C# - Chuyển đổi kiểu

Type conversion is converting one type of data to another type. It is also known as Type Casting. In C#, type casting has two forms −

  • Implicit type conversion − These conversions are performed by C# in a type-safe manner. For example, are conversions from smaller to larger integral types and conversions from derived classes to base classes.

  • Explicit type conversion − These conversions are done explicitly by users using the pre-defined functions. Explicit conversions require a cast operator.

The following example shows an explicit type conversion −

Live Demo

using System;

namespace TypeConversionApplication {
   class ExplicitConversion {
      static void Main(string[] args) {
         double d = 5673.74; 
         int i;
         
         // cast double to int.
         i = (int)d;
         Console.WriteLine(i);
         Console.ReadKey();
      }
   }
}

When the above code is compiled and executed, it produces the following result −

5673

C# Type Conversion Methods

C# provides the following built-in type conversion methods −

Sr.No. Methods & Description
1

ToBoolean

Converts a type to a Boolean value, where possible.

2

ToByte

Converts a type to a byte.

3

ToChar

Converts a type to a single Unicode character, where possible.

4

ToDateTime

Converts a type (integer or string type) to date-time structures.

5

ToDecimal

Converts a floating point or integer type to a decimal type.

6

ToDouble

Converts a type to a double type.

7

ToInt16

Converts a type to a 16-bit integer.

8

ToInt32

Converts a type to a 32-bit integer.

9

ToInt64

Converts a type to a 64-bit integer.

10

ToSbyte

Converts a type to a signed byte type.

11

ToSingle

Converts a type to a small floating point number.

12

ToString

Converts a type to a string.

13

ToType

Converts a type to a specified type.

14

ToUInt16

Converts a type to an unsigned int type.

15

ToUInt32

Converts a type to an unsigned long type.

16

ToUInt64

Converts a type to an unsigned big integer.

The following example converts various value types to string type −

Live Demo

using System;

namespace TypeConversionApplication {
   class StringConversion {
      static void Main(string[] args) {
         int i = 75;
         float f = 53.005f;
         double d = 2345.7652;
         bool b = true;

         Console.WriteLine(i.ToString());
         Console.WriteLine(f.ToString());
         Console.WriteLine(d.ToString());
         Console.WriteLine(b.ToString());
         Console.ReadKey();
            
      }
   }
}

When the above code is compiled and executed, it produces the following result −

75
53.005
2345.7652
True