WPFでWatermark(透かし)を使ったときのメモ

参照設定

Microsoft.TeamFoundation.Controls
※.NET Framework4.5

サンプル

MainWindowViewModel.cs

using Codeplex.Reactive;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Reactive.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;

namespace WatermarkSample
{
    public class MainWindowViewModel : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        private string _name { get; set; }
        private string _numberstring { get; set; }

        public ReactiveProperty<string> Name { get; set; }
        public ReactiveProperty<string> NumberString { get; set; }
        public ReactiveCommand ClickCommand { get; private set; }

        public ReactiveCollection<string> ComboBoxSource { get; private set; }

        public MainWindowViewModel()
        {
            ComboBoxSource = Observable.Range(0, 100).Select(i => i.ToString()).ToReactiveCollection();

            Name = ReactiveProperty.FromObject(this, o => o._name).ToReactiveProperty();
            NumberString = ReactiveProperty.FromObject(this, o => o._numberstring).ToReactiveProperty();

            ClickCommand = Name.CombineLatest(NumberString, (l, r) =>
            {
                return !string.IsNullOrEmpty(l) && !string.IsNullOrEmpty(r);
            }).ToReactiveCommand();
            ClickCommand.Subscribe(param =>
            {
                MessageBox.Show(string.Format("TextBox:{0}{1}ComboBox:{2}", Name.Value, Environment.NewLine, NumberString.Value));
            });
        }

        protected void RaisePropertyChanged(string propertyName)
        {
            var handler = PropertyChanged;
            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
}

MainWindow.xaml

<Window x:Class="WatermarkSample.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:l="clr-namespace:WatermarkSample"
        xmlns:wm="clr-namespace:Microsoft.TeamFoundation.Controls.WPF;assembly=Microsoft.TeamFoundation.Controls"
        Title="MainWindow" Height="350" Width="525">
    <Window.DataContext>
        <l:MainWindowViewModel/>
    </Window.DataContext>
    <Grid>
        <TextBox HorizontalAlignment="Left" Height="23" Margin="142,84,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120" Text="{Binding Name.Value, Mode=TwoWay}">
            <wm:Watermark.HintText>enter your id</wm:Watermark.HintText>
        </TextBox>
        <ComboBox HorizontalAlignment="Left" Margin="142,152,0,0" VerticalAlignment="Top" Width="120" ItemsSource="{Binding ComboBoxSource, Mode=OneTime}" SelectedIndex="{Binding NumberString.Value,Mode=TwoWay}">
            <wm:Watermark.HintText>select</wm:Watermark.HintText>
        </ComboBox>
        <Button Content="Button" HorizontalAlignment="Left" Margin="142,211,0,0" VerticalAlignment="Top" Width="75" Command="{Binding ClickCommand}"/>
    </Grid>
</Window>