I am looking for a way to add placeholder text to a textbox like you can with a textbox in html5.
I.e. if the textbox has no text, then it adds the text Enter some text here, when the user clicks on it the placeholder text disappears and allows the user to enter their own text, and if the textbox loses focus and there is still no text then the placeholder is added back to the textbox.
I know this is an old thread, but .NET Core and .NET 5.0 have implemented the TextBox.PlaceholderText Property.
Here I come with this solution inspired by @Kemal Karadag.
I noticed that every solution posted here is relying on the focus,
While I wanted my placeholder to be the exact clone of a standard HTML placeholder in Google Chrome.
Instead of hiding/showing the placeholder when the box is focused,
I hide/show the placeholder depending on the text length of the box:
If the box is empty, the placeholder is shown, and if you type in the box, the placeholder disappears.
As it is inherited from a standard TextBox, you can find it in your Toolbox!
using System;
using System.Drawing;
using System.Windows.Forms;
public class PlaceHolderTextBox : TextBox
{
private bool isPlaceHolder = true;
private string placeHolderText;
public string PlaceHolderText
{
get { return placeHolderText; }
set
{
placeHolderText = value;
SetPlaceholder();
}
}
public PlaceHolderTextBox()
{
TextChanged += OnTextChanged;
}
private void SetPlaceholder()
{
if (!isPlaceHolder)
{
this.Text = placeHolderText;
this.ForeColor = Color.Gray;
isPlaceHolder = true;
}
}
private void RemovePlaceHolder()
{
if (isPlaceHolder)
{
this.Text = this.Text[0].ToString(); // Remove placeHolder text, but keep the character we just entered
this.Select(1, 0); // Place the caret after the character we just entered
this.ForeColor = System.Drawing.SystemColors.WindowText;
isPlaceHolder = false;
}
}
private void OnTextChanged(object sender, EventArgs e)
{
if (this.Text.Length == 0)
{
SetPlaceholder();
}
else
{
RemovePlaceHolder();
}
}
}
This is a extension method for the texbox. Simply Add the Placeholder Text programmatically:
myTextBox.AddPlaceholderText("Hello World!");
The extension method:
public static void AddPlaceholderText(this TextBox textBox, string placeholderText)
{
if (string.IsNullOrWhiteSpace(textBox.Text))
textBox.Text = placeholderText;
textBox.SetResourceReference(Control.ForegroundProperty,
textBox.Text != placeholderText
? "SystemControlForegroundBaseHighBrush"
: "SystemControlForegroundBaseMediumBrush");
var ignoreSelectionChanged = false;
textBox.SelectionChanged += (sender, args) =>
{
if (ignoreSelectionChanged) { ignoreSelectionChanged = false; return; }
if (textBox.Text != placeholderText) return;
ignoreSelectionChanged = true;
textBox.Select(0, 0);
};
var lastText = textBox.Text;
var ignoreTextChanged = false;
textBox.TextChanged += (sender, args) =>
{
if (ignoreTextChanged) { ignoreTextChanged = false; return; }
if (string.IsNullOrWhiteSpace(textBox.Text))
{
ignoreTextChanged = true;
textBox.Text = placeholderText;
textBox.Select(0, 0);
}
else if (lastText == placeholderText)
{
ignoreTextChanged = true;
textBox.Text = textBox.Text.Substring(0, 1);
textBox.Select(1, 0);
}
textBox.SetResourceReference(Control.ForegroundProperty,
textBox.Text != placeholderText
? "SystemControlForegroundBaseHighBrush"
: "SystemControlForegroundBaseMediumBrush");
lastText = textBox.Text;
};
}
Happy coding, BierDav
there are BETTER solutions, but the easiest solution is here: set the textbox text to your desired string then create a function that deletes the text, have that function fire on textbox Focus Enter event
I wrote a reusable custom control, maybe it can help someone that need to implement multiple placeholder textboxes in his project.
here is the custom class with implementation example of an instance, you can test easily by pasting this code on a new winforms project using VS:
namespace reusebleplaceholdertextbox
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
// implementation
CustomPlaceHolderTextbox myCustomTxt = new CustomPlaceHolderTextbox(
"Please Write Text Here...", Color.Gray, new Font("ARIAL", 11, FontStyle.Italic)
, Color.Black, new Font("ARIAL", 11, FontStyle.Regular)
);
myCustomTxt.Multiline = true;
myCustomTxt.Size = new Size(200, 50);
myCustomTxt.Location = new Point(10, 10);
this.Controls.Add(myCustomTxt);
}
}
class CustomPlaceHolderTextbox : System.Windows.Forms.TextBox
{
public string PlaceholderText { get; private set; }
public Color PlaceholderForeColor { get; private set; }
public Font PlaceholderFont { get; private set; }
public Color TextForeColor { get; private set; }
public Font TextFont { get; private set; }
public CustomPlaceHolderTextbox(string placeholdertext, Color placeholderforecolor,
Font placeholderfont, Color textforecolor, Font textfont)
{
this.PlaceholderText = placeholdertext;
this.PlaceholderFont = placeholderfont;
this.PlaceholderForeColor = placeholderforecolor;
this.PlaceholderFont = placeholderfont;
this.TextForeColor = textforecolor;
this.TextFont = textfont;
if (!string.IsNullOrEmpty(this.PlaceholderText))
{
SetPlaceHolder(true);
this.Update();
}
}
private void SetPlaceHolder(bool addEvents)
{
if (addEvents)
{
this.LostFocus += txt_lostfocus;
this.Click += txt_click;
}
this.Text = PlaceholderText;
this.ForeColor = PlaceholderForeColor;
this.Font = PlaceholderFont;
}
private void txt_click(object sender, EventArgs e)
{
// IsNotFirstClickOnThis:
// if there is no other control in the form
// we will have a problem after the first load
// because we dont other focusable control to move the focus to
// and we dont want to remove the place holder
// only on first time the place holder will be removed by click event
RemovePlaceHolder();
this.GotFocus += txt_focus;
// no need for this event listener now
this.Click -= txt_click;
}
private void RemovePlaceHolder()
{
this.Text = "";
this.ForeColor = TextForeColor;
this.Font = TextFont;
}
private void txt_lostfocus(object sender, EventArgs e)
{
if (string.IsNullOrEmpty(this.Text))
{
// set placeholder again
SetPlaceHolder(false);
}
}
private void txt_focus(object sender, EventArgs e)
{
if (this.Text == PlaceholderText)
{
// IsNotFirstClickOnThis:
// if there is no other control in the form
// we will have a problem after the first load
// because we dont other focusable control to move the focus to
// and we dont want to remove the place holder
RemovePlaceHolder();
}
}
}
}
Let's extend the TextBox with PlcaeHoldText and PlaceHoldBackround. I stripped some code form my project.
say goodbye to Grid or Canvas!
<TextBox x:Class="VcpkgGui.View.PlaceHoldedTextBox"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:VcpkgGui.View"
mc:Ignorable="d"
Name="placeHoldTextBox"
TextAlignment="Left"
>
<TextBox.Resources>
<local:FrameworkWidthConverter x:Key="getElemWidth"/>
<local:FrameworkHeightConverter x:Key="getElemHeight"/>
<VisualBrush x:Key="PlaceHoldTextBrush" TileMode="None" Stretch="None" AlignmentX="Left" AlignmentY="Center" Opacity="1">
<VisualBrush.Visual>
<Border Background="{Binding ElementName=placeHoldTextBox, Path=PlaceHoldBackground}"
BorderThickness="0"
Margin="0,0,0,0"
Width="{Binding Mode=OneWay, ElementName=placeHoldTextBox, Converter={StaticResource getElemWidth}}"
Height="{Binding Mode=OneWay, ElementName=placeHoldTextBox, Converter={StaticResource getElemHeight}}"
>
<Label Content="{Binding ElementName=placeHoldTextBox, Path=PlaceHoldText}"
Background="Transparent"
Foreground="#88000000"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
HorizontalContentAlignment="Left"
VerticalContentAlignment="Center"
ClipToBounds="True"
Padding="0,0,0,0"
FontSize="14"
FontStyle="Normal"
Opacity="1"/>
</Border>
</VisualBrush.Visual>
</VisualBrush>
</TextBox.Resources>
<TextBox.Style>
<Style TargetType="TextBox">
<Style.Triggers>
<Trigger Property="Text" Value="{x:Null}">
<Setter Property="Background" Value="{StaticResource PlaceHoldTextBrush}"/>
</Trigger>
<Trigger Property="Text" Value="">
<Setter Property="Background" Value="{StaticResource PlaceHoldTextBrush}"/>
</Trigger>
</Style.Triggers>
</Style>
</TextBox.Style>
</TextBox>
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace VcpkgGui.View
{
/// <summary>
/// PlaceHoldedTextBox.xaml 的交互逻辑
/// </summary>
public partial class PlaceHoldedTextBox : TextBox
{
public string PlaceHoldText
{
get { return (string)GetValue(PlaceHoldTextProperty); }
set { SetValue(PlaceHoldTextProperty, value); }
}
// Using a DependencyProperty as the backing store for PlaceHolderText. This enables animation, styling, binding, etc...
public static readonly DependencyProperty PlaceHoldTextProperty =
DependencyProperty.Register("PlaceHoldText", typeof(string), typeof(PlaceHoldedTextBox), new PropertyMetadata(string.Empty));
public Brush PlaceHoldBackground
{
get { return (Brush)GetValue(PlaceHoldBackgroundProperty); }
set { SetValue(PlaceHoldBackgroundProperty, value); }
}
public static readonly DependencyProperty PlaceHoldBackgroundProperty =
DependencyProperty.Register(nameof(PlaceHoldBackground), typeof(Brush), typeof(PlaceHoldedTextBox), new PropertyMetadata(Brushes.White));
public PlaceHoldedTextBox() :base()
{
InitializeComponent();
}
}
[ValueConversion(typeof(FrameworkElement), typeof(double))]
internal class FrameworkWidthConverter : System.Windows.Data.IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
if(value is FrameworkElement elem)
return double.IsNaN(elem.Width) ? elem.ActualWidth : elem.Width;
else
return DependencyProperty.UnsetValue;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
return DependencyProperty.UnsetValue;
}
}
[ValueConversion(typeof(FrameworkElement), typeof(double))]
internal class FrameworkHeightConverter : System.Windows.Data.IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
if (value is FrameworkElement elem)
return double.IsNaN(elem.Height) ? elem.ActualHeight : elem.Height;
else
return DependencyProperty.UnsetValue;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
return DependencyProperty.UnsetValue;
}
}
}
Very effective solution here for WindowsForms TextBox control. (not sure about XAML).
This will work in Multliline mode also.
Probably it may be extended for other controls, like ComboBox control (not checked)
Works like a charm.
public class WTextBox : TextBox
{
private string _placeholder;
[Category("Appearance")]
public string Placeholder
{
get { return _placeholder; }
set
{
_placeholder = value ?? string.Empty;
Invalidate();
}
}
public WTextBox()
{
_placeholder = string.Empty;
}
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
if (m.Msg != 0xF || Focused || !string.IsNullOrEmpty(Text) || string.IsNullOrWhiteSpace(_placeholder))
{
return;
}
using (var g = CreateGraphics())
{
TextRenderer.DrawText(g, _placeholder, Font, ClientRectangle, SystemColors.GrayText, BackColor, TextFormatFlags.Left);
}
}
}