2009-06-12 10 views
26

que tiene un genéricouso propio IComparer <T> con LINQ OrdenarPor

List<MyClass> 

donde MyClass tiene una propiedad InvoiceNumber que contiene valores como:

200906/1
200906/2
..
200906/10
200906/11
200906/12

Mi lista se une a una

BindingList<T> 

que apoya la clasificación con LINQ:

protected override void ApplySortCore(
      PropertyDescriptor property, ListSortDirection direction) 
{ 

    _sortProperty = property; 
    _sortDirection = direction; 

    var items = this.Items; 

    switch (direction) 
    { 
     case ListSortDirection.Ascending: 
      items = items.OrderByDescending(x => property.GetValue(x)).ToList(); 
      break; 
     case ListSortDirection.Descending: 
      items = items.OrderByDescending(x => property.GetValue(x)).ToList(); 
      break; 
    } 

    this.Items = items; 

} 

Sin embargo las clases comparador predeterminado (como se suponía) como este:

200906/1
200906/10
200906/11
200906/1 2
200906/2

que es desagradable en este caso.

Ahora quiero usar mi propio IComparer<T> con esto. Se ve así:

public class MyComparer : IComparer<Object> 
{ 

    public int Compare(Object stringA, Object stringB) 
    { 
     String[] valueA = stringA.ToString().Split('/'); 
     String[] valueB = stringB.ToString().Split('/'); 

     if(valueA .Length != 2 || valueB .Length != 2) 
      return String.Compare(stringA.ToString(), stringB.ToString()); 

     if (valueA[0] == valueB[0]) 
     { 
      return String.Compare(valueA[1], valueB[1]); 
     } 
     else 
     { 
      return String.Compare(valueA[0], valueB[0]); 
     } 

    } 

} 

y cambió el código ApplySortCore utilizar este IComparer:

case ListSortDirection.Ascending: 
    MyComparer comparer = new MyComparer(); 
    items = items.OrderByDescending(
       x => property.GetValue(x), comparer).ToList(); 
    break; 

Cuando puedo depurar mi código, veo que MyComparer.Compare(object, object) se llama varias veces y devuelve los valores de la derecha (- 1, 0, 1) para un método de comparación.

Pero mi lista todavía se ordena de la manera "incorrecta". ¿Me estoy perdiendo de algo? No tengo ni idea.

Respuesta

17

Su comparador me parece incorrecto. Todavía está ordenando el orden predeterminado de texto. Seguramente usted quiere ser analizar los dos números y la clasificación basada en lo siguiente:

public int Compare(Object stringA, Object stringB) 
{ 
    string[] valueA = stringA.ToString().Split('/'); 
    string[] valueB = stringB.ToString().Split('/'); 

    if (valueA.Length != 2 || valueB.Length != 2) 
    { 
     stringA.ToString().CompareTo(stringB.ToString())); 
    } 

    // Note: do error checking and consider i18n issues too :) 
    if (valueA[0] == valueB[0]) 
    { 
     return int.Parse(valueA[1]).CompareTo(int.Parse(valueB[1])); 
    } 
    else 
    { 
     return int.Parse(valueA[0]).CompareTo(int.Parse(valueB[0])); 
    } 
} 

(Tenga en cuenta que esto no se sienta bien con su pregunta afirmando que ha depurado a través y verificó que se compara devolver el valor correcto - pero me temo que sospecho que el error humano en ese frente.)

Además, Sven está a la derecha - cambiar el valor de items no cambia en absoluto su lista encuadernada. Debe agregar:

this.Items = items; 

en la parte inferior de su método.

+0

Lo siento, el código shortend un poco. En mi código original, hago esto. Artículos = artículos; (Si no, no ordenaría de todos modos) Pero la conversión int funciona (debo haber estado ciego || estúpido para perder eso). Muchas gracias. –

2

La lista ordenada solo está vinculada a los elementos variables locales, no a la propiedad Artículos de su lista de enlaces, por lo tanto, sigue sin clasificarse.

[Editar] Básicamente, usted es simplemente tirar el resultado de sus esfuerzos de clasificación ;-)

7

me encontré con el problema de la clasificación general y natural, escribió en su blog la solución aquí:

Natural Sort Compare with Linq OrderBy()

public class NaturalSortComparer<T> : IComparer<string>, IDisposable 
{ 
    private bool isAscending; 

    public NaturalSortComparer(bool inAscendingOrder = true) 
    { 
     this.isAscending = inAscendingOrder; 
    } 

    #region IComparer<string> Members 

    public int Compare(string x, string y) 
    { 
     throw new NotImplementedException(); 
    } 

    #endregion 

    #region IComparer<string> Members 

    int IComparer<string>.Compare(string x, string y) 
    { 
     if (x == y) 
      return 0; 

     string[] x1, y1; 

     if (!table.TryGetValue(x, out x1)) 
     { 
      x1 = Regex.Split(x.Replace(" ", ""), "([0-9]+)"); 
      table.Add(x, x1); 
     } 

     if (!table.TryGetValue(y, out y1)) 
     { 
      y1 = Regex.Split(y.Replace(" ", ""), "([0-9]+)"); 
      table.Add(y, y1); 
     } 

     int returnVal; 

     for (int i = 0; i < x1.Length && i < y1.Length; i++) 
     { 
      if (x1[i] != y1[i]) 
      { 
       returnVal = PartCompare(x1[i], y1[i]); 
       return isAscending ? returnVal : -returnVal; 
      } 
     } 

     if (y1.Length > x1.Length) 
     { 
      returnVal = 1; 
     } 
     else if (x1.Length > y1.Length) 
     { 
      returnVal = -1; 
     } 
     else 
     { 
      returnVal = 0; 
     } 

     return isAscending ? returnVal : -returnVal; 
    } 

    private static int PartCompare(string left, string right) 
    { 
     int x, y; 
     if (!int.TryParse(left, out x)) 
      return left.CompareTo(right); 

     if (!int.TryParse(right, out y)) 
      return left.CompareTo(right); 

     return x.CompareTo(y); 
    } 

    #endregion 

    private Dictionary<string, string[]> table = new Dictionary<string, string[]>(); 

    public void Dispose() 
    { 
     table.Clear(); 
     table = null; 
    } 
} 
5

puede utilizar ALPHANUM El Algoritmo:

(...) 
    items.OrderBy(x => property.GetValue(x), new AlphanumComparator()) 
    (...) 

AlphanumComparator

/* 
* The Alphanum Algorithm is an improved sorting algorithm for strings 
* containing numbers. Instead of sorting numbers in ASCII order like 
* a standard sort, this algorithm sorts numbers in numeric order. 
* 
* The Alphanum Algorithm is discussed at http://www.DaveKoelle.com 
* 
* Based on the Java implementation of Dave Koelle's Alphanum algorithm. 
* Contributed by Jonathan Ruckwood <[email protected]> 
* 
* Adapted by Dominik Hurnaus <[email protected]> to 
* - correctly sort words where one word starts with another word 
* - have slightly better performance 
* 
* Released under the MIT License - https://opensource.org/licenses/MIT 
* 
* Permission is hereby granted, free of charge, to any person obtaining 
* a copy of this software and associated documentation files (the "Software"), 
* to deal in the Software without restriction, including without limitation 
* the rights to use, copy, modify, merge, publish, distribute, sublicense, 
* and/or sell copies of the Software, and to permit persons to whom the 
* Software is furnished to do so, subject to the following conditions: 
* 
* The above copyright notice and this permission notice shall be included 
* in all copies or substantial portions of the Software. 
* 
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 
* USE OR OTHER DEALINGS IN THE SOFTWARE. 
* 
*/ 
using System; 
using System.Collections; 
using System.Text; 

/* 
* Please compare against the latest Java version at http://www.DaveKoelle.com 
* to see the most recent modifications 
*/ 
namespace AlphanumComparator 
{ 
    public class AlphanumComparator : IComparer 
    { 
     private enum ChunkType {Alphanumeric, Numeric}; 
     private bool InChunk(char ch, char otherCh) 
     { 
      ChunkType type = ChunkType.Alphanumeric; 

      if (char.IsDigit(otherCh)) 
      { 
       type = ChunkType.Numeric; 
      } 

      if ((type == ChunkType.Alphanumeric && char.IsDigit(ch)) 
       || (type == ChunkType.Numeric && !char.IsDigit(ch))) 
      { 
       return false; 
      } 

      return true; 
     } 

     public int Compare(object x, object y) 
     { 
      String s1 = x as string; 
      String s2 = y as string; 
      if (s1 == null || s2 == null) 
      { 
       return 0; 
      } 

      int thisMarker = 0, thisNumericChunk = 0; 
      int thatMarker = 0, thatNumericChunk = 0; 

      while ((thisMarker < s1.Length) || (thatMarker < s2.Length)) 
      { 
       if (thisMarker >= s1.Length) 
       { 
        return -1; 
       } 
       else if (thatMarker >= s2.Length) 
       { 
        return 1; 
       } 
       char thisCh = s1[thisMarker]; 
       char thatCh = s2[thatMarker]; 

       StringBuilder thisChunk = new StringBuilder(); 
       StringBuilder thatChunk = new StringBuilder(); 

       while ((thisMarker < s1.Length) && (thisChunk.Length==0 ||InChunk(thisCh, thisChunk[0]))) 
       { 
        thisChunk.Append(thisCh); 
        thisMarker++; 

        if (thisMarker < s1.Length) 
        { 
         thisCh = s1[thisMarker]; 
        } 
       } 

       while ((thatMarker < s2.Length) && (thatChunk.Length==0 ||InChunk(thatCh, thatChunk[0]))) 
       { 
        thatChunk.Append(thatCh); 
        thatMarker++; 

        if (thatMarker < s2.Length) 
        { 
         thatCh = s2[thatMarker]; 
        } 
       } 

       int result = 0; 
       // If both chunks contain numeric characters, sort them numerically 
       if (char.IsDigit(thisChunk[0]) && char.IsDigit(thatChunk[0])) 
       { 
        thisNumericChunk = Convert.ToInt32(thisChunk.ToString()); 
        thatNumericChunk = Convert.ToInt32(thatChunk.ToString()); 

        if (thisNumericChunk < thatNumericChunk) 
        { 
         result = -1; 
        } 

        if (thisNumericChunk > thatNumericChunk) 
        { 
         result = 1; 
        } 
       } 
       else 
       { 
        result = thisChunk.ToString().CompareTo(thatChunk.ToString()); 
       } 

       if (result != 0) 
       { 
        return result; 
       } 
      } 

      return 0; 
     } 
    } 
} 
3

no podemos hacerlo así:

public class MyComparer : IComparer<string> 
{ 

    public int Compare(string stringA, string stringB) 
    { 
     string small = stringA; 
     string big = stringB; 
     if (stringA.Length > stringB.Length) 
     { 
      small = stringB; 
      big = stringA; 
     } 
     else if (stringA.Length < stringB.Length) 
     { 
      small = stringA; 
      big = stringB; 
     } 
     for (int j = 0; j < small.Length; j++) 
     { 
      if (Convert.ToInt32(small[j]) > Convert.ToInt32(big[j])) return -1; 
      if (Convert.ToInt32(small[j]) < Convert.ToInt32(big[j])) return 1; 
     } 

     //big is indeed bigger 
     if (big.Length > small.Length) return 1; 

     //finally they are smae 
     return 0; 
    } 
} 

Uso:

string[] inputStrings = {"_abc*&","#almnp","abc" }; 
//string[] inputStrings = { "#", "_", "_a", "@", "_" }; 
MyComparer computer = new MyComparer(); 
var kola = inputStrings.OrderBy(x => x, new MyComparer()).ToArray(); 

Ésta es la misma como:

Array.Sort(inputStrings, StringComparer.Ordinal); 
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