Dynamic search in entity framework

Question

Hi,

I currently try to extend NavigationToolBar with a search functionality. The idea is using the BindingSource to access the Entity Framework ObjectQuery then using a given parameter to specify the table field where to search a value given in my toolbar TextBox. The point is to get it generic on any entity framework data context. 

here is draft of my class :

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;

using System.Text.RegularExpressions;
using System.Data.Metadata.Edm;
using System.Data.Objects;
using System.Data.Entity;
using System.Data.Objects.DataClasses;
using Microsoft.CSharp;
using System.Reflection; 

namespace UCbindingNav
{
    public partial class BindingNav : UserControl
    {
        public BindingSource BindingSource { get; set; }
        public int Position { get; set; }
        public string SearchFeild{ get; set; }


        public BindingNav()
        { 
            InitializeComponent();
        }

        private void BindingNav_Load(object sender, EventArgs e)
        {
            positionItem.Text = (BindingSource.Position + 1).ToString();
            countItem.Text = "/ {" + BindingSource.Count + "}";
            firstItem.Enabled = false;
            previousItem.Enabled = false;
        }



        private void firstItem_Click(object sender, EventArgs e)
        {
            BindingSource.MoveFirst();
            positionItem.Text = (BindingSource.Position + 1).ToString();
            countItem.Text = "of {" + BindingSource.Count + "}";
            firstItem.Enabled = false;
            previousItem.Enabled = false;
            nextItem.Enabled = true;
            lastItem.Enabled = true;
        }

        private void previousItem_Click(object sender, EventArgs e)
        {
            BindingSource.MovePrevious();
            positionItem.Text = (BindingSource.Position + 1).ToString();
            countItem.Text = "of {" + BindingSource.Count + "}";
            if (BindingSource.Position == 0)
            {
                firstItem.Enabled = false;
                previousItem.Enabled = false;
            }
            else
            {
                firstItem.Enabled = true;
                previousItem.Enabled = true;
            }
            nextItem.Enabled = true;
            lastItem.Enabled = true;

        }

        private void nextItem_Click(object sender, EventArgs e)
        {

            this.Enabled = false;         
            Cursor = Cursors.WaitCursor;  

            BindingSource.MoveNext();
            positionItem.Text = (BindingSource.Position + 1).ToString();
            countItem.Text = "of {" + BindingSource.Count + "}";
            if ((BindingSource.Position + 1) == BindingSource.Count)
            {
                nextItem.Enabled = false;
                lastItem.Enabled = false;
            }
            else
            {
                nextItem.Enabled = true;
                lastItem.Enabled = true;
            }
            firstItem.Enabled = true;
            previousItem.Enabled = true;

            Cursor = Cursors.Default;
            this.Enabled = true;
        }

        private void lastItem_Click(object sender, EventArgs e)
        {
            BindingSource.MoveLast();
            positionItem.Text = (BindingSource.Position + 1).ToString();
            countItem.Text = "of {" + BindingSource.Count + "}";
            nextItem.Enabled = false;
            lastItem.Enabled = false;
            firstItem.Enabled = true;
            previousItem.Enabled = true;
        }

        private void addItem_Click(object sender, EventArgs e)
        {
            BindingSource.AddNew();
            positionItem.Text = (BindingSource.Position + 1).ToString();
            countItem.Text = "of {" + BindingSource.Count + "}";
            Position = BindingSource.Position + 1;
            nextItem.Enabled = false;
            lastItem.Enabled = false;
            firstItem.Enabled = true;
            previousItem.Enabled = true;
        }

        private void deleteItem_Click(object sender, EventArgs e)
        {
            BindingSource.RemoveCurrent();
            positionItem.Text = (BindingSource.Position + 1).ToString();
            countItem.Text = "of {" + BindingSource.Count + "}";
            Position = BindingSource.Position;
        }

        private void positionItem_KeyPress(object sender, KeyPressEventArgs e)
        {
            Regex expr = new Regex(@"^[1-9]{1}[0-9]*$");
            if (expr.IsMatch(positionItem.Text) && (e.KeyChar == '\r'))
            {
                if (Convert.ToInt32(positionItem.Text) > 0 && Convert.ToInt32(positionItem.Text) <= BindingSource.Count)
                {
                    BindingSource.Position = Convert.ToInt32(positionItem.Text) - 1;

                    if (Convert.ToInt32(positionItem.Text) == 1)
                    {
                        firstItem.Enabled = false;
                        previousItem.Enabled = false;
                        nextItem.Enabled = true;
                        lastItem.Enabled = true;
                    }
                    else if (Convert.ToInt32(positionItem.Text) == BindingSource.Count)
                    {
                        firstItem.Enabled = true;
                        previousItem.Enabled = true;
                        nextItem.Enabled = false;
                        lastItem.Enabled = false;
                    }
                    else
                    {
                        firstItem.Enabled = true;
                        previousItem.Enabled = true;
                        nextItem.Enabled = true;
                        lastItem.Enabled = true;
                    }
                }

            }

        }

        private void saveItem_Click(object sender, EventArgs e)
        {
            Cursor c = ParentForm.Cursor;
            try
            {
                ParentForm.Cursor = Cursors.WaitCursor;
                ParentForm.Validate();
                ((System.Data.Objects.ObjectQuery)BindingSource.DataSource).Context.SaveChanges();
            }
            finally
            {
                ParentForm.Cursor = c;
            }
        }

        private void searchValue_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar == '\r') search_Click(this, null);
        }

        private void search_Click(object sender, EventArgs e)
        {
// Where i'm stuck in !!!            
        }
    }
}