. Net Data Type conversions

Implicitly-Typed conversions:

Small range to large range;

Char to other types is possible, and vice versa.

Display Type conversions:

Simple Type

1. char a = (char) 1;   Simple type of conversion, compile times wrong. (4.6 to 4, straight to decimal)
2. int b = Convert.ToInt32 (123.4);   Simple type of conversion, execution times wrong. (4.6 is 5, rounded, decimal is 5 o'clock, return even)
3. int c = Int32.Parse ("123");   Only string to number, execution times wrong. ("4.6" simultaneous failed with format error)

2 and 3 differences: The result of Convert.ToInt32 (null) is 0,int32.parse (null) ArgumentNullException exception.

Reference type

Key words	Data type	Parameter relationships	Run-time failure
CType	Any data type	Widening or narrowing conversions must be defined between two types of data	Trigger InvalidCastException
DirectCast	Any data type	A type must inherit from or implement another type	Trigger InvalidCastException
TryCast	Reference type only	A type must inherit from or implement another type	Return Nothing

Dim p as Product
p = CType (obj, Product)
p = DirectCast (obj, Product)

Example: c = DirectCast (f, System.Windows.Forms.Control) The best efficiency
P =trycast (obj, Product)

. Net Data Type conversions