Code generation with .net Hello, today I would like to introduce code generation with c# and .NET. (It may be usefull when dealing with repetitive Database access code).

To start with this feature, here is a complete sample on how to build a ".exe" file, using natives code generation and compilation tools.

The following code will produce, after compilation with csc.exe, a winform application.
This application has one purpose: produce another application, a console one.
Two framework's objects are important here: System.CodeDom.Compiler.ICodeGenerator and System.CodeDom.Compiler.ICodeCompiler.
The first is a common interface to generate .net code. The second one is used to compile the code. Here I use the cSharp implementation of these interfaces to produce a basic console application.

using System;

using System.Collections;

using System.ComponentModel;

using System.Windows.Forms;

using System.Data;

using System.CodeDom;

using System.CodeDom.Compiler;

using Microsoft.CSharp;

using System.Collections.Specialized;

namespace WindowsApplication2

{

    /// Main form



    public class Form1 : System.Windows.Forms.Form

    {

        private System.Windows.Forms.Button button1;

        private System.Windows.Forms.RichTextBox rt1;

        private System.Windows.Forms.ListBox listBox1;

        private System.ComponentModel.Container components = null;



        public Form1()

        {

            //

            // Requis pour la prise en charge du Concepteur Windows Forms

            //

            InitializeComponent();

        }



        /// Nettoyage des ressources utilisées.

        protected override void Dispose( bool disposing )

        {

            if( disposing )

            {

                if (components != null)

                {

                    components.Dispose();

                }

            }

            base.Dispose( disposing );

        }



        #region Code généré par le Concepteur Windows Form

        /// <summary>

        /// Méthode requise pour la prise en charge du concepteur - ne modifiez pas

        /// le contenu de cette méthode avec l'éditeur de code.

        /// </summary>

        private void InitializeComponent()

        {

            this.button1 = new System.Windows.Forms.Button();

            this.rt1 = new System.Windows.Forms.RichTextBox();

            this.listBox1 = new System.Windows.Forms.ListBox();

            this.SuspendLayout();

            // 

            // button1

            // 

            this.button1.Location = new System.Drawing.Point(432, 8);

            this.button1.Name = "button1";

            this.button1.Size = new System.Drawing.Size(232, 104);

            this.button1.TabIndex = 0;

            this.button1.Text = "button1";

            this.button1.Click += new System.EventHandler(this.button1_Click);

            // 

            // rt1

            // 

            this.rt1.Location = new System.Drawing.Point(24, 16);

            this.rt1.Name = "rt1";

            this.rt1.Size = new System.Drawing.Size(384, 192);

            this.rt1.TabIndex = 1;

            this.rt1.Text = "richTextBox1";

            // 

            // listBox1

            // 

            this.listBox1.Location = new System.Drawing.Point(24, 224);

            this.listBox1.Name = "listBox1";

            this.listBox1.Size = new System.Drawing.Size(896, 251);

            this.listBox1.TabIndex = 3;

            // 

            // Form1

            // 

            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);

            this.ClientSize = new System.Drawing.Size(936, 526);

            this.Controls.Add(this.listBox1);

            this.Controls.Add(this.rt1);

            this.Controls.Add(this.button1);

            this.Name = "Form1";

            this.Text = "Form1";

            this.Load += new System.EventHandler(this.Form1_Load);

            this.ResumeLayout(false);



        }

        #endregion



        /// Point d'entrée principal de l'application.

        [STAThread]

        static void Main()

        {

            Application.Run(new Form1());

        }



        private void Form1_Load(object sender, System.EventArgs e)

        {

        //nothing special here 

        }



        private void button1_Click(object sender, System.EventArgs e)

        {// here is starting the main part of the code:

    //

    //the CodeCompileUnit  is the  abstract code structure:



            // Create a new CodeCompileUnit to contain the program graph

            CodeCompileUnit CompileUnit = new CodeCompileUnit();

            // Declare a new namespace called Samples.

            CodeNamespace Samples = new CodeNamespace("Samples");

            // Add the new namespace to the compile unit.

            CompileUnit.Namespaces.Add( Samples );



            // Add the new namespace import for the System namespace.

            Samples.Imports.Add( new CodeNamespaceImport("System") );



            // Declare a new type called Class1.

            CodeTypeDeclaration Class1 = new CodeTypeDeclaration("echo");

            // Add the new type to the namespace's type collection.

            Samples.Types.Add(Class1);



            //a variable declaration

            CodeVariableDeclarationStatement Var = new

CodeVariableDeclarationStatement("System.String","str1");

            // Declare a new code entry point method

            CodeEntryPointMethod Start = new CodeEntryPointMethod();

            // Create a new method invocation expression.

            CodeMethodInvokeExpression cs1 =

new CodeMethodInvokeExpression(

                // Call the System.Console.WriteLine method.

                

newCodeTypeReferenceExpression("System.Console"), "ReadLine");

            CodeAssignStatement as1 = new CodeAssignStatement(

new CodeVariableReferenceExpression("str1"),cs1);



            // Create a new method invocation expression.

            CodeMethodInvokeExpression cs2 =

 new CodeMethodInvokeExpression(

                // Call the System.Console.WriteLine method.

                new CodeTypeReferenceExpression("System.Console"), "WriteLine");

            cs2.Parameters.Add(new CodeVariableReferenceExpression(Var.Name));



            Start.Statements.Add(Var);

            // Add the new method code statement.

            Start.Statements.Add( as1);

            // Add the new method code statement.

            Start.Statements.Add(new CodeExpressionStatement(cs2));



            // Add the code entry point method to the type's members collection

            Class1.Members.Add( Start );





            System.IO.StringWriter Sw = new System.IO.StringWriter();



        

        Microsoft.CSharp.CSharpCodeProvider provider =

        new CSharpCodeProvider();

        System.CodeDom.Compiler.ICodeGenerator generator = provider.CreateGenerator(Sw);

            CodeGeneratorOptions genOptions = new CodeGeneratorOptions();



            // The code generator should insert blank lines 

            genOptions.BlankLinesBetweenMembers = true;



            try

            {

                generator.GenerateCodeFromCompileUnit(CompileUnit,Sw,genOptions);

            }

            catch (Exception Exc)

            {

            System.Windows.Forms.MessageBox.Show (Exc.Message);

            }

            rt1.Text = Sw.ToString();



///

//            Compilation 

            //instanciate csharp compiler

            System.CodeDom.Compiler.ICodeCompiler MyCompiler = provider.CreateCompiler();

            System.CodeDom.Compiler.CompilerParameters cp = new CompilerParameters();

                        cp.GenerateExecutable = true;

                        cp.CompilerOptions= " /target:exe";



            //where your exe will be  saved

            cp.OutputAssembly = "c:\\echo.exe";

            // Invoke compilation.

            CompilerResults cr = MyCompiler.CompileAssemblyFromSource ( cp,rt1.Text);

        //

        // Return the results of compilation.



            //eventually load compilation output to the listbox (usefull to debug)

            listBox1.DataSource=cr.Output;



            //where is it? 

            MessageBox.Show ( cr.PathToAssembly );





          }

    }

}

  ¶ 9:56 AM