Reflection in Visual Basic .NET

Generation QR Code in Visual Basic .NET Reflection

14
QR Code ISO/IEC18004 Creation In VB.NET
Using Barcode creation for .NET framework Control to generate, create QR-Code image in Visual Studio .NET applications.
www.OnBarcode.com
Reading QR Code JIS X 0510 In Visual Basic .NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
Reflection
Create Bar Code In Visual Basic .NET
Using Barcode generation for .NET framework Control to generate, create barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Bar Code Recognizer In Visual Basic .NET
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
6. Add a description to both solutions by editing the AssemblyDescription attribute in the AssemblyInfo file or by clicking the Assembly Information button on the Assembly tab of the Project Properties dialog box. For Addon-console, set the description to Displays a greeting to the console. For Addon-dialog, set the description to Displays a greeting in a dialog box. 7. Build both solutions. Then, copy the DLL files to the Greeter build folder. 8. Build and run the Greeter solution. It should find both assemblies, display the AssemblyDescription value, and then call the Greet method. Developers could create any number of assemblies and copy them to the application folder, and the Greeter application would run them all, provided that they meet the file, type, and method naming requirements.
Generate Denso QR Bar Code In Visual C#
Using Barcode maker for .NET framework Control to generate, create QR image in VS .NET applications.
www.OnBarcode.com
QR Generator In Visual Studio .NET
Using Barcode creation for ASP.NET Control to generate, create QR-Code image in ASP.NET applications.
www.OnBarcode.com
Lesson Summary
Generate Denso QR Bar Code In Visual Studio .NET
Using Barcode generation for Visual Studio .NET Control to generate, create QR Code ISO/IEC18004 image in VS .NET applications.
www.OnBarcode.com
Encoding UCC.EAN - 128 In Visual Basic .NET
Using Barcode creation for VS .NET Control to generate, create GTIN - 128 image in .NET framework applications.
www.OnBarcode.com
Reflection allows you to load assemblies at runtime, create instances of types defined within a dynamically loaded assembly, and call methods defined within a dynamically loaded assembly. You can use reflection to make your application extensible by allowing developers to create their own assemblies that offer custom functionality. The Assembly class includes several methods you can use to load an assembly dynamically: Load, LoadFrom, LoadFile, ReflectionOnlyLoad, and ReflectionOnlyLoadFrom. After loading an assembly, call Assembly.GetType to load a type from the assembly, and call Type.GetConstructor to create an instance of ConstructorInfo. Then you can create an instance of the type by calling ConstructorInfo.Invoke. To call a method, call Type.GetMethod to create an instance of MethodInfo. Once you create an instance of MethodInfo, you can call the method using MethodInfo.Invoke. Assembly attributes describe the assembly and are defined in the AssemblyInfo file. You can read attributes by calling Assembly.GetCustomAttributes. Use the Builder classes to create assemblies, modules, types, constructors, methods, and other members dynamically. You can create an instance of ILGenerator to write code for methods or constructors.
Creating Code 39 Extended In Visual Basic .NET
Using Barcode encoder for VS .NET Control to generate, create Code 39 Full ASCII image in VS .NET applications.
www.OnBarcode.com
Encode 2D Barcode In VB.NET
Using Barcode encoder for .NET Control to generate, create Matrix Barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Lesson Review
Linear 1D Barcode Maker In VB.NET
Using Barcode generator for Visual Studio .NET Control to generate, create Linear Barcode image in VS .NET applications.
www.OnBarcode.com
Making Leitcode In VB.NET
Using Barcode generator for Visual Studio .NET Control to generate, create Leitcode image in VS .NET applications.
www.OnBarcode.com
You can use the following questions to test your knowledge of the information in Lesson 1, Using Reflection. The questions are also available on the companion CD if you prefer to review them in electronic form.
Decoding PDF417 In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Making Bar Code In Java
Using Barcode maker for Android Control to generate, create bar code image in Android applications.
www.OnBarcode.com
Lesson 1: Using Reflection
Generating GS1 DataBar-14 In .NET
Using Barcode generation for .NET framework Control to generate, create GS1 DataBar Limited image in .NET framework applications.
www.OnBarcode.com
Bar Code Printer In Java
Using Barcode printer for Eclipse BIRT Control to generate, create bar code image in BIRT reports applications.
www.OnBarcode.com
NOTE
Generate EAN 128 In None
Using Barcode creation for Software Control to generate, create UCC.EAN - 128 image in Software applications.
www.OnBarcode.com
Creating PDF417 In None
Using Barcode encoder for Software Control to generate, create PDF417 image in Software applications.
www.OnBarcode.com
Answers
QR Code JIS X 0510 Drawer In Java
Using Barcode printer for BIRT reports Control to generate, create Denso QR Bar Code image in Eclipse BIRT applications.
www.OnBarcode.com
Print EAN / UCC - 14 In None
Using Barcode generation for Excel Control to generate, create GS1 128 image in Excel applications.
www.OnBarcode.com
Answers to these questions and explanations of why each answer choice is right or wrong are located in the Answers section at the end of the book.
1. You need to load an assembly and run a method contained within a type dynamically. Which class should you use to run the method A. MethodBase B. MethodInfo C. MethodBuilder D. ConstructorInfo 2. You need to write code equivalent to the following, but using reflection:
' VB Dim d As New DateTime(2008, 5, 1) Console.WriteLine(d.ToShortDateString()) // C# DateTime d = new DateTime(2008, 5, 1); Console.WriteLine(d.ToShortDateString());
Which code sample does this correctly A.
' VB Dim t As Type = GetType(DateTime) Dim mi As MethodInfo = t.GetConstructor( _ New Type() {GetType(Integer), GetType(Integer), GetType(Integer)}) Dim d As Object = mi.Invoke(New Object() {2008, 5, 1}) Dim dToShortDateString As ConstructorInfo = t.GetMethod("ToShortDateString") Console.WriteLine(DirectCast(dToShortDateString.Invoke(d, Nothing), String)) // C# Type t = typeof(DateTime); MethodInfo mi = t.GetConstructor( new Type[] { typeof(int), typeof(int), typeof(int) }); Object d = mi.Invoke(new Object[] { 2008, 5, 1 }); ConstructorInfo dToShortDateString = t.GetMethod("ToShortDateString"); Console.WriteLine((string)dToShortDateString.Invoke(d, null));
' VB Dim t As Type = GetType(DateTime) Dim ci As ConstructorInfo = t.GetConstructor(New Object() {2008, 5, 1}) Dim d As Object = ci.Invoke( _ New Type() {GetType(Integer), GetType(Integer), GetType(Integer)}) Dim dToShortDateString As MethodInfo = t.GetMethod("ToShortDateString") Console.WriteLine(DirectCast(dToShortDateString.Invoke(d, Nothing), String))
14
Reflection
// C# Type t = typeof(DateTime); ConstructorInfo ci = t.GetConstructor(new Object[] { 2008, 5, 1 }); Object d = ci.Invoke( new Object[] { new Type[] { typeof(int), typeof(int), typeof(int) }); MethodInfo dToShortDateString = t.GetMethod("ToShortDateString"); Console.WriteLine((string)dToShortDateString.Invoke(d, null));
' VB Dim t As Type = GetType(DateTime) Dim dToShortDateString As MethodInfo = t.GetMethod("ToShortDateString") Console.WriteLine(DirectCast(dToShortDateString.Invoke(t, Nothing), String)) // C# Type t = typeof(DateTime); MethodInfo dToShortDateString = t.GetMethod("ToShortDateString"); Console.WriteLine((string)dToShortDateString.Invoke(t, null));
' VB Dim t As Type = GetType(DateTime) Dim ci As ConstructorInfo = _ t.GetConstructor(New Type() {GetType(Integer), GetType(Integer), GetType(Integer)}) Dim d As Object = ci.Invoke(New Object() {2008, 5, 1}) Dim dToShortDateString As MethodInfo = t.GetMethod("ToShortDateString") Console.WriteLine(DirectCast(dToShortDateString.Invoke(d, Nothing), String)) // C# Type t = typeof(DateTime); ConstructorInfo ci = t.GetConstructor(new Type[] { typeof(int), typeof(int), typeof(int) }); Object d = ci.Invoke(new Object[] { 2008, 5, 1 }); MethodInfo dToShortDateString = t.GetMethod("ToShortDateString"); Console.WriteLine((string)dToShortDateString.Invoke(d, null));
3. You need to examine an assembly s metadata from an application. The assembly is located in the GAC. However, the assembly was developed for a different platform, and you cannot run the code contained within the assembly. Which method should you call A. Assembly.ReflectionOnlyLoad B. Assembly.LoadFrom C. Assembly.LoadFile D. Assembly.ReflectionOnlyLoadFrom
Copyright © OnBarcode.com . All rights reserved.