Suppose I have two exes WindowsApplication1.exe WindowsApplication2.exe..On the form load of WindowsApplication2.exe,I m calling WindowsApplication1.exe & sending the command line arguements..I copy the WindowsApplication1.exe into the debug folder of WindowsApplication2.exe.

WindowsApplication2.exe

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Process.Start(Application.StartupPath & "\" & "WindowsApplication1.exe", "one" & "two")
    End Sub

WindowsApplication1.exe

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        MsgBox(Command)
    End Sub

On form load of WindowsApplication2.exe,WindowsApplication1.exe is started & arguments are sent.
Now I want to check on form load of WindowsApplication2.exe,I do not want to start WindowsApplication1.exe, i just want to send the arguments to the WindowsApplication1.exe. Is is possible? To send the command line arguments to the ruunning exe.

Is is possible? To send the command line arguments to the ruunning exe

No, it isn't because your WindowsApplication2.exe instance is already running.

You could use sockets for inter-process communication or see what the Windows Communication Foundation (.NET 3.5) has to offer.

One simple solution would be to use files. WindowsApplication2 polls a directory, with timer or FileSystemWatcher control, until WindowsApplication1 creates a file containing parameters you want to pass back to WindowsApplication2.

HTH

hi sknake,below is the C# code

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.Text;


namespace From_C_Sharp
{
	/// <summary>
	/// Summary description for Form1.
	/// </summary>
	/// 
	public class Form1 : System.Windows.Forms.Form
	{
#if _DEBUG
const string WmCpyDta = "WmCpyDta_d.dll";
#else
const string WmCpyDta = "WmCpyDta.dll";
#endif

		[DllImport("user32.dll",EntryPoint="FindWindow")]
		private static extern int FindWindow(string _ClassName, string _WindowName);


		[DllImport(WmCpyDta,EntryPoint="WmCpyDta_SetMessageId")]
		private static extern int WmCpyDta_SetMessageId(int iMsgId);

		[DllImport(WmCpyDta,EntryPoint="WmCpyDta_GetMessageId")]
		private static extern int WmCpyDta_GetMessageId();

		[DllImport(WmCpyDta,EntryPoint="WmCpyDta_SendMessage_sTagData")]
		private static extern int WmCpyDta_SendMessage_sTagData(int hReceiver , int hSender, string _strTag, string _strData);

		[DllImport(WmCpyDta,EntryPoint="WmCpyDta_SetEncrypt")]
		private static extern void WmCpyDta_SetEncrypt(char c);

		private System.Windows.Forms.Button button1;
		private System.Windows.Forms.Button button2;
		/// <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.button2 = new System.Windows.Forms.Button();
			this.SuspendLayout();
			// 
			// button1
			// 
			this.button1.Location = new System.Drawing.Point(8, 16);
			this.button1.Name = "button1";
			this.button1.Size = new System.Drawing.Size(264, 40);
			this.button1.TabIndex = 0;
			this.button1.Text = "Ping -  send a message to the TO apps if they are running";
			this.button1.Click += new System.EventHandler(this.button1_Click);
			// 
			// button2
			// 
			this.button2.Location = new System.Drawing.Point(16, 72);
			this.button2.Name = "button2";
			this.button2.Size = new System.Drawing.Size(248, 40);
			this.button2.TabIndex = 1;
			this.button2.Text = "Close";
			this.button2.Click += new System.EventHandler(this.button2_Click);
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(292, 133);
			this.Controls.AddRange(new System.Windows.Forms.Control[] {
																		  this.button2,
																		  this.button1});
			this.Name = "Form1";
			this.Text = "From C Sharp";
			this.ResumeLayout(false);

		}
		#endregion

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

		private void button2_Click(object sender, System.EventArgs e)
		{
			this.Close();
		}

		public IntPtr FindProcessByName(string strProcessName)
		{
			IntPtr HandleOfToProcess = IntPtr.Zero;
			Process []p = Process.GetProcesses();
			foreach(Process p1 in p)
			{
				Debug.WriteLine(p1.ProcessName.ToUpper());
				if(p1.ProcessName.ToUpper() == strProcessName)
				{
					HandleOfToProcess = p1.MainWindowHandle;
					break;
				}
			}
			return HandleOfToProcess;
		}//ListAllProcess

		private void button1_Click(object sender, System.EventArgs e)
		{
			//Step 1.
			//To send a message to another application the first thing we need is the 
			//handle of the receiving application.
			//One way is to use the FindWindow API
			[B]string cstrReceiverWindowName = "I AM THE C++ RECEIVER WINDOW";[/B]
			int WindowHandleOfToProcess  = FindWindow(null, cstrReceiverWindowName);//find by window name
			IntPtr WindowHandle = new IntPtr(WindowHandleOfToProcess);
			//The second way is to iter through all processes 
			//Since a windows title can change, I perfer the second method
			[B]string cstrProcessName = "TO_C";[/B]
			IntPtr ProcessHandle = FindProcessByName(cstrProcessName);

			//Step 2.
			//Create some information to send.
			string strTag ="Tag1";
			StringBuilder strMsg = new StringBuilder();
			String strDateTime = DateTime.Now.ToLongTimeString() ;
			DateTime currentDate = new DateTime();
			//currentDate.Now;
			strMsg.Append("Send this string - ");
			strMsg.Append(strDateTime); 
			String strData = strMsg.ToString();

			//Option 1 - Encryption
			//To make a message a little more difficult to hack we can make it look like a bad piece of memory.
			//The receiver must also set the same value.
			WmCpyDta_SetEncrypt('d'); // 'd' is a bitwise seed value. I like to use d because it 
			//makes the message look like bad memory

			/*Option 2
			//If your receiver wants to conditional handle the received message
			//then define new ids based on the default.
			//This example does not need this so we will define a few but not use them.
			WPARAM wCustomMsgId_1 = WmCpyDta_BaseDefaultMsgId() + 1;
			WPARAM wCustomMsgId_2 = WmCpyDta_BaseDefaultMsgId() + 2;
				If some condition then
				WmCpyDta_SetMessageId(wCustomMsgId_1);
				else some other conditin WmCpyDta_SetMessageId(wCustomMsgId_2);
			*/

	
			/* Option 3
			The default behavior of the dll is only to accept messages send by the dll.
			If you want to be more specific then set WmCpyDta_SetSenderId(HWND hSenderId);
			The receiver can then use this value to decide if the message should be accepted.

			The 2nd parameter == NULL in WmCpyDta_SendMessage_sTagData() is the same as
			explicity using WmCpyDta_GetSenderId().

			I do not want to couple my programs that tightly, so I will stick with the default behavior.
			*/
			
			int iResult = 0;
			if(ProcessHandle.ToInt32() != 0)
				iResult = WmCpyDta_SendMessage_sTagData(ProcessHandle.ToInt32() , 0, strTag, strData);
			//------------------------------------------------
			//Now lets send the same message to the C Shape program

			string cstrProcessNameCShape = "TO_C_SHARP";
			IntPtr ProcessHandleCShape = FindProcessByName(cstrProcessNameCShape);
			if(ProcessHandleCShape.ToInt32() != 0)
				iResult = WmCpyDta_SendMessage_sTagData(ProcessHandleCShape.ToInt32() , 0, strTag, strData);
				
		}
	}
}

can u plz tell me
1) suppose i want to send the msg from WindowsApp1 to WindowsApp2,
string cstrReceiverWindowName = "I AM THE C# RECEIVER WINDOW";
In the above line what is in place of I AM THE C# RECEIVER WINDOW?


string cstrProcessName = "TO_C";

what is in place of TO_C?

Tell me one thing that how to receive these messages on WindowsApp2??

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