C# File Open Save Dialog

[창공]

// https://www.youtube.com/watch?v=0hNJWIDIQ7I

    public partial class FileOpenSave : Form

    {

        public FileOpenSave()

        {

            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e)

        {

            OpenFileDialog openDialog = new OpenFileDialog();

            string defaultPath = Application.StartupPath + "\\Data";

            openDialog.Filter = "text File|*.txt|All Files|*.*";

            openDialog.InitialDirectory = defaultPath;

            if(!Directory.Exists(defaultPath))

                Directory.CreateDirectory(defaultPath);

            try

            {

                if(openDialog.ShowDialog()==DialogResult.OK)

                    label1.Text = openDialog.FileName;

                else

                    return ;

            }

            catch(System.Exception ex)

            {

                label1.Text = ex.Message;

                return ;

            }

            textBox1.Text = "";

/*

            // method 1

            // Pass the file path and file name to the StreamReader constructor

            StreamReader sr = new StreamReader(openDialog.FileName);

            string line = sr.ReadLine();           //Read the first line of text

            while(line!=null)

            {

                textBox1.Text += (line+"\r\n");

                line = sr.ReadLine();       // Read the next line

            }

            sr.Close();

*/

            // method 2

            string[] lines = System.IO.File.ReadAllLines(openDialog.FileName);

            foreach(string line in lines)

                textBox1.Text += (line+"\r\n");

        }

        private void button2_Click(object sender, EventArgs e)

        {

            if(label1.Text=="") return ;

/*

            // method1

            try

            {

                StreamWriter sw = new StreamWriter(label1.Text);

                sw.Write(textBox1.Text);

                sw.Close();     // close the file

                MessageBox.Show("File Save Done");

            }

            catch(Exception ex)

            {

                MessageBox.Show(ex.Message);

            }

*/

            // method 2

            try

            {

                System.IO.File.WriteAllText(label1.Text, textBox1.Text);

                MessageBox.Show("File Save Done!");

            }

            catch(Exception ex)

            {

                MessageBox.Show(ex.Message);

            }

        }

        private void button3_Click(object sender, EventArgs e)

        {   // Save As

            SaveFileDialog saveDialog = new SaveFileDialog();

            try

            {

                if(saveDialog.ShowDialog()==DialogResult.OK)

                    label1.Text = saveDialog.FileName;

            }

            catch(System.Exception ex)

            {

                label1.Text = ex.Message;

                return ;

            }

            button2_Click(null, null);            

        }

    }