(C#) .NET Windows Form Application เขียนโปรแกรมบน Windows Form Application ด้วย .NET Framework

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

namespace WindowsFormsApplication
{
    public partial class frmMain : Form
    {
        // By https://www.thaicreate.com (mr.win)//

        public frmMain()
        {
            InitializeComponent();
        }

        private void btnHome_Click(object sender, EventArgs e)
        {
            this.Hide();
            frmHome f = new frmHome();
            f.Show();
        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            if (MessageBox.Show("Are you sure to exit?", "Confirm.", MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button1) == DialogResult.Yes)
            {
                Application.Exit();
            }
        }
    }
}

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

namespace WindowsFormsApplication
{
    public partial class frmHome : Form
    {
        // By https://www.thaicreate.com (mr.win)//

        public frmHome()
        {
            InitializeComponent();
        }

        private void frmHome_Load(object sender, EventArgs e)
        {
            BindDataGrid();
        }

        private void BindDataGrid()
        {
            SqlCeConnection myConnection = default(SqlCeConnection);
            DataTable dt = new DataTable();
            SqlCeDataAdapter Adapter = default(SqlCeDataAdapter);
            //myConnection = new SqlCeConnection("Data Source =" + (System.IO.Path.GetDirectoryName( System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase ) + "\\AppDatabase1.sdf;"));
            myConnection = new SqlCeConnection("Data Source =C:\\WindowsFormsApplication\\WindowsFormsApplication\\Database1.sdf;");
            myConnection.Open();
            SqlCeCommand myCommand = myConnection.CreateCommand();
            myCommand.CommandText = "SELECT [id], [name], [email] FROM [mytable]";
            myCommand.CommandType = CommandType.Text;

            Adapter = new SqlCeDataAdapter(myCommand);
            Adapter.Fill(dt);

            myConnection.Close();

            this.dgName.DataSource = dt;

            this.dgName.Columns.Clear();

            DataGridViewTextBoxColumn column;

            column = new DataGridViewTextBoxColumn();
            column.DataPropertyName = "id";
            column.HeaderText = "ID";
            column.Width = 50;
            this.dgName.Columns.Add(column);

            column = new DataGridViewTextBoxColumn();
            column.DataPropertyName = "name";
            column.HeaderText = "Name";
            column.Width = 100;
            this.dgName.Columns.Add(column);

            column = new DataGridViewTextBoxColumn();
            column.DataPropertyName = "email";
            column.HeaderText = "Email";
            column.Width = 150;
            this.dgName.Columns.Add(column);

            dt = null;
        }


        private void btnAdd_Click(object sender, EventArgs e)
        {
            this.Hide();
            frmAdd f = new frmAdd();
            f.Show();
        }

        private void btnEdit_Click(object sender, EventArgs e)
        {
            this.Hide();
            frmEdit f = new frmEdit();
            f._strID = this.dgName[0, this.dgName.CurrentCell.RowIndex].Value.ToString();
            f.Show();
        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            this.Hide();
            frmMain f = new frmMain();
            f.Show();
        }

        private void btnDel_Click(object sender, EventArgs e)
        {
            if (MessageBox.Show("Are you sure to delete?", "Confirm.", MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button1) == DialogResult.Yes)
            {
                string strID = this.dgName[0, this.dgName.CurrentCell.RowIndex].Value.ToString();

                SqlCeConnection myConnection = default(SqlCeConnection);
                //myConnection = new SqlCeConnection("Data Source =" + (System.IO.Path.GetDirectoryName( System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase ) + "\\AppDatabase1.sdf;"));
                myConnection = new SqlCeConnection("Data Source =C:\\WindowsFormsApplication\\WindowsFormsApplication\\Database1.sdf;");
                myConnection.Open();
                SqlCeCommand myCommand = myConnection.CreateCommand();
                myCommand.CommandText = "DELETE FROM [mytable] WHERE id = '" + strID + "'";
                myCommand.CommandType = CommandType.Text;
                myCommand.ExecuteNonQuery();
                myConnection.Close();
                MessageBox.Show("Delete Successfully");

                BindDataGrid();
            }
        }

    }
}

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

namespace WindowsFormsApplication
{
    public partial class frmAdd : Form
    {
        // By https://www.thaicreate.com (mr.win)//

        public frmAdd()
        {
            InitializeComponent();
        }

        private void btnAdd_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(this.txtName.Text))
            {
                MessageBox.Show("Please input (Name)");
                this.txtName.Focus();
                return;
            }

            if (string.IsNullOrEmpty(this.txtEmail.Text))
            {
                MessageBox.Show("Please input (Email)");
                this.txtEmail.Focus();
                return;
            }

            SqlCeConnection myConnection = default(SqlCeConnection);
            //myConnection = new SqlCeConnection("Data Source =" + (System.IO.Path.GetDirectoryName( System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase ) + "\\AppDatabase1.sdf;"));
            myConnection = new SqlCeConnection("Data Source =C:\\WindowsFormsApplication\\WindowsFormsApplication\\Database1.sdf;");
            myConnection.Open();
            SqlCeCommand myCommand = myConnection.CreateCommand();
            myCommand.CommandText = "INSERT INTO [mytable] ([name], [email]) VALUES  " + " ('" + this.txtName.Text + "','" + this.txtEmail.Text + "' ) ";
            myCommand.CommandType = CommandType.Text;
            myCommand.ExecuteNonQuery();
            myConnection.Close();

            MessageBox.Show("Save Successfully");

            this.Hide();
            frmHome f = new frmHome();
            f.Show();
        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            this.Hide();
            frmHome f = new frmHome();
            f.Show();
        }

    }
}

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

namespace WindowsFormsApplication
{
    public partial class frmEdit : Form
    {
        // By https://www.thaicreate.com (mr.win)//

        public frmEdit()
        {
            InitializeComponent();
        }

        string strID = "";
        public string _strID
        {
            get { return strID; }
            set { strID = value; }
        }

        private void frmEdit_Load(object sender, EventArgs e)
        {
            SqlCeConnection myConnection = default(SqlCeConnection);
            DataTable dt = new DataTable();
            SqlCeDataAdapter Adapter = default(SqlCeDataAdapter);
            //myConnection = new SqlCeConnection("Data Source =" + (System.IO.Path.GetDirectoryName( System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase ) + "\\AppDatabase1.sdf;"));
            myConnection = new SqlCeConnection("Data Source =C:\\WindowsFormsApplication\\WindowsFormsApplication\\Database1.sdf;");
            myConnection.Open();
            SqlCeCommand myCommand = myConnection.CreateCommand();
            myCommand.CommandText = "SELECT [id], [name], [email] FROM [mytable] WHERE id = '" + strID + "' ";
            myCommand.CommandType = CommandType.Text;

            Adapter = new SqlCeDataAdapter(myCommand);
            Adapter.Fill(dt);

            myConnection.Close();

            if (dt.Rows.Count > 0)
            {
                this.txtName.Text = dt.Rows[0]["name"].ToString();
                this.txtEmail.Text = dt.Rows[0]["email"].ToString();
            }

            dt = null;
        }

        private void btnEdit_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(this.txtName.Text))
            {
                MessageBox.Show("Please input (Name)");
                this.txtName.Focus();
                return;
            }

            if (string.IsNullOrEmpty(this.txtEmail.Text))
            {
                MessageBox.Show("Please input (Email)");
                this.txtEmail.Focus();
                return;
            }

            SqlCeConnection myConnection = default(SqlCeConnection);
            //myConnection = new SqlCeConnection("Data Source =" + (System.IO.Path.GetDirectoryName( System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase ) + "\\AppDatabase1.sdf;"));
            myConnection = new SqlCeConnection("Data Source =C:\\WindowsFormsApplication\\WindowsFormsApplication\\Database1.sdf;");
            myConnection.Open();
            SqlCeCommand myCommand = myConnection.CreateCommand();
            myCommand.CommandText = "UPDATE [mytable] SET " + " [name] = '" + this.txtName.Text + "', [email] = '" + this.txtEmail.Text + "'  " + " WHERE id = '" + strID + "' ";
            myCommand.CommandType = CommandType.Text;
            myCommand.ExecuteNonQuery();
            myConnection.Close();

            MessageBox.Show("Update Successfully");

            this.Hide();
            frmHome f = new frmHome();
            f.Show();
        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            this.Hide();
            frmHome f = new frmHome();
            f.Show();
        }
    }
}