.net 如何向 WPF 文本框添加提示文本？
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How can I add a hint text to WPF textbox?
提问by Louis Rhys
For example, Facebook has a "Search" hint text in the Search text box when the textbox is empty.
例如，当文本框为空时，Facebook 在搜索文本框中有一个“搜索”提示文本。
How to achieve this with WPF text boxes??
如何使用 WPF 文本框实现此目的？
回答by sellmeadog
You can accomplish this much more easily with a VisualBrushand some triggers in a Style:
您可以使用 aVisualBrush和a 中的一些触发器更轻松地完成此操作Style：
<TextBox>
<TextBox.Style>
<Style TargetType="TextBox" xmlns:sys="clr-namespace:System;assembly=mscorlib">
<Style.Resources>
<VisualBrush x:Key="CueBannerBrush" AlignmentX="Left" AlignmentY="Center" Stretch="None">
<VisualBrush.Visual>
<Label Content="Search" Foreground="LightGray" />
</VisualBrush.Visual>
</VisualBrush>
</Style.Resources>
<Style.Triggers>
<Trigger Property="Text" Value="{x:Static sys:String.Empty}">
<Setter Property="Background" Value="{StaticResource CueBannerBrush}" />
</Trigger>
<Trigger Property="Text" Value="{x:Null}">
<Setter Property="Background" Value="{StaticResource CueBannerBrush}" />
</Trigger>
<Trigger Property="IsKeyboardFocused" Value="True">
<Setter Property="Background" Value="White" />
</Trigger>
</Style.Triggers>
</Style>
</TextBox.Style>
</TextBox>
To increase the re-usability of this Style, you can also create a set of attached properties to control the actual cue banner text, color, orientation etc.
为了增加 this 的Style可重用性，您还可以创建一组附加属性来控制实际提示横幅文本、颜色、方向等。
回答by Martin Schmidt
This is my simple solution, adapted from Microsoft (https://code.msdn.microsoft.com/windowsapps/How-to-add-a-hint-text-to-ed66a3c6)
这是我的简单解决方案，改编自微软（https://code.msdn.microsoft.com/windowsapps/How-to-add-a-hint-text-to-ed66a3c6）
<Grid Background="White" HorizontalAlignment="Right" VerticalAlignment="Top" >
<!-- overlay with hint text -->
<TextBlock Margin="5,2" MinWidth="50" Text="Suche..."
Foreground="LightSteelBlue" Visibility="{Binding ElementName=txtSearchBox, Path=Text.IsEmpty, Converter={StaticResource MyBoolToVisibilityConverter}}" />
<!-- enter term here -->
<TextBox MinWidth="50" Name="txtSearchBox" Background="Transparent" />
</Grid>
回答by mxgg250
Do it in the code-behind by setting the text color initially to gray and adding event handlers for gaining and losing keyboard focus.
通过将文本颜色最初设置为灰色并添加用于获得和失去键盘焦点的事件处理程序，在代码隐藏中执行此操作。
TextBox tb = new TextBox();
tb.Foreground = Brushes.Gray;
tb.Text = "Text";
tb.GotKeyboardFocus += new KeyboardFocusChangedEventHandler(tb_GotKeyboardFocus);
tb.LostKeyboardFocus += new KeyboardFocusChangedEventHandler(tb_LostKeyboardFocus);
Then the event handlers:
然后是事件处理程序：
private void tb_GotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
if(sender is TextBox)
{
//If nothing has been entered yet.
if(((TextBox)sender).Foreground == Brushes.Gray)
{
((TextBox)sender).Text = "";
((TextBox)sender).Foreground = Brushes.Black;
}
}
}
private void tb_LostKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
//Make sure sender is the correct Control.
if(sender is TextBox)
{
//If nothing was entered, reset default text.
if(((TextBox)sender).Text.Trim().Equals(""))
{
((TextBox)sender).Foreground = Brushes.Gray;
((TextBox)sender).Text = "Text";
}
}
}
回答by Mahdi Khalili
what about using materialDesignHintAssist ? i'm using this which also you can add floating hint too :
使用materialDesignHintAssist 怎么样？我正在使用它，您也可以添加浮动提示：
<TextBox Width="150" Height="40" Text="hello" materialDesign:HintAssist.Hint="address" materialDesign:HintAssist.IsFloating="True"></TextBox>
i installed Material Design with Nuget Package there is installation guide in documentationlink
我使用 Nuget Package 安装了 Material Design，文档链接中有安装指南
回答by Kishore Kumar
You have to create a custom control by inheriting the textbox. Below link has an excellent example about the search textbox sample. Please have a look at this
您必须通过继承文本框来创建自定义控件。下面的链接有一个关于搜索文本框示例的很好的例子。请看看这个
http://davidowens.wordpress.com/2009/02/18/wpf-search-text-box/
http://davidowens.wordpress.com/2009/02/18/wpf-search-text-box/
回答by makertoo
You can do in a very simple way. The idea is to place a Label in the same place as your textbox. Your Label will be visible if textbox has no text and hasn't the focus.
你可以用一种非常简单的方式来做。这个想法是在与文本框相同的位置放置一个标签。如果文本框没有文本并且没有焦点，您的标签将可见。
<Label Name="PalceHolder" HorizontalAlignment="Left" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Height="40" VerticalAlignment="Top" Width="239" FontStyle="Italic" Foreground="BurlyWood">PlaceHolder Text Here
<Label.Style>
<Style TargetType="{x:Type Label}">
<Setter Property="Visibility" Value="Hidden"/>
<Style.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding ="{Binding ElementName=PalceHolder, Path=Text.Length}" Value="0"/>
<Condition Binding ="{Binding ElementName=PalceHolder, Path=IsFocused}" Value="False"/>
</MultiDataTrigger.Conditions>
<Setter Property="Visibility" Value="Visible"/>
</MultiDataTrigger>
</Style.Triggers>
</Style>
</Label.Style>
</Label>
<TextBox Background="Transparent" Name="TextBox1" HorizontalAlignment="Left" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Height="40"TextWrapping="Wrap" Text="{Binding InputText,Mode=TwoWay}" VerticalAlignment="Top" Width="239" />
Bonus:If you want to have default value for your textBox, be sure after to set it when submitting data (for example:"InputText"="PlaceHolder Text Here" if empty).
奖励：如果您想为 textBox 设置默认值，请确保在提交数据时设置它（例如：“InputText”="PlaceHolder Text Here" 如果为空）。
回答by Mat
Another approach ;-)
另一种方法;-)
this works also with PasswordBox. If you want to use it with TextBox, simply exchange PasswordChangedwith TextChanged.
这也适用于PasswordBox. 如果您想与 一起使用TextBox，只需PasswordChanged与交换即可TextChanged。
XAML:
XAML：
<Grid>
<!-- overlay with hint text -->
<TextBlock Margin="5,2"
Text="Password"
Foreground="Gray"
Name="txtHintPassword"/>
<!-- enter user here -->
<PasswordBox Name="txtPassword"
Background="Transparent"
PasswordChanged="txtPassword_PasswordChanged"/>
</Grid>
CodeBehind:
代码隐藏：
private void txtPassword_PasswordChanged(object sender, RoutedEventArgs e)
{
txtHintPassword.Visibility = Visibility.Visible;
if (txtPassword.Password.Length > 0)
{
txtHintPassword.Visibility = Visibility.Hidden;
}
}
回答by Mohammad Mahroz
I once got into the same situation, I solved it following way. I've only fulfilled the requirements of a hint box, you can make it more interactive by adding effects and other things on other events like on focus etc.
我曾经遇到过同样的情况，我通过以下方式解决了它。我只满足了提示框的要求，您可以通过在其他事件（如焦点等）上添加效果和其他内容来使其更具交互性。
WPF CODE(I've removed styling to make it readable)
WPF 代码（我删除了样式以使其可读）
<Grid Margin="0,0,0,0" Background="White">
<Label Name="adminEmailHint" Foreground="LightGray" Padding="6" FontSize="14">Admin Email</Label>
<TextBox Padding="4,7,4,8" Background="Transparent" TextChanged="adminEmail_TextChanged" Height="31" x:Name="adminEmail" Width="180" />
</Grid>
<Grid Margin="10,0,10,0" Background="White" >
<Label Name="adminPasswordHint" Foreground="LightGray" Padding="6" FontSize="14">Admin Password</Label>
<PasswordBox Padding="4,6,4,8" Background="Transparent" PasswordChanged="adminPassword_PasswordChanged" Height="31" x:Name="adminPassword" VerticalContentAlignment="Center" VerticalAlignment="Center" Width="180" FontFamily="Helvetica" FontWeight="Light" FontSize="14" Controls:TextBoxHelper.Watermark="Admin Password" FontStyle="Normal" />
</Grid>
C# Code
C# 代码
private void adminEmail_TextChanged(object sender, TextChangedEventArgs e)
{
if(adminEmail.Text.Length == 0)
{
adminEmailHint.Visibility = Visibility.Visible;
}
else
{
adminEmailHint.Visibility = Visibility.Hidden;
}
}
private void adminPassword_PasswordChanged(object sender, RoutedEventArgs e)
{
if (adminPassword.Password.Length == 0)
{
adminPasswordHint.Visibility = Visibility.Visible;
}
else
{
adminPasswordHint.Visibility = Visibility.Hidden;
}
}
回答by StefanG
Another solution is to use a WPF toolkit like MahApps.Metro. It has many nice features, like a text box watermark:
另一种解决方案是使用像 MahApps.Metro 这样的 WPF 工具包。它有很多不错的功能，比如文本框水印：
Controls:TextBoxHelper.Watermark="Search..."
Controls:TextBoxHelper.Watermark="Search..."
回答by StarLordBlair
I used the got and lost focus events:
我使用了得到和失去焦点事件：
Private Sub txtSearchBox_GotFocus(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles txtSearchBox.GotFocus
If txtSearchBox.Text = "Search" Then
txtSearchBox.Text = ""
Else
End If
End Sub
Private Sub txtSearchBox_LostFocus(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles txtSearchBox.LostFocus
If txtSearchBox.Text = "" Then
txtSearchBox.Text = "Search"
Else
End If
End Sub
It works well, but the text is in gray still. Needs cleaning up. I was using VB.NET
它运行良好，但文本仍然是灰色的。需要清理。我正在使用 VB.NET
