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Metodo String.Equals (String, StringComparison)

 

Data di pubblicazione: ottobre 2016

Determina se questa stringa e un oggetto String specificato hanno lo stesso valore. Un parametro specifica le impostazioni cultura, l'eventuale distinzione fra maiuscole e minuscole e le regole di ordinamento usate per effettuare il confronto.

Spazio dei nomi:   System
Assembly:  mscorlib (in mscorlib.dll)

public bool Equals(
	string value,
	StringComparison comparisonType
)

Parametri

value
Type: System.String

Stringa da confrontare con questa istanza.

comparisonType
Type: System.StringComparison

Uno dei valori di enumerazione che specifica la modalità di confronto delle stringhe.

Valore restituito

Type: System.Boolean

true se il valore del parametro value corrisponde a quello di questa stringa; in caso contrario, false.

Exception Condition
ArgumentException

comparisonType non è un valore di StringComparison.

The comparisonType parameter indicates whether the comparison should use the current or invariant culture, honor or ignore the case of the two strings being compared, or use word or ordinal sort rules.

The following example creates a string array that consists of an uppercase "I", a lowercase "i", and a dotless "ı". It then calls the M:System.String.Equals(System.String,System.StringComparison) method to compare them by using each possible T:System.StringComparison enumeration value.

using System;

class Sample 
{
   public static void Main() 
   {
      // Define a string array with the following three "I" characters:
      //      U+0069, U+0131, and U+0049.  
      string[] threeIs = { "i", "ı", "I" };
      // Define Type object representing StringComparison type.
      Type scType = typeof(StringComparison);  

      // Show the current culture (for culture-sensitive string comparisons).
      Console.WriteLine("The current culture is {0}.\n", 
                        System.Globalization.CultureInfo.CurrentCulture.Name);

      // Perform comparisons using each StringComparison member. 
      foreach (string scName in Enum.GetNames(scType))
      {
         StringComparison sc = (StringComparison) Enum.Parse(scType, scName);
         Console.WriteLine("Comparisons using {0}:", sc);
         // Compare each character in character array.
         for (int ctr = 0; ctr <= 1; ctr++)
         {
            string instanceChar = threeIs[ctr];
            for (int innerCtr = ctr + 1; innerCtr <= threeIs.GetUpperBound(0); innerCtr++)
            {
               string otherChar = threeIs[innerCtr];
               Console.WriteLine("{0} (U+{1}) = {2} (U+{3}): {4}", 
                                 instanceChar, Convert.ToInt16(Char.Parse(instanceChar)).ToString("X4"), 
                                 otherChar, Convert.ToInt16(Char.Parse(otherChar)).ToString("X4"), 
                                 instanceChar.Equals(otherChar, sc));
            }
            Console.WriteLine();
         }
      }   
   }
}
// The example displays the following output:
//       The current culture is en-US.
//       
//       Comparisons using CurrentCulture:
//       i (U+0069) = i (U+0131): False
//       i (U+0069) = I (U+0049): False
//       
//       i (U+0131) = I (U+0049): False
//       
//       Comparisons using CurrentCultureIgnoreCase:
//       i (U+0069) = i (U+0131): False
//       i (U+0069) = I (U+0049): True
//       
//       i (U+0131) = I (U+0049): False
//       
//       Comparisons using InvariantCulture:
//       i (U+0069) = i (U+0131): False
//       i (U+0069) = I (U+0049): False
//       
//       i (U+0131) = I (U+0049): False
//       
//       Comparisons using InvariantCultureIgnoreCase:
//       i (U+0069) = i (U+0131): False
//       i (U+0069) = I (U+0049): True
//       
//       i (U+0131) = I (U+0049): False
//       
//       Comparisons using Ordinal:
//       i (U+0069) = i (U+0131): False
//       i (U+0069) = I (U+0049): False
//       
//       i (U+0131) = I (U+0049): False
//       
//       Comparisons using OrdinalIgnoreCase:
//       i (U+0069) = i (U+0131): False
//       i (U+0069) = I (U+0049): True
//       
//       i (U+0131) = I (U+0049): False

The following example compares four sets of words by using each member of the T:System.StringComparison enumeration. The comparisons use the conventions of the English (United States) and Sami (Upper Sweden) cultures. Note that the strings "encyclopædia" and "encyclopedia" are considered equivalent in the en-US culture but not in the Sami (Northern Sweden) culture.

using System;
using System.Globalization;
using System.Threading;

public class Example
{
   public static void Main()
   {
      String[] cultureNames = { "en-US", "se-SE" };
      String[] strings1 = { "case",  "encyclopædia",  
                            "encyclopædia", "Archæology" };
      String[] strings2 = { "Case", "encyclopaedia", 
                            "encyclopedia" , "ARCHÆOLOGY" };
      StringComparison[] comparisons = (StringComparison[]) Enum.GetValues(typeof(StringComparison));

      foreach (var cultureName in cultureNames) {
         Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture(cultureName);
         Console.WriteLine("Current Culture: {0}", CultureInfo.CurrentCulture.Name);
         for (int ctr = 0; ctr <= strings1.GetUpperBound(0); ctr++) {
            foreach (var comparison in comparisons) 
               Console.WriteLine("   {0} = {1} ({2}): {3}", strings1[ctr],
                                 strings2[ctr], comparison, 
                                 strings1[ctr].Equals(strings2[ctr], comparison));

            Console.WriteLine();         
         }
         Console.WriteLine();
      }
   }
}
// The example displays the following output:
//    Current Culture: en-US
//       case = Case (CurrentCulture): False
//       case = Case (CurrentCultureIgnoreCase): True
//       case = Case (InvariantCulture): False
//       case = Case (InvariantCultureIgnoreCase): True
//       case = Case (Ordinal): False
//       case = Case (OrdinalIgnoreCase): True
//    
//       encyclopædia = encyclopaedia (CurrentCulture): True
//       encyclopædia = encyclopaedia (CurrentCultureIgnoreCase): True
//       encyclopædia = encyclopaedia (InvariantCulture): True
//       encyclopædia = encyclopaedia (InvariantCultureIgnoreCase): True
//       encyclopædia = encyclopaedia (Ordinal): False
//       encyclopædia = encyclopaedia (OrdinalIgnoreCase): False
//    
//       encyclopædia = encyclopedia (CurrentCulture): False
//       encyclopædia = encyclopedia (CurrentCultureIgnoreCase): False
//       encyclopædia = encyclopedia (InvariantCulture): False
//       encyclopædia = encyclopedia (InvariantCultureIgnoreCase): False
//       encyclopædia = encyclopedia (Ordinal): False
//       encyclopædia = encyclopedia (OrdinalIgnoreCase): False
//    
//       Archæology = ARCHÆOLOGY (CurrentCulture): False
//       Archæology = ARCHÆOLOGY (CurrentCultureIgnoreCase): True
//       Archæology = ARCHÆOLOGY (InvariantCulture): False
//       Archæology = ARCHÆOLOGY (InvariantCultureIgnoreCase): True
//       Archæology = ARCHÆOLOGY (Ordinal): False
//       Archæology = ARCHÆOLOGY (OrdinalIgnoreCase): True
//    
//    
//    Current Culture: se-SE
//       case = Case (CurrentCulture): False
//       case = Case (CurrentCultureIgnoreCase): True
//       case = Case (InvariantCulture): False
//       case = Case (InvariantCultureIgnoreCase): True
//       case = Case (Ordinal): False
//       case = Case (OrdinalIgnoreCase): True
//    
//       encyclopædia = encyclopaedia (CurrentCulture): False
//       encyclopædia = encyclopaedia (CurrentCultureIgnoreCase): False
//       encyclopædia = encyclopaedia (InvariantCulture): True
//       encyclopædia = encyclopaedia (InvariantCultureIgnoreCase): True
//       encyclopædia = encyclopaedia (Ordinal): False
//       encyclopædia = encyclopaedia (OrdinalIgnoreCase): False
//    
//       encyclopædia = encyclopedia (CurrentCulture): False
//       encyclopædia = encyclopedia (CurrentCultureIgnoreCase): False
//       encyclopædia = encyclopedia (InvariantCulture): False
//       encyclopædia = encyclopedia (InvariantCultureIgnoreCase): False
//       encyclopædia = encyclopedia (Ordinal): False
//       encyclopædia = encyclopedia (OrdinalIgnoreCase): False
//    
//       Archæology = ARCHÆOLOGY (CurrentCulture): False
//       Archæology = ARCHÆOLOGY (CurrentCultureIgnoreCase): True
//       Archæology = ARCHÆOLOGY (InvariantCulture): False
//       Archæology = ARCHÆOLOGY (InvariantCultureIgnoreCase): True
//       Archæology = ARCHÆOLOGY (Ordinal): False
//       Archæology = ARCHÆOLOGY (OrdinalIgnoreCase): True

Universal Windows Platform
Disponibile da 8
.NET Framework
Disponibile da 2.0
Libreria di classi portabile
Supportato in: piattaforme .NET portabili
Silverlight
Disponibile da 2.0
Windows Phone Silverlight
Disponibile da 7.0
Windows Phone
Disponibile da 8.1
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