Enhanced SimpleGridLayout

SimpleGridLayout.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls;

namespace Wpf {
    /*
     * This code is made available with no warranty. It comes as-is, but discuss changes if you like.
     * I consider this in the public domain.
     *
     * Stolen from Sam Naseri @ http://samondotnet.blogspot.com/2012/03/wpf-grid-layout-simplified-using-rows.html
     * 
     * [from the article]
     * This code adds these attached properties to Grid
     * 
     * Grid.Rows 
     * Grid.Columns 
     * 
     * and adds these attached properties to UIElemnet
     * 
     * 
     * Cell 
     * 
     * Grid.Rows and Grid.Columns are same thing but one is for specifying rows and one is for columns.
     * These two properties are simply text value which you can set it according to the following Rules:
     * 
     * Separate items with semi colon(;) , Example "auto;auto;*" 
     * Use auto for adding an Auto sized row or column , Example "auto;auto" 
     * Specify * for adding an star sized row or column, Example "1*;2*; *" 
     * Specify only a number for adding a fixed size row or column, Example "200;200;100" 
     * Append # followed by a number to add multiple rows and columns of same sizing. "1*#4;auto" 
     * The number of starts in an item will multiplies star factor. Example "**;***;*" instead of "2*;3*;*" 
     * 
     * XAML Sample:
     * 
     * 
     * <Grid s:Grid.Rows="auto;1*;auto;auto" s:Grid.Columns="*#5;auto"> ... </Grid>
     * 
     * [added by Jeff Walker]
     * 
     * <Grid s:SimpleGridLayout.Columns="[_SharedSizeGroup1],[_SharedSizeGroup2],*"
     *    s:SimpleGridLayout.SharedSizeGroupPrefix="Prefix">...</Grid>
     * 
     * This will produce a grid with three colums, the first is like:
     *  <ColumnDefinition Width="Auto" SharedSizeGroup="Prefix_SharedGroup1"/>
     *  <ColumnDefinition Width="Auto" SharedSizeGroup="Prefix_SharedGroup2"/>
     *  <ColumnDefinition Width="*" />
     *  
     * The only senseble width setting for a SharedSizeGroup column is Auto, so that is forced on you.
     * (Also, * doesn't work with a SharedSizeGroup)
     * 
     */
    public static class SimpleGridLayout {
        internal struct GridDefinitionInformation {
            public GridLength GridLength;
            public string SharedSizeGroup;
        }

        #region helper methods

        internal static IEnumerable<GridDefinitionInformation> Parse(string text) {
            if (text.Contains("#")) {
                var parts = text.Split(new[] { '#' }, StringSplitOptions.RemoveEmptyEntries);
                var count = int.Parse(parts[1].Trim());
                return Enumerable.Repeat(ParseGridDefinition(parts[0]), count);
            } else {
                return new[] { ParseGridDefinition(text) };
            }
        }

        internal static GridLength ParseGridLength(string text) {
            text = text.Trim();
            if (text.ToLower() == "auto")
                return GridLength.Auto;
            if (text.Contains("*")) {
                var startCount = text.ToCharArray().Count(c => c == '*');
                var pureNumber = text.Replace("*", "");
                var ratio = string.IsNullOrWhiteSpace(pureNumber) ? 1 : double.Parse(pureNumber);
                return new GridLength(startCount * ratio, GridUnitType.Star);
            }
            var pixelsCount = double.Parse(text);
            return new GridLength(pixelsCount, GridUnitType.Pixel);
        }

        internal static GridDefinitionInformation ParseGridDefinition(string text) {
            text = text.Trim();
            var result = new GridDefinitionInformation();
            if ( text.StartsWith("[") && text.EndsWith("]")) {
                result.SharedSizeGroup = text.Substring(1, text.Length - 2); // inside the []s
                result.GridLength = GridLength.Auto;
            } else {
                result.GridLength = ParseGridLength(text);
            }

            return result;
        }

        static string CalculateSharedSize(string sharedSizeGroup, string sharedSizeGroupPrefix) {
            if (sharedSizeGroup != null && sharedSizeGroupPrefix != null) {
                return sharedSizeGroupPrefix + sharedSizeGroup;
            }
            return sharedSizeGroup;
        }

        #endregion

        #region GridColumnsLayout

        public static string GetColumns(DependencyObject obj) {
            return (string)obj.GetValue(ColumnsProperty);
        }
        public static void SetColumns(DependencyObject obj, string value) {
            obj.SetValue(ColumnsProperty, value);
        }

        public static readonly DependencyProperty ColumnsProperty =
            DependencyProperty.RegisterAttached("Columns", typeof(string), typeof(SimpleGridLayout),
            new FrameworkPropertyMetadata("", FrameworkPropertyMetadataOptions.AffectsArrange | FrameworkPropertyMetadataOptions.AffectsMeasure, Columns_PropertyChangedCallback));

        static void Columns_PropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e) {
            var grid = d as Grid;
            var oldValue = e.OldValue as string;
            var newValue = e.NewValue as string;
            if (grid == null || oldValue == null || newValue == null)
                return;

            var prefix = GetSharedSizeGroupPrefix(grid);

            if (oldValue != newValue) {
                grid.ColumnDefinitions.Clear();
                newValue
                    .Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries)
                    .SelectMany(Parse)
                    .Select(gridDefInfo => new ColumnDefinition {
                                                                    Width = gridDefInfo.GridLength,
                                                                    SharedSizeGroup = CalculateSharedSize(gridDefInfo.SharedSizeGroup, prefix)
                                                                })
                    .ToList().ForEach(grid.ColumnDefinitions.Add);
            }
        }

        #endregion

        #region Rows

        public static string GetRows(DependencyObject obj) {
            return (string)obj.GetValue(RowsProperty);
        }
        public static void SetRows(DependencyObject obj, string value) {
            obj.SetValue(RowsProperty, value);
        }

        public static readonly DependencyProperty RowsProperty =
            DependencyProperty.RegisterAttached("Rows", typeof(string), typeof(SimpleGridLayout),
            new FrameworkPropertyMetadata("", FrameworkPropertyMetadataOptions.AffectsArrange | FrameworkPropertyMetadataOptions.AffectsMeasure, Rows_PropertyChangedCallback));

        static void Rows_PropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e) {
            var grid = d as Grid;
            var oldValue = e.OldValue as string;
            var newValue = e.NewValue as string;
            if (grid == null || oldValue == null || newValue == null)
                return;

            var prefix = GetSharedSizeGroupPrefix(grid);
            
            if (oldValue != newValue) {
                grid.RowDefinitions.Clear();
                newValue
                    .Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries)
                    .SelectMany(Parse)
                    .Select(gridDefInfo => new RowDefinition {
                                                                 Height = gridDefInfo.GridLength,
                                                                 SharedSizeGroup = CalculateSharedSize(gridDefInfo.SharedSizeGroup, prefix)
                                                             })
                    .ToList().ForEach(grid.RowDefinitions.Add);
            }
        }

        #endregion

        #region Cell

        public static string GetCell(DependencyObject obj) {
            return (string)obj.GetValue(CellProperty);
        }
        public static void SetCell(DependencyObject obj, string value) {
            obj.SetValue(CellProperty, value);
        }

        public static readonly DependencyProperty CellProperty =
            DependencyProperty.RegisterAttached("Cell", typeof(string), typeof(SimpleGridLayout),
            new FrameworkPropertyMetadata("", FrameworkPropertyMetadataOptions.AffectsArrange | FrameworkPropertyMetadataOptions.AffectsMeasure, Cell_PropertyChangedCallback));

        static void Cell_PropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e) {
            var element = d as UIElement;
            var oldValue = e.OldValue as string;
            var newValue = e.NewValue as string;
            if (element == null || oldValue == null || newValue == null)
                return;

            if (oldValue != newValue) {
                var rowAndColumn = newValue.Split(new[] { ' ', ';' });
                // only set row and/or column if they are specified
                // "1" or "1;" for only row, ";1" for column only
                if ( !string.IsNullOrEmpty(rowAndColumn[0])) {
                    var row = int.Parse(rowAndColumn[0]);
                    Grid.SetRow(element, row);
                }

                if (!string.IsNullOrEmpty(rowAndColumn[1])) {
                    var column = int.Parse(rowAndColumn[1]);
                    Grid.SetColumn(element, column);
                }
            }
        }
        #endregion

        #region SharedSizeGroupPrefix

        public static string GetSharedSizeGroupPrefix(DependencyObject obj) {
            return (string)obj.GetValue(SharedSizeGroupPrefixProperty);
        }

        public static void SetSharedSizeGroupPrefix(DependencyObject obj, string value) {
            obj.SetValue(SharedSizeGroupPrefixProperty, value);
        }

        public static readonly DependencyProperty SharedSizeGroupPrefixProperty =
            DependencyProperty.RegisterAttached("SharedSizeGroupPrefix", typeof(string), typeof(SimpleGridLayout), new FrameworkPropertyMetadata("", FrameworkPropertyMetadataOptions.AffectsArrange | FrameworkPropertyMetadataOptions.AffectsMeasure));

        #endregion
    }

}