C＃Keydown事件不起作用

Question

I'm trying to get the application to navigate to a certain URL in the web browser component once the ENTER key has been pressed (a barcode reader inputs the data into the Barcode textbox and is programmed to add "ENTER" at the end of each scan). The barcode number is then sent to the server for validation via the URL and a result is displayed in the web browser.

After reading up on Stack Overflow at first I came the conclusion that this.KeyPreview had not been set - however even after setting this to True it still wouldn't.

All I want it to do is when ENTER has been pressed anywhere on Form2 it should change the WebBrowser component URL to the data contained in the Barcode Textbox.

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 SUBWAY_deliverX_2017_POSlink
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
            this.ActiveControl = Barcode;
        }

        private void Form2_Load(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            Close();
        }

        private void button2_Click(object sender, EventArgs e)
        {

        }

        private void Barcode_TextChanged(object sender, EventArgs e)
        {

        }

        private void Barcode_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Enter)
            {
                webBrowser1.Navigate("https://10.0.0.142/deliverXPOSquery.php?barcode=" + Barcode.Text);
            }
        }
    }
}

And the Designer file:

namespace SUBWAY_deliverX_2017_POSlink
{
    partial class Form2
    {
        /// <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()
        {
            System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(Form2));
            this.button1 = new System.Windows.Forms.Button();
            this.Barcode = new System.Windows.Forms.TextBox();
            this.pictureBox1 = new System.Windows.Forms.PictureBox();
            this.webBrowser1 = new System.Windows.Forms.WebBrowser();
            this.button2 = new System.Windows.Forms.Button();
            ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
            this.SuspendLayout();
            // 
            // button1
            // 
            this.button1.Font = new System.Drawing.Font("Microsoft Sans Serif", 15.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.button1.Location = new System.Drawing.Point(177, 241);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(249, 79);
            this.button1.TabIndex = 0;
            this.button1.Text = "Return to SubShop";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // Barcode
            // 
            this.Barcode.BackColor = System.Drawing.SystemColors.Control;
            this.Barcode.BorderStyle = System.Windows.Forms.BorderStyle.None;
            this.Barcode.Font = new System.Drawing.Font("Microsoft Sans Serif", 15.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.Barcode.Location = new System.Drawing.Point(178, 323);
            this.Barcode.Name = "Barcode";
            this.Barcode.Size = new System.Drawing.Size(249, 24);
            this.Barcode.TabIndex = 1;
            this.Barcode.TextChanged += new System.EventHandler(this.Barcode_TextChanged);
            // 
            // pictureBox1
            // 
            this.pictureBox1.Image = global::SUBWAY_deliverX_2017_POSlink.Properties.Resources.delxstoreheader;
            this.pictureBox1.Location = new System.Drawing.Point(0, -2);
            this.pictureBox1.Name = "pictureBox1";
            this.pictureBox1.Size = new System.Drawing.Size(589, 102);
            this.pictureBox1.TabIndex = 3;
            this.pictureBox1.TabStop = false;
            // 
            // webBrowser1
            // 
            this.webBrowser1.Location = new System.Drawing.Point(12, 106);
            this.webBrowser1.MinimumSize = new System.Drawing.Size(20, 20);
            this.webBrowser1.Name = "webBrowser1";
            this.webBrowser1.Size = new System.Drawing.Size(563, 120);
            this.webBrowser1.TabIndex = 4;
            this.webBrowser1.Url = new System.Uri("https://10.0.0.142/deliverXPOSquery.php", System.UriKind.Absolute);
            // 
            // button2
            // 
            this.button2.Location = new System.Drawing.Point(471, 256);
            this.button2.Name = "button2";
            this.button2.Size = new System.Drawing.Size(75, 23);
            this.button2.TabIndex = 5;
            this.button2.Text = "button2";
            this.button2.UseVisualStyleBackColor = true;
            this.button2.Click += new System.EventHandler(this.button2_Click);
            // 
            // Form2
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(587, 346);
            this.ControlBox = false;
            this.KeyPreview = true;
            this.Controls.Add(this.button2);
            this.Controls.Add(this.webBrowser1);
            this.Controls.Add(this.pictureBox1);
            this.Controls.Add(this.Barcode);
            this.Controls.Add(this.button1);
            this.Icon = ((System.Drawing.Icon)(resources.GetObject("$this.Icon")));
            this.MaximumSize = new System.Drawing.Size(603, 385);
            this.MinimumSize = new System.Drawing.Size(603, 385);
            this.Name = "Form2";
            this.SizeGripStyle = System.Windows.Forms.SizeGripStyle.Hide;
            this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
            this.Text = "deliverX 2017 - Order Validation";
            this.TopMost = true;
            this.Load += new System.EventHandler(this.Form2_Load);
            ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.TextBox Barcode;
        private System.Windows.Forms.PictureBox pictureBox1;
        private System.Windows.Forms.WebBrowser webBrowser1;
        private System.Windows.Forms.Button button2;
    }
}

Answer 1

In your code :

 this.Barcode.BackColor = System.Drawing.SystemColors.Control;
            this.Barcode.BorderStyle = System.Windows.Forms.BorderStyle.None;
            this.Barcode.Font = new System.Drawing.Font("Microsoft Sans Serif", 15.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.Barcode.Location = new System.Drawing.Point(178, 323);
            this.Barcode.Name = "Barcode";
            this.Barcode.Size = new System.Drawing.Size(249, 24);
            this.Barcode.TabIndex = 1;
            this.Barcode.TextChanged += new System.EventHandler(this.Barcode_TextChanged);

At no point have you linked the keydown code to the control you think you did. So no it wont.

Personally in my own barcode reading app, I used the text changed and on finding a barcode that matches spec, then auto submitted it.. but mine was for tape scanning and so they could be scanning in 250+ tapes and wouldnt want to press a button each time