Focus in 3tier application

hello

i want focus on proper textbox after data validation in bll. correct way?

1- returning different value , decide in presentation layer(in way need evaluate returned value again - once in bll , in ui)

2- set focus on proper textbox bll.

thank you

the ui should be unware of bll , the  bll unaware of ui. missing another piece you should put  into place sits between ui , bll part of presentation layer.  

http://www.codeproject.com/articles/228214/understanding-basics-of-ui-design-pattern-mvc-mvp

https://en.wikipedia.org/wiki/model%e2%80%93view%e2%80%93presenter

you should watch entire show feel.

http://polymorphicpodcast.com/shows/mv-patterns/

watching above show first should link below. , can find other links mvpvm.

http://aviadezra.blogspot.com/2009/08/mvp-mvvm-winforms-data-binding.html

below mvp being applied windows forms ui solution n-tier being applied tutorial given ado.net entity framework. may come point stop thinking using datasets, datatables , tableadapters , learn how use objects dto(s) being sent tiers , other types of objects, bll objects , dao objects. should learn how use list<t>.

https://en.wikipedia.org/wiki/data_transfer_object

a dto based off of using auto properties. dtoemployee  without class constructor.

https://msdn.microsoft.com/en-us/library/bb384054.aspx?f=255&mspperror=-2147217396

https://en.wikipedia.org/wiki/data_access_object

http://www.tutorialspoint.com/design_pattern/data_access_object_pattern.htm

it's showing dao usage in java, can applied c# or vb, because java , .net oo language platforms. 

the use of mvp little different, since bll , dal sitting behind wcf web service , service layer making calls wcf web service.

the interface.........................

using bll.dto;
using system.collections.generic;
using system.windows.forms;

namespace demowindowsformapp.views
{
    public interface iauthorview :iview
    {
        int idx { get; set; }
        list<dtoauthor> dtoauthors { get; set; }
        label lblauthorid { get; set; }
        textbox tbxfirstname { get; set; }
        textbox tbxlastname { get; set; }
    }
}

the form/the view..............................

using system;
using system.collections.generic;
using system.windows.forms;
using bll.dto;
using demowindowsformapp.presenters;
using demowindowsformapp.views;
using services;

namespace demowindowsformapp
{
    public partial class authorview : form, iauthorview
    {
        #region members
        private authorviewpresenter mpresenter;
        #endregion

        public authorview()
        {
            mpresenter = new authorviewpresenter(this, theservice1.instance);
            initializecomponent();
        }

        public int idx { get; set; }
     
        public list<dtoauthor> dtoauthors { get; set; }
       
        public label lblauthorid
        {
            { return lblauthorid; }
            set { lblauthorid = value; }
        }

        public textbox tbxfirstname
        {
            { return tbxfirstname; }
            set { tbxfirstname = value; }
        }

        public textbox tbxlastname
        {
            { return tbxlastname; }
            set { tbxlastname = value; }
        }

        private void authorview_load(object sender, eventargs e)
        {
            mpresenter.load();
        }

        private void btnfirst_click(object sender, eventargs e)
        {
            mpresenter.btnfirstclick();
        }

        private void btnprev_click(object sender, eventargs e)
        {
            mpresenter.btnprevclick();
        }

        private void btnnext_click(object sender, eventargs e)
        {
            mpresenter.btnnextclick();
        }

        private void btnlast_click(object sender, eventargs e)
        {
            mpresenter.btnlastclick();
        }

        private void btnclear_click(object sender, eventargs e)
        {
            mpresenter.btnclearclick();
        }

        private void btnupdate_click(object sender, eventargs e)
        {
            mpresenter.btnupdateclick();
        }

        private void btnnew_click(object sender, eventargs e)
        {
            mpresenter.btnnewclick();
        }

        private void btnsend_click(object sender, eventargs e)
        {
            mpresenter.btnsendclick();
        }
       
    }
}

the presenter....................

using system.linq;
using system.collections.generic;
using demowindowsformapp.views;
using bll.dto;
using services.iservices;

namespace demowindowsformapp.presenters
{
    public class authorviewpresenter
    {
        private readonly iauthorview mview;
        private readonly iservice1 mservice;

        #region constructor

        public authorviewpresenter(iauthorview view, iservice1  theservice)
        {
            mview = view;
            mservice = theservice;
        }

        #endregion

        #region public methods

        public void load()
        {
         
            var authors = mservice.getauthorswhere();
            mview.dtoauthors = authors;
            mview.idx = 0;

            populatefields(mview.dtoauthors, mview.idx);
        }

        public void btnfirstclick()
        {
            mview.idx = 0;
            populatefields(mview.dtoauthors, mview.idx);
        }

        public void btnprevclick()
        {
            if(mview.idx == 0)
            {
                populatefields(mview.dtoauthors, mview.idx);
            }
            else
            {
                mview.idx -= 1;
                populatefields(mview.dtoauthors, mview.idx);
            }
        }

        public void btnnextclick()
        {
            if (mview.idx == mview.dtoauthors.count - 1)
            {
                populatefields(mview.dtoauthors, mview.idx);
            }
            else
            {
                mview.idx += 1;
                populatefields(mview.dtoauthors, mview.idx);
            }
        }

        public void btnlastclick()
        {
            mview.idx = mview.dtoauthors.count - 1;
            populatefields(mview.dtoauthors, mview.idx);
        }

        public void btnupdateclick()
        {
            var author = mview.dtoauthors[mview.idx];

            author.firstname = mview.tbxfirstname.text;
            author.lastname = mview.tbxlastname.text;
            author.isupdate = true;
        }

        public void btnclearclick()
        {
            mview.tbxfirstname.text = "";
            mview.tbxlastname.text = "";
            mview.lblauthorid.text = "author not saved yet.";
        }

        public void btnsendclick()
        {
            var atleastoneauthor = (from in mview.dtoauthors.where(a => a.isupdate
                                     || a.authorid == -1)
                                    select a).firstordefault();

            if (atleastoneauthor != null)
            {
                mview.dtoauthors = mservice.saveauthors(mview.dtoauthors);
                populatefields(mview.dtoauthors, mview.idx);
            }
        }
        public void btnnewclick()
        {
            if (mview.tbxfirstname.text != ""
                && mview.tbxlastname.text != "")
            {
                var author = new dtoauthor
                                 {
                                     authorid = -1,
                                     firstname = mview.tbxfirstname.text,
                                     lastname = mview.tbxlastname.text,
                                     isupdate = false
                                 };

                mview.dtoauthors.add(author);
                mview.idx = mview.dtoauthors.count - 1;
            }
        }

        #endregion

        #region private methods
       
        private void populatefields(list<dtoauthor> authors, int idx)
        {
            var author = authors[idx];

            mview.lblauthorid.text = author.authorid.tostring();
            mview.tbxfirstname.text = author.firstname;
            mview.tbxlastname.text = author.lastname;
        }

        #endregion
    }
}

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