Gewusst wie: Erstellen einer Klasse mit CodeDOM

Artikel
09/02/2008

Aktualisiert: November 2007

Die folgenden Verfahren zeigen, wie ein CodeDOM-Diagramm erstellt und kompiliert wird, das eine Klasse mit zwei Feldern, drei Eigenschaften, einer Methode, einem Konstruktor und einem Einstiegspunkt generiert.

Erstellen Sie eine Konsolenanwendung, die CodeDOM-Code verwendet, um den Quellcode für eine Klasse zu generieren.

In diesem Beispiel wird die generierende Klasse als Sample bezeichnet, und der generierte Code ist eine Klasse mit dem Namen CodeDOMCreatedClass in der Datei SampleCode.
Initialisieren Sie in der generierenden Klasse das CodeDOM-Diagramm, und verwenden Sie CodeDOM-Methoden, um die Member, den Konstruktor und den Einstiegspunkt (Main-Methode) der generierten Klasse zu definieren.

In diesem Beispiel besitzt die generierte Klasse zwei Felder, drei Eigenschaften, einen Konstruktor, eine Methode und eine Main-Methode.
Erstellen Sie in der generierenden Klasse einen sprachspezifischen Codeanbieter, und rufen Sie dessen GenerateCodeFromCompileUnit-Methode auf, um den Code aus dem Diagramm zu generieren.
Kompilieren und führen Sie die Anwendung aus, um den Code zu generieren.

In diesem Beispiel ist der generierte Code in einer Datei mit dem Namen SampleCode. Kompilieren und führen Sie diesen Code aus, um die Beispielausgabe zu sehen.

So erstellen Sie die Anwendung, die den CodeDOM-Code ausführt

Erstellen Sie eine Konsolenanwendungsklasse für den CodeDOM-Code. Definieren Sie die in der Klasse zu verwendenden globalen Felder, um auf die Assembly (CodeCompileUnit) und die Klasse (CodeTypeDeclaration) zu verweisen, geben Sie den Namen der generierten Quelldatei an, und deklarieren Sie die Main-Methode.

Imports System
Imports System.Reflection
Imports System.IO
Imports System.CodeDom
Imports System.CodeDom.Compiler
Imports Microsoft.CSharp



Class Sample
    Private targetUnit As CodeCompileUnit
    Private targetClass As CodeTypeDeclaration
    Private Const outputFileName As String = "SampleCode.cs"

    Shared Sub Main(ByVal args() As String) 

    End Sub 'Main
End Class 'Sample

using System;
using System.Reflection;
using System.IO;
using System.CodeDom;
using System.CodeDom.Compiler;
using Microsoft.CSharp;

namespace SampleCodeDom
{
    class Sample
    {
        CodeCompileUnit targetUnit;
        CodeTypeDeclaration targetClass;
        private const string outputFileName = "SampleCode.cs";
        static void Main(string[] args)
        {
        }
    }
}

So initialisieren Sie das CodeDOM-Diagramm

Initialisieren Sie im Konstruktor für die Konsolenanwendungsklasse die Assembly und die Klasse, und fügen Sie dem CodeDOM-Diagramm die geeigneten Deklarationen hinzu.

Public Sub New()
    targetUnit = New CodeCompileUnit()
    Dim samples As New CodeNamespace("CodeDOMSample")
    samples.Imports.Add(New CodeNamespaceImport("System"))
    targetClass = New CodeTypeDeclaration("CodeDOMCreatedClass")
    targetClass.IsClass = True
    targetClass.TypeAttributes = _
        TypeAttributes.Public Or TypeAttributes.Sealed
    samples.Types.Add(targetClass)
    targetUnit.Namespaces.Add(samples)

End Sub 'New

public Sample()
{
    targetUnit = new CodeCompileUnit();
    CodeNamespace samples = new CodeNamespace("CodeDOMSample");
    samples.Imports.Add(new CodeNamespaceImport("System"));
    targetClass = new CodeTypeDeclaration("CodeDOMCreatedClass");
    targetClass.IsClass = true;
    targetClass.TypeAttributes =
        TypeAttributes.Public | TypeAttributes.Sealed;
    samples.Types.Add(targetClass);
    targetUnit.Namespaces.Add(samples);
}

So fügen Sie dem CodeDOM-Diagramm Member hinzu

Fügen Sie dem CodeDOM-Diagramm Felder hinzu, indem Sie CodeMemberField-Objekte zur Members-Eigenschaft der Klasse hinzufügen.

Public Sub AddFields()
    ' Declare the widthValue field.
    Dim widthValueField As New CodeMemberField()
    widthValueField.Attributes = MemberAttributes.Private
    widthValueField.Name = "widthValue"
    widthValueField.Type = _
        New CodeTypeReference(GetType(System.Double))
    widthValueField.Comments.Add(New CodeCommentStatement( _
        "The width of the object."))
    targetClass.Members.Add(widthValueField)

    ' Declare the heightValue field
    Dim heightValueField As New CodeMemberField()
    heightValueField.Attributes = MemberAttributes.Private
    heightValueField.Name = "heightValue"
    heightValueField.Type = _
        New CodeTypeReference(GetType(System.Double))
    heightValueField.Comments.Add(New CodeCommentStatement( _
        "The height of the object."))
    targetClass.Members.Add(heightValueField)

End Sub 'AddFields

public void AddFields()
{
    // Declare the widthValue field.
    CodeMemberField widthValueField = new CodeMemberField();
    widthValueField.Attributes = MemberAttributes.Private;
    widthValueField.Name = "widthValue";
    widthValueField.Type = new CodeTypeReference(typeof(System.Double));
    widthValueField.Comments.Add(new CodeCommentStatement(
        "The width of the object."));
    targetClass.Members.Add(widthValueField);

    // Declare the heightValue field
    CodeMemberField heightValueField = new CodeMemberField();
    heightValueField.Attributes = MemberAttributes.Private;
    heightValueField.Name = "heightValue";
    heightValueField.Type =
        new CodeTypeReference(typeof(System.Double));
    heightValueField.Comments.Add(new CodeCommentStatement(
        "The height of the object."));
    targetClass.Members.Add(heightValueField);
}

Fügen Sie dem CodeDOM-Diagramm Eigenschaften hinzu, indem Sie CodeMemberProperty-Objekte zur Members-Eigenschaft der Klasse hinzufügen.

Public Sub AddProperties()
    ' Declare the read only Width property.
    Dim widthProperty As New CodeMemberProperty()
    widthProperty.Attributes = _
        MemberAttributes.Public Or MemberAttributes.Final
    widthProperty.Name = "Width"
    widthProperty.HasGet = True
    widthProperty.Type = New CodeTypeReference(GetType(System.Double))
    widthProperty.Comments.Add(New CodeCommentStatement( _
        "The width property for the object."))
    widthProperty.GetStatements.Add(New CodeMethodReturnStatement( _
        New CodeFieldReferenceExpression( _
        New CodeThisReferenceExpression(), "widthValue")))
    targetClass.Members.Add(widthProperty)

    ' Declare the read-only Height property.
    Dim heightProperty As New CodeMemberProperty()
    heightProperty.Attributes = _
        MemberAttributes.Public Or MemberAttributes.Final
    heightProperty.Name = "Height"
    heightProperty.HasGet = True
    heightProperty.Type = New CodeTypeReference(GetType(System.Double))
    heightProperty.Comments.Add(New CodeCommentStatement( _
        "The Height property for the object."))
    heightProperty.GetStatements.Add(New CodeMethodReturnStatement( _
        New CodeFieldReferenceExpression( _
        New CodeThisReferenceExpression(), "heightValue")))
    targetClass.Members.Add(heightProperty)

    ' Declare the read only Area property.
    Dim areaProperty As New CodeMemberProperty()
    areaProperty.Attributes = _
        MemberAttributes.Public Or MemberAttributes.Final
    areaProperty.Name = "Area"
    areaProperty.HasGet = True
    areaProperty.Type = New CodeTypeReference(GetType(System.Double))
    areaProperty.Comments.Add(New CodeCommentStatement( _
        "The Area property for the object."))

    ' Create an expression to calculate the area for the get accessor
    ' of the Area property.
    Dim areaExpression As New CodeBinaryOperatorExpression( _
        New CodeFieldReferenceExpression( _
        New CodeThisReferenceExpression(), "widthValue"), _
        CodeBinaryOperatorType.Multiply, _
        New CodeFieldReferenceExpression( _
        New CodeThisReferenceExpression(), "heightValue"))
    areaProperty.GetStatements.Add( _
        New CodeMethodReturnStatement(areaExpression))
    targetClass.Members.Add(areaProperty)

End Sub 'AddProperties

public void AddProperties()
{
    // Declare the read-only Width property.
    CodeMemberProperty widthProperty = new CodeMemberProperty();
    widthProperty.Attributes =
        MemberAttributes.Public | MemberAttributes.Final;
    widthProperty.Name = "Width";
    widthProperty.HasGet = true;
    widthProperty.Type = new CodeTypeReference(typeof(System.Double));
    widthProperty.Comments.Add(new CodeCommentStatement(
        "The Width property for the object."));
    widthProperty.GetStatements.Add(new CodeMethodReturnStatement(
        new CodeFieldReferenceExpression(
        new CodeThisReferenceExpression(), "widthValue")));
    targetClass.Members.Add(widthProperty);

    // Declare the read-only Height property.
    CodeMemberProperty heightProperty = new CodeMemberProperty();
    heightProperty.Attributes =
        MemberAttributes.Public | MemberAttributes.Final;
    heightProperty.Name = "Height";
    heightProperty.HasGet = true;
    heightProperty.Type = new CodeTypeReference(typeof(System.Double));
    heightProperty.Comments.Add(new CodeCommentStatement(
        "The Height property for the object."));
    heightProperty.GetStatements.Add(new CodeMethodReturnStatement(
        new CodeFieldReferenceExpression(
        new CodeThisReferenceExpression(), "heightValue")));
    targetClass.Members.Add(heightProperty);

    // Declare the read only Area property.
    CodeMemberProperty areaProperty = new CodeMemberProperty();
    areaProperty.Attributes =
        MemberAttributes.Public | MemberAttributes.Final;
    areaProperty.Name = "Area";
    areaProperty.HasGet = true;
    areaProperty.Type = new CodeTypeReference(typeof(System.Double));
    areaProperty.Comments.Add(new CodeCommentStatement(
        "The Area property for the object."));

    // Create an expression to calculate the area for the get accessor 
    // of the Area property.
    CodeBinaryOperatorExpression areaExpression =
        new CodeBinaryOperatorExpression(
        new CodeFieldReferenceExpression(
        new CodeThisReferenceExpression(), "widthValue"),
        CodeBinaryOperatorType.Multiply,
        new CodeFieldReferenceExpression(
        new CodeThisReferenceExpression(), "heightValue"));
    areaProperty.GetStatements.Add(
        new CodeMethodReturnStatement(areaExpression));
    targetClass.Members.Add(areaProperty);
}

Fügen Sie dem CodeDOM-Diagramm eine Methode hinzu, indem Sie ein CodeMemberMethod-Objekt zur Members-Eigenschaft der Klasse hinzufügen.

Public Sub AddMethod()
    ' Declaring a ToString method.
    Dim toStringMethod As New CodeMemberMethod()
    toStringMethod.Attributes = _
        MemberAttributes.Public Or MemberAttributes.Override
    toStringMethod.Name = "ToString"
    toStringMethod.ReturnType = _
        New CodeTypeReference(GetType(System.String))

    Dim widthReference As New CodeFieldReferenceExpression( _
        New CodeThisReferenceExpression(), "Width")
    Dim heightReference As New CodeFieldReferenceExpression( _
        New CodeThisReferenceExpression(), "Height")
    Dim areaReference As New CodeFieldReferenceExpression( _
        New CodeThisReferenceExpression(), "Area")

    ' Declaring a return statement for method ToString.
    Dim returnStatement As New CodeMethodReturnStatement()

    ' This statement returns a string representation of the width,
    ' height, and area.
    Dim formattedOutput As String = "The object:" & Environment.NewLine _
        & " width = {0}," & Environment.NewLine & " height = {1}," _
        & Environment.NewLine & " area = {2}"
    returnStatement.Expression = New CodeMethodInvokeExpression( _
        New CodeTypeReferenceExpression("System.String"), "Format", _
        New CodePrimitiveExpression(formattedOutput), widthReference, _
        heightReference, areaReference)
    toStringMethod.Statements.Add(returnStatement)
    targetClass.Members.Add(toStringMethod)

End Sub 'AddMethod

public void AddMethod()
{
    // Declaring a ToString method
    CodeMemberMethod toStringMethod = new CodeMemberMethod();
    toStringMethod.Attributes =
        MemberAttributes.Public | MemberAttributes.Override;
    toStringMethod.Name = "ToString";
    toStringMethod.ReturnType =
        new CodeTypeReference(typeof(System.String));

    CodeFieldReferenceExpression widthReference =
        new CodeFieldReferenceExpression(
        new CodeThisReferenceExpression(), "Width");
    CodeFieldReferenceExpression heightReference =
        new CodeFieldReferenceExpression(
        new CodeThisReferenceExpression(), "Height");
    CodeFieldReferenceExpression areaReference =
        new CodeFieldReferenceExpression(
        new CodeThisReferenceExpression(), "Area");

    // Declaring a return statement for method ToString.
    CodeMethodReturnStatement returnStatement =
        new CodeMethodReturnStatement();

    // This statement returns a string representation of the width,
    // height, and area.
    string formattedOutput = "The object:" + Environment.NewLine +
        " width = {0}," + Environment.NewLine +
        " height = {1}," + Environment.NewLine +
        " area = {2}";
    returnStatement.Expression =
        new CodeMethodInvokeExpression(
        new CodeTypeReferenceExpression("System.String"), "Format",
        new CodePrimitiveExpression(formattedOutput),
        widthReference, heightReference, areaReference);
    toStringMethod.Statements.Add(returnStatement);
    targetClass.Members.Add(toStringMethod);
}

Fügen Sie dem CodeDOM-Diagramm einen Konstruktor hinzu, indem Sie ein CodeConstructor-Objekt zur Members-Eigenschaft der Klasse hinzufügen.

Public Sub AddConstructor()
    ' Declare the constructor
    Dim constructor As New CodeConstructor()
    constructor.Attributes = _
        MemberAttributes.Public Or MemberAttributes.Final

    ' Add parameters.
    constructor.Parameters.Add( _
        New CodeParameterDeclarationExpression( _
        GetType(System.Double), "width"))
    constructor.Parameters.Add( _
        New CodeParameterDeclarationExpression( _
        GetType(System.Double), "height"))

    ' Add field initialization logic
    Dim widthReference As New CodeFieldReferenceExpression( _
        New CodeThisReferenceExpression(), "widthValue")
    constructor.Statements.Add(New CodeAssignStatement( _
        widthReference, New CodeArgumentReferenceExpression("width")))
    Dim heightReference As New CodeFieldReferenceExpression( _
        New CodeThisReferenceExpression(), "heightValue")
    constructor.Statements.Add( _
        New CodeAssignStatement(heightReference, _
        New CodeArgumentReferenceExpression("height")))
    targetClass.Members.Add(constructor)

End Sub 'AddConstructor

public void AddConstructor()
{
    // Declare the constructor
    CodeConstructor constructor = new CodeConstructor();
    constructor.Attributes =
        MemberAttributes.Public | MemberAttributes.Final;

    // Add parameters.
    constructor.Parameters.Add(new CodeParameterDeclarationExpression(
        typeof(System.Double), "width"));
    constructor.Parameters.Add(new CodeParameterDeclarationExpression(
        typeof(System.Double), "height"));

    // Add field initialization logic
    CodeFieldReferenceExpression widthReference =
        new CodeFieldReferenceExpression(
        new CodeThisReferenceExpression(), "widthValue");
    constructor.Statements.Add(new CodeAssignStatement(widthReference,
        new CodeArgumentReferenceExpression("width")));
    CodeFieldReferenceExpression heightReference =
        new CodeFieldReferenceExpression(
        new CodeThisReferenceExpression(), "heightValue");
    constructor.Statements.Add(new CodeAssignStatement(heightReference,
        new CodeArgumentReferenceExpression("height")));
    targetClass.Members.Add(constructor);
}

Fügen Sie dem CodeDOM-Diagramm einen Einstiegspunkt hinzu, indem Sie ein CodeEntryPointMethod-Objekt zur Members-Eigenschaft der Klasse hinzufügen.

Public Sub AddEntryPoint()
    Dim start As New CodeEntryPointMethod()
    Dim objectCreate As New CodeObjectCreateExpression( _
        New CodeTypeReference("CodeDOMCreatedClass"), _
        New CodePrimitiveExpression(5.3), _
        New CodePrimitiveExpression(6.9))

    ' Add the statement:
    ' "CodeDOMCreatedClass testClass = _
    '     new CodeDOMCreatedClass(5.3, 6.9);"
    start.Statements.Add(New CodeVariableDeclarationStatement( _
        New CodeTypeReference("CodeDOMCreatedClass"), _
        "testClass", objectCreate))

    ' Creat the expression:
    ' "testClass.ToString()"
    Dim toStringInvoke As New CodeMethodInvokeExpression( _
        New CodeVariableReferenceExpression("testClass"), "ToString")

    ' Add a System.Console.WriteLine statement with the previous 
    ' expression as a parameter.
    start.Statements.Add(New CodeMethodInvokeExpression( _
        New CodeTypeReferenceExpression("System.Console"), _
        "WriteLine", toStringInvoke))
    targetClass.Members.Add(start)

End Sub 'AddEntryPoint

public void AddEntryPoint()
{
    CodeEntryPointMethod start = new CodeEntryPointMethod();
    CodeObjectCreateExpression objectCreate =
        new CodeObjectCreateExpression(
        new CodeTypeReference("CodeDOMCreatedClass"),
        new CodePrimitiveExpression(5.3),
        new CodePrimitiveExpression(6.9));

    // Add the statement:
    // "CodeDOMCreatedClass testClass = 
    //     new CodeDOMCreatedClass(5.3, 6.9);"
    start.Statements.Add(new CodeVariableDeclarationStatement(
        new CodeTypeReference("CodeDOMCreatedClass"), "testClass",
        objectCreate));

    // Creat the expression:
    // "testClass.ToString()"
    CodeMethodInvokeExpression toStringInvoke =
        new CodeMethodInvokeExpression(
        new CodeVariableReferenceExpression("testClass"), "ToString");

    // Add a System.Console.WriteLine statement with the previous 
    // expression as a parameter.
    start.Statements.Add(new CodeMethodInvokeExpression(
        new CodeTypeReferenceExpression("System.Console"),
        "WriteLine", toStringInvoke));
    targetClass.Members.Add(start);
}

So generieren Sie den Code aus dem CodeDOM-Diagramm

Generieren Sie Quellcode aus dem CodeDOM-Diagramm, indem Sie die GenerateCodeFromCompileUnit-Methode aufrufen.

Public Sub GenerateVBCode(ByVal fileName As String)
    Dim provider As CodeDomProvider
    provider = CodeDomProvider.CreateProvider("VisualBasic")
    Dim options As New CodeGeneratorOptions()
    Dim sourceWriter As New StreamWriter(fileName)
    Try
        provider.GenerateCodeFromCompileUnit( _
            targetUnit, sourceWriter, options)
    Finally
        sourceWriter.Dispose()
    End Try

End Sub 'GenerateVBCode

public void GenerateCSharpCode(string fileName)
{
    CodeDomProvider provider = CodeDomProvider.CreateProvider("CSharp");
    CodeGeneratorOptions options = new CodeGeneratorOptions();
    options.BracingStyle = "C";
    using (StreamWriter sourceWriter = new StreamWriter(fileName))
    {
        provider.GenerateCodeFromCompileUnit(
            targetUnit, sourceWriter, options);
    }
}

So erstellen Sie das Diagramm und generieren den Code

Fügen Sie der im ersten Schritt definierten Main-Methode die in den vorhergehenden Schritten erstellten Methoden hinzu.

    Shared Sub Main()
        Dim sample As New Sample()
        sample.AddFields()
        sample.AddProperties()
        sample.AddMethod()
        sample.AddConstructor()
        sample.AddEntryPoint()
        sample.GenerateVBCode(outputFileName)

    End Sub 'Main
End Class 'Sample

static void Main()
{
    Sample sample = new Sample();
    sample.AddFields();
    sample.AddProperties();
    sample.AddMethod();
    sample.AddConstructor();
    sample.AddEntryPoint();
    sample.GenerateCSharpCode(outputFileName);
}

Kompilieren und führen Sie die generierende Klasse aus.

Beispiel

Im folgenden Codebeispiel wird der Code der vorangehenden Schritte veranschaulicht.

Imports System
Imports System.Reflection
Imports System.IO
Imports System.CodeDom
Imports System.CodeDom.Compiler
Imports Microsoft.VisualBasic

' This code example creates a graph using a CodeCompileUnit and  
' generates source code for the graph using the VBCodeProvider.
Class Sample

    ' Define the compile unit to use for code generation. 
    Private targetUnit As CodeCompileUnit

    ' The only class in the compile unit. This class contains 2 fields,
    ' 3 properties, a constructor, an entry point, and 1 simple method. 
    Private targetClass As CodeTypeDeclaration

    ' The name of the file to contain the source code.
    Private Const outputFileName As String = "SampleCode.vb"

    ' Define the class.
    Public Sub New()
        targetUnit = New CodeCompileUnit()
        Dim samples As New CodeNamespace("CodeDOMSample")
        samples.Imports.Add(New CodeNamespaceImport("System"))
        targetClass = New CodeTypeDeclaration("CodeDOMCreatedClass")
        targetClass.IsClass = True
        targetClass.TypeAttributes = _
            TypeAttributes.Public Or TypeAttributes.Sealed
        samples.Types.Add(targetClass)
        targetUnit.Namespaces.Add(samples)

    End Sub 'New

    ' Adds two fields to the class.
    Public Sub AddFields()
        ' Declare the widthValue field.
        Dim widthValueField As New CodeMemberField()
        widthValueField.Attributes = MemberAttributes.Private
        widthValueField.Name = "widthValue"
        widthValueField.Type = _
            New CodeTypeReference(GetType(System.Double))
        widthValueField.Comments.Add(New CodeCommentStatement( _
            "The width of the object."))
        targetClass.Members.Add(widthValueField)

        ' Declare the heightValue field
        Dim heightValueField As New CodeMemberField()
        heightValueField.Attributes = MemberAttributes.Private
        heightValueField.Name = "heightValue"
        heightValueField.Type = _
            New CodeTypeReference(GetType(System.Double))
        heightValueField.Comments.Add(New CodeCommentStatement( _
            "The height of the object."))
        targetClass.Members.Add(heightValueField)

    End Sub 'AddFields

    ' Add three properties to the class.
    Public Sub AddProperties()
        ' Declare the read only Width property.
        Dim widthProperty As New CodeMemberProperty()
        widthProperty.Attributes = _
            MemberAttributes.Public Or MemberAttributes.Final
        widthProperty.Name = "Width"
        widthProperty.HasGet = True
        widthProperty.Type = New CodeTypeReference(GetType(System.Double))
        widthProperty.Comments.Add(New CodeCommentStatement( _
            "The width property for the object."))
        widthProperty.GetStatements.Add(New CodeMethodReturnStatement( _
            New CodeFieldReferenceExpression( _
            New CodeThisReferenceExpression(), "widthValue")))
        targetClass.Members.Add(widthProperty)

        ' Declare the read-only Height property.
        Dim heightProperty As New CodeMemberProperty()
        heightProperty.Attributes = _
            MemberAttributes.Public Or MemberAttributes.Final
        heightProperty.Name = "Height"
        heightProperty.HasGet = True
        heightProperty.Type = New CodeTypeReference(GetType(System.Double))
        heightProperty.Comments.Add(New CodeCommentStatement( _
            "The Height property for the object."))
        heightProperty.GetStatements.Add(New CodeMethodReturnStatement( _
            New CodeFieldReferenceExpression( _
            New CodeThisReferenceExpression(), "heightValue")))
        targetClass.Members.Add(heightProperty)

        ' Declare the read only Area property.
        Dim areaProperty As New CodeMemberProperty()
        areaProperty.Attributes = _
            MemberAttributes.Public Or MemberAttributes.Final
        areaProperty.Name = "Area"
        areaProperty.HasGet = True
        areaProperty.Type = New CodeTypeReference(GetType(System.Double))
        areaProperty.Comments.Add(New CodeCommentStatement( _
            "The Area property for the object."))

        ' Create an expression to calculate the area for the get accessor
        ' of the Area property.
        Dim areaExpression As New CodeBinaryOperatorExpression( _
            New CodeFieldReferenceExpression( _
            New CodeThisReferenceExpression(), "widthValue"), _
            CodeBinaryOperatorType.Multiply, _
            New CodeFieldReferenceExpression( _
            New CodeThisReferenceExpression(), "heightValue"))
        areaProperty.GetStatements.Add( _
            New CodeMethodReturnStatement(areaExpression))
        targetClass.Members.Add(areaProperty)

    End Sub 'AddProperties

    ' Adds a method to the class. This method multiplies values stored 
    ' in both fields.
    Public Sub AddMethod()
        ' Declaring a ToString method.
        Dim toStringMethod As New CodeMemberMethod()
        toStringMethod.Attributes = _
            MemberAttributes.Public Or MemberAttributes.Override
        toStringMethod.Name = "ToString"
        toStringMethod.ReturnType = _
            New CodeTypeReference(GetType(System.String))

        Dim widthReference As New CodeFieldReferenceExpression( _
            New CodeThisReferenceExpression(), "Width")
        Dim heightReference As New CodeFieldReferenceExpression( _
            New CodeThisReferenceExpression(), "Height")
        Dim areaReference As New CodeFieldReferenceExpression( _
            New CodeThisReferenceExpression(), "Area")

        ' Declaring a return statement for method ToString.
        Dim returnStatement As New CodeMethodReturnStatement()

        ' This statement returns a string representation of the width,
        ' height, and area.
        Dim formattedOutput As String = "The object:" & Environment.NewLine _
            & " width = {0}," & Environment.NewLine & " height = {1}," _
            & Environment.NewLine & " area = {2}"
        returnStatement.Expression = New CodeMethodInvokeExpression( _
            New CodeTypeReferenceExpression("System.String"), "Format", _
            New CodePrimitiveExpression(formattedOutput), widthReference, _
            heightReference, areaReference)
        toStringMethod.Statements.Add(returnStatement)
        targetClass.Members.Add(toStringMethod)

    End Sub 'AddMethod

    ' Add a constructor to the class.
    Public Sub AddConstructor()
        ' Declare the constructor
        Dim constructor As New CodeConstructor()
        constructor.Attributes = _
            MemberAttributes.Public Or MemberAttributes.Final

        ' Add parameters.
        constructor.Parameters.Add( _
            New CodeParameterDeclarationExpression( _
            GetType(System.Double), "width"))
        constructor.Parameters.Add( _
            New CodeParameterDeclarationExpression( _
            GetType(System.Double), "height"))

        ' Add field initialization logic
        Dim widthReference As New CodeFieldReferenceExpression( _
            New CodeThisReferenceExpression(), "widthValue")
        constructor.Statements.Add(New CodeAssignStatement( _
            widthReference, New CodeArgumentReferenceExpression("width")))
        Dim heightReference As New CodeFieldReferenceExpression( _
            New CodeThisReferenceExpression(), "heightValue")
        constructor.Statements.Add( _
            New CodeAssignStatement(heightReference, _
            New CodeArgumentReferenceExpression("height")))
        targetClass.Members.Add(constructor)

    End Sub 'AddConstructor

    ' Add an entry point to the class.
    Public Sub AddEntryPoint()
        Dim start As New CodeEntryPointMethod()
        Dim objectCreate As New CodeObjectCreateExpression( _
            New CodeTypeReference("CodeDOMCreatedClass"), _
            New CodePrimitiveExpression(5.3), _
            New CodePrimitiveExpression(6.9))

        ' Add the statement:
        ' "CodeDOMCreatedClass testClass = _
        '     new CodeDOMCreatedClass(5.3, 6.9);"
        start.Statements.Add(New CodeVariableDeclarationStatement( _
            New CodeTypeReference("CodeDOMCreatedClass"), _
            "testClass", objectCreate))

        ' Creat the expression:
        ' "testClass.ToString()"
        Dim toStringInvoke As New CodeMethodInvokeExpression( _
            New CodeVariableReferenceExpression("testClass"), "ToString")

        ' Add a System.Console.WriteLine statement with the previous 
        ' expression as a parameter.
        start.Statements.Add(New CodeMethodInvokeExpression( _
            New CodeTypeReferenceExpression("System.Console"), _
            "WriteLine", toStringInvoke))
        targetClass.Members.Add(start)

    End Sub 'AddEntryPoint

    ' Generate Visual Basic source code from the compile unit.
    Public Sub GenerateVBCode(ByVal fileName As String)
        Dim provider As CodeDomProvider
        provider = CodeDomProvider.CreateProvider("VisualBasic")
        Dim options As New CodeGeneratorOptions()
        Dim sourceWriter As New StreamWriter(fileName)
        Try
            provider.GenerateCodeFromCompileUnit( _
                targetUnit, sourceWriter, options)
        Finally
            sourceWriter.Dispose()
        End Try

    End Sub 'GenerateVBCode

    ' Create the CodeDOM graph and generate the code.
    Shared Sub Main()
        Dim sample As New Sample()
        sample.AddFields()
        sample.AddProperties()
        sample.AddMethod()
        sample.AddConstructor()
        sample.AddEntryPoint()
        sample.GenerateVBCode(outputFileName)

    End Sub 'Main
End Class 'Sample

using System;
using System.Reflection;
using System.IO;
using System.CodeDom;
using System.CodeDom.Compiler;
using Microsoft.CSharp;

namespace SampleCodeDom
{
    /// <summary>
    /// This code example creates a graph using a CodeCompileUnit and  
    /// generates source code for the graph using the CSharpCodeProvider.
    /// </summary>
    class Sample
    {
        /// <summary>
        /// Define the compile unit to use for code generation. 
        /// </summary>
        CodeCompileUnit targetUnit;

        /// <summary>
        /// The only class in the compile unit. This class contains 2 fields,
        /// 3 properties, a constructor, an entry point, and 1 simple method. 
        /// </summary>
        CodeTypeDeclaration targetClass;

        /// <summary>
        /// The name of the file to contain the source code.
        /// </summary>
        private const string outputFileName = "SampleCode.cs";

        /// <summary>
        /// Define the class.
        /// </summary>
        public Sample()
        {
            targetUnit = new CodeCompileUnit();
            CodeNamespace samples = new CodeNamespace("CodeDOMSample");
            samples.Imports.Add(new CodeNamespaceImport("System"));
            targetClass = new CodeTypeDeclaration("CodeDOMCreatedClass");
            targetClass.IsClass = true;
            targetClass.TypeAttributes =
                TypeAttributes.Public | TypeAttributes.Sealed;
            samples.Types.Add(targetClass);
            targetUnit.Namespaces.Add(samples);
        }

        /// <summary>
        /// Adds two fields to the class.
        /// </summary>
        public void AddFields()
        {
            // Declare the widthValue field.
            CodeMemberField widthValueField = new CodeMemberField();
            widthValueField.Attributes = MemberAttributes.Private;
            widthValueField.Name = "widthValue";
            widthValueField.Type = new CodeTypeReference(typeof(System.Double));
            widthValueField.Comments.Add(new CodeCommentStatement(
                "The width of the object."));
            targetClass.Members.Add(widthValueField);

            // Declare the heightValue field
            CodeMemberField heightValueField = new CodeMemberField();
            heightValueField.Attributes = MemberAttributes.Private;
            heightValueField.Name = "heightValue";
            heightValueField.Type =
                new CodeTypeReference(typeof(System.Double));
            heightValueField.Comments.Add(new CodeCommentStatement(
                "The height of the object."));
            targetClass.Members.Add(heightValueField);
        }
        /// <summary>
        /// Add three properties to the class.
        /// </summary>
        public void AddProperties()
        {
            // Declare the read-only Width property.
            CodeMemberProperty widthProperty = new CodeMemberProperty();
            widthProperty.Attributes =
                MemberAttributes.Public | MemberAttributes.Final;
            widthProperty.Name = "Width";
            widthProperty.HasGet = true;
            widthProperty.Type = new CodeTypeReference(typeof(System.Double));
            widthProperty.Comments.Add(new CodeCommentStatement(
                "The Width property for the object."));
            widthProperty.GetStatements.Add(new CodeMethodReturnStatement(
                new CodeFieldReferenceExpression(
                new CodeThisReferenceExpression(), "widthValue")));
            targetClass.Members.Add(widthProperty);

            // Declare the read-only Height property.
            CodeMemberProperty heightProperty = new CodeMemberProperty();
            heightProperty.Attributes =
                MemberAttributes.Public | MemberAttributes.Final;
            heightProperty.Name = "Height";
            heightProperty.HasGet = true;
            heightProperty.Type = new CodeTypeReference(typeof(System.Double));
            heightProperty.Comments.Add(new CodeCommentStatement(
                "The Height property for the object."));
            heightProperty.GetStatements.Add(new CodeMethodReturnStatement(
                new CodeFieldReferenceExpression(
                new CodeThisReferenceExpression(), "heightValue")));
            targetClass.Members.Add(heightProperty);

            // Declare the read only Area property.
            CodeMemberProperty areaProperty = new CodeMemberProperty();
            areaProperty.Attributes =
                MemberAttributes.Public | MemberAttributes.Final;
            areaProperty.Name = "Area";
            areaProperty.HasGet = true;
            areaProperty.Type = new CodeTypeReference(typeof(System.Double));
            areaProperty.Comments.Add(new CodeCommentStatement(
                "The Area property for the object."));

            // Create an expression to calculate the area for the get accessor 
            // of the Area property.
            CodeBinaryOperatorExpression areaExpression =
                new CodeBinaryOperatorExpression(
                new CodeFieldReferenceExpression(
                new CodeThisReferenceExpression(), "widthValue"),
                CodeBinaryOperatorType.Multiply,
                new CodeFieldReferenceExpression(
                new CodeThisReferenceExpression(), "heightValue"));
            areaProperty.GetStatements.Add(
                new CodeMethodReturnStatement(areaExpression));
            targetClass.Members.Add(areaProperty);
        }

        /// <summary>
        /// Adds a method to the class. This method multiplies values stored 
        /// in both fields.
        /// </summary>
        public void AddMethod()
        {
            // Declaring a ToString method
            CodeMemberMethod toStringMethod = new CodeMemberMethod();
            toStringMethod.Attributes =
                MemberAttributes.Public | MemberAttributes.Override;
            toStringMethod.Name = "ToString";
            toStringMethod.ReturnType =
                new CodeTypeReference(typeof(System.String));

            CodeFieldReferenceExpression widthReference =
                new CodeFieldReferenceExpression(
                new CodeThisReferenceExpression(), "Width");
            CodeFieldReferenceExpression heightReference =
                new CodeFieldReferenceExpression(
                new CodeThisReferenceExpression(), "Height");
            CodeFieldReferenceExpression areaReference =
                new CodeFieldReferenceExpression(
                new CodeThisReferenceExpression(), "Area");

            // Declaring a return statement for method ToString.
            CodeMethodReturnStatement returnStatement =
                new CodeMethodReturnStatement();

            // This statement returns a string representation of the width,
            // height, and area.
            string formattedOutput = "The object:" + Environment.NewLine +
                " width = {0}," + Environment.NewLine +
                " height = {1}," + Environment.NewLine +
                " area = {2}";
            returnStatement.Expression =
                new CodeMethodInvokeExpression(
                new CodeTypeReferenceExpression("System.String"), "Format",
                new CodePrimitiveExpression(formattedOutput),
                widthReference, heightReference, areaReference);
            toStringMethod.Statements.Add(returnStatement);
            targetClass.Members.Add(toStringMethod);
        }
        /// <summary>
        /// Add a constructor to the class.
        /// </summary>
        public void AddConstructor()
        {
            // Declare the constructor
            CodeConstructor constructor = new CodeConstructor();
            constructor.Attributes =
                MemberAttributes.Public | MemberAttributes.Final;

            // Add parameters.
            constructor.Parameters.Add(new CodeParameterDeclarationExpression(
                typeof(System.Double), "width"));
            constructor.Parameters.Add(new CodeParameterDeclarationExpression(
                typeof(System.Double), "height"));

            // Add field initialization logic
            CodeFieldReferenceExpression widthReference =
                new CodeFieldReferenceExpression(
                new CodeThisReferenceExpression(), "widthValue");
            constructor.Statements.Add(new CodeAssignStatement(widthReference,
                new CodeArgumentReferenceExpression("width")));
            CodeFieldReferenceExpression heightReference =
                new CodeFieldReferenceExpression(
                new CodeThisReferenceExpression(), "heightValue");
            constructor.Statements.Add(new CodeAssignStatement(heightReference,
                new CodeArgumentReferenceExpression("height")));
            targetClass.Members.Add(constructor);
        }

        /// <summary>
        /// Add an entry point to the class.
        /// </summary>
        public void AddEntryPoint()
        {
            CodeEntryPointMethod start = new CodeEntryPointMethod();
            CodeObjectCreateExpression objectCreate =
                new CodeObjectCreateExpression(
                new CodeTypeReference("CodeDOMCreatedClass"),
                new CodePrimitiveExpression(5.3),
                new CodePrimitiveExpression(6.9));

            // Add the statement:
            // "CodeDOMCreatedClass testClass = 
            //     new CodeDOMCreatedClass(5.3, 6.9);"
            start.Statements.Add(new CodeVariableDeclarationStatement(
                new CodeTypeReference("CodeDOMCreatedClass"), "testClass",
                objectCreate));

            // Creat the expression:
            // "testClass.ToString()"
            CodeMethodInvokeExpression toStringInvoke =
                new CodeMethodInvokeExpression(
                new CodeVariableReferenceExpression("testClass"), "ToString");

            // Add a System.Console.WriteLine statement with the previous 
            // expression as a parameter.
            start.Statements.Add(new CodeMethodInvokeExpression(
                new CodeTypeReferenceExpression("System.Console"),
                "WriteLine", toStringInvoke));
            targetClass.Members.Add(start);
        }
        /// <summary>
        /// Generate CSharp source code from the compile unit.
        /// </summary>
        /// <param name="filename">Output file name</param>
        public void GenerateCSharpCode(string fileName)
        {
            CodeDomProvider provider = CodeDomProvider.CreateProvider("CSharp");
            CodeGeneratorOptions options = new CodeGeneratorOptions();
            options.BracingStyle = "C";
            using (StreamWriter sourceWriter = new StreamWriter(fileName))
            {
                provider.GenerateCodeFromCompileUnit(
                    targetUnit, sourceWriter, options);
            }
        }

        /// <summary>
        /// Create the CodeDOM graph and generate the code.
        /// </summary>
        static void Main()
        {
            Sample sample = new Sample();
            sample.AddFields();
            sample.AddProperties();
            sample.AddMethod();
            sample.AddConstructor();
            sample.AddEntryPoint();
            sample.GenerateCSharpCode(outputFileName);
        }
    }
}

Wenn das vorangehende Beispiel kompiliert und ausgeführt wird, erzeugt es den folgenden Quellcode.

'--------------------------------------------------------------------------
' <auto-generated>
'     This code was generated by a tool.
'     Runtime Version:2.0.50727.42
'
'     Changes to this file may cause incorrect behavior and will be lost if
'     the code is regenerated.
' </auto-generated>
'--------------------------------------------------------------------------

Option Strict Off
Option Explicit On

Imports System

Namespace CodeDOMSample

    Public NotInheritable Class CodeDOMCreatedClass

        'The width of the object.
        Private widthValue As Double

        'The height of the object.
        Private heightValue As Double

        Public Sub New(ByVal width As Double, ByVal height As Double)
            MyBase.New
            Me.widthValue = width
            Me.heightValue = height
        End Sub

        'The width property for the object.
        Public ReadOnly Property Width() As Double
            Get
                Return Me.widthValue
            End Get
        End Property

        'The Height property for the object.
        Public ReadOnly Property Height() As Double
            Get
                Return Me.heightValue
            End Get
        End Property

        'The Area property for the object.
        Public ReadOnly Property Area() As Double
            Get
                Return (Me.widthValue * Me.heightValue)
            End Get
        End Property

        Public Overrides Function ToString() As String
            Return String.Format("The object:"& _
                Global.Microsoft.VisualBasic.ChrW(13)& _
                Global.Microsoft.VisualBasic.ChrW(10)& _
                " width = {0},"&Global.Microsoft.VisualBasic.ChrW(13)& _
                Global.Microsoft.VisualBasic.ChrW(10)& _
                " height = {1},"&Global.Microsoft.VisualBasic.ChrW(13)& _
                Global.Microsoft.VisualBasic.ChrW(10)&" area = {2}", _
                Me.Width, Me.Height, Me.Area)
        End Function

        Public Shared Sub Main()
            Dim testClass As CodeDOMCreatedClass = _
                New CodeDOMCreatedClass(5.3, 6.9)
            System.Console.WriteLine(testClass.ToString)
        End Sub
    End Class
End Namespace

//--------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//     Runtime Version:2.0.50727.42
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//--------------------------------------------------------------------------

namespace CodeDOMSample
{
    using System;


    public sealed class CodeDOMCreatedClass
    {

        // The width of the object.
        private double widthValue;

        // The height of the object.
        private double heightValue;

        public CodeDOMCreatedClass(double width, double height)
        {
            this.widthValue = width;
            this.heightValue = height;
        }

        // The Width property for the object.
        public double Width
        {
            get
            {
                return this.widthValue;
            }
        }

        // The Height property for the object.
        public double Height
        {
            get
            {
                return this.heightValue;
            }
        }

        // The Area property for the object.
        public double Area
        {
            get
            {
                return (this.widthValue * this.heightValue);
            }
        }

        public override string ToString()
        {
            return string.Format(
                "The object:\r\n width = {0},\r\n height = {1},\r\n area = {2}", 
                this.Width, this.Height, this.Area);
        }

        public static void Main()
        {
            CodeDOMCreatedClass testClass = new CodeDOMCreatedClass(5.3, 6.9);
            System.Console.WriteLine(testClass.ToString());
        }
    }
}

Der generierte Quellcode erzeugt die folgende Ausgabe, wenn er kompiliert und ausgeführt wird.

The object:
 width = 5.3,
 height = 6.9,
 area = 36.57

Kompilieren des Codes

Dieses Codebeispiel erfordert den FullTrust-Berechtigungssatz, um erfolgreich ausgeführt werden zu können.

Siehe auch

Konzepte

Verwenden von CodeDOM

Generieren von Quellcode und Kompilieren eines Programms aus einem CodeDOM-Diagramm