create barcode image vb.net // Convert int to Person. in Visual C#

Encode Data Matrix ECC200 in Visual C# // Convert int to Person.

// Convert int to Person.
Data Matrix Encoder In C#.NET
Using Barcode printer for Visual Studio .NET Control to generate, create Data Matrix 2d barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Decode Data Matrix ECC200 In C#
Using Barcode decoder for .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
CHAPTER 18 CONVERSIONS
PDF 417 Drawer In Visual C#
Using Barcode generator for VS .NET Control to generate, create PDF-417 2d barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Barcode Drawer In C#.NET
Using Barcode printer for .NET framework Control to generate, create Barcode image in VS .NET applications.
www.OnBarcode.com
This code produces the following output: Person Info: bill, 25 Person Info: Nemo, 35 If you had defined the same conversion operators as explicit rather than implicit, then you would have needed to use cast expressions to perform the conversions, as shown here: Explicit ... public static explicit operator int( Person p ) { return p.Age; } ... static void Main( ) { ... Requires cast expression int age = (int) bill; ...
Print Code 39 Full ASCII In C#.NET
Using Barcode creation for VS .NET Control to generate, create Code-39 image in .NET applications.
www.OnBarcode.com
2D Barcode Printer In Visual C#.NET
Using Barcode drawer for .NET framework Control to generate, create Matrix 2D Barcode image in VS .NET applications.
www.OnBarcode.com
CHAPTER 18 CONVERSIONS
Data Matrix Creator In C#.NET
Using Barcode generation for .NET Control to generate, create Data Matrix 2d barcode image in .NET framework applications.
www.OnBarcode.com
ISSN - 13 Drawer In Visual C#
Using Barcode generation for Visual Studio .NET Control to generate, create ISSN image in Visual Studio .NET applications.
www.OnBarcode.com
Evaluating User-Defined Conversions
ECC200 Printer In None
Using Barcode drawer for Software Control to generate, create Data Matrix 2d barcode image in Software applications.
www.OnBarcode.com
Generate Data Matrix ECC200 In .NET
Using Barcode creation for .NET Control to generate, create Data Matrix image in VS .NET applications.
www.OnBarcode.com
The user-defined conversions discussed so far have directly converted the source type to an object of the target type in a single step, as shown in Figure 18-26.
QR Code Maker In None
Using Barcode creator for Microsoft Excel Control to generate, create Quick Response Code image in Office Excel applications.
www.OnBarcode.com
Data Matrix ECC200 Printer In Visual Studio .NET
Using Barcode generation for .NET Control to generate, create ECC200 image in .NET framework applications.
www.OnBarcode.com
Figure 18-26. Single-step user-defined conversion But user-defined conversions can have up to three steps in the full conversion. Figure 18-27 illustrates these stages, which include the following: The preliminary standard conversion The user-defined conversion The following standard conversion There is never more than a single user-defined conversion in the chain.
Scan QR Code JIS X 0510 In C#.NET
Using Barcode scanner for VS .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Creating Barcode In .NET Framework
Using Barcode drawer for Reporting Service Control to generate, create Barcode image in Reporting Service applications.
www.OnBarcode.com
Figure 18-27. Multistep user-defined conversion
Encode Barcode In None
Using Barcode drawer for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Recognizing Universal Product Code Version A In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
Example of a Multistep User-Defined Conversion
UCC-128 Creation In VS .NET
Using Barcode encoder for ASP.NET Control to generate, create USS-128 image in ASP.NET applications.
www.OnBarcode.com
EAN13 Scanner In Visual Basic .NET
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
The following code declares class Employee, which is derived from class Person. Several sections ago, the code sample declared a user-defined conversion from class Person to int. So if there is a standard conversion from Employee to Person and one from int to float, you can convert from Employee to float. There is a standard conversion from Employee to Person, since Employee is derived from Person. There is a standard conversion from int to float, since that is an implicit numeric conversion.
Generate Matrix 2D Barcode In Java
Using Barcode creator for Java Control to generate, create Matrix Barcode image in Java applications.
www.OnBarcode.com
Generating Universal Product Code Version A In Objective-C
Using Barcode generation for iPad Control to generate, create Universal Product Code version A image in iPad applications.
www.OnBarcode.com
Since all three parts of the chain exist, you can convert from Employee to float. Figure 18-28 illustrates how the compiler performs the conversion.
CHAPTER 18 CONVERSIONS
class Employee : Person { } class Person { public string Name; public int Age; // Convert a Person object to an int. public static implicit operator int(Person p) { return p.Age; } } class Program { static void Main( ) { Employee bill = new Employee(); bill.Name = "William"; bill.Age = 25; Convert an Employee to a float. float fVar = bill; Console.WriteLine("Person Info: {0}, {1}", bill.Name, fVar); } } This code produces the following output: Person Info: William, 25
Figure 18-28. Conversion of Employee to float
CHAPTER 18 CONVERSIONS
The is Operator
As shown previously, some conversion attempts are not successful and raise an InvalidCastException exception at run time. Instead of blindly attempting a conversion, you can use the is operator to check whether a conversion would complete successfully. The syntax of the is operator is the following, where Expr is the source expression: Returns a bool Expr is TargetType The operator returns true if Expr can be successfully converted to the target type through any of the following: A reference conversion A boxing conversion An unboxing conversion
For example, in the following code, you use the is operator to check whether variable bill of type Employee can be converted to type Person, and then you take the appropriate action. class Employee : Person { } class Person { public string Name = "Anonymous"; public int Age = 25; } class Program { static void Main() { Employee bill = new Employee(); Person p; // Check if variable bill can be converted to type Person if( bill is Person ) { p = bill; Console.WriteLine("Person Info: {0}, {1}", p.Name, p.Age); } } } The is operator can be used only for reference conversions and boxing and unboxing conversions. It cannot be used for user-defined conversions.
CHAPTER 18 CONVERSIONS
The as Operator
The as operator is like the cast operator, except that it does not raise an exception. If the conversion fails, rather than raising an exception, it returns null. The syntax of the as operator is the following, where Expr is the source expression. TargetType is the target type, which must be a reference type.
Returns a reference Expr as TargetType Since the as operator returns a reference expression, it can be used as the source for an assignment. For example, variable bill of type Employee is converted to type Person, using the as operator, and assigned to variable p of type Person. You then check to see whether p is null before using it. class Employee : Person { } class Person { public string Name = "Anonymous"; public int Age = 25; } class Program { static void Main() { Employee bill = new Employee(); Person p; p = bill as Person; if( p != null ) { Console.WriteLine("Person Info: {0}, {1}", p.Name, p.Age); } } } Like the is operator, the as operator can be used only for reference conversions and boxing conversions. It cannot be used for user-defined conversions or conversions to a value type.
Copyright © OnBarcode.com . All rights reserved.