Convert.ToDouble Method (String)

 

Converts the specified string representation of a number to an equivalent double-precision floating-point number.

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

Public Shared Function ToDouble (
	value As String
) As Double

Parameters

value
Type: System.String

A string that contains the number to convert.

Return Value

Type: System.Double

A double-precision floating-point number that is equivalent to the number in value, or 0 (zero) if value is null.

Exception Condition
FormatException

value is not a number in a valid format.

OverflowException

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

Using the ToDouble(String) method is equivalent to passing value to the Double.Parse(String) method. value is interpreted by using the formatting conventions of the current thread culture.

If you prefer not to handle an exception if the conversion fails, you can call the Double.TryParse method instead. It returns a Boolean value that indicates whether the conversion succeeded or failed.

The following example attempts to convert each element in an array of numeric strings to a Double. The example's output is from a system whose current culture is en-US.

Module Example
   Public Sub Main()
      Dim values() As String = { "-1,035.77219", "1AFF", "1e-35", _
                                 "1,635,592,999,999,999,999,999,999", "-17.455", _
                                 "190.34001", "1.29e325"}
      Dim result As Double

      For Each value As String In values
         Try
            result = Convert.ToDouble(value)
            Console.WriteLine("Converted '{0}' to {1}.", value, result)
         Catch e As FormatException
            Console.WriteLine("Unable to convert '{0}' to a Double.", value)            
         Catch e As OverflowException
            Console.WriteLine("'{0}' is outside the range of a Double.", value)
         End Try
      Next       
   End Sub   
End Module
' The example displays the following output:
'       Converted '-1,035.77219' to -1035.77219.
'       Unable to convert '1AFF' to a Double.
'       Converted '1e-35' to 1E-35.
'       Converted '1,635,592,999,999,999,999,999,999' to 1.635593E+24.
'       Converted '-17.455' to -17.455.
'       Converted '190.34001' to 190.34001.
'       '1.29e325' is outside the range of a Double.

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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