } // RefTable
    public string ColumnName { get; set; } //RefColumn
    public List<Dependency> Dependencies { get; set; } // Table
}

但我不知道如何填充类：

- TableName=Person , ColumnName=Id , Dependencies=Factory,Car
--TableName=Car    , ColumnName=Id , Dependencies=Factory

Factory
  '
  '---- Person
  '---- Car

Car
  '
  '---- Person

谁能帮我递归地提交依赖类？

【问题讨论】：

标签： c# oop self-reference

【解决方案1】：

解决方案：

public class Link
{
    public string FKName { get; set; }
    public string SchemaName { get; set; }
    public string Table { get; set; }
    public string Column { get; set; }
    public string RefTable { get; set; }
    public string RefColumn { get; set; }
}

public class Dependency
{
    public string TableName { get; set; } // RefTable
    public string ColumnName { get; set; } //RefColumn
    public List<Dependency> Dependencies { get; set; } // Table
}

private static void ProcessItem(Dependency target, List<Dependency> dictionary)
{
    if(target.Dependencies != null)
        foreach(var dep in target.Dependencies)
        {
            var children = dictionary.Where(x => x.TableName == dep.TableName).FirstOrDefault();
            dep.Dependencies = children == null ? null : children.Dependencies;
            ProcessItem(dep, dictionary);
        }
}

public static List<Dependency> ProcessItems(List<Link> links)
{
    var initial = links.GroupBy(x => new { x.RefTable, x.RefColumn })
        .Select(x => new Dependency {
            TableName = x.Key.RefTable,
            ColumnName = x.Key.RefColumn,
            Dependencies = x.Select(y => new Dependency {
                TableName = y.Table,
                ColumnName = y.Column
            }).ToList()
        }).ToList();

    var js = new JavaScriptSerializer();
    var temp = js.Deserialize<List<Dependency>>(js.Serialize(initial));        

    initial.ForEach(x => ProcessItem(x, temp));
    return initial;
}

实施：

var links = new List<Link> {
    new Link { FKName = "FK_Factory_Person", SchemaName = "dbo", Table = "Factory", Column = "PersonId", RefTable = "Person", RefColumn = "Id" },
    new Link { FKName = "FK_Car_Person", SchemaName = "dbo", Table = "Car", Column = "PersonId", RefTable = "Person", RefColumn = "Id" },
    new Link { FKName = "FK_Factory_Car", SchemaName = "dbo", Table = "Factory", Column = "CarId", RefTable = "Car", RefColumn = "Id" },

    new Link { FKName = "FK_TEST", SchemaName = "dbo", Table = "Person", Column = "TestId", RefTable = "Test", RefColumn = "Id" }
};

var answer = ProcessItems(links);

附：如果你有循环依赖， StackOveflowException 将是扔了。

【讨论】：