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Convert.ToSingle Method (Object, IFormatProvider)

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.

ExceptionCondition
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

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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