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AOP using System.Reflection.Emit - Code Injection IL

, 2 Jun 2006 63.2K 1.2K 71
Very often, we need to intercept method calls and enable some code to run before/after a method call of an external type (.NET object). Learn how to do this.
interceptor.zip
WinTestAspect
App.ico
bin
Debug
SadasSof.Aspects.dll
WinTestAspect.exe
obj
Debug
temp
TempPE
WinTestAspect.csproj.user
SadasSoft.Aspects
bin
Debug
SadasSof.Aspects.dll
obj
Debug
InterceptorSample.dll
temp
TempPE
Release
Sadas.Reflection.dll
temp
TempPE
SadasSof.Aspects.csproj.user
WebTestAspects
bin
EnterpriseDemo.dll
SadasSof.Aspects.dll
WebTestAspects.dll
Global.asax
WebTestAspects.csproj.webinfo
wintestaspect.zip
EnterpriseDemo.dll
SadasSof.Aspects.dll
WinTestAspect.exe
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Reflection;
using System.Reflection.Emit;
using EnterpriseDemo;
using SadasSof.Aspects;
using SadasSof.Aspects.Attributes;

namespace WinTestAspect
{
	/// <summary>
	/// Summary description for Form1.
	/// </summary>
	public class Form1 : System.Windows.Forms.Form
	{
		private System.Windows.Forms.Button button1;
		private System.Windows.Forms.CheckBox ckbFilter;
		private System.Windows.Forms.TextBox TextBox1;
		private System.Windows.Forms.DataGrid DataGrid1;
		private System.Windows.Forms.RadioButton rdDelegation1;
		private System.Windows.Forms.RadioButton rdDelegation2;
		private System.Windows.Forms.RadioButton rdDelegation3;
		/// <summary>
		/// Required designer variable.
		/// </summary>
		private System.ComponentModel.Container components = null;

		public Form1()
		{
			//
			// Required for Windows Form Designer support
			//
			InitializeComponent();

			//
			// TODO: Add any constructor code after InitializeComponent call
			//
		}

		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows Form Designer generated code
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			this.button1 = new System.Windows.Forms.Button();
			this.TextBox1 = new System.Windows.Forms.TextBox();
			this.DataGrid1 = new System.Windows.Forms.DataGrid();
			this.ckbFilter = new System.Windows.Forms.CheckBox();
			this.rdDelegation1 = new System.Windows.Forms.RadioButton();
			this.rdDelegation2 = new System.Windows.Forms.RadioButton();
			this.rdDelegation3 = new System.Windows.Forms.RadioButton();
			((System.ComponentModel.ISupportInitialize)(this.DataGrid1)).BeginInit();
			this.SuspendLayout();
			// 
			// button1
			// 
			this.button1.Location = new System.Drawing.Point(40, 56);
			this.button1.Name = "button1";
			this.button1.Size = new System.Drawing.Size(80, 23);
			this.button1.TabIndex = 0;
			this.button1.Text = "GetEmployees";
			this.button1.Click += new System.EventHandler(this.button1_Click);
			// 
			// TextBox1
			// 
			this.TextBox1.Location = new System.Drawing.Point(400, 64);
			this.TextBox1.Name = "TextBox1";
			this.TextBox1.Size = new System.Drawing.Size(64, 20);
			this.TextBox1.TabIndex = 3;
			this.TextBox1.Text = "";
			// 
			// DataGrid1
			// 
			this.DataGrid1.DataMember = "";
			this.DataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText;
			this.DataGrid1.Location = new System.Drawing.Point(32, 104);
			this.DataGrid1.Name = "DataGrid1";
			this.DataGrid1.Size = new System.Drawing.Size(440, 208);
			this.DataGrid1.TabIndex = 6;
			this.DataGrid1.Visible = false;
			// 
			// ckbFilter
			// 
			this.ckbFilter.Location = new System.Drawing.Point(128, 56);
			this.ckbFilter.Name = "ckbFilter";
			this.ckbFilter.TabIndex = 7;
			this.ckbFilter.Text = "External Filter";
			// 
			// rdDelegation1
			// 
			this.rdDelegation1.Checked = true;
			this.rdDelegation1.Location = new System.Drawing.Point(240, 16);
			this.rdDelegation1.Name = "rdDelegation1";
			this.rdDelegation1.TabIndex = 9;
			this.rdDelegation1.TabStop = true;
			this.rdDelegation1.Text = "Madrid";
			// 
			// rdDelegation2
			// 
			this.rdDelegation2.Location = new System.Drawing.Point(240, 40);
			this.rdDelegation2.Name = "rdDelegation2";
			this.rdDelegation2.TabIndex = 10;
			this.rdDelegation2.Text = "Paris";
			// 
			// rdDelegation3
			// 
			this.rdDelegation3.Location = new System.Drawing.Point(240, 64);
			this.rdDelegation3.Name = "rdDelegation3";
			this.rdDelegation3.TabIndex = 11;
			this.rdDelegation3.Text = "London";
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(496, 350);
			this.Controls.Add(this.rdDelegation3);
			this.Controls.Add(this.rdDelegation2);
			this.Controls.Add(this.rdDelegation1);
			this.Controls.Add(this.ckbFilter);
			this.Controls.Add(this.DataGrid1);
			this.Controls.Add(this.TextBox1);
			this.Controls.Add(this.button1);
			this.Name = "Form1";
			this.Text = "Form1";
			this.Load += new System.EventHandler(this.Form1_Load);
			((System.ComponentModel.ISupportInitialize)(this.DataGrid1)).EndInit();
			this.ResumeLayout(false);

		}
		#endregion

		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[STAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}

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

		}

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

			try
			{
				IBussinesLogicEmployees iBLExternal=null;

				if(ckbFilter.Checked)
					iBLExternal=(IBussinesLogicEmployees)CodeInjection.Create(
						new BussinesLogicEmployees(),
						typeof(IBussinesLogicEmployeesExternalFilter));
				else
					iBLExternal=(IBussinesLogicEmployees)CodeInjection.Create(
						new BussinesLogicEmployees(),
						typeof(IBussinesLogicEmployeesAll));
			
				Employees dsE=null;

				string delegation=string.Empty;
				if(rdDelegation1.Checked)
					delegation="Madrid";
				else if(rdDelegation2.Checked)
					delegation="Paris";
				else
					delegation="London";
			
				switch(delegation)
				{
					case "Madrid":
						dsE = iBLExternal.GetEmployees(BussinesLogicEmployees.Delegation.Madrid);
						break;

					case "Paris":
						dsE = iBLExternal.GetEmployees(BussinesLogicEmployees.Delegation.Paris);
						break;

					case "London":
						dsE = iBLExternal.GetEmployees(BussinesLogicEmployees.Delegation.London);
						break;
				}
				TextBox1.Text = CountingCalls.Calls("GetEmployees").ToString();
			
				DataGrid1.Visible=true;
				DataGrid1.DataSource=dsE.Tables[0];
			}
			catch(Exception ex)
			{
				DataGrid1.Visible=false;
				MessageBox.Show(ex.InnerException.ToString());
			}
			
		}



	}



	public interface IBussinesLogicEmployees
	{
		EnterpriseDemo.Employees GetEmployees(EnterpriseDemo.BussinesLogicEmployees.Delegation delegation);
		
	}
		
	public interface IBussinesLogicEmployeesAll:IBussinesLogicEmployees
	{
		[CountingCalls]
		[LoggerExceptionToFile]
		new EnterpriseDemo.Employees GetEmployees(EnterpriseDemo.BussinesLogicEmployees.Delegation delegation);
	}

	public interface IBussinesLogicEmployeesExternalFilter:IBussinesLogicEmployees
	{
		[CountingCalls]
		[ExternalFilter]
		[LoggerToFile]
		[LoggerExceptionToFile]
		new EnterpriseDemo.Employees GetEmployees(EnterpriseDemo.BussinesLogicEmployees.Delegation delegation);
	}

}

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About the Author

Roberto Loreto
Web Developer
Spain Spain
No Biography provided

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