using System;
using System.Drawing;
using System.Windows.Forms;
using System.Data;
using System.Data.SqlClient;
public class ComboBoxes : Form
{
ComboBox cmb;
Button btnDisplay;
Button btnInsert;
Button btnSelect;
Label lblEdit;
TextBox txtDisplay;
Boolean boolChange = false;
Boolean boolProcessed = false;
public ComboBoxes()
{
Size = new Size(300,400);
this.Load += new EventHandler(this_Load);
cmb = new ComboBox();
cmb.Parent = this;
cmb.Location = new Point(10,10);
cmb.Size = new Size(ClientSize.Width / 2, Height - 200);
cmb.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom;
cmb.DropDownStyle = ComboBoxStyle.DropDown;
cmb.DropDownStyle = ComboBoxStyle.Simple;
cmb.DropDownWidth = (int)(cmb.Width * 1.5);
cmb.MaxDropDownItems = 12;
cmb.MaxLength = 20;
cmb.SelectionChangeCommitted += new EventHandler(cmb_SelectionChangeCommitted);
cmb.Leave += new EventHandler(cmb_Leave);
btnInsert = new Button();
btnInsert.Parent = this;
btnInsert.Text = "&Insert Item";
btnInsert.Size = new Size((int)(Font.Height * .75) * btnInsert.Text.Length, cmb.Height);
btnInsert.Location = new Point(cmb.Right + 10, cmb.Top);
btnInsert.Click += new System.EventHandler(btnInsert_Click);
lblEdit = new Label();
lblEdit.Parent = this;
lblEdit.BorderStyle = BorderStyle.Fixed3D;
lblEdit.Location = new Point(cmb.Left, cmb.Bottom + 10);
lblEdit.BackColor = Color.LightGray;
lblEdit.Text = "";
lblEdit.Size = new Size(cmb.DropDownWidth, Font.Height * 2);
btnDisplay = new Button();
btnDisplay.Parent = this;
btnDisplay.Text = "&Display Items";
btnDisplay.Size = new Size((int)(Font.Height * .75) * btnDisplay.Text.Length, cmb.Height);
btnDisplay.Location = new Point(lblEdit.Left, lblEdit.Bottom + 10);
btnDisplay.Click += new System.EventHandler(btnDisplay_Click);
txtDisplay = new TextBox();
txtDisplay.Parent = this;
txtDisplay.Location = new Point(btnDisplay.Left, btnDisplay.Bottom + 10);
txtDisplay.Multiline = true;
txtDisplay.ReadOnly = true;
txtDisplay.BackColor = Color.LightGray;
txtDisplay.ScrollBars = ScrollBars.Vertical;
txtDisplay.Text = "";
txtDisplay.Size = new Size(cmb.DropDownWidth, 200);
btnSelect = new Button();
btnSelect.Parent = this;
btnSelect.Text = "&Select 4";
btnSelect.Size = new Size((int)(Font.Height * .75) * btnSelect.Text.Length, cmb.Height);
btnSelect.Location = new Point(btnDisplay.Right + 10, btnDisplay.Top);
btnSelect.Click += new System.EventHandler(btnSelect_Click);
cmb.Items.Add("A");
cmb.Items.Add("B");
cmb.Items.Add("C");
cmb.Items.Add("D");
cmb.Items.Add("E");
cmb.SelectedIndex = 0;
}
static void Main()
{
Application.Run(new ComboBoxes());
}
private void this_Load(object sender, EventArgs e)
{
cmb.TextChanged += new EventHandler(cmb_TextChanged);
cmb.SelectedIndexChanged += new EventHandler(cmb_SelectedIndexChanged);
}
private void cmb_TextChanged(object sender, EventArgs e)
{
if (!boolProcessed)
lblEdit.Text = cmb.Text;
boolChange = true;
}
private void cmb_SelectedIndexChanged(object sender, EventArgs e)
{
if (boolChange)
{
boolChange = false;
boolProcessed = false;
}
}
private void cmb_SelectionChangeCommitted(object sender, EventArgs e)
{
if (boolChange)
ProcessChange();
}
private void cmb_Leave(object sender, EventArgs e)
{
if (boolChange)
{
ProcessChange();
boolChange = false;
}
}
private void ProcessChange()
{
lblEdit.Text = "Edited: " + cmb.Text;
boolProcessed = true;
}
private void btnDisplay_Click(object sender, EventArgs e)
{
string str = DateTime.Now.ToString() + "\r\n";
foreach (object item in cmb.Items)
{
str += item.ToString() + "\r\n";
}
txtDisplay.Text = str;
}
private void btnSelect_Click(object sender, EventArgs e)
{
cmb.Select(1,2);
}
private void btnInsert_Click(object sender, EventArgs e)
{
if (cmb.FindStringExact(cmb.Text) != -1)
{
MessageBox.Show("'" + cmb.Text + "' already exists in the list.\r\n" +
"Will not be added again.",
"Already Exists!");
}
else if (cmb.Text == "")
{
MessageBox.Show("There is nothing to add.","Nothing There");
}
else
{
cmb.Items.Add(cmb.Text);
}
}
}
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