Using ListBox in C#

Description

 

Tools: Windows 2000 & VS.NET SDK Beta 2.0

 

The source code demonstrates how to use a listbox control in C# - adding, deleting and altering strings. The source code is self-explanatory. To compile the code, install .NET SDK including C# compiler and use the following commands on MS-DOS prompt:

 

>csc ListBox.cs 

>ListBox.exe

 

 

 

The source code listed in the following table. 

namespace test
{
    using System;
    using System.Drawing;
    using System.Collections;
    using System.ComponentModel;
    using System.Windows.Forms;
    using System.Data;
    public class ListBox : System.Windows.Forms.Form
    {
        private System.ComponentModel.Container container;
        private System.Windows.Forms.Button buttonAdd;
        private System.Windows.Forms.Button buttonClose;
        private System.Windows.Forms.Button buttonModify;
        private System.Windows.Forms.Button buttonDelete;
        private System.Windows.Forms.Button buttonMoveUp;
        private System.Windows.Forms.Button buttonMoveDown;
        private System.Windows.Forms.ListBox listbox;
        private System.Windows.Forms.TextBox textbox;
        private System.Windows.Forms.Label label;
        private int nSelectedIndex;
        //*********SIZE & LOCATION******************//
        // COMPONENT - BUTTON(s) aligned along X-axis.
        const int BUTTON_LENGTH = 50;
        const int BUTTON_HEIGHT = 20;
        const int FIRSTBUTTON_XPOS = 20;
        const int FIRSTBUTTON_YPOS =220;
        const int XSPACING = 70; // (Note: XSPACING >= BUTTON_LENGTH)
        const int YSPACING = 0;
        //COMPONENT - MOVE BUTTONS
        const int MBUTTON_LENGTH = 20;
        const int MBUTTON_HEIGHT = 20;
        const int FIRSTMBUTTON_XPOS = 220;
        const int FIRSTMBUTTON_YPOS =70;
        const int SECONDMBUTTON_XPOS = 220;
        const int SECONDMBUTTON_YPOS =100;
        // COMPONENT - LISTBOX
        const int LISTBOX_LENGTH = 3*BUTTON_LENGTH;
        const int LISTBOX_HEIGHT = 6*BUTTON_HEIGHT;
        const int LISTBOX_XPOS = 50;
        const int LISTBOX_YPOS = 50;
        // COMPONENT - LABEL
        const int LABEL_LENGTH = 50;
        const int LABEL_HEIGHT = 50;
        const int LABEL_XPOS = 20; // align it with first button
        const int LABEL_YPOS = 173;
        // COMPONENT - TEXTBOX
        const int TEXTBOX_LENGTH = 120;
        const int TEXTBOX_HEIGHT = 50;
        const int TEXTBOX_XPOS = 70;
        const int TEXTBOX_YPOS = 170;
        public ListBox() : base()
        {
            InitializeComponent();
        }
        public override void Dispose()
        {
            base.Dispose();
            container.Dispose();
        }
        private void InitializeComponent()
        {
            // this
            this.container = new System.ComponentModel.Container();
            this.Text="List Box";
            // buttonAdd
            this.buttonAdd = new System.Windows.Forms.Button();
            buttonAdd.Location = new System.Drawing.Point(FIRSTBUTTON_XPOS,FIRSTBUTTON_YPOS);
            buttonAdd.Text = "&Add";
            buttonAdd.Size = new System.Drawing.Size(BUTTON_LENGTH,BUTTON_HEIGHT);
            buttonAdd.Click += new System.EventHandler(this.buttonAdd_Click); buttonAdd.Enabled = false;
            this.Controls.Add(this.buttonAdd);
            //buttonModify
            this.buttonModify = new System.Windows.Forms.Button();
            buttonModify.Location = new System.Drawing.Point(FIRSTBUTTON_XPOS+XSPACING,FIRSTBUTTON_YPOS+YSPACING);
            buttonModify.Text = "&Modify";
            buttonModify.Size = new System.Drawing.Size(BUTTON_LENGTH,BUTTON_HEIGHT);
            buttonModify.Click += new System.EventHandler(this.buttonModify_Click); buttonModify.Enabled = false;
            this.Controls.Add(this.buttonModify);
            //buttonDelete
            this.buttonDelete = new System.Windows.Forms.Button();
            buttonDelete.Location = new System.Drawing.Point(FIRSTBUTTON_XPOS+2*XSPACING,FIRSTBUTTON_YPOS+2*YSPACING); buttonDelete.Text = "&Delete";
            buttonDelete.Size = new System.Drawing.Size(BUTTON_LENGTH,BUTTON_HEIGHT);
            buttonDelete.Enabled = false;
            buttonDelete.Click += new System.EventHandler(this.buttonDelete_Click);
            this.Controls.Add(this.buttonDelete);
            // buttonClose
            this.buttonClose = new System.Windows.Forms.Button();
            buttonClose.Location = new System.Drawing.Point(FIRSTBUTTON_XPOS+3*XSPACING,FIRSTBUTTON_YPOS+3*YSPACING); buttonClose.Text = "&Close";
            buttonClose.Size = new System.Drawing.Size(BUTTON_LENGTH,BUTTON_HEIGHT);
            buttonClose.Click += new System.EventHandler(this.buttonClose_Click);
            this.Controls.Add(this.buttonClose);
            // listbox
            this.listbox = new System.Windows.Forms.ListBox();
            listbox.Location = new System.Drawing.Point(LISTBOX_XPOS,LISTBOX_YPOS);
            listbox.Size = new System.Drawing.Size(LISTBOX_LENGTH,LISTBOX_HEIGHT);
            listbox.Click += new System.EventHandler(this.listbox_SelectedIndexChanged);
            listbox.BackColor = (Color)System.Drawing.SystemColors.Desktop;
            this.Controls.Add(this.listbox);
            // label
            this.label = new System.Windows.Forms.Label();
            label.Location = new System.Drawing.Point(LABEL_XPOS,LABEL_YPOS);
            label.Size = new System.Drawing.Size(LABEL_LENGTH,LABEL_HEIGHT);
            label.Text = "Enter:";
            this.Controls.Add(this.label);
            // textbox
            this.textbox = new System.Windows.Forms.TextBox();
            textbox.Location = new System.Drawing.Point(TEXTBOX_XPOS,TEXTBOX_YPOS); textbox.Click += new System.EventHandler(this.textbox_Click);
            textbox.Size = new System.Drawing.Size(TEXTBOX_LENGTH,TEXTBOX_HEIGHT);
            this.Controls.Add(this.textbox);
            // buttonMoveUp
            this.buttonMoveUp = new System.Windows.Forms.Button();
            buttonMoveUp.Location = new System.Drawing.Point(FIRSTMBUTTON_XPOS,FIRSTMBUTTON_YPOS);
            buttonMoveUp.Text = "<";
            buttonMoveUp.Size = new System.Drawing.Size(MBUTTON_LENGTH,MBUTTON_HEIGHT);
            buttonMoveUp.Click += new System.EventHandler(this.buttonMoveUp_Click);
            buttonMoveUp.Enabled = false;
            this.Controls.Add(this.buttonMoveUp);
            // buttonMoveDown
            this.buttonMoveDown = new System.Windows.Forms.Button();
            buttonMoveDown.Location = new System.Drawing.Point(SECONDMBUTTON_XPOS,SECONDMBUTTON_YPOS);
            buttonMoveDown.Text = ">";
            buttonMoveDown.Size = new System.Drawing.Size(MBUTTON_LENGTH,MBUTTON_HEIGHT);
            buttonMoveDown.Click += new System.EventHandler(this.buttonMoveDown_Click);
            buttonMoveDown.Enabled = false;
            this.Controls.Add(this.buttonMoveDown);
        }
        protected void textbox_Click(Object sender, System.EventArgs e)
        {
            this.buttonAdd.Enabled = true;
            if (this.listbox.Items.Count>0)
                EnableAllListBoxButtons();
        }
        protected void listbox_SelectedIndexChanged(object sender, System.EventArgs e)
        {
            nSelectedIndex = this.listbox.SelectedIndex;
            string szSelected = (string)this.listbox.SelectedItem;
            this.textbox.Text = szSelected;
        }
        protected void buttonAdd_Click(Object sender, System.EventArgs e)
        {
            if (this.textbox.Text !="")
            {
                this.listbox.Items.Add(this.textbox.Text);
                this.textbox.Text = "";
                EnableAllListBoxButtons();
            }
        }
        protected void buttonModify_Click(Object sender, System.EventArgs e)
        {
            this.listbox.Items[nSelectedIndex] = this.textbox.Text;
        }
        protected void buttonDelete_Click(Object sender, System.EventArgs e)
        {
            nSelectedIndex = this.listbox.SelectedIndex;
            this.listbox.Items.Remove(nSelectedIndex);
            System.Console.WriteLine("Remove fn does not work...");
        }
        protected void buttonClose_Click(Object sender, System.EventArgs e)
        {
            this.Close();
        }
        protected void buttonMoveUp_Click(Object sender, System.EventArgs e)
        {
            if (this.listbox.SelectedIndex >0)
                this.listbox.SelectedIndex--;
        }
        protected void buttonMoveDown_Click(Object sender, System.EventArgs e)
        {
            if (this.listbox.SelectedIndex < this.listbox.Items.Count-1)
                this.listbox.SelectedIndex++;
        }
        private void EnableAllListBoxButtons()
        {
            this.buttonAdd.Enabled = true;
            this.buttonModify.Enabled = true;
            this.buttonDelete.Enabled = true;
            this.buttonMoveUp.Enabled = true;
            this.buttonMoveDown.Enabled = true;
        }
        [STAThread]
        public static void Main(string[] args)
        {
            Application.Run(new ListBox());
        }
    } // class
} // namespace

Further Readings

 

Here are more articles on ListBox control.

• Mastering ListBox in C#
• Transferring data from one ListBox to another in WPF
• Owner Draw ListBox Control with Images
• Editable ListBox in C#
• Databinding in Listbox from XML file
• Using ListBox in C#
• Adding & Retrieving items from listbox and check list box
• Owner Draw ListBox Control in Windows Forms and C#
• Editable ListView Control
• Adding Items to a ListBox
• Checked ListBox Control In C#
• Editable ListBox Control