Create new project > application with C#

Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using WindowsApplication2.DAL;

namespace WindowsApplication2
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            DAL.DAL srv = new WindowsApplication2.DAL.DAL();
            dataGridView1.DataSource = srv.GetData().Tables[0];

        }
    }
}

*************************************************************************************************** Add SQL DATABASE with click right mouse in name application (Solution Explorer), add new, SQL DATABASE
Then will show POP-UP MENU

Add new folder with click right mouse in name application (Solution Explorer), add new, folder
Named it wit DAL, then ADD new class in folder DAL with click right mouse in folder, ADD New, Class.
Named new class : DAL.CS
**************************************************************************************************** 

DAL.CS 
using System;
using System.Collections.Generic;
using System.Text;
using System.Data.SqlClient;

namespace WindowsApplication2.DAL
{
    public class DAL
    {
        SqlConnection conn = new SqlConnection();
        SqlCommand cmd = new SqlCommand();

        public System.Data.DataSet GetData()
        {
            conn.ConnectionString = @"Data Source=.\SQLEXPRESS;AttachDbFilename='C:\Documents and Settings\DHARMAWW\My Documents\Visual Studio 2005\Projects\WindowsApplication2\WindowsApplication2\Database1.mdf';Integrated Security=True;User Instance=True";
            conn.Open();
            cmd.CommandType = System.Data.CommandType.Text;
            cmd.CommandText = "SELECT * FROM EMPLOYEE";
            cmd.Connection = conn;
            SqlDataAdapter adap = new SqlDataAdapter();
            adap.SelectCommand = cmd;
            System.Data.DataSet ds = new System.Data.DataSet();
            adap.Fill(ds);
            conn.Close();
            return ds;
        }
    }
}

Form1.designer.cs
namespace WindowsApplication2
{
    partial class Form1
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (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.dataGridView1 = new System.Windows.Forms.DataGridView();
            ((System.ComponentModel.ISupportInitialize)(this.dataGridView1)).BeginInit();
            this.SuspendLayout();
            //
            // button1
            //
            this.button1.Location = new System.Drawing.Point(21, 65);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(75, 23);
            this.button1.TabIndex = 0;
            this.button1.Text = "button1";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            //
            // dataGridView1
            //
            this.dataGridView1.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize;
            this.dataGridView1.Location = new System.Drawing.Point(21, 94);
            this.dataGridView1.Name = "dataGridView1";
            this.dataGridView1.Size = new System.Drawing.Size(456, 199);
            this.dataGridView1.TabIndex = 1;
            //
            // Form1
            //
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(501, 331);
            this.Controls.Add(this.dataGridView1);
            this.Controls.Add(this.button1);
            this.Name = "Form1";
            this.Text = "Form1";
            ((System.ComponentModel.ISupportInitialize)(this.dataGridView1)).EndInit();
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.DataGridView dataGridView1;
    }
}