ExtendedTextBox.cs

Toto je zdrojový kód souboru ExtendedTextBox.cs

Silverlight TextBox control with Watermark support and IsTabStop settings automatic by IsReadOnly value.

using System;
using System.Windows;
using System.Windows.Controls;

namespace IMP.Windows.Controls
{
    /// <summary>
    /// TextBox with IsTabStop property settings automatic by IsReadOnly value
    /// </summary>
    /// <remarks>
    /// <c>IsTabStop</c> property settings automatic by <c>IsReadOnly</c> value
    /// <c>Watermark</c> support
    /// </remarks>
    [TemplatePart(Name = "Watermark", Type = typeof(ContentControl))]
    [TemplateVisualState(Name = "Normal", GroupName = "CommonStates")]
    [TemplateVisualState(Name = "MouseOver", GroupName = "CommonStates")]
    [TemplateVisualState(Name = "Disabled", GroupName = "CommonStates")]
    [TemplateVisualState(Name = "Unfocused", GroupName = "FocusStates")]
    [TemplateVisualState(Name = "Focused", GroupName = "FocusStates")]
    [TemplateVisualState(Name = "Unwatermarked", GroupName = "WatermarkStates")]
    [TemplateVisualState(Name = "Watermarked", GroupName = "WatermarkStates")]
    public class ExtendedTextBox : TextBox
    {
        #region member varible and default property initialization
        private bool m_NewIsTabStop;
        #endregion

        #region constructors and destructors
        /// <summary>
        /// ExtendedTextBox control constructor
        /// </summary>
        public ExtendedTextBox()
        {
            this.DefaultStyleKey = typeof(ExtendedTextBox);

            m_NewIsTabStop = base.IsTabStop;

            this.TextChanged += OnTextChanged;

            SetTabStop();
        }
        #endregion

        #region action methods
        /// <summary>
        /// Called when template is applied to the control.
        /// </summary>
        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            OnWatermarkChanged();
            SetWatermarkState(false);
        }
        #endregion

        #region property getters/setters
        /// <summary>
        /// Gets or sets a value that indicates whether a control is included in tab navigation.
        /// </summary>
        public new bool IsTabStop
        {
            get { return m_NewIsTabStop; }
            set
            {
                m_NewIsTabStop = value;
                SetTabStop();
            }
        }

        /// <summary>
        /// IsReadOnly dependency property
        /// </summary>
        public new static readonly DependencyProperty IsReadOnlyProperty = DependencyProperty.Register("IsReadOnly", typeof(bool), typeof(ExtendedTextBox), new PropertyMetadata(OnIsReadOnlyPropertyChanged));

        /// <summary>
        /// Gets or sets the value that determines if the user can change the text in the text box.
        /// </summary>
        public new bool IsReadOnly
        {
            get { return (bool)base.GetValue(IsReadOnlyProperty); }
            set { base.SetValue(IsReadOnlyProperty, value); }
        }

        private static void OnIsReadOnlyPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
        {
            var extendedTextBox = sender as ExtendedTextBox;
            extendedTextBox.OnIsReadOnlyChanged((bool)args.OldValue, (bool)args.NewValue);
        }

        /// <summary>
        /// IsReadOnly changed
        /// </summary>
        protected virtual void OnIsReadOnlyChanged(bool oldValue, bool newValue)
        {
            base.IsReadOnly = newValue;
            SetTabStop();
        }

        /// <summary>
        /// Watermark dependency property
        /// </summary>
        public new static readonly DependencyProperty WatermarkProperty = DependencyProperty.Register("Watermark", typeof(object), typeof(ExtendedTextBox), new PropertyMetadata(OnWatermarkPropertyChanged));

        /// <summary>
        /// Watermark content
        /// </summary>
        /// <value>The watermark.</value>
        public new object Watermark
        {
            get { return (object)GetValue(WatermarkProperty); }
            set { SetValue(WatermarkProperty, value); }
        }

        private static void OnWatermarkPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
        {
            var extendedTextBox = sender as ExtendedTextBox;
            extendedTextBox.OnWatermarkChanged();
            extendedTextBox.SetWatermarkState(true);
        }

        private void OnWatermarkChanged()
        {
            var watermarkContentElement = GetTemplateChild("Watermark") as ContentControl;
            if (watermarkContentElement != null)
            {
                var watermarkControl = this.Watermark as Control;
                if (watermarkControl != null)
                {
                    watermarkControl.IsTabStop = false;
                    watermarkControl.IsHitTestVisible = false;
                }
            }
        }
        #endregion

        #region private member functions
        /// <summary>
        /// Overrides OnMouseLeftButtonDown
        /// </summary>
        protected override void OnMouseLeftButtonDown(System.Windows.Input.MouseButtonEventArgs e)
        {
            base.IsTabStop = true;
            base.OnMouseLeftButtonDown(e);
        }

        /// <summary>
        /// Overrides OnLostFocus
        /// </summary>
        protected override void OnLostFocus(System.Windows.RoutedEventArgs e)
        {
            SetTabStop();
            base.OnLostFocus(e);
        }

        private void OnTextChanged(object sender, TextChangedEventArgs e)
        {
            SetWatermarkState(true);
        }

        private void SetTabStop()
        {
            base.IsTabStop = m_NewIsTabStop && !this.IsReadOnly;
        }

        private void SetWatermarkState(bool useTransitions)
        {
            // Update the WatermarkStates group
            if (this.Watermark != null && string.IsNullOrEmpty(this.Text))
            {
                GoToState(this, useTransitions, "Watermarked", "Unwatermarked");
            }
            else
            {
                GoToState(this, useTransitions, "Unwatermarked");
            }
        }

        private static void GoToState(Control control, bool useTransitions, params string[] stateNames)
        {
            if (control == null)
            {
                throw new ArgumentNullException("control");
            }

            if (stateNames != null)
            {
                foreach (string str in stateNames)
                {
                    if (VisualStateManager.GoToState(control, str, useTransitions))
                    {
                        return;
                    }
                }
            }
        }
        #endregion
    }
}