Java的比較倍率相當於在C＃

Question

我想下面的類轉換從Java到C＃：

public class ValueComparator implements Comparator{ 

    @Override 
    public int compare(Object ob1, Object ob2){ 
     int retval = 0; 
     if (ob1 instanceof DataCol && ob2 instanceof DataCol){ 
      DataCol c1 = (DataCol) ob1; 
      DataCol c2 = (DataCol) ob2; 
      if(c1.value < c2.value) retval = 1; 
      if(c1.value > c2.value) retval = -1; 
     } else { 
      throw new ClassCastException("ValueComparator: Illegal arguments!"); 
     } 
     return(retval); 
    }  
} 

Answer 1

爲什麼不直接實現非通用IComparer接口？也就是說，非泛型Java接口轉換爲非泛型C＃接口：

public class ValueComparator : System.Collections.IComparer 
{ 
    public int Compare(object ob1, object ob2) 
    { 
     int retval = 0; 
     if (ob1 is DataCol && ob2 is DataCol) 
     { 
      DataCol c1 = (DataCol) ob1; 
      DataCol c2 = (DataCol) ob2; 
      if (c1.value < c2.value) retval = 1; 
      if (c1.value > c2.value) retval = -1; 
     } 
     else 
     { 
      throw new ClassCastException("ValueComparator: Illegal arguments!"); 
     } 
     return (retval); 
    } 
} 

Answer 2

您可以通過從Comparer<T>繼承實現IComparer<T>。

class DataColComparer:Comparer<DataCol> 
{ 
    public override int Compare(DataCol x, DataCol y) 
    { 
     if(ReferenceEquals(x,y)) 
     return 0; 
     if(x==null) 
     return -1; 
     if(y==null) 
     return +1; 
     return Comparer<TValue>.Default.Compare(y.Value, x.Value); 
    } 
}