我最近做了。
您可以在以下位置查看我的代码：CodeProject
或者直接使用这个类如图：
用法：
<TextBox MinWidth="120" wrapPanelWithFill:WrapPanelFill.UseToFill="True">*</TextBox>
代码：
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Windows;
using System.Windows.Controls;
namespace WrapPanelWithFill
{
public class WrapPanelFill : WrapPanel
{
// ******************************************************************
public static readonly DependencyProperty UseToFillProperty = DependencyProperty.RegisterAttached("UseToFill", typeof(Boolean),
typeof(WrapPanelFill), new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.AffectsRender));
// ******************************************************************
public static void SetUseToFill(UIElement element, Boolean value)
{
element.SetValue(UseToFillProperty, value);
}
// ******************************************************************
public static Boolean GetUseToFill(UIElement element)
{
return (Boolean)element.GetValue(UseToFillProperty);
}
// ******************************************************************
const double DBL_EPSILON = 2.2204460492503131e-016; /* smallest such that 1.0+DBL_EPSILON != 1.0 */
// ******************************************************************
private static bool DoubleAreClose(double value1, double value2)
{
//in case they are Infinities (then epsilon check does not work)
if (value1 == value2) return true;
// This computes (|value1-value2| / (|value1| + |value2| + 10.0)) < DBL_EPSILON
double eps = (Math.Abs(value1) + Math.Abs(value2) + 10.0) * DBL_EPSILON;
double delta = value1 - value2;
return (-eps < delta) && (eps > delta);
}
// ******************************************************************
private static bool DoubleGreaterThan(double value1, double value2)
{
return (value1 > value2) && !DoubleAreClose(value1, value2);
}
// ******************************************************************
private bool _atLeastOneElementCanHasItsWidthExpanded = false;
// ******************************************************************
/// <summary>
/// <see cref="FrameworkElement.MeasureOverride"/>
/// </summary>
protected override Size MeasureOverride(Size constraint)
{
UVSize curLineSize = new UVSize(Orientation);
UVSize panelSize = new UVSize(Orientation);
UVSize uvConstraint = new UVSize(Orientation, constraint.Width, constraint.Height);
double itemWidth = ItemWidth;
double itemHeight = ItemHeight;
bool itemWidthSet = !Double.IsNaN(itemWidth);
bool itemHeightSet = !Double.IsNaN(itemHeight);
Size childConstraint = new Size(
(itemWidthSet ? itemWidth : constraint.Width),
(itemHeightSet ? itemHeight : constraint.Height));
UIElementCollection children = InternalChildren;
// EO
LineInfo currentLineInfo = new LineInfo(); // EO, the way it works it is always like we are on the current line
_lineInfos.Clear();
_atLeastOneElementCanHasItsWidthExpanded = false;
for (int i = 0, count = children.Count; i < count; i++)
{
UIElement child = children[i] as UIElement;
if (child == null) continue;
//Flow passes its own constrint to children
child.Measure(childConstraint);
//this is the size of the child in UV space
UVSize sz = new UVSize(
Orientation,
(itemWidthSet ? itemWidth : child.DesiredSize.Width),
(itemHeightSet ? itemHeight : child.DesiredSize.Height));
if (DoubleGreaterThan(curLineSize.U + sz.U, uvConstraint.U)) //need to switch to another line
{
// EO
currentLineInfo.Size = curLineSize;
_lineInfos.Add(currentLineInfo);
panelSize.U = Math.Max(curLineSize.U, panelSize.U);
panelSize.V += curLineSize.V;
curLineSize = sz;
// EO
currentLineInfo = new LineInfo();
var feChild = child as FrameworkElement;
if (GetUseToFill(feChild))
{
currentLineInfo.ElementsWithNoWidthSet.Add(feChild);
_atLeastOneElementCanHasItsWidthExpanded = true;
}
if (DoubleGreaterThan(sz.U, uvConstraint.U)) //the element is wider then the constrint - give it a separate line
{
currentLineInfo = new LineInfo();
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);
// EO
var feChild = child as FrameworkElement;
if (GetUseToFill(feChild))
{
currentLineInfo.ElementsWithNoWidthSet.Add(feChild);
_atLeastOneElementCanHasItsWidthExpanded = true;
}
}
}
if (curLineSize.U > 0)
{
currentLineInfo.Size = curLineSize;
_lineInfos.Add(currentLineInfo);
}
//the last line size, if any should be added
panelSize.U = Math.Max(curLineSize.U, panelSize.U);
panelSize.V += curLineSize.V;
// EO
if (_atLeastOneElementCanHasItsWidthExpanded)
{
return new Size(constraint.Width, panelSize.Height);
}
//go from UV space to W/H space
return new Size(panelSize.Width, panelSize.Height);
}
// ************************************************************************
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 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; }
}
}
// ************************************************************************
private class LineInfo
{
public List<UIElement> ElementsWithNoWidthSet = new List<UIElement>();
// public double SpaceLeft = 0;
// public double WidthCorrectionPerElement = 0;
public UVSize Size;
public double Correction = 0;
}
private List<LineInfo> _lineInfos = new List<LineInfo>();
// ************************************************************************
/// <summary>
/// <see cref="FrameworkElement.ArrangeOverride"/>
/// </summary>
protected override Size ArrangeOverride(Size finalSize)
{
int lineIndex = 0;
int firstInLine = 0;
double itemWidth = ItemWidth;
double itemHeight = ItemHeight;
double accumulatedV = 0;
double itemU = (Orientation == Orientation.Horizontal ? itemWidth : itemHeight);
UVSize curLineSize = new UVSize(Orientation);
UVSize uvFinalSize = new UVSize(Orientation, finalSize.Width, finalSize.Height);
bool itemWidthSet = !Double.IsNaN(itemWidth);
bool itemHeightSet = !Double.IsNaN(itemHeight);
bool useItemU = (Orientation == Orientation.Horizontal ? itemWidthSet : itemHeightSet);
UIElementCollection children = InternalChildren;
for (int i = 0, count = children.Count; i < count; i++)
{
UIElement child = children[i] as UIElement;
if (child == null) continue;
UVSize sz = new UVSize(
Orientation,
(itemWidthSet ? itemWidth : child.DesiredSize.Width),
(itemHeightSet ? itemHeight : child.DesiredSize.Height));
if (DoubleGreaterThan(curLineSize.U + sz.U, uvFinalSize.U)) //need to switch to another line
{
arrangeLine(lineIndex, accumulatedV, curLineSize.V, firstInLine, i, useItemU, itemU, uvFinalSize);
lineIndex++;
accumulatedV += curLineSize.V;
curLineSize = sz;
if (DoubleGreaterThan(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
arrangeLine(lineIndex, accumulatedV, sz.V, i, ++i, useItemU, itemU, uvFinalSize);
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)
{
arrangeLine(lineIndex, accumulatedV, curLineSize.V, firstInLine, children.Count, useItemU, itemU, uvFinalSize);
}
return finalSize;
}
// ************************************************************************
private void arrangeLine(int lineIndex, double v, double lineV, int start, int end, bool useItemU, double itemU, UVSize uvFinalSize)
{
double u = 0;
bool isHorizontal = (Orientation == Orientation.Horizontal);
Debug.Assert(lineIndex < _lineInfos.Count);
LineInfo lineInfo = _lineInfos[lineIndex];
double lineSpaceAvailableForCorrection = Math.Max(uvFinalSize.U - lineInfo.Size.U, 0);
double perControlCorrection = 0;
if (lineSpaceAvailableForCorrection > 0 && lineInfo.Size.U > 0)
{
perControlCorrection = lineSpaceAvailableForCorrection / lineInfo.ElementsWithNoWidthSet.Count;
if (double.IsInfinity(perControlCorrection))
{
perControlCorrection = 0;
}
}
int indexOfControlToAdjustSizeToFill = 0;
UIElement uIElementToAdjustNext = indexOfControlToAdjustSizeToFill < lineInfo.ElementsWithNoWidthSet.Count ? lineInfo.ElementsWithNoWidthSet[indexOfControlToAdjustSizeToFill] : null;
UIElementCollection children = InternalChildren;
for (int i = start; i < end; i++)
{
UIElement child = children[i] as UIElement;
if (child != null)
{
UVSize childSize = new UVSize(Orientation, child.DesiredSize.Width, child.DesiredSize.Height);
double layoutSlotU = (useItemU ? itemU : childSize.U);
if (perControlCorrection > 0 && child == uIElementToAdjustNext)
{
layoutSlotU += perControlCorrection;
indexOfControlToAdjustSizeToFill++;
uIElementToAdjustNext = indexOfControlToAdjustSizeToFill < lineInfo.ElementsWithNoWidthSet.Count ? lineInfo.ElementsWithNoWidthSet[indexOfControlToAdjustSizeToFill] : null;
}
child.Arrange(new Rect(
(isHorizontal ? u : v),
(isHorizontal ? v : u),
(isHorizontal ? layoutSlotU : lineV),
(isHorizontal ? lineV : layoutSlotU)));
u += layoutSlotU;
}
}
}
// ************************************************************************
}
}