/// <summary>
/// This is called when the watermark color is changed
/// </summary>
/// <param name="dpo"></param>
/// <param name="e"></param>
private static void OnColorChanged(DependencyObject dpo, DependencyPropertyChangedEventArgs e)
{
WatermarkTextBehavior wtb = (WatermarkTextBehavior)dpo;
if (wtb.AssociatedObject != null)
{
wtb.OnChangeWatermarkColor();
}
}
/// <summary>
/// This is called when the watermark visibility changes.
/// </summary>
/// <param name="dpo"></param>
/// <param name="e"></param>
private static void OnChangeWatermarkVisibility(DependencyObject dpo, DependencyPropertyChangedEventArgs e)
{
WatermarkTextBehavior wtb = (WatermarkTextBehavior)dpo;
if ((bool)e.NewValue == true)
{
if (!wtb.OnSetWatermarkText())
{
wtb.IsWatermarkVisible = false;
}
}
else
{
wtb.OnRemoveWatermarkText();
}
}
/// <summary>
/// This is called when the watermark text is changed on either a WatermarkTextboxBehavior
/// OR on a TextBox directly to attach/detach the behavior.
/// </summary>
/// <param name="dpo"></param>
/// <param name="e"></param>
private static void OnTextChanged(DependencyObject dpo, DependencyPropertyChangedEventArgs e)
{
WatermarkTextBehavior wtb = dpo as WatermarkTextBehavior;
if (wtb != null)
{
if (wtb.AssociatedObject != null)
{
wtb.IsWatermarkVisible = true;
}
}
// Attach/Detach request
else
{
TextBox tb = dpo as TextBox;
if (tb != null)
{
string text = (e.NewValue ?? "").ToString();
var behaviors = Interaction.GetBehaviors(tb);
var thisBehavior =
behaviors.FirstOrDefault(b => b is WatermarkTextBehavior) as WatermarkTextBehavior;
if (string.IsNullOrWhiteSpace(text))
{
if (thisBehavior != null)
{
behaviors.Remove(thisBehavior);
}
}
else
{
if (thisBehavior == null)
{
thisBehavior = new WatermarkTextBehavior()
{
WatermarkText = text
};
behaviors.Add(thisBehavior);
}
else
{
thisBehavior.WatermarkText = text;
}
}
}
}
}
