水印控件

Windows Phone 7自定义一个控件库跟Silverlight的是基本一样的，第一步创建一个类库，然后添加一个Themes文件夹，在文件夹里面添加上 generic.xaml文件作为默认的控件样式文件，记住一定要写这个名字否则就找不到样式了，大小写都可以。新建一个控件类 MyContro1.cs,MyContro2.cs在这里面就可以写控件的处理逻辑了。

下面看一下一个水印控件的处理：

generic.xaml文件

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:Phone.Controls;assembly=Phone.Controls"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"   
    mc:Ignorable="d"
    >
    <Style  TargetType="local:WatermarkedTextBox">
        <Setter Property="FontFamily" Value="{StaticResource PhoneFontFamilyNormal}"/>
        <Setter Property="FontSize" Value="{StaticResource PhoneFontSizeMediumLarge}"/>
        <Setter Property="Background" Value="White"/>
        <Setter Property="Foreground" Value="#FF3880B2"/>
        <Setter Property="BorderBrush" Value="#FF3880B2"/>
        <Setter Property="SelectionBackground" Value="#FF3880B2"/>
        <Setter Property="SelectionForeground" Value="{StaticResource PhoneTextBoxSelectionForegroundBrush}"/>
        <Setter Property="BorderThickness" Value="{StaticResource PhoneBorderThickness}"/>
        <Setter Property="Padding" Value="2"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="local:WatermarkedTextBox">
                    <Grid Background="Transparent">
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="CommonStates">
                                <VisualState x:Name="Normal"/>
                                <VisualState x:Name="MouseOver"/>
                                <VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="EnabledBorder">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Collapsed</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="DisabledOrReadonlyBorder">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Visible</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="ReadOnly">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="EnabledBorder">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Collapsed</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="DisabledOrReadonlyBorder">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Visible</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="DisabledOrReadonlyBorder">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="White"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="DisabledOrReadonlyBorder">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="#FF3880B2"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="DisabledOrReadonlyContent">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneTextBoxReadOnlyBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                            <VisualStateGroup x:Name="FocusStates">
                                <VisualState x:Name="Focused">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="EnabledBorder">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="White"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="EnabledBorder">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="#FF3880B2"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Unfocused"/>

                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <Border x:Name="EnabledBorder" BorderBrush="#FF3880B2" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Margin="{StaticResource PhoneTouchTargetOverhang}">
                            <Grid>
                                <ContentControl x:Name="watermarkContent"  HorizontalContentAlignment="Left" Style="{TemplateBinding WatermarkStyle}" Content="{TemplateBinding Watermark}" Background="Transparent" Opacity="0.5"/>
                                <ContentControl x:Name="ContentElement" BorderThickness="0" HorizontalContentAlignment="Stretch" Margin="{StaticResource PhoneTextBoxInnerMargin}" Padding="{TemplateBinding Padding}" VerticalContentAlignment="Stretch"/>
                            </Grid>
                        </Border>
                        <Border x:Name="DisabledOrReadonlyBorder" BorderBrush="{StaticResource PhoneDisabledBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="White" Margin="{StaticResource PhoneTouchTargetOverhang}" Visibility="Collapsed">
                            <TextBox x:Name="DisabledOrReadonlyContent" Background="White" Foreground="{StaticResource PhoneDisabledBrush}"
                                     FontWeight="{TemplateBinding FontWeight}" FontStyle="{TemplateBinding FontStyle}" FontSize="{TemplateBinding FontSize}"
                                     FontFamily="{TemplateBinding FontFamily}" IsReadOnly="True" SelectionForeground="{TemplateBinding SelectionForeground}" 
                                     SelectionBackground="{TemplateBinding SelectionBackground}" TextAlignment="{TemplateBinding TextAlignment}" 
                                     TextWrapping="{TemplateBinding TextWrapping}" Text="{TemplateBinding Text}" Template="{StaticResource PhoneDisabledTextBoxTemplate}" />
                        </Border>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

</ResourceDictionary>

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

namespace Phone.Controls
{
    public class WatermarkedTextBox : TextBox
    {
        ContentControl WatermarkContent;
        public static readonly DependencyProperty WatermarkProperty =
      DependencyProperty.Register("Watermark", typeof(object), typeof(WatermarkedTextBox), new PropertyMetadata(OnWatermarkPropertyChanged));

        public static readonly DependencyProperty WatermarkStyleProperty =
      DependencyProperty.Register("WatermarkStyle", typeof(Style), typeof(WatermarkedTextBox), null);

        public Style WatermarkStyle
        {
            get { return base.GetValue(WatermarkStyleProperty) as Style; }
            set { base.SetValue(WatermarkStyleProperty, value); }
        }

        public object Watermark
        {
            get { return base.GetValue(WatermarkProperty) as object; }
            set { base.SetValue(WatermarkProperty, value); }
        }

        public WatermarkedTextBox()
        {
            DefaultStyleKey = typeof(WatermarkedTextBox);
        }

        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();
            this.WatermarkContent = this.GetTemplateChild("watermarkContent") as ContentControl;
            if(WatermarkContent != null)
            {
              DetermineWatermarkContentVisibility();
            }
        }

        protected override void OnGotFocus(RoutedEventArgs e)
        {
            if (WatermarkContent != null && string.IsNullOrEmpty(this.Text))
            {
                this.WatermarkContent.Visibility = Visibility.Collapsed;
            }
            base.OnGotFocus(e);
        }

        protected override void OnLostFocus(RoutedEventArgs e)
        {
            if (WatermarkContent != null && string.IsNullOrEmpty(this.Text))
            {
                this.WatermarkContent.Visibility = Visibility.Visible;
            }
            base.OnLostFocus(e);
        }

        private static void OnWatermarkPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
        {
            WatermarkedTextBox watermarkTextBox = sender as WatermarkedTextBox;
            if(watermarkTextBox != null && watermarkTextBox.WatermarkContent !=null)
            {
              watermarkTextBox.DetermineWatermarkContentVisibility();
            }
        }

        private void DetermineWatermarkContentVisibility()
        {
            if (string.IsNullOrEmpty(this.Text))
            {
                this.WatermarkContent.Visibility = Visibility.Visible;
            }
            else
            {
                this.WatermarkContent.Visibility = Visibility.Collapsed;
            }
        }
    }
}