How can I show a Balloon Tip over a textbox?

I have a C# WPF application using XAML and MVVM. My question is: How can I show a balloon开发者_运维百科 tooltip above a text box for some invalid data entered by the user?

I want to use Microsoft's native balloon control for this. How would I implement this into my application?

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Just add a reference to System.Windows.Forms and C:\Program Files\Reference Assemblies\Microsoft\Framework.NETFramework\v4.0\WindowsFormsIntegration.dll and then:

    WindowsFormsHost host =new WindowsFormsHost();

    var toolTip1 = new System.Windows.Forms.ToolTip();

    toolTip1.AutoPopDelay = 5000;
    toolTip1.InitialDelay = 1000;
    toolTip1.ReshowDelay = 500;
    toolTip1.ShowAlways = true;
    toolTip1.IsBalloon = true;
    toolTip1.ToolTipIcon = System.Windows.Forms.ToolTipIcon.Info;
    toolTip1.ToolTipTitle = "Title:";

    System.Windows.Forms.TextBox tb = new System.Windows.Forms.TextBox();
    tb.Text="Go!";
    toolTip1.SetToolTip(tb, "My Info!");
    host.Child = tb;
    grid1.Children.Add(host);  //a container for windowsForm textBox 

and this is a sample for WinForm ToolTip Ballon in WPF:

Hope this help!

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This BalloonDecorator Project is one that I am using on a current project to show help hints and error notifications. I know you could modify your error template to show this decorator, just like you could show an icon instead of the red borders. The benefit of using a decorator is you can make it look however you'd like, and won't have to depend on WinForms.

BalloonDecorator.cs

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;

namespace MyNamespace
{
public class BalloonDecorator : Decorator
{
    private static double _thickness = 0;
    private static int OpeningGap = 10;

    public static readonly DependencyProperty BackgroundProperty =
        DependencyProperty.Register("Background", typeof (Brush), typeof (BalloonDecorator));

    public static readonly DependencyProperty BorderBrushProperty =
        DependencyProperty.Register("BorderBrush", typeof (Brush), typeof (BalloonDecorator));

    public static readonly DependencyProperty PointerLengthProperty = 
        DependencyProperty.Register("PointerLength", typeof (double), typeof (BalloonDecorator),
        new FrameworkPropertyMetadata(10.0, FrameworkPropertyMetadataOptions.AffectsRender |
        FrameworkPropertyMetadataOptions.AffectsMeasure));

    public static readonly DependencyProperty CornerRadiusProperty = 
        DependencyProperty.Register("CornerRadius", typeof (double), typeof (BalloonDecorator),
        new FrameworkPropertyMetadata(10.0, FrameworkPropertyMetadataOptions.AffectsRender |
        FrameworkPropertyMetadataOptions.AffectsMeasure));

    public Brush Background
    {
        get { return (Brush) GetValue(BackgroundProperty); }
        set { SetValue(BackgroundProperty, value); }
    }

    public Brush BorderBrush
    {
        get { return (Brush) GetValue(BorderBrushProperty); }
        set { SetValue(BorderBrushProperty, value); }
    }

    public double PointerLength
    {
        get { return (double) GetValue(PointerLengthProperty); }
        set { SetValue(PointerLengthProperty, value); }
    }

    public double CornerRadius
    {
        get { return (double) GetValue(CornerRadiusProperty); }
        set { SetValue(CornerRadiusProperty, value); }
    }

    protected override Size ArrangeOverride(Size arrangeSize)
    {
        UIElement child = Child;
        if (child != null)
        {
            double pLength = PointerLength;
            Rect innerRect =
                Rect.Inflate(new Rect(pLength, 0, Math.Max(0, arrangeSize.Width - pLength), arrangeSize.Height),
                             -1 * _thickness, -1 * _thickness);
            child.Arrange(innerRect);
        }

        return arrangeSize;
    }

    protected override Size MeasureOverride(Size constraint)
    {
        UIElement child = Child;
        Size size = new Size();
        if (child != null)
        {
            Size innerSize = new Size(Math.Max(0, constraint.Width - PointerLength), constraint.Height);
            child.Measure(innerSize);
            size.Width += child.DesiredSize.Width;
            size.Height += child.DesiredSize.Height;
        }

        Size borderSize = new Size(2 * _thickness, 2 * _thickness);
        size.Width += borderSize.Width + PointerLength;
        size.Height += borderSize.Height;

        return size;
    }

    protected override void OnRender(DrawingContext dc)
    {
        Rect rect = new Rect(0, 0, RenderSize.Width, RenderSize.Height);

        dc.PushClip(new RectangleGeometry(rect));
        dc.DrawGeometry(Background, new Pen(BorderBrush, _thickness), CreateBalloonGeometry(rect));
        dc.Pop();
    }

    private StreamGeometry CreateBalloonGeometry(Rect rect)
    {
        double radius = Math.Min(CornerRadius, rect.Height / 2);
        double pointerLength = PointerLength;

        // All the points on the path
        Point[] points =
            {
                new Point(pointerLength + radius, 0), new Point(rect.Width - radius, 0), // Top
                new Point(rect.Width, radius), new Point(rect.Width, rect.Height - radius), // Right
                new Point(rect.Width - radius, rect.Height), // Bottom
                new Point(pointerLength + radius, rect.Height), // Bottom
                new Point(pointerLength, rect.Height - radius), // Left
                new Point(pointerLength, radius) // Left
            };

        StreamGeometry geometry = new StreamGeometry();
        geometry.FillRule = FillRule.Nonzero;
        using (StreamGeometryContext ctx = geometry.Open())
        {
            ctx.BeginFigure(points[0], true, true);
            ctx.LineTo(points[1], true, false);
            ctx.ArcTo(points[2], new Size(radius, radius), 0, false, SweepDirection.Clockwise, true, false);
            ctx.LineTo(points[3], true, false);
            ctx.ArcTo(points[4], new Size(radius, radius), 0, false, SweepDirection.Clockwise, true, false);
            ctx.LineTo(points[5], true, false);

            ctx.ArcTo(points[6], new Size(radius, radius), 0, false, SweepDirection.Clockwise, true, false);

            // Pointer
            if (pointerLength > 0)
            {
                ctx.LineTo(rect.BottomLeft, true, false);
                ctx.LineTo(new Point(pointerLength, rect.Height - radius - OpeningGap), true, false);
            }
            ctx.LineTo(points[7], true, false);

            ctx.ArcTo(points[0], new Size(radius, radius), 0, false, SweepDirection.Clockwise, true, false);
        }
        return geometry;
    }
}
}

Just make sure that this class's namespace is loaded into the XAML imports (I use a namespace called "Framework"), and it is simple to use:

    <Framework:BalloonDecorator  Background="#FFFF6600" PointerLength="50"
     CornerRadius="5" Opacity=".9" Margin="200,120,0,0"
     HorizontalAlignment="Left" VerticalAlignment="Top" Visibility="{Binding UnitPriceChangedBalloonVisibility}">
        <Border CornerRadius="2">
            <Border CornerRadius="2">
                <Button Height="Auto" Command="{Binding CloseUnitPriceChangedBalloonCommand}" Background="Transparent" BorderBrush="{x:Null}">
                <TextBlock Text="Please review the price. The Units have changed."
                     HorizontalAlignment="Left"
                     VerticalAlignment="Top"
                     FontStyle="Italic"
                     TextWrapping="Wrap"
                     Margin="10"
                     />
                     </Button>
            </Border>
        </Border>
    </Framework:BalloonDecorator>

Obviously, I tie the visibility to a binding, but you could just set it to true and put this inside your Validation.ErrorTemplate.

Hope this helps!

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I've been searching for a better solution than the BalloonDecorator, and ran across the http://www.hardcodet.net/projects/wpf-notifyicon project. It is using the WinAPI at the lowest level, which might give you a head start on building your own solution. It appears that at first glance it could potentially solve it, but I haven't had enough time to verify that the BalloonTip can be made to behave as you've described.

Good luck on your project!

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Maybe you can host a Windows Forms control in WPF using the WindowsFormsHost type.

There is a walkthrough available on MSDN on how to do this:

Hosting a Windows Forms Composite Control in WPF

Using this technique you could perhaps use the System.Windows.Forms.ToolTip control. If you set this control's IsBalloon property to true it will display as a balloon window.