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Metodo Decimal.Equals (Decimal)

 

Data di pubblicazione: ottobre 2016

Restituisce un valore che indica se l'istanza e un oggetto Decimal specificato rappresentano lo stesso valore.

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

public bool Equals(
	decimal value
)

Parametri

value
Type: System.Decimal

Oggetto da confrontare con questa istanza.

Valore restituito

Type: System.Boolean

true se value è uguale all'istanza; in caso contrario, false.

This method implements the T:System.IEquatable`1 interface, and performs slightly better than M:System.Decimal.Equals(System.Object) because it does not have to convert the value parameter to an object.

If value has fewer bits (is narrower) than the instance type, some programming languages perform an implicit widening conversion that transforms the value of the parameter into a value with more bits.

For example, suppose the instance type is T:System.Int32 and the parameter type is T:System.Byte. The Microsoft C# compiler generates instructions to represent the value of the parameter as an T:System.Int32 object, then generates a M:System.Int32.CompareTo(System.Int32) method to compare the T:System.Int32 instance and parameter representation.

Consult your programming language's documentation to determine whether its compiler performs implicit widening conversions on numeric types.

Note per i chiamanti:

Compiler overload resolution may account for an apparent difference in the behavior of the two M:System.Decimal.Equals(System.Object) method overloads. If an implicit conversion between the obj argument and a T:System.Decimal is defined and the argument is not typed as an T:System.Object, compilers may perform an implicit conversion and call the M:System.Decimal.Equals(System.Decimal) method. Otherwise, they call the M:System.Decimal.Equals(System.Object) method, which always returns false if its obj argument is not a T:System.Decimal value. The following example illustrates the difference in behavior between the two method overloads. In the case of all primitive integral types, including both signed and unsigned types, the first comparison returns true because the compiler automatically performs a widening conversion and calls the M:System.Decimal.Equals(System.Decimal) method, whereas the second comparison returns false because the compiler calls the M:System.Decimal.Equals(System.Object) method.

using System;

public class Example
{
   static decimal value = 112m;

   public static void Main()
   {
      byte byte1= 112;
      Console.WriteLine("value = byte1: {0,17}", value.Equals(byte1));
      TestObjectForEquality(byte1);

      short short1 = 112;
      Console.WriteLine("value = short1: {0,17}", value.Equals(short1));
      TestObjectForEquality(short1);

      int int1 = 112;
      Console.WriteLine("value = int1: {0,19}", value.Equals(int1));
      TestObjectForEquality(int1);

      long long1 = 112;
      Console.WriteLine("value = long1: {0,18}", value.Equals(long1));
      TestObjectForEquality(long1);

      sbyte sbyte1 = 112;
      Console.WriteLine("value = sbyte1: {0,17}", value.Equals(sbyte1));
      TestObjectForEquality(sbyte1);

      ushort ushort1 = 112;
      Console.WriteLine("value = ushort1: {0,17}", value.Equals(ushort1));
      TestObjectForEquality(ushort1);

      uint uint1 = 112;
      Console.WriteLine("value = uint1: {0,19}", value.Equals(uint1));
      TestObjectForEquality(uint1);

      ulong ulong1 = 112;
      Console.WriteLine("value = ulong1: {0,18}", value.Equals(ulong1));
      TestObjectForEquality(ulong1);

      float sng1 = 112;
      Console.WriteLine("value = sng1: {0,21}", value.Equals(sng1));
      TestObjectForEquality(sng1);

      double dbl1 = 112;
      Console.WriteLine("value = dbl1: {0,21}", value.Equals(dbl1));
      TestObjectForEquality(dbl1);
   }

   private static void TestObjectForEquality(Object obj)
   {
      Console.WriteLine("{0} ({1}) = {2} ({3}): {4}\n",
                        value, value.GetType().Name,
                        obj, obj.GetType().Name,
                        value.Equals(obj));
   }
}
// The example displays the following output:
//       value = byte1:             True
//       112 (Double) = 112 (Byte): False
//
//       value = short1:             True
//       112 (Double) = 112 (Int16): False
//
//       value = int1:               True
//       112 (Double) = 112 (Int32): False
//
//       value = long1:              True
//       112 (Double) = 112 (Int64): False
//
//       value = sbyte1:             True
//       112 (Double) = 112 (SByte): False
//
//       value = ushort1:             True
//       112 (Double) = 112 (UInt16): False
//
//       value = uint1:               True
//       112 (Double) = 112 (UInt32): False
//
//       value = ulong1:              True
//       112 (Double) = 112 (UInt64): False
//
//       value = dec1:                 False
//       112 (Double) = 112 (Decimal): False
//
//       value = sng1:                True
//       112 (Double) = 112 (Single): False

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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