我们经常使用List泛型进行数据的封装,但是有时候,在某种需求下,你可能需要对这个泛型进行排序,而排序规则是根据model中的某一个属性进行排序,这时棘手的事情来了,怎么办?!!
这个时候我们需要自己扩展一个排序方法,以下我给出一个继承自IComparer接口的类,此类内置好升序和降序的排序规则:
[csharp]
///
/// T为泛用类型
public class Reverser : IComparer
{
private Type type = null;
private ReverserInfo info;
///
///
///
///
public Reverser(Type type, string name, ReverserInfo.Direction direction)
{
this.type = type;
this.info.name = name;
if (direction != ReverserInfo.Direction.ASC)
this.info.direction = direction;
}
///
///
///
///
public Reverser(string className, string name, ReverserInfo.Direction direction)
{
try
{
this.type = Type.GetType(className, true);
this.info.name = name;
this.info.direction = direction;
}
catch (Exception e)
{
throw new Exception(e.Message);
}
}
///
///
///
///
public Reverser(T t, string name, ReverserInfo.Direction direction)
{
this.type = t.GetType();
this.info.name = name;
this.info.direction = direction;
}
//必须!实现IComparer的比较方法。
int IComparer.Compare(T t1, T t2)
{
object x = this.type.InvokeMember(this.info.name, BindingFlags.Public | BindingFlags.Instance | BindingFlags.GetProperty, null, t1, null);
object y = this.type.InvokeMember(this.info.name, BindingFlags.Public | BindingFlags.Instance | BindingFlags.GetProperty, null, t2, null);
if (this.info.direction != ReverserInfo.Direction.ASC)
Swap(ref x, ref y);
return (new CaseInsensitiveComparer())。Compare(x, y);
}
//交换操作数
private void Swap(ref object x, ref object y)
{
object temp = null;
temp = x;
x = y;
y = temp;
}
}
///
public struct ReverserInfo
{
///
public enum Direction
{
ASC = 0,
DESC,
};
public enum Target
{
CUSTOMER = 0,
FORM,
FIELD,
SERVER,
};
public string name;
public Direction direction;
public Target target;
}
///
/// T为泛用类型
public class Reverser : IComparer
{
private Type type = null;
private ReverserInfo info;
///
///
///
///
public Reverser(Type type, string name, ReverserInfo.Direction direction)
{
this.type = type;
this.info.name = name;
if (direction != ReverserInfo.Direction.ASC)
this.info.direction = direction;
}
///
///
///
///
public Reverser(string className, string name, ReverserInfo.Direction direction)
{
try
{
this.type = Type.GetType(className, true);
this.info.name = name;
this.info.direction = direction;
}
catch (Exception e)
{
throw new Exception(e.Message);
}
}
///
///
///
///
public Reverser(T t, string name, ReverserInfo.Direction direction)
{
this.type = t.GetType();
this.info.name = name;
this.info.direction = direction;
}
//必须!实现IComparer的比较方法。
int IComparer.Compare(T t1, T t2)
{
object x = this.type.InvokeMember(this.info.name, BindingFlags.Public | BindingFlags.Instance | BindingFlags.GetProperty, null, t1, null);
object y = this.type.InvokeMember(this.info.name, BindingFlags.Public | BindingFlags.Instance | BindingFlags.GetProperty, null, t2, null);
if (this.info.direction != ReverserInfo.Direction.ASC)
Swap(ref x, ref y);
return (new CaseInsensitiveComparer())。Compare(x, y);
}
//交换操作数
private void Swap(ref object x, ref object y)
{
object temp = null;
temp = x;
x = y;
y = temp;
}
}
///
public struct ReverserInfo
{
///
public enum Direction
{
ASC = 0,
DESC,
};
public enum Target
{
CUSTOMER = 0,
FORM,
FIELD,
SERVER,
};
public string name;
public Direction direction;
public Target target;
}
此时写好后,就只需要知道如何调用就行了:
[csharp]
Reverser reverser = new Reverser(typeof(Model), “btnIndex”, ReverserInfo.Direction.ASC);
Reverser reverser = new Reverser(typeof(Model), “btnIndex”, ReverserInfo.Direction.ASC);我们通过这样的调用方式,就得到一个定义好的排序规则 reverser,假设我们的泛型实例名为 list,则按照如下调用:
[csharp]
list.Sort(reverser);
list.Sort(reverser);
至此,就完成了特定的排序规则处理了。
后感:
虽然这种需求不多,但是在自定义构造的泛型中,需要根据某一属性进行有序显示的时候,就非常实用。
同时任何自定义的类组成的泛型集合都可以实现自定义排序,可以做成一个通用类,没有必要每一个自定义类都去实现排序的接口。
PS:转载来源:暗客安全网:http://www.akhack.com
原帖地址:http://www.akhack.com/thread-4572-1-5.html