[Silverlight]实现DataGrid使用CheckBox选择行（2）

先写一个XAML，主意在属性中将生成的操作改为“嵌入的资源”

Resources.xaml   <Style x:Key="SelectColumnHeaderStyle"
           TargetType="ContentControl">
        <Setter Property="ContentTemplate">
            <Setter.Value>
                <DataTemplate>
                    <local:MyCheckBox  Content="Select All"
                                       VerticalContentAlignment="Center"
                                       VerticalAlignment="Center" />
                </DataTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <DataTemplate x:Key="SelectColumnCellTemplate">
        <CheckBox IsChecked="{Binding Selected,Mode=TwoWay}"
                  VerticalAlignment="Center"
                  HorizontalAlignment="Center" />
    </DataTemplate

其中的MyCheckBox：

MyCheckBox   public class MyCheckBox : CheckBox
    {
        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();
            DataGrid dataGrid = this.GetParent<DataGrid>();
            if (dataGrid == null)
                return;

            dataGrid.SetSelectCheckBox(this);
        }

为了调用方便，写几个扩展方法

DataGridExtensions internal static DataGridSelectColumn GetSelectColumn(this DataGrid dataGrid)
        {
            DataGridSelectColumn result = null;
            for (int i = 0; i < dataGrid.Columns.Count; i++)
            {
                result = dataGrid.Columns[i] as DataGridSelectColumn;
                if (result != null)
                    break;
            }
            return result;
        }


        internal static void SetSelectCheckBox(this DataGrid dataGrid, CheckBox checkBox)
        {
            DataGridSelectColumn column = GetSelectColumn(dataGrid);
            column.EnableSelect(dataGrid, checkBox);
        }

        public static void SelectAll(this DataGrid dataGrid)
        {
            DataGridSelectColumn column = GetSelectColumn(dataGrid);
            if (column == null)
                throw new Exception("No Select Column");
            column.SelecteAll();
        }

        public static void UnselectAll(this DataGrid dataGrid)
        {
            DataGridSelectColumn column = GetSelectColumn(dataGrid);
            if (column == null)
                throw new Exception("No Select Column");
            column.UnselectAll();
        }

        public static List<T> GetSelectedItems<T>(this DataGrid dataGrid)
        {
            DataGridSelectColumn column = GetSelectColumn(dataGrid);
            if (column == null)
                throw new Exception("No Select Column");
            return column.GetSelectedItems<T>();

最后是SelectColumn

DataGridSelectColumn     public class DataGridSelectColumn : DataGridTemplateColumn
    {
        private const string SelectColumnHeaderStyle = "SelectColumnHeaderStyle";
        private const string SelectColumnCellTemplate = "SelectColumnCellTemplate";
        private const string TemplateXamlPath = "DataGridTestLib.Assets.Resources.xaml";

        private static ResourceDictionary _resourceDictionary;

        private DataGrid _dataGrid;
        private CheckBox _headerCheckBox;
        private Dictionary<object, MarkObject> _markObjects;

        public DataGridSelectColumn()
        {
            HeaderStyle = GetResourceDictionary()[SelectColumnHeaderStyle] as Style;
            CellTemplate = GetResourceDictionary()[SelectColumnCellTemplate] as DataTemplate;
            IsReadOnly = true;
        }

        private ResourceDictionary GetResourceDictionary()
        {
            if (_resourceDictionary == null)
            {
                Stream stream = this.GetType().Assembly.GetManifestResourceStream(TemplateXamlPath);
                using (StreamReader reader = new StreamReader(stream))
                {
                    string resourceXaml = reader.ReadToEnd();
                    _resourceDictionary = XamlReader.Load(resourceXaml) as ResourceDictionary;
                }
            }
            return _resourceDictionary;
        }

        internal void EnableSelect(DataGrid dataGrid, CheckBox checkBox)
        {
            _dataGrid = dataGrid;
            _headerCheckBox = checkBox;

            _markObjects = new Dictionary<object, MarkObject>();
            _headerCheckBox.Checked += (sender, e) => SetAllSelectedStates(true);
            _headerCheckBox.Unchecked += (sender, e) => SetAllSelectedStates(false);
            _dataGrid.LoadingRow += OnLoadingRow;
        }

        private void OnLoadingRow(object sender, DataGridRowEventArgs e)
        {
            object dataContext = e.Row.DataContext;
            FrameworkElement element = this.GetCellContent(e.Row);
            element.DataContext = GetMarkObject(dataContext);
        }

        private void SetAllSelectedStates(bool value)
        {
            if (_dataGrid.ItemsSource == null)
                return;

            var enu = _dataGrid.ItemsSource.GetEnumerator();
            while (enu.MoveNext())
            {
                GetMarkObject(enu.Current).Selected = value;
            }
        }

        private MarkObject GetMarkObject(Object obj)
        {
            if (_markObjects.ContainsKey(obj) == false)
            {
                MarkObject markObject;
                markObject = new MarkObject();
                _markObjects.Add(obj, markObject);
            }

            return _markObjects[obj];
        }


        public void SelecteAll()
        {
            if (_headerCheckBox != null)
                _headerCheckBox.IsChecked = true;
            SetAllSelectedStates(true);
        }

        public void UnselectAll()
        {
            if (_headerCheckBox != null)
                _headerCheckBox.IsChecked = false;
            SetAllSelectedStates(false);
        }

        public List<T> GetSelectedItems<T>()
        {
            List<T> result = new List<T>();
            if (_dataGrid.ItemsSource != null)
            {
                var enu = _dataGrid.ItemsSource.GetEnumerator();
                while (enu.MoveNext())
                {
                    if (GetMarkObject(enu.Current).Selected)
                        result.Add((T)enu.Current);
                }
            }
            return result;
        }

其中GetResourceDictionary方法就是读取XAML的函数。

最终的调用方式如下：