CODEWITHSUNDEEP
c#winformstextboxkeyboard
Franqo Balsamo
Franqo Balsamo

Reputation: 223

Deleting characters in a textbox

I am trying to configure the TextBox so that when the ctrl + delete keys are pressed the TextBox is cleaned.

This is my entire code:

using System;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Windows.Forms;

namespace pruebaMensajes
{
    public partial class Providus : Form{
        public Providus(){
            InitializeComponent();
            txtUsuario.MaxLength = 20;//max character
            txtContrasena.MaxLength = 16;
            txtContrasena.PasswordChar = '*';//type
        }

        private void Button1_Click(object sender, EventArgs e){//para el login
            string usuario = txtUsuario.Text;
            string contrasena = txtContrasena.Text;
            SqlConnection con = new SqlConnection("stringChain");
            SqlDataAdapter sda = new SqlDataAdapter("SELECT COUNT(*) FROM usuariosProvidus WHERE usuario='" + usuario + "' AND contrasena='" + contrasena + "'", con);
            DataTable dt = new DataTable();
            sda.Fill(dt);
            if (dt.Rows[0][0].ToString() == "1"){
                this.Hide();
                new Inicio().Show();
            } else{
                MessageBox.Show("Wrong user o password.","Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        private void Providus_Load(object sender, EventArgs e){ }

        private void TxtContrasena_KeyPress_1(object sender, KeyPressEventArgs e){//manejar el enter para el login en contraseña
            if ((int)e.KeyChar == (int)Keys.Enter){
                string usuario = txtUsuario.Text;
                string contrasena = txtContrasena.Text;
                SqlConnection con = new SqlConnection("Data Source=PC-HELP;Initial Catalog=apiTiny;Integrated Security=True");
                SqlDataAdapter sda = new SqlDataAdapter("SELECT COUNT(*) FROM usuariosProvidus WHERE usuario='" + usuario + "' AND contrasena='" + contrasena + "'", con);
                DataTable dt = new DataTable();
                sda.Fill(dt);
                if (dt.Rows[0][0].ToString() == "1"){
                    this.Hide();
                    new Inicio().Show();
                }else if(txtUsuario.Text==String.Empty){
                    lblMensaje.BackColor = Color.FromArgb(255, 0, 0);
                    lblMensaje.Text = "Wrong user.";
                    txtUsuario.Focus();
                }else if (txtContrasena.Text == String.Empty){
                    lblMensaje.BackColor = Color.FromArgb(255, 0, 0);
                    lblMensaje.Text = "Wrong password.";
                    txtContrasena.Focus();
                }
            }
        }

        private void TxtUsuario_KeyPress(object sender, KeyPressEventArgs e){//enter para el txt usuario
            if ((int)e.KeyChar == (int)Keys.Enter){
                string usuario = txtUsuario.Text;
                string contrasena = txtContrasena.Text;
                SqlConnection con = new SqlConnection("Data Source=PC-HELP;Initial Catalog=apiTiny;Integrated Security=True");
                SqlDataAdapter sda = new SqlDataAdapter("SELECT COUNT(*) FROM usuariosProvidus WHERE usuario='" + usuario + "' AND contrasena='" + contrasena + "'", con);
                DataTable dt = new DataTable();
                sda.Fill(dt);
                if (dt.Rows[0][0].ToString() == "1"){
                    this.Hide();
                    new Inicio().Show();
                }
                else if (txtUsuario.Text == String.Empty){
                    lblMensaje.BackColor = Color.FromArgb(255, 0, 0);
                    lblMensaje.Text = "Worng user.";
                    txtUsuario.Focus();
                }
                else if (txtContrasena.Text == String.Empty){
                    lblMensaje.BackColor = Color.FromArgb(255, 0, 0);
                    lblMensaje.Text = "Worng password.";
                    txtContrasena.Focus();
                }
            };
        }

        private void TxtUsuario_KeyDown(object sender, KeyEventArgs e){
            if (e.KeyCode == Keys.Delete && e.Modifiers == Keys.ControlKey){
                e.Handled = true;
                txtUsuario.Text = "";
            }
        }

        private void TxtContrasena_KeyDown(object sender, KeyEventArgs e){
            if (e.KeyCode == Keys.Delete && e.Modifiers == Keys.Control){
                e.Handled = true;
                txtContrasena.Text = "";
            }
        }
    }
}

Does anyone know how I can do it? Cause when i press the keys ctrl + delete this adds a character instead of clearing the textbox. I use the keydown event to realize this but it is not working for me

In a gif:

enter image description here

Upvotes: 1

Views: 1058

Answers (3)

Mong Zhu
Mong Zhu

Reputation: 23732

Mate you are simply using the wrong key, and/or are talking about the wrong key.

You are talking about the Backspace key event though you call it "delete".

The Delete key is a different one and will actually work!

If you really want to use the backspace key you would need to check also for it in the code:

if (e.Control && e.KeyCode == Keys.Back)
{
    textBox1.Text = "";
    e.Handled = true;
}

unfortunately this will leave one last 0x7F or DEL ascii character remaining in the textbox. I haven't figured it out how to get rid of it entirely yet :)

I would advise to use your code and press the real del button

Upvotes: 1

Carra
Carra

Reputation: 17964

You can check the modifier, also see here: KeyDown : recognizing multiple keys

private void MyTextBox_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.Delete && e.Modifiers == Keys.Control)
    {
        //do stuff
    }
}

Upvotes: 1

nellowl
nellowl

Reputation: 389

Bind to the event KeyDown of the textbox the method : 

private void txtContrasena_KeyDown(object sender, KeyEventArgs e)
{
   if (e.Control && e.KeyCode == Keys.Delete)
      txtContrasena.Text = "";
}

Upvotes: 0

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