Convert.ToSingle Method (Object, IFormatProvider)

 
System_CAPS_noteNote

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Converts the value of the specified object to an single-precision floating-point number, using the specified culture-specific formatting information.

Namespace:   System
Assembly:  mscorlib (in mscorlib.dll)

public static float ToSingle(
	object value,
	IFormatProvider provider
)

Parameters

value
Type: System.Object

An object that implements the IConvertible interface.

provider
Type: System.IFormatProvider

An object that supplies culture-specific formatting information.

Return Value

Type: System.Single

A single-precision floating-point number that is equivalent to value, or zero if value is null.

Exception Condition
FormatException

value is not in an appropriate format.

InvalidCastException

value does not implement IConvertible.

OverflowException

value represents a number that is less than Single.MinValue or greater than Single.MaxValue.

The return value is the result of invoking the IConvertible.ToSingle method of the underlying type of value.

provider enables the user to specify culture-specific conversion information about the contents of value. For example, if value is a String that represents a number, provider could supply culture-specific information about the notation used to represent that number.

The base types ignore provider; however, the parameter may be used if value is a user-defined type that implements the IConvertible interface.

The following example defines a Temperature class that implements the IConvertible interface. Its implementation of the IConvertible.ToSingle method returns the internal value of a private Single variable that represents the temperature.

using System;
using System.Globalization;

public class Temperature : IConvertible
{
   private float m_Temp;

   public Temperature(float temperature)
   {
      this.m_Temp = temperature;
   }

   public float Celsius
   {
      get { return this.m_Temp; }   
   }

   public float Kelvin
   {
      get { return this.m_Temp + 273.15f; }    
   }

   public float Fahrenheit
   {
      get { return (float) Math.Round(this.m_Temp * 9 / 5 + 32, 2); }
   }

   public override string ToString()
   {
      return m_Temp.ToString("N2") + " °C";
   }

   // IConvertible implementations.
   public TypeCode GetTypeCode()
   {
      return TypeCode.Object;
   }

   public bool ToBoolean(IFormatProvider provider) 
   {
      if (m_Temp == 0)
         return false;
      else
         return true;
   } 

   public byte ToByte(IFormatProvider provider)
   {
      if (m_Temp < Byte.MinValue || m_Temp > Byte.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the Byte type.", 
                                                   this.m_Temp));
      else
         return Convert.ToByte(this.m_Temp);
   }

   public char ToChar(IFormatProvider provider)
   {
      throw new InvalidCastException("Temperature to Char conversion is not supported.");
   } 

   public DateTime ToDateTime(IFormatProvider provider)
   {
      throw new InvalidCastException("Temperature to DateTime conversion is not supported.");
   }

   public decimal ToDecimal(IFormatProvider provider)
   {
      return Convert.ToDecimal(this.m_Temp);
   }

   public double ToDouble(IFormatProvider provider)
   {
      return Convert.ToDouble(this.m_Temp);
   }   

   public short ToInt16(IFormatProvider provider)
   {
      if (this.m_Temp < Int16.MinValue || this.m_Temp > Int16.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the Int16 type.",
                                                   this.m_Temp));
      else
         return Convert.ToInt16(this.m_Temp);
   }

   public int ToInt32(IFormatProvider provider)
      {
      if (this.m_Temp < Int32.MinValue || this.m_Temp > Int32.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the Int32 type.",
                                                   this.m_Temp));
      else
         return Convert.ToInt32(this.m_Temp);
   }

   public long ToInt64(IFormatProvider provider)
   {
      if (this.m_Temp < Int64.MinValue || this.m_Temp > Int64.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the Int64 type.",
                                                   this.m_Temp));
      else
         return Convert.ToInt64(this.m_Temp);
   }

   public sbyte ToSByte(IFormatProvider provider)
   {
      if (this.m_Temp < SByte.MinValue || this.m_Temp > SByte.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the SByte type.",
                                                   this.m_Temp));
      else
         return Convert.ToSByte(this.m_Temp);
   }

   public float ToSingle(IFormatProvider provider)
   {
      return this.m_Temp;
   }

   public string ToString(IFormatProvider provider)
   {
      return m_Temp.ToString("N2", provider) + " °C";
   }

   public object ToType(Type conversionType, IFormatProvider provider)
   {
      switch (Type.GetTypeCode(conversionType))
      {
         case TypeCode.Boolean: 
            return this.ToBoolean(null);
         case TypeCode.Byte:
            return this.ToByte(null);
         case TypeCode.Char:
            return this.ToChar(null);
         case TypeCode.DateTime:
            return this.ToDateTime(null);
         case TypeCode.Decimal:
            return this.ToDecimal(null);
         case TypeCode.Double:
            return this.ToDouble(null);
         case TypeCode.Int16:
            return this.ToInt16(null);
         case TypeCode.Int32:
            return this.ToInt32(null);
         case TypeCode.Int64:
            return this.ToInt64(null);
         case TypeCode.Object:
            if (typeof(Temperature).Equals(conversionType))
               return this;
            else
               throw new InvalidCastException(String.Format("Conversion to a {0} is not supported.",
                                                            conversionType.Name));
         case TypeCode.SByte:
            return this.ToSByte(null);
         case TypeCode.Single:
            return this.ToSingle(null);
         case TypeCode.String:
            return this.ToString(provider);
         case TypeCode.UInt16:
            return this.ToUInt16(null);
         case TypeCode.UInt32:
            return this.ToUInt32(null);
         case TypeCode.UInt64:
            return this.ToUInt64(null);   
         default:
            throw new InvalidCastException(String.Format("Conversion to {0} is not supported.", conversionType.Name));   
      }
   }

   public ushort ToUInt16(IFormatProvider provider)
   {
      if (this.m_Temp < UInt16.MinValue || this.m_Temp > UInt16.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the UInt16 type.",
                                                   this.m_Temp));
      else
         return Convert.ToUInt16(this.m_Temp);
   }

   public uint ToUInt32(IFormatProvider provider)
   {
      if (this.m_Temp < UInt32.MinValue || this.m_Temp > UInt32.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the UInt32 type.",
                                                   this.m_Temp));
      else
         return Convert.ToUInt32(this.m_Temp);
   }

   public ulong ToUInt64(IFormatProvider provider)
   {
      if (this.m_Temp < UInt64.MinValue || this.m_Temp > UInt64.MaxValue)
         throw new OverflowException(String.Format("{0} is out of range of the UInt64 type.",
                                                   this.m_Temp));
      else
         return Convert.ToUInt64(this.m_Temp);
   }
}

The following example illustrates how a call to the Convert.ToSingle(Object, IFormatProvider) method, in turn, calls the IConvertible.ToSingle implementation of the Temperature class.

public class Example
{
   public static void Main()
   {
      Temperature cold = new Temperature(-40);
      Temperature freezing = new Temperature(0);
      Temperature boiling = new Temperature(100);

      Console.WriteLine(Convert.ToInt32(cold, null));
      Console.WriteLine(Convert.ToInt32(freezing, null));
      Console.WriteLine(Convert.ToDouble(boiling, null));
   }
}
// The example dosplays the following output:
//       -40
//       0
//       100

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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