FrameworkElement.MaxWidth Property
Gets or sets the maximum width constraint of the element.
Namespace: System.Windows
Assembly: PresentationFramework (in PresentationFramework.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation
[LocalizabilityAttribute(LocalizationCategory.None, Readability = Readability.Unreadable)] [TypeConverterAttribute(typeof(LengthConverter))] public double MaxWidth { get; set; }
<object MaxWidth="double"/> - or - <object MaxWidth="qualifiedDouble"/>
XAML Values
Property Value
Type: System.DoubleThe maximum width of the element, in device-independent units (1/96th inch per unit). The default value is PositiveInfinity. This value can be any value equal to or greater than 0.0. PositiveInfinity is also valid.
This is one of three properties on FrameworkElement that specify width information. The other two are MinWidth and Width. If there is a conflict between these values, the order of application for actual width determination is first MinWidth must be honored, then MaxWidth, and finally if each of these are within bounds, Width.
The value restrictions on the Double value are enforced by a ValidateValueCallback mechanism. If you attempt to set an invalid value, a run-time exception is thrown.
This example visually shows the differences in rendering behavior among the four width-related properties in Windows Presentation Foundation (WPF).
The FrameworkElement class exposes four properties that describe the width characteristics of an element. These four properties can conflict, and when they do, the value that takes precedence is determined as follows: the MinWidth value takes precedence over the MaxWidth value, which in turn takes precedence over the Width value. A fourth property, ActualWidth, is read-only, and reports the actual width as determined by interactions with the layout process.
The following Extensible Application Markup Language (XAML) examples draw a Rectangle element (rect1) as a child of Canvas. You can change the width properties of a Rectangle by using a series of ListBox elements that represent the property values of MinWidth, MaxWidth, and Width. In this manner, the precedence of each property is visually displayed.
<Canvas Height="200" MinWidth="200" Background="#b0c4de" VerticalAlignment="Top" HorizontalAlignment="Center" Name="myCanvas"> <Rectangle HorizontalAlignment="Center" Canvas.Top="50" Canvas.Left="50" Name="rect1" Fill="#4682b4" Width="100" Height="100"/> </Canvas> ... <TextBlock Grid.Row="1" Grid.Column="0" Margin="10,0,0,0" TextWrapping="Wrap">Set the Rectangle Width:</TextBlock> <ListBox Grid.Column="1" Grid.Row="1" Margin="10,0,0,0" Width="50" Height="50" SelectionChanged="changeWidth"> <ListBoxItem>25</ListBoxItem> <ListBoxItem>50</ListBoxItem> <ListBoxItem>75</ListBoxItem> <ListBoxItem>100</ListBoxItem> <ListBoxItem>125</ListBoxItem> <ListBoxItem>150</ListBoxItem> <ListBoxItem>175</ListBoxItem> <ListBoxItem>200</ListBoxItem> <ListBoxItem>225</ListBoxItem> <ListBoxItem>250</ListBoxItem> </ListBox> <TextBlock Grid.Row="1" Grid.Column="2" Margin="10,0,0,0" TextWrapping="Wrap">Set the Rectangle MinWidth:</TextBlock> <ListBox Grid.Column="3" Grid.Row="1" Margin="10,0,0,0" Width="50" Height="50" SelectionChanged="changeMinWidth"> <ListBoxItem>25</ListBoxItem> <ListBoxItem>50</ListBoxItem> <ListBoxItem>75</ListBoxItem> <ListBoxItem>100</ListBoxItem> <ListBoxItem>125</ListBoxItem> <ListBoxItem>150</ListBoxItem> <ListBoxItem>175</ListBoxItem> <ListBoxItem>200</ListBoxItem> <ListBoxItem>225</ListBoxItem> <ListBoxItem>250</ListBoxItem> </ListBox> <TextBlock Grid.Row="1" Grid.Column="4" Margin="10,0,0,0" TextWrapping="Wrap">Set the Rectangle MaxWidth:</TextBlock> <ListBox Grid.Column="5" Grid.Row="1" Margin="10,0,0,0" Width="50" Height="50" SelectionChanged="changeMaxWidth"> <ListBoxItem>25</ListBoxItem> <ListBoxItem>50</ListBoxItem> <ListBoxItem>75</ListBoxItem> <ListBoxItem>100</ListBoxItem> <ListBoxItem>125</ListBoxItem> <ListBoxItem>150</ListBoxItem> <ListBoxItem>175</ListBoxItem> <ListBoxItem>200</ListBoxItem> <ListBoxItem>225</ListBoxItem> <ListBoxItem>250</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 width-related property. The width values are also converted to a string and written to various TextBlock elements (definition of those elements is not shown in the selected XAML).
private void changeWidth(object sender, SelectionChangedEventArgs args) { ListBoxItem li = ((sender as ListBox).SelectedItem as ListBoxItem); Double sz1 = Double.Parse(li.Content.ToString()); rect1.Width = sz1; rect1.UpdateLayout(); txt1.Text = "ActualWidth is set to " + rect1.ActualWidth; txt2.Text = "Width is set to " + rect1.Width; txt3.Text = "MinWidth is set to " + rect1.MinWidth; txt4.Text = "MaxWidth is set to " + rect1.MaxWidth; } private void changeMinWidth(object sender, SelectionChangedEventArgs args) { ListBoxItem li = ((sender as ListBox).SelectedItem as ListBoxItem); Double sz1 = Double.Parse(li.Content.ToString()); rect1.MinWidth = sz1; rect1.UpdateLayout(); txt1.Text = "ActualWidth is set to " + rect1.ActualWidth; txt2.Text = "Width is set to " + rect1.Width; txt3.Text = "MinWidth is set to " + rect1.MinWidth; txt4.Text = "MaxWidth is set to " + rect1.MaxWidth; } private void changeMaxWidth(object sender, SelectionChangedEventArgs args) { ListBoxItem li = ((sender as ListBox).SelectedItem as ListBoxItem); Double sz1 = Double.Parse(li.Content.ToString()); rect1.MaxWidth = sz1; rect1.UpdateLayout(); txt1.Text = "ActualWidth is set to " + rect1.ActualWidth; txt2.Text = "Width is set to " + rect1.Width; txt3.Text = "MinWidth is set to " + rect1.MinWidth; txt4.Text = "MaxWidth is set to " + rect1.MaxWidth; }
For the complete sample, see Width Properties Comparison Sample.
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
