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FrameworkElement.Height Property

Gets or sets the suggested height of the element. This is a dependency property.

Namespace: System.Windows
Assembly: PresentationFramework (in presentationframework.dll)
XML Namespace:  http://schemas.microsoft.com/winfx/2006/xaml/presentation

[LocalizabilityAttribute(LocalizationCategory.None, Readability=Readability.Unreadable)] 
[TypeConverterAttribute(typeof(LengthConverter))] 
public double Height { get; set; }
/** @property */
public final double get_Height ()

/** @property */
public final void set_Height (double value)

public final function get Height () : double

public final function set Height (value : double)

<object Height="double"/>
- or -
<object Height="qualifiedDouble"/>
- or -
<object Height="Auto"/>
 double   Double  String representation of a Double value equal to or greater than 0.0. See Remarks for upper bound information. This value is interpreted as a device-independent unit (1/96th inch) measurement. Strings need not explicitly include decimal points. For instance a value of 1 is acceptable.   qualifiedDouble  A double value as described above, followed by one of the following unit declaration strings: px, in, cm, pt.  px (default) is device-independent units (1/96th inch per unit)  in is inches; 1in==96px  cm is centimeters; 1cm==(96/2.54) px  pt is points; 1pt==(96/72) px  Auto  Enables autosizing behavior. See Remarks. 

Property Value

The height of the element, in device-independent units (1/96th inch per unit). The default value is Double.NaN. This value must be equal to or greater than 0.0. See Remarks for upper bound information.

Identifier field

HeightProperty

Metadata properties set to true

AffectsMeasure

Height is one of three writable properties on FrameworkElement that specify height information. The other two are MinHeight and MaxHeight. If there is a conflict between these values, the order of application for actual height determination is that first MinHeight must be honored, then MaxHeight, and finally, if it is within bounds, Height.

If this element is a child element within some other element, then setting this property to a value is really only a suggested value. The layout system as well as the particular layout logic of the parent element will use the value as a nonbinding input during the layout process. In practical terms, a FrameworkElement is almost always the child element of something else; even when you set the Height on Window. (For Window, that value is used when the underlying application model establishes the basic rendering assumptions that create the Hwnd that hosts the application.)

In addition to acceptable Double values, this property can also be Double.NaN. This is how you specify auto sizing behavior in code. In XAML you set the value to the string "Auto" (case insensitive) to enable the auto sizing behavior. Auto sizing behavior implies that the element will fill the height available to it. Note however that specific controls frequently supply default values through their default theme styles that will disable the auto sizing behavior unless it is specifically re-enabled.

The return value of this property is always the same as any value that was set to it. In contrast, the value of the ActualHeight may vary. This can happen either statically because the layout rejected the suggested size for some reason, or momentarily. The layout system itself works asynchronously relative to the property system's set of Height and may not have processed that particular sizing property change yet.

The value restrictions on the Double value are enforced by a ValidateValueCallback mechanism. If you attempt to set an invalid value, a runtime exception is raised.

In addition to the validation check, there is a nondeterministic upper value bound for Height that is enforced by the layout system (this is a very large number, larger than Single.MaxValue but smaller than Double.MaxValue). If you exceed this bound, the element will not render, and no exception is raised. Do not set Height to a value that is significantly larger than the maximum size of any possible visual display, or you may exceed this nondeterministic upper bound.

This example visually shows the differences in rendering behavior among the four height-related properties in Windows Presentation Foundation (WPF).

The FrameworkElement class exposes four properties that describe the height characteristics of an element. These four properties can conflict, and when they do, the value that takes precedence is determined as follows: the MinHeight value takes precedence over the MaxHeight value, which in turn takes precedence over the Height value. The fourth property, ActualHeight, is read-only.

The following Extensible Application Markup Language (XAML) examples draw a Rectangle element (rect1) as a child of Canvas. You can change the height properties of a Rectangle by using a series of ListBoxes that represent the property values of MinHeight, MaxHeight, and Height. In this manner, the precedence of each property is visually displayed.

<Canvas Height="200" MinWidth="200" Background="#b0c4de" VerticalAlignment="Top"  HorizontalAlignment="Center" Name="myCanvas" Margin="0,0,0,50">
    <Rectangle HorizontalAlignment="Center" Canvas.Top="50" Canvas.Left="50"  Name="rect1" Fill="#4682b4" Height="100" Width="100"/>
</Canvas>

...

  <TextBlock Grid.Row="1" Grid.Column="0" Margin="10,0,0,0" TextWrapping="Wrap">Set the Rectangle Height:</TextBlock>
  <ListBox Grid.Column="1" Grid.Row="1" Margin="10,0,0,0" Height="50" Width="50" SelectionChanged="changeHeight">
    <ListBoxItem>25</ListBoxItem>
    <ListBoxItem>50</ListBoxItem>
    <ListBoxItem>75</ListBoxItem>
    <ListBoxItem>100</ListBoxItem>
    <ListBoxItem>125</ListBoxItem>
    <ListBoxItem>150</ListBoxItem>
    <ListBoxItem>175</ListBoxItem>
    <ListBoxItem>200</ListBoxItem>
  </ListBox>

  <TextBlock Grid.Row="1" Grid.Column="2" Margin="10,0,0,0" TextWrapping="Wrap">Set the Rectangle MinHeight:</TextBlock>
  <ListBox Grid.Column="3" Grid.Row="1" Margin="10,0,0,0" Height="50" Width="50" SelectionChanged="changeMinHeight">
    <ListBoxItem>25</ListBoxItem>
    <ListBoxItem>50</ListBoxItem>
    <ListBoxItem>75</ListBoxItem>
    <ListBoxItem>100</ListBoxItem>
    <ListBoxItem>125</ListBoxItem>
    <ListBoxItem>150</ListBoxItem>
    <ListBoxItem>175</ListBoxItem>
    <ListBoxItem>200</ListBoxItem>
</ListBox>      
   
  <TextBlock Grid.Row="1" Grid.Column="4" Margin="10,0,0,0" TextWrapping="Wrap">Set the Rectangle MaxHeight:</TextBlock>
  <ListBox Grid.Column="5" Grid.Row="1" Margin="10,0,0,0" Height="50" Width="50" SelectionChanged="changeMaxHeight">
    <ListBoxItem>25</ListBoxItem>
    <ListBoxItem>50</ListBoxItem>
    <ListBoxItem>75</ListBoxItem>
    <ListBoxItem>100</ListBoxItem>
    <ListBoxItem>125</ListBoxItem>
    <ListBoxItem>150</ListBoxItem>
    <ListBoxItem>175</ListBoxItem>
    <ListBoxItem>200</ListBoxItem> 
  </ListBox>

The following code-behind examples handle the events that the SelectionChanged event raises. Each custom method takes the input from the ListBox, parses the value as a Double, and applies the value to the specified height-related property. The height values are also converted to a string and written to a TextBlock element named txt1.

public void changeHeight(object sender, SelectionChangedEventArgs args)
{
    ListBoxItem li = ((sender as ListBox).SelectedItem as ListBoxItem);
    Double sz1 = Double.Parse(li.Content.ToString());
    rect1.Height = sz1;
    rect1.UpdateLayout();
    txt1.Text= "ActualHeight is set to " + rect1.ActualHeight;
    txt2.Text= "Height is set to " + rect1.Height;
    txt3.Text= "MinHeight is set to " + rect1.MinHeight;
    txt4.Text= "MaxHeight is set to " + rect1.MaxHeight;
}
public void changeMinHeight(object sender, SelectionChangedEventArgs args)
{
    ListBoxItem li = ((sender as ListBox).SelectedItem as ListBoxItem);
    Double sz1 = Double.Parse(li.Content.ToString());
    rect1.MinHeight = sz1;
    rect1.UpdateLayout();
    txt1.Text= "ActualHeight is set to " + rect1.ActualHeight;
    txt2.Text= "Height is set to " + rect1.Height;
    txt3.Text= "MinHeight is set to " + rect1.MinHeight;
    txt4.Text= "MaxHeight is set to " + rect1.MaxHeight;
}
public void changeMaxHeight(object sender, SelectionChangedEventArgs args)
{
    ListBoxItem li = ((sender as ListBox).SelectedItem as ListBoxItem);
    Double sz1 = Double.Parse(li.Content.ToString());
    rect1.MaxHeight = sz1;
    rect1.UpdateLayout();
    txt1.Text= "ActualHeight is set to " + rect1.ActualHeight;
    txt2.Text= "Height is set to " + rect1.Height;
    txt3.Text= "MinHeight is set to " + rect1.MinHeight;
    txt4.Text= "MaxHeight is set to " + rect1.MaxHeight;
}

For the complete sample, see Height Properties Sample.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0
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