I'd like to create an ItemsControl where child items are placed like a WrapPanel, but child Items should take as much space as it can. So that when the window size gets larger or smaller, the child items should stretch according to a certain width:height ratio. When the child items get added or removed from the ItemsControl's ItemsSource, the WrapPanel should place linebreaks among items appropriately to keep child item's width:height ratio.
Below is what I have so far. Is it possible to do this in Xaml? or should I create a custom control for this? Thanks in advance!
<Window>
<Grid>
<ItemsControl ItemsSource="{Binding DataCollection}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel Orientation="Vertical"/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemTemplate>
<DataTemplate>
<Border BorderBrush="Black" BorderThickness="1" HorizontalAlignment="Stretch">
<StackPanel Orientation="Horizontal" >
<TextBlock TextWrapping="Wrap" Text="{Binding Name}" />
<TextBlock TextWrapping="Wrap" Text="{Binding Value}"/>
<TextBlock TextWrapping="Wrap" Text="{Binding Time, StringFormat='hh:mm:ss' }"/>
</StackPanel>
</Border>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</Grid>
</Window>
Use a UniformGrid rather than a WrapPanel. Just set the number of columns you want with the Columns property, and it should give you the desired result.
As another solution (sometimes width might be different, so UniformGrid won’t work), here is modified WrapPanel which would stretch elements to fit lines (while keeping proportion the same):
public class StretchyWrapPanel : Panel {
public static readonly DependencyProperty ItemWidthProperty = DependencyProperty.Register(nameof(ItemWidth),
typeof(double), typeof(StretchyWrapPanel), new FrameworkPropertyMetadata(double.NaN, FrameworkPropertyMetadataOptions.AffectsMeasure));
[TypeConverter(typeof(LengthConverter))]
public double ItemWidth {
get { return (double)GetValue(ItemWidthProperty); }
set { SetValue(ItemWidthProperty, value); }
}
public static readonly DependencyProperty ItemHeightProperty = DependencyProperty.Register(nameof(ItemHeight),
typeof(double), typeof(StretchyWrapPanel), new FrameworkPropertyMetadata(double.NaN, FrameworkPropertyMetadataOptions.AffectsMeasure));
[TypeConverter(typeof(LengthConverter))]
public double ItemHeight {
get { return (double)GetValue(ItemHeightProperty); }
set { SetValue(ItemHeightProperty, value); }
}
public static readonly DependencyProperty OrientationProperty = StackPanel.OrientationProperty.AddOwner(typeof(StretchyWrapPanel),
new FrameworkPropertyMetadata(Orientation.Horizontal, FrameworkPropertyMetadataOptions.AffectsMeasure, OnOrientationChanged));
public Orientation Orientation {
get { return _orientation; }
set { SetValue(OrientationProperty, value); }
}
private static void OnOrientationChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
((StretchyWrapPanel)d)._orientation = (Orientation)e.NewValue;
}
private Orientation _orientation = Orientation.Horizontal;
public static readonly DependencyProperty StretchProportionallyProperty = DependencyProperty.Register(nameof(StretchProportionally), typeof(bool),
typeof(StretchyWrapPanel), new PropertyMetadata(true, OnStretchProportionallyChanged));
public bool StretchProportionally {
get { return _stretchProportionally; }
set { SetValue(StretchProportionallyProperty, value); }
}
private static void OnStretchProportionallyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e) {
((StretchyWrapPanel)o)._stretchProportionally = (bool)e.NewValue;
}
private bool _stretchProportionally = true;
private struct UVSize {
internal UVSize(Orientation orientation, double width, double height) {
U = V = 0d;
_orientation = orientation;
Width = width;
Height = height;
}
internal UVSize(Orientation orientation) {
U = V = 0d;
_orientation = orientation;
}
internal double U;
internal double V;
private readonly Orientation _orientation;
internal double Width {
get { return _orientation == Orientation.Horizontal ? U : V; }
set {
if (_orientation == Orientation.Horizontal) {
U = value;
} else {
V = value;
}
}
}
internal double Height {
get { return _orientation == Orientation.Horizontal ? V : U; }
set {
if (_orientation == Orientation.Horizontal) {
V = value;
} else {
U = value;
}
}
}
}
protected override Size MeasureOverride(Size constraint) {
var curLineSize = new UVSize(Orientation);
var panelSize = new UVSize(Orientation);
var uvConstraint = new UVSize(Orientation, constraint.Width, constraint.Height);
var itemWidth = ItemWidth;
var itemHeight = ItemHeight;
var itemWidthSet = !double.IsNaN(itemWidth);
var itemHeightSet = !double.IsNaN(itemHeight);
var childConstraint = new Size(
itemWidthSet ? itemWidth : constraint.Width,
itemHeightSet ? itemHeight : constraint.Height);
var children = InternalChildren;
for (int i = 0, count = children.Count; i < count; i++) {
var child = children[i];
if (child == null) continue;
// Flow passes its own constrint to children
child.Measure(childConstraint);
// This is the size of the child in UV space
var sz = new UVSize(Orientation,
itemWidthSet ? itemWidth : child.DesiredSize.Width,
itemHeightSet ? itemHeight : child.DesiredSize.Height);
if (curLineSize.U + sz.U > uvConstraint.U) {
// Need to switch to another line
panelSize.U = Math.Max(curLineSize.U, panelSize.U);
panelSize.V += curLineSize.V;
curLineSize = sz;
if (sz.U > uvConstraint.U) {
// The element is wider then the constrint - give it a separate line
panelSize.U = Math.Max(sz.U, panelSize.U);
panelSize.V += sz.V;
curLineSize = new UVSize(Orientation);
}
} else {
// Continue to accumulate a line
curLineSize.U += sz.U;
curLineSize.V = Math.Max(sz.V, curLineSize.V);
}
}
// The last line size, if any should be added
panelSize.U = Math.Max(curLineSize.U, panelSize.U);
panelSize.V += curLineSize.V;
// Go from UV space to W/H space
return new Size(panelSize.Width, panelSize.Height);
}
protected override Size ArrangeOverride(Size finalSize) {
var firstInLine = 0;
var itemWidth = ItemWidth;
var itemHeight = ItemHeight;
double accumulatedV = 0;
var itemU = Orientation == Orientation.Horizontal ? itemWidth : itemHeight;
var curLineSize = new UVSize(Orientation);
var uvFinalSize = new UVSize(Orientation, finalSize.Width, finalSize.Height);
var itemWidthSet = !double.IsNaN(itemWidth);
var itemHeightSet = !double.IsNaN(itemHeight);
var useItemU = Orientation == Orientation.Horizontal ? itemWidthSet : itemHeightSet;
var children = InternalChildren;
for (int i = 0, count = children.Count; i < count; i++) {
var child = children[i];
if (child == null) continue;
var sz = new UVSize(Orientation, itemWidthSet ? itemWidth : child.DesiredSize.Width, itemHeightSet ? itemHeight : child.DesiredSize.Height);
if (curLineSize.U + sz.U > uvFinalSize.U) {
// Need to switch to another line
if (!useItemU && StretchProportionally) {
ArrangeLineProportionally(accumulatedV, curLineSize.V, firstInLine, i, uvFinalSize.Width);
} else {
ArrangeLine(accumulatedV, curLineSize.V, firstInLine, i, true, useItemU ? itemU : uvFinalSize.Width / Math.Max(1, i - firstInLine - 1));
}
accumulatedV += curLineSize.V;
curLineSize = sz;
if (sz.U > uvFinalSize.U) {
// The element is wider then the constraint - give it a separate line
// Switch to next line which only contain one element
if (!useItemU && StretchProportionally) {
ArrangeLineProportionally(accumulatedV, sz.V, i, ++i, uvFinalSize.Width);
} else {
ArrangeLine(accumulatedV, sz.V, i, ++i, true, useItemU ? itemU : uvFinalSize.Width);
}
accumulatedV += sz.V;
curLineSize = new UVSize(Orientation);
}
firstInLine = i;
} else {
// Continue to accumulate a line
curLineSize.U += sz.U;
curLineSize.V = Math.Max(sz.V, curLineSize.V);
}
}
// Arrange the last line, if any
if (firstInLine < children.Count) {
if (!useItemU && StretchProportionally) {
ArrangeLineProportionally(accumulatedV, curLineSize.V, firstInLine, children.Count, uvFinalSize.Width);
} else {
ArrangeLine(accumulatedV, curLineSize.V, firstInLine, children.Count, true,
useItemU ? itemU : uvFinalSize.Width / Math.Max(1, children.Count - firstInLine - 1));
}
}
return finalSize;
}
private void ArrangeLineProportionally(double v, double lineV, int start, int end, double limitU) {
var u = 0d;
var horizontal = Orientation == Orientation.Horizontal;
var children = InternalChildren;
var total = 0d;
for (var i = start; i < end; i++) {
total += horizontal ? children[i].DesiredSize.Width : children[i].DesiredSize.Height;
}
var uMultipler = limitU / total;
for (var i = start; i < end; i++) {
var child = children[i];
if (child != null) {
var childSize = new UVSize(Orientation, child.DesiredSize.Width, child.DesiredSize.Height);
var layoutSlotU = childSize.U * uMultipler;
child.Arrange(new Rect(horizontal ? u : v, horizontal ? v : u,
horizontal ? layoutSlotU : lineV, horizontal ? lineV : layoutSlotU));
u += layoutSlotU;
}
}
}
private void ArrangeLine(double v, double lineV, int start, int end, bool useItemU, double itemU) {
var u = 0d;
var horizontal = Orientation == Orientation.Horizontal;
var children = InternalChildren;
for (var i = start; i < end; i++) {
var child = children[i];
if (child != null) {
var childSize = new UVSize(Orientation, child.DesiredSize.Width, child.DesiredSize.Height);
var layoutSlotU = useItemU ? itemU : childSize.U;
child.Arrange(new Rect(horizontal ? u : v, horizontal ? v : u,
horizontal ? layoutSlotU : lineV, horizontal ? lineV : layoutSlotU));
u += layoutSlotU;
}
}
}
}
In action:
Have you tried the HorizontalContentAlignment="Stretch" property in the itemscontrol.
To achieve the desired behavior you may try to use Width or MaxWidth properties of WrapPanel, for example by this way
<ListView
Name="RootControl"
ItemsSource="{Binding [icons]}"
ItemTemplate="{StaticResource IconTemplate}">
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel
Width="{Binding ElementName=RootControl, Path=ActualWidth}"/>
</ItemsPanelTemplate>
</ListView.ItemsPanel>
</ListView>
It works
来源：https://stackoverflow.com/questions/8004981/how-to-make-wpf-wrappanel-child-items-to-stretch