Posts Tagged ‘WPF’

WPF: Focus DatePicker on Text in TextBox

February 20th, 2011

I’ve been using the DatePicker control (which can be found in WPF 4.0 as well as the WPF Toolkit) and have come across a situation where I would like to set keyboard focus on a DatePicker programmatically so that the user can immediately begin typing a date into the control. Well like many other people out there I attempted to do this by calling the controls Focus() method and when that didn’t have the desired results I tried Keyboard.Focus() and passed it the DatePicker. This also didn’t accomplish what I was looking for.

In the above cases the DatePicker would indeed gain focus, however you could not immediately begin typing in a date. If you pressed a navigational key on the keyboard such as Tab or any of the directional arrows it would then put the keyboard focus into the TextBox portion of the control and highlight any existing text.

DatePicker without focus on text

Focus, but not on text...



DatePicker with focus on text

Focus on text!


Since this is exactly the end result I was after I set about automating this in code and arrived at the following solution. Basically all I’m doing is simulating the Up Arrow being pressed on the DatePicker control, this causes the control to move focus to the internal TextBox. It’s very hacky but it’s the best thing I could come up with without inheriting from DatePicker which I’d like to avoid. I wrapped the code up in a nice extension method for ease of use, and that’s what you see below.

using System.Windows.Controls;
using System.Windows.Input;
 
namespace CGS
{
    public static class DatePickerExtensions
    {
        public static void FocusOnText(this DatePicker datePicker)
        {
            Keyboard.Focus(datePicker);
 
            var eventArgs = new KeyEventArgs(Keyboard.PrimaryDevice,
                                             Keyboard.PrimaryDevice.ActiveSource,
                                             0,
                                             Key.Up);
            eventArgs.RoutedEvent = DatePicker.KeyDownEvent;
 
            datePicker.RaiseEvent(eventArgs);
        }
    }
}

If anyone knows of a cleaner, more legitimate way to accomplish this please let me know! As always questions and comments are welcome and appreciated.

WPF: Time Control 12 Hour Format

March 15th, 2010
Time Control 12 Hour Format

Time Control 12 Hour Format

I’ve spent a bit of time scouring the internet for a WPF Time Control that supports 12-hour format. There are several examples out there that are in 24-hour format, but I haven’t seen any for 12-hour format, so I wrote one. I began with some code located here and then modified it extensively to work for my situation. I didn’t need to display seconds, however it would be pretty easy to add them.

This control supports a wide range of keyboard input. You can enter the value for Hour, Minute, and Part of Day by either using the up/down arrow keys or by typing in numbers and letters. If you have any questions/suggestions/praise/opinions please feel free to leave a comment!

XAML:

<UserControl x:Class="CGS.TimeControl"
             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:CGS"
             Height="Auto" Width="Auto" x:Name="UserControl">
    <UserControl.Resources>
        <local:MinuteSecondToStringConverter x:Key="minuteSecondConverter" />
    </UserControl.Resources>
 
    <Border BorderBrush="Black" BorderThickness="1" CornerRadius="1">
        <Grid x:Name="LayoutRoot" Width="Auto" Height="Auto" Margin="2" Background="White">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="0.2*"/>
                <ColumnDefinition Width="0.05*"/>
                <ColumnDefinition Width="0.2*"/>
                <ColumnDefinition Width="0.05*"/>
                <ColumnDefinition Width="0.2*"/>
            </Grid.ColumnDefinitions>
 
            <Grid x:Name="hour" Focusable="True" KeyDown="Down" GotFocus="Grid_GotFocus" LostFocus="Grid_LostFocus" MouseDown="Grid_MouseDown">
                <TextBlock TextWrapping="Wrap" Text="{Binding Path=Hours, ElementName=UserControl, Mode=Default}"
                 TextAlignment="Center" VerticalAlignment="Center" FontSize="{Binding ElementName=UserControl, Path=FontSize}"/>
            </Grid>
 
            <Grid  Grid.Column="1">
                <TextBlock  x:Name="sep1" TextWrapping="Wrap" VerticalAlignment="Center" Background="{x:Null}"
                  FontSize="{Binding ElementName=UserControl, Path=FontSize}" Text=":" TextAlignment="Center"/>
            </Grid>
 
            <Grid  Grid.Column="2" x:Name="min" Focusable="True" KeyDown="Down" GotFocus="Grid_GotFocus" LostFocus="Grid_LostFocus" MouseDown="Grid_MouseDown">
                <TextBlock  TextWrapping="Wrap" Text="{Binding Path=Minutes, ElementName=UserControl, Mode=Default, Converter={StaticResource minuteSecondConverter}}"
                  TextAlignment="Center" VerticalAlignment="Center" FontSize="{Binding ElementName=UserControl, Path=FontSize}"/>
            </Grid>
 
            <Grid  Grid.Column="4" Name="half" Focusable="True" KeyDown="Down" GotFocus="Grid_GotFocus" LostFocus="Grid_LostFocus" MouseDown="Grid_MouseDown">                
                <TextBlock TextWrapping="Wrap" Text="{Binding Path=DayHalf, ElementName=UserControl, Mode=Default}"
                 TextAlignment="Center" VerticalAlignment="Center" FontSize="{Binding ElementName=UserControl, Path=FontSize}"/>
            </Grid>
 
        </Grid>
    </Border>
</UserControl>

Code:

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Data;
 
namespace CGS
{
    /// <summary>
    /// Interaction logic for TimeControl.xaml
    /// </summary>
    public partial class TimeControl : UserControl
    {
        const string amText = "am";
        const string pmText = "pm";
 
        static SolidColorBrush brBlue = new SolidColorBrush(Colors.LightBlue);
        static SolidColorBrush brWhite = new SolidColorBrush(Colors.White);
 
        DateTime _lastKeyDown;
 
        public TimeControl()
        {
            InitializeComponent();
 
            _lastKeyDown = DateTime.Now;
        }
 
        public TimeSpan Value
        {
            get { return (TimeSpan)GetValue(ValueProperty); }
            set { SetValue(ValueProperty, value); }
        }
        public static readonly DependencyProperty ValueProperty =
        DependencyProperty.Register("Value", typeof(TimeSpan), typeof(TimeControl),
        new UIPropertyMetadata(DateTime.Now.TimeOfDay, new PropertyChangedCallback(OnValueChanged)));
 
        private static void OnValueChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
        {
            TimeControl control = obj as TimeControl;
 
            TimeSpan newTime = ((TimeSpan)e.NewValue);
 
            int timehours = newTime.Hours;
            int hours = timehours % 12;
            hours = (hours > 0) ? hours : 12;
 
            control._hours = newTime.Hours;
            control.Hours = hours;
            control.Minutes = ((TimeSpan)e.NewValue).Minutes;
            control.DayHalf = ((timehours - 12) >= 0) ? pmText : amText;
 
        }
 
        private int _hours;
        public int Hours
        {
            get { return (int)GetValue(HoursProperty); }
            set { SetValue(HoursProperty, value); }
        }
        public static readonly DependencyProperty HoursProperty =
        DependencyProperty.Register("Hours", typeof(int), typeof(TimeControl),
        new UIPropertyMetadata(0));
 
        public int Minutes
        {
            get { return (int)GetValue(MinutesProperty); }
            set { SetValue(MinutesProperty, value); }
        }
        public static readonly DependencyProperty MinutesProperty =
        DependencyProperty.Register("Minutes", typeof(int), typeof(TimeControl),
        new UIPropertyMetadata(0));
 
 
        public string DayHalf
        {
            get { return (string)GetValue(DayHalfProperty); }
            set { SetValue(DayHalfProperty, value); }
        }
        public static readonly DependencyProperty DayHalfProperty =
        DependencyProperty.Register("DayHalf", typeof(string), typeof(TimeControl),
        new UIPropertyMetadata(amText));
 
        private void Down(object sender, KeyEventArgs args)
        {
            bool updateValue = false;
 
            if (args.Key == Key.Up || args.Key == Key.Down)
            {
                switch (((Grid)sender).Name)
                {
                    case "min":
                        if (args.Key == Key.Up)
                            if (this.Minutes + 1 > 59)
                            {
                                this.Minutes = 0;
                                goto case "hour";
                            }
                            else
                            {
                                this.Minutes++;
                            }
                        if (args.Key == Key.Down)
                            if (this.Minutes - 1 < 0)
                            {
                                this.Minutes = 59;
                                goto case "hour";
                            }
                            else
                            {
                                this.Minutes--;
                            }
                        break;
 
                    case "hour":
                        if (args.Key == Key.Up)
                            this._hours = (_hours + 1 > 23) ? 0 : _hours + 1;
                        if (args.Key == Key.Down)
                            this._hours = (_hours - 1 < 0) ? 23 : _hours - 1;
                        break;
 
                    case "half":
                        this.DayHalf = (this.DayHalf == amText) ? pmText : amText;
 
                        int timeHours = this.Hours;
                        timeHours = (timeHours == 12) ? 0 : timeHours;
                        timeHours += (this.DayHalf == amText) ? 0 : 12;
 
                        _hours = timeHours;
                        break;
                }
 
                updateValue = true;
 
                args.Handled = true;
            }
            else if ((args.Key >= Key.D0 && args.Key <= Key.D9) || (args.Key >= Key.NumPad0 && args.Key <= Key.NumPad9))
            {
                int keyValue = (int)args.Key;
                int number = 0;
 
                number = keyValue - ((args.Key >= Key.D0 && args.Key <= Key.D9) ?
                                        (int)Key.D0 :
                                        (int)Key.NumPad0
                                    );
 
                bool attemptAdd = (DateTime.Now - _lastKeyDown).TotalSeconds < 1.5;
 
                switch (((Grid)sender).Name)
                {
                    case "min":
                        if (attemptAdd)
                        {
                            number += this.Minutes * 10;
 
                            if (number < 0 || number >= 60)
                            {
                                number -= this.Minutes * 10;
                            }
                        }
 
                        this.Minutes = number;
                        break;
 
                    case "hour":
                        if (attemptAdd)
                        {
                            number += this.Hours * 10;
 
                            if (number < 0 || number >= 13)
                            {
                                number -= this.Hours * 10;
                            }
                        }
 
                        number = (number == 12) ? 0 : number;
                        number += (this.DayHalf == amText) ? 0 : 12;
 
                        _hours = number;
                        break;
 
                    default:
                        break;
                }
 
                updateValue = true;
 
                args.Handled = true;
            }
            else if (args.Key == Key.A || args.Key == Key.P)
            {
                if (((Grid)sender).Name == "half")
                {
                    this.DayHalf = (args.Key == Key.A) ? amText : pmText;
 
                    updateValue = true; 
                }
            }
 
            if (updateValue)
            {
                this.Value = new TimeSpan(_hours, this.Minutes, 0);
            }
 
            _lastKeyDown = DateTime.Now;
        }
 
        private void Grid_GotFocus(object sender, RoutedEventArgs e)
        {
            var grd = sender as Grid;
 
            grd.Background = brBlue;
        }
 
        private void Grid_LostFocus(object sender, RoutedEventArgs e)
        {
            var grd = sender as Grid;
 
            grd.Background = brWhite;
        }
 
        private void Grid_MouseDown(object sender, MouseButtonEventArgs e)
        {
            var grd = sender as Grid;
 
            grd.Focus();
        }
    }
 
 
    public class MinuteSecondToStringConverter : IValueConverter
    {
        #region IValueConverter Members
 
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            if (value != null)
            {
                if (value is int)
                {
                    return ((int)value).ToString("00");
                }
            }
 
            return string.Empty;
        }
 
        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            if (value != null)
            {
                if (value is string)
                {
                    int number;
                    if (int.TryParse(value as string, out number))
                    {
                        return number;
                    }
                }
            }
 
            return 0;
        }
 
        #endregion
    }
}

And here’s an example of how to use it:

<cgs:TimeControl x:Name="timeControl" Margin="15,0,0,0" Height="25" Width="70"
                                 xmlns:cgs="clr-namespace:CGS"/>
// Set the time of the control
this.timeControl.Value = DateTime.Now.TimeOfDay;
 
// Get the time from the control
TimeSpan time = this.timeControl.Value;

WPF: Simple Vista Image Viewer

September 25th, 2009

Preview of WPF Image Viewer

Download source code – 72.2 KB
Download sample app – 67.8 KB

What does it do?

This lightweight WPF UserControl will display a single image in a manner similar to the Windows Photo Gallery. It doesn’t manage more than one image in a gallery or slideshow fashion however, but it does:

  • Zoom In/Out both with the mouse and with a slider control
  • Pan the image with the mouse
  • Rotate the image clockwise or counter-clockwise 90 degrees
  • Keep the image fully visible in the display area when not in zoom mode

How can I use it?

You can use this image viewer in any WPF application with little effort since it’s built as a WPF UserControl. By leveraging the WPF Interoperability in WinForms it’s possible to use this in a Windows Forms application as well, see the article here for instructions on accomplishing that.

To get started using the control, download the source project from the above link. You can play around with the sample application to see an example of how to use the image viewer. The sample program simply provides a Window for the control and sets the path for the image to display; the control does all the rest.

To use the control in your own application you simply need to include the necessary source files in your own project or solution (CgsImageViewer.xaml(.cs), PanAndZoom.cs, and the images for the buttons). Once you’ve got them, you’ll begin by inserting the viewer into your XAML, like so:

<Window x:Class="ImageViewer.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:iv="clr-namespace:ImageViewer"
    Title="Image Viewer Sample" Height="418" Width="410">
    <Grid>
        <iv:CgsImageViewer x:Name="cgsImageViewer" />
    </Grid>
</Window>

This is just placing the image viewer in a window and giving it a name. Now to load up an image all that you need to do is provide a path to the image or a BitmapImage object. You can do this in the business code or in the XAML by means of a data binding. Here’s an example of setting the image in the business code:

cgsImageViewer.CurrentImagePath = @"c:\test images\cat-plans-your-doom.jpg";

That’s all you really need to know to use the image viewer. Continue on for some extra info.

Class Members you might want to know about:

  •  CurrentImage – Gets or sets the current BitmapImage used by the viewer.
  •  CurrentImagePath – Gets or sets a string representing the Uri to load an image from.
  •  ZoomLevel – Gets or sets a double representing the percentage to zoom.
  •  ScaleToFit – Resizes the image to fit within the visible bounds.
  •  RotateLeft – Rotates the image 90 degrees to the left and scales it to fit.
  •  RotateRight – Rotates the image 90 degrees to the right and scales it to fit.

(Note: The code for panning and zooming was found here)

A little background and explanation:

I wrote this control in a grand total of about two days, which included testing. It was written for use in a WPF project I’m currently working on where users needed to be able to preview graphic files inside the program. I decided to make something that could be re-used and would provide simple viewing capabilities.

So here you go. If you’ve used it and like it why not leave a comment or trackback. If you find any bugs or have some ideas to improve on it let me know. I’m always looking to make things better!

WPF: CheckBox as GroupBox Header

August 7th, 2009

This is a followup post to the one I wrote on Enabling Controls with a CheckBox. In that post we created some XAML that would enable/disable controls in the GUI based on the IsChecked property of a checkbox.

Here’s an enhancement to that:

Checkbox as header for Groupbox

So what we’re doing is giving the controls on our dialog a nice visual grouping letting the user know that they’re associated. The GroupBox element has long existed to fulfill this need. However, with this little XAML change it also doubles as a sort of access control for the items it contains.

Here’s the XAML:

<GroupBox Padding="5" HorizontalAlignment="Stretch">
    <GroupBox.Header>
        <CheckBox x:Name="chkEnableBackup">Run Backup Sets</CheckBox>
    </GroupBox.Header>
 
    <StackPanel IsEnabled="{Binding ElementName=chkEnableBackup, Path=IsChecked}">
        <StackPanel Orientation="Horizontal">
            <Label Margin="12,0,0,0">Run backup every</Label>
            <ComboBox Width="70" SelectedIndex="0">
                <ComboBoxItem>Minute</ComboBoxItem>
                <ComboBoxItem>Hour</ComboBoxItem>
                <ComboBoxItem>Day</ComboBoxItem>
            </ComboBox>
        </StackPanel>
        <StackPanel Margin="12,10,0,0">
            <Label>Path to Backup:</Label>
            <TextBox Width="200" Margin="5,0,0,0"/>
        </StackPanel>
    </StackPanel>
</GroupBox>

So all we’ve done here is add the CheckBox to the <GroupBox.Header> element of the GroupBox. Pretty slick!

This little technique is complete UI Candy and in my opinion illustrates one of the many powerful features of WPF: the ability to customize the GUI in any way you want, down to any level!

WPF: Creating a Pop Up Button Style

August 7th, 2009

So I’ve been getting pretty fancy with my GUI development, and today I wanted to design a button that would appear as just flat text until you hovered over it with the mouse, at which point it would “pop up” and look like an actual button.

Regular Button'Flat' Button

The following solution only works when run on a system with a Windows Vista/7 theme enabled, such as Aero or Basic. It will not work when run with the Windows Classic theme.

The ‘Flat’ Pop Up Button was achieved by simply setting the background and border to transparent. Here’s the XAML:

<Button Content="Click Me!" Background="Transparent" BorderBrush="Transparent"/>

The next step was to make it so that when the mouse hovers over the button it “pops up” visually and looks like your standard button. At first I tried several methods for accomplishing this using triggers to set the style of the button which were all turning out to be pretty messy since I’m not the best graphical designer.

But silly me, I didn’t realize that in this case I didn’t have to do anything special at all! I could just leave the button as it is in the XAML above and the baked in triggers for the Button would still kick in and change the appearance when the mouse hovered over it.

Here’s what that looks like:

Pop Up Button

It looks pretty cool in spots where you want a nice, Aero style button, but if the user isn’t interacting with it you don’t want all those pixels distracting from the clean whiteness that is your polished application.