attacth.cs

 private static bool TryAttachVisualStudioDebugger(int processId)
        {
            try
            {
                // Get the DTE object for the current Visual Studio instance
                var dte = GetCurrentVisualStudioDTE();
                if (dte == null)
                    return false;

                // Get the debugger
                var debugger = dte.Debugger;
                
                // Get local processes
                var processes = debugger.LocalProcesses;
                
                // Find the target process
                foreach (EnvDTE.Process process in processes)
                {
                    if (process.ProcessID == processId)
                    {
                        // Attach to the process with mixed mode debugging
                        process.Attach();
                        return true;
                    }
                }
                
                return false;
            }
            catch
            {
                // If we can't attach programmatically, return false
                return false;
            }
        }

        /// <summary>
        /// Gets the DTE object for the currently running Visual Studio instance that's debugging us.
        /// </summary>
        private static EnvDTE.DTE GetCurrentVisualStudioDTE()
        {
            try
            {
                // Try to get the VS DTE from the Running Object Table
                IRunningObjectTable rot;
                IEnumMoniker enumMoniker;
                int retVal = GetRunningObjectTable(0, out rot);
                
                if (retVal != 0)
                    return null;

                rot.EnumRunning(out enumMoniker);
                enumMoniker.Reset();

                IntPtr fetched = IntPtr.Zero;
                IMoniker[] moniker = new IMoniker[1];
                
                while (enumMoniker.Next(1, moniker, fetched) == 0)
                {
                    IBindCtx bindCtx;
                    CreateBindCtx(0, out bindCtx);
                    
                    string displayName;
                    moniker[0].GetDisplayName(bindCtx, null, out displayName);
                    
                    // Look for Visual Studio DTE objects
                    if (displayName.StartsWith("!VisualStudio.DTE."))
                    {
                        object obj;
                        rot.GetObject(moniker[0], out obj);
                        
                        if (obj is EnvDTE.DTE dte)
                        {
                            // Check if this VS instance is currently debugging
                            try
                            {
                                // If VS is in debug mode, it's likely the one debugging our test process
                                if (dte.Debugger.CurrentMode != EnvDTE.dbgDebugMode.dbgDesignMode)
                                {
                                    return dte;
                                }
                            }
                            catch
                            {
                                // Continue searching
                            }
                        }
                    }
                }
                
                return null;
            }
            catch
            {
                return null;
            }
        }