如何在WPF中轻松地将TextBox更改为水印TextBox？

Question

将TextBox代码更改为水印TextBox的最简单方法是什么？

<TextBox Grid.Column="1" Name="txtBoxAddress" Width="200" GotKeyboardFocus="TxtBoxAddress_GotKeyboardFocus" Text="" KeyUp="TxtBoxAddress_KeyUp"></TextBox>

Answer 1

选项一将是use a background image，如MSDN中所述。如果你想使用绑定，这可能是最好的方法。

<强> XAML     

  <StackPanel>
    <TextBox Name="myTextBox" TextChanged="OnTextBoxTextChanged" Width="200">
      <TextBox.Background>
        <ImageBrush ImageSource="TextBoxBackground.gif" AlignmentX="Left" Stretch="None" />
      </TextBox.Background>
    </TextBox>
  </StackPanel>
</Page>

<强>代码

using System;
using System.Windows;
using System.Windows.Input;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace SDKSample
{
    public partial class TextBoxBackgroundExample : Page
    {

        void OnTextBoxTextChanged(object sender, TextChangedEventArgs e)
        {

            if (myTextBox.Text == "")
            {
                // Create an ImageBrush.
                ImageBrush textImageBrush = new ImageBrush();
                textImageBrush.ImageSource =
                    new BitmapImage(
                        new Uri(@"TextBoxBackground.gif", UriKind.Relative)
                    );
                textImageBrush.AlignmentX = AlignmentX.Left;
                textImageBrush.Stretch = Stretch.None;
                // Use the brush to paint the button's background.
                myTextBox.Background = textImageBrush;

            }
            else
            {

                myTextBox.Background = null;
            }

        }

    }

或者您可以使用this codeproject article中所述的BooleanToVisibilityConverter。