public static void ShowProgressDialog<T>(string message, Action<T> action, T arg)
    {

        ESRI.ArcGIS.esriSystem.ITrackCancel trackCancel = new ESRI.ArcGIS.Display.CancelTrackerClass();

        ESRI.ArcGIS.Framework.IProgressDialogFactory progressDialogFactory = new ESRI.ArcGIS.Framework.ProgressDialogFactoryClass();

        // Set the properties of the Step Progressor
        System.Int32 int32_hWnd = ArcMap.Application.hWnd;
        ESRI.ArcGIS.esriSystem.IStepProgressor stepProgressor = progressDialogFactory.Create(trackCancel, int32_hWnd);


        ESRI.ArcGIS.Framework.IProgressDialog2 progressDialog2 = (ESRI.ArcGIS.Framework.IProgressDialog2)stepProgressor; // Explict Cast

        progressDialog2.CancelEnabled = false;
        progressDialog2.Description = message;
        progressDialog2.Animation = ESRI.ArcGIS.Framework.esriProgressAnimationTypes.esriProgressSpiral;

        action.Invoke(arg);

        trackCancel = null;
        progressDialog2.HideDialog();
        progressDialog2 = null;

    }

stepProgressor.Hide();
progressDialog2.ShowDialog();