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Convert.ToDouble Method (Object)

Converts the value of the specified object to a double-precision floating-point number.

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

public static double ToDouble(
	Object value


Type: System.Object
An object that implements the IConvertible interface, or null.

Return Value

Type: System.Double
A double-precision floating-point number that is equivalent to value, or zero if value is null.


value is not in an appropriate format for a Double type.


value does not implement the IConvertible interface.


The conversion is not supported.


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

If value is not null, this method wraps a call to the IConvertible.ToDouble implementation of the underlying type of value.

The following example attempts to convert each value in an object array to a Double.

object[] values = { true, 'a', 123, 1.764e32f, "9.78", "1e-02",
                    1.67e03f, "A100", "1,033.67", DateTime.Now,
                    Decimal.MaxValue };   
double result;

foreach (object value in values)
   try {
      result = Convert.ToDouble(value);
      Console.WriteLine("Converted the {0} value {1} to {2}.",
                        value.GetType().Name, value, result);
   catch (FormatException) {
      Console.WriteLine("The {0} value {1} is not recognized as a valid Double value.",
                        value.GetType().Name, value);
   catch (InvalidCastException) {
      Console.WriteLine("Conversion of the {0} value {1} to a Double is not supported.",
                        value.GetType().Name, value);
// The example displays the following output:
//    Converted the Boolean value True to 1.
//    Conversion of the Char value a to a Double is not supported.
//    Converted the Int32 value 123 to 123.
//    Converted the Single value 1.764E+32 to 1.76399995098587E+32.
//    Converted the String value 9.78 to 9.78.
//    Converted the String value 1e-02 to 0.01.
//    Converted the Single value 1670 to 1670.
//    The String value A100 is not recognized as a valid Double value.
//    Converted the String value 1,033.67 to 1033.67.
//    Conversion of the DateTime value 10/21/2008 07:12:12 AM to a Double is not supported.
//    Converted the Decimal value 79228162514264337593543950335 to 7.92281625142643E+28.      

.NET Framework

Supported in: 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

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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