NET 系列教程2310B_03.ppt

1、Module 3:Using Microsoft .NET- Based Languages,Overview,Overview of the .NET-Based Languages Comparison of the .NET-Based Languages Creating a Component Using Visual Studio .NET,Lesson: Overview of the .NET-Based Languages,Multiple Language Support The Common Language Runtime The Common Language Run

2、time Components Runtime Compilation and Execution What are Namespaces? Using Namespaces,Multiple Language Support,The .NET Framework is designed to support many languages More than 20 languages currently supported Microsoft provides Visual Basic .NET, C#, Visual J# .NET, and JScript .NET Benefits of

3、 multiple-language support Code modules are reusable API access is the same for all languages The right language is used for the right task Performance is roughly equal between all languages,The Common Language Runtime,One runtime for all . NET-Based Languages Manages threads and memory Garbage coll

4、ection Enforces code security Eliminates DLL versioning problems Multiple versions of a DLL can run simultaneously Applications can specify a version of a DLL to use,The Common Language Runtime Components,.NET Framework Class Library Support,Thread Support,COM Marshaler,MSIL to Native Compilers,Code

5、 Manager,Garbage Collector,Security Engine,Debug Engine,Class Loader,Runtime Compilation and Execution,Nativecode,C# code,Visual Basic .NET code,default.aspx,Runtime,HTML,What are Namespaces?,Group related classes Logical, not physical, grouping Namespaces are hierarchical Decrease naming conflicts

6、Imports keyword in Visual Basic .NET code Using keyword in C# code,Imports System.Data.SqlClient,using System.Data.SqlClient;,Using Namespaces,Implicit object declaration Explicit object declaration,Dim listBox1 As New System.Web.UI.WebControls.ListBox() listBox1.Items.Add(First Item),Imports System

7、.Web.UI.WebControls . Dim listBox1 As New ListBox() listBox1.Items.Add(First Item),using System.Web.UI.WebControls; . ListBox listBox1 = new ListBox(); listBox1.Items.Add(First Item);,System.Web.UI.WebControls.ListBox listBox1 = new System.Web.UI.WebControls.ListBox(); listBox1.Items.Add(First Item)

8、;,Lesson: Comparison of the .NET-Based Languages,Visual Basic .NET C# Choosing a Language Practice: Language Translation,Visual Basic .NET,Visual Basic .NET is the latest version of Visual Basic True object-oriented language Visual Basic Scripting Edition (and JScript) are still used for client-side

9、 script,Private Sub Button1_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles Button1.Click Dim i As Integer = 0 Dim x As Double = TextBox1.Text For i = 0 To 4 x *= 2 Label1.Text = Label1.Text double x = Convert.ToDouble(TextBox1.Text); for (i=0; i=4; i+) x *= 2; Label1.Tex

10、t = Label1.Text + x + ,; ,Choosing a Language,.NET Framework class library is the same regardless of language Performance All languages are compiled to MSIL Only performance difference is how each language compiler compiles to MSIL The runtime compiles all MSIL the same, regardless of its origin Dev

11、elopment experience C# is similar to Java, C, Visual C+, and Pascal Visual Basic .NET is similar to Visual Basic Browser compatibility ASP.NET code is server-side code, so browser compatibility is not an issue,Practice: Language Translation,Students are: Given code in C#, and will then translate it

12、into Visual Basic .NET Given code in Visual Basic .NET, and will then translate it into C# Time: 5 minutes,Lesson: Creating a Component Using Visual Studio .NET,What are Classes and Components? Creating a Class Using Components in an ASP.NET Web Form Demonstration: Creating a Class in Visual Studio

13、.NET,What are Classes and Components?,Classes are groups of code with no user interface Components are compiled classes Components are compiled as DLL files Components are used for sharing code between applications,Web application,Windows application,Web application,Create a Class Library project in

14、 Visual Studio .NET Visual Studio .NET creates a default namespace Create methods of the class,Creating a Class,Public Class Shipping Function ShippingCost _ (ByVal sngPrice As Single) As Single Return (sngShipping) End Function End Class,public class Shipping public Single ShippingCost (Single sngP

15、rice) / return sngShipping; ,Using Components in an ASP.NET Web Form,Add a reference to the DLL Instantiate the class object: Use the object:,sngShipping = x.ShippingCost(sngPrice);,Dim x As New CompanyA.Shipping,Namespace CompanyA Class Shipping Function ShippingCost () End ClassEnd Namespace,compo

16、nent.dll,sngShipping = _ x.ShippingCost(sngPrice),CompanyA.Shipping x = new CompanyA.Shipping();,namespace CompanyA class Shipping public void ShippingCost () ,component.dll,Demonstration: Creating a Class in Visual Studio .NET,Create a new Class Library project Create a “Hello World” method Call it

17、 from an ASP.NET page,Review,Overview of the .NET-Based Languages Comparison of the .NET-Based Languages Creating a Component Using Visual Studio .NET,Lab 3: Building a Microsoft Visual Studio .NET Component,MedicalMedical.aspx,BenefitsHome PageDefault.aspx,Life InsuranceLife.aspx,RetirementRetireme

18、nt.aspx,DentalDental.aspx,Dentists,DoctorsDoctors.aspx,Doctors,Logon Page Login.aspx,Registration Register.aspx,CohoWinery,ProspectusProspectus.aspx,XML Web ServicedentalService1.asmx,Page HeaderHeader.ascx,ASPState,tempdb,Lab Web Application,User Controlnamedate.ascx,Menu ComponentClass1.vb,XML Files,Web.config,MedicalMedical.aspx,BenefitsHome PageDefault.aspx