The return value is the result of invoking the Double.Parse method on value. provider is an IFormatProvider instance that obtains a NumberFormatInfo object. The NumberFormatInfo object provides culture-specific information about the format of value.
https://msdn.microsoft.com/en-us/library/9s9ak971(v=vs.110).aspx
Use the IsDate function to determine if date can be converted to a date or time. CDate recognizes date literals and time literals as well as some numbers that fall within the range of acceptable dates. When converting a number to a date, the whole number portion is converted to a date.
https://support.office.com/en-us/article/Type-Conversion-Functions-8EBB0E94-2D43-4975-BB13-87AC8D1A2202
For example, use CCur to force currency arithmetic in cases where single-precision, double-precision, or integer arithmetic normally would occur. You should use the data-type conversion functions instead of Val to provide internationally aware conversions from one data type to another.
https://support.office.com/en-us/article/Type-Conversion-Functions-8EBB0E94-2D43-4975-BB13-87AC8D1A2202
The ToString() method formats a Double value in the default (G, or general) format of the current culture. If you want to specify a different format, precision, or culture, use the other overloads of the ToString method, as follows: To use format. For culture. Use the overload.
https://msdn.microsoft.com/en-us/library/3hfd35ad(v=vs.110).aspx
This example uses the CDate function to convert a string to a Date. In general, hard-coding dates and times as strings (as shown in this example) is not recommended. Use date literals and time literals, such as #2/12/1969# and #4:45:23 PM#, instead.
https://support.office.com/en-us/article/Type-Conversion-Functions-8EBB0E94-2D43-4975-BB13-87AC8D1A2202
A double-precision floating-point number that is equivalent to the number in value, or 0 (zero) if value is null. value is not a number in a valid format. value represents a number that is less than Double.MinValue or greater than Double.MaxValue.
https://msdn.microsoft.com/en-us/library/9s9ak971(v=vs.110).aspx
Each function coerces an expression to a specific data type. The required expressionargument is any string expression or numeric expression. Any valid string or numeric expression. 0 to 255. -922,337,203,685,477.5808 to 922,337,203,685,477.5807. Any valid date expression.
https://support.office.com/en-us/article/Type-Conversion-Functions-8EBB0E94-2D43-4975-BB13-87AC8D1A2202
Convert.ToDouble Method (String, IFormatProvider) Converts the specified string representation of a number to an equivalent double-precision floating-point number, using the specified culture-specific formatting information.
https://msdn.microsoft.com/en-us/library/9s9ak971(v=vs.110).aspx
The return value can be PositiveInfinitySymbol, NegativeInfinitySymbol, NaNSymbol, or a string of the form: [sign]integral-digits[.[fractional-digits]][e[sign]exponential-digits] Optional elements are framed in square brackets ([ and ]). Elements that contain the term digits consist of a series of numeric characters ranging from 0 to 9. The elements listed in the following table are supported.
https://msdn.microsoft.com/en-us/library/3hfd35ad(v=vs.110).aspx
The following example converts string representations of Double values with the ToDouble method, using an IFormatProvider object.
https://msdn.microsoft.com/en-us/library/9s9ak971(v=vs.110).aspx
convert double to string
Convert double to string by using String.value Of (double d) method , which takes a double value as an argument and returns it in a form of String literal.