Chris
Sat May 21 04:52:15 CDT 2005
Thanks for that, it is easier than I thought it would be.
Chris
"Bruce Wood" <brucewood@canada.com> wrote in message
news:1116633373.106895.268310@g43g2000cwa.googlegroups.com...
> Here is my version. You can remove the autocompletion stuff, as it has
> a minor problem, but the read-only part seems to work well.
>
> using System;
> using System.ComponentModel;
> using System.Drawing;
> using System.Windows.Forms;
>
> namespace MyControls
> {
> /// <summary>
> /// A combo box that offers a <c>ReadOnly</c> property that
> /// will display the currently selected item clearly but not
> /// allow the user to change it, and moves the selection
> /// down the list as the user types the text of an entry.
> /// </summary>
> public class ComboBoxWithAutocompletionReadOnly :
> System.Windows.Forms.ComboBox
> {
> #region Private members
>
> private bool ro;
> private Color roBackColor;
> private Color roForeColor;
> private Color backColorSave;
> private Color foreColorSave;
> private ComboBoxStyle dropDownStyleSave;
> private ContextMenu contextMenuSave;
>
> #endregion
>
> #region Constructor
>
> /// <summary>
> /// Creates a new combo box with a <c>null</c> items
> collection,
> /// and the default display member of <c>"Description"</c>.
> /// </summary>
> public ComboBoxWithAutocompletionReadOnly()
> {
> this.ro = false;
> this.roBackColor = SystemColors.Control;
> this.roForeColor = SystemColors.WindowText;
> }
>
> #endregion
>
> #region Static constructor
>
> static ComboBoxWithAutocompletionReadOnly()
> {
>
>
Agama.AgamaRegistry.Reg.AddControlSerialization(typeof(ComboBoxWithAutocompl
etionReadOnly),
> null, null, false);
> }
>
> #endregion
>
> #region Public properties
>
> /// <summary>
> /// Sets the combo box so that it still has the standard
> /// (enabled) appearance, but it cannot be manipulated by the
> /// user.
> /// </summary>
> /// <value><c>true</c> if the user should not be allowed to
> /// change the currently selected item in the combo box,
> <c>false</c> if the user should
> /// be able to change the combo box contents.</value>
> [Description("Controls whether the user can change the combo
> box state"), Category("Behavior"), DefaultValue(false)]
> public bool ReadOnly
> {
> get { return this.ro; }
> set
> {
> if (this.ro != value)
> {
> this.ro = value;
> if (this.ReadOnly)
> {
> this.backColorSave = base.BackColor;
> this.foreColorSave = base.ForeColor;
> this.dropDownStyleSave = base.DropDownStyle;
> this.contextMenuSave = base.ContextMenu;
>
> base.BackColor = this.roBackColor;
> base.ForeColor = this.roForeColor;
> base.DropDownStyle = ComboBoxStyle.Simple;
> base.ContextMenu = new ContextMenu();
> }
> else
> {
> base.BackColor = this.backColorSave;
> base.ForeColor = this.foreColorSave;
> base.DropDownStyle = this.dropDownStyleSave;
> base.ContextMenu = this.contextMenuSave;
> }
> }
> }
> }
>
> /// <summary>
> /// Gets or sets a value specifying the style of the combo box.
> /// This property replaces the <see
> cref="ComboBox.DropDownStyle"/> property.
> /// </summary>
> new public ComboBoxStyle DropDownStyle
> {
> get { return base.DropDownStyle; }
> set
> {
> if (this.ReadOnly)
> {
> this.dropDownStyleSave = value;
> }
> else
> {
> base.DropDownStyle = value;
> }
> }
> }
>
> /// <summary>
> /// Gets or sets the shortcut menu associated with the control.
> /// This property overrides the <see
> cref="Control.ContextMenu"/> property.
> /// </summary>
> public override ContextMenu ContextMenu
> {
> get { return base.ContextMenu; }
> set
> {
> if (this.ReadOnly)
> {
> this.contextMenuSave = value;
> }
> else
> {
> base.ContextMenu = value;
> }
> }
> }
>
> /// <summary>
> /// Gets or sets the background color for the combo box.
> /// This property overrides the <see cref="Control.BackColor"/>
> property.
> /// </summary>
> public override Color BackColor
> {
> get { return base.BackColor; }
> set
> {
> if (this.ReadOnly)
> {
> this.backColorSave = value;
> }
> else
> {
> base.BackColor = value;
> }
> }
> }
>
> /// <summary>
> /// Gets or sets the foreground color for the combo box.
> /// This property overrides the <see cref="Control.ForeColor"/>
> property.
> /// </summary>
> public override Color ForeColor
> {
> get { return base.ForeColor; }
> set
> {
> if (this.ReadOnly)
> {
> this.foreColorSave = value;
> }
> else
> {
> base.ForeColor = value;
> }
> }
> }
>
> #endregion
>
> #region Methods for implementing auto-completion and read-only
>
> /// <summary>
> /// This method provides "auto-complete" functionality for the
> /// combo box. As the user types characters in the combo box,
> /// the box searches down the list of available items and
> /// offers the user an auto-complete for the stock code. The
> /// box also moves the currently selected item down to the
> first
> /// item that begins with the text the user typed.
> /// </summary>
> /// <param name="e">Further details about the key-up event,
> /// including which key was pressed.</param>
> protected override void OnKeyUp(KeyEventArgs e)
> {
> if (this.ro)
> {
> e.Handled = true;
> }
> else
> {
> base.OnKeyUp (e);
>
> switch (e.KeyCode)
> {
> case Keys.Left:
> case Keys.Right:
> case Keys.Up:
> case Keys.Down:
> case Keys.Tab:
> return;
>
> default:
> break;
> }
>
> if (this.DropDownStyle != ComboBoxStyle.DropDownList &&
> this.Enabled)
> {
> int insertionPointIndex = this.SelectionStart;
> int firstMatchingItemIndex =
> this.FindString(this.Text.Substring(0, insertionPointIndex));
> if (firstMatchingItemIndex > 0)
> {
> this.SelectedIndex = firstMatchingItemIndex;
> this.SelectionStart = insertionPointIndex;
> this.SelectionLength = this.Text.Length;
> }
> }
> }
> }
>
> /// <summary>
> /// This method throws away keypresses in "read-only" mode,
> preventing
> /// the user from interacting with the control.
> /// </summary>
> /// <param name="e">Further information about the key down
> event.</param>
> protected override void OnKeyDown(KeyEventArgs e)
> {
> if (this.ReadOnly)
> {
> e.Handled = true;
> }
> else
> {
> base.OnKeyDown (e);
> }
> }
>
> /// <summary>
> /// This method throws away keypresses in "read-only" mode,
> preventing
> /// the user from interacting with the control.
> /// </summary>
> /// <param name="e">Further information about the key press
> event.</param>
> protected override void OnKeyPress(KeyPressEventArgs e)
> {
> if (this.ReadOnly)
> {
> e.Handled = true;
> }
> else
> {
> base.OnKeyPress (e);
> }
> }
>
> #endregion
> }
> }
>