任意长度

Question

我的数据网格的项目源是一组对象，如：

Public Property Quarter As Integer
Public Property MyColumns() As New List(Of MyColumn)

现在我希望网格绑定的方式与生成的网格类似

- Quarter - Column1 - Column2 - Column3 .... ColumnX

数据源中的所有项目都具有相同的MyColumns。

有没有办法将集合绑定到网格列？

Answer 1

这是解决方案。它不是最漂亮或最简单的，但它是可配置的。它主要基于帖子WPF: Dictionary<int, List<string>> in DataGrid的想法，只是变成了一个带有一些表达和反思的更通用的版本。

用作ItemsSource的项目是否包含相应集合属性中包含的相同或不同数量的项目将起作用。

任意长度

以下是必需的组件：

using System.Reflection;
using Expressions = System.Linq.Expressions;

// See - https://stackoverflow.com/questions/2132791/reflecting-over-all-properties-of-an-interface-including-inherited-ones
public static class ReflectionExtensions
{
    public static PropertyInfo GetInterfaceProperty(this Type type, String propName, Type returnType)
    {
        if (propName == null)
            throw new ArgumentNullException("propName");
        if (returnType == null)
            throw new ArgumentNullException("propType");

        return type.GetInterfaces()
            .Select(parentInterface =>
                parentInterface.GetProperty(propName, returnType))
            .Where(prop =>
                prop != null)
            .Single();
    }
}

public static class CollectionPropertyDataGridBindingHelper
{
    public static void RemoveAutoGeneratedColumns(this DataGrid dataGrid, String propertyName)
    {
        if (dataGrid == null)
            throw new ArgumentNullException("dataGrid");
        if (propertyName == null)
            throw new ArgumentNullException("propertyName");

        var autogeneratedColumns = dataGrid
            .Columns
            .OfType<DataGridBoundColumn>()
            .Where(col =>
                (col.Binding as Binding).Path.Path.Equals(propertyName));

        foreach (var autoColumn in autogeneratedColumns)
        {
            dataGrid.Columns.Remove(autoColumn);
        }
    }


    public static void RegenerateColumns<TItem, TPropertyCollectionItem>(
        this DataGrid dataGrid,
        Expressions.Expression<Func<TItem, IEnumerable<TPropertyCollectionItem>>> propertyExpression, 
        IEnumerable<TItem> items)
    {
        RegenerateColumns<TItem, TPropertyCollectionItem>(dataGrid,
            propertyExpression,
            items,
            (index) =>
                String.Format("Column - {0}", index));
    }


    public static void RegenerateColumns<TItem, TPropertyCollectionItem>(
        this DataGrid dataGrid, 
        Expressions.Expression<Func<TItem, IEnumerable<TPropertyCollectionItem>>> collectionPropertyExpression, 
        IEnumerable<TItem> items, 
        Func<Int32, String> formatHeader)
    {
        if (dataGrid == null)
            throw new ArgumentNullException("dataGrid");
        if (collectionPropertyExpression == null)
            throw new ArgumentNullException("propertyExpression");
        if (items == null)
            throw new ArgumentNullException("items");
        if (formatHeader == null)
            throw new ArgumentNullException("formatHeader");

        var collectionPropInfo = GetCollectionPropertyInfoFor<TItem, TPropertyCollectionItem>(collectionPropertyExpression);
        var propertyName = collectionPropInfo.Name;
        var getCount = GetCountGetter<TItem, TPropertyCollectionItem>(
            collectionPropertyExpression.Compile(),
            collectionPropInfo);

        // Remove old autocolumns
        dataGrid.RemoveAutoGeneratedColumns(propertyName);

        Int32 columnsRequired = items.Select(item => getCount(item)).Max();

        // Create new columns
        GenerateColumns(dataGrid,
            formatHeader,
            propertyName,
            columnsRequired);
    }    

    private static void GenerateColumns(DataGrid dataGrid,
        Func<Int32, String> formatHeader,
        String propertyName,
        Int32 columnsRequired)
    {
        for (int columnNumber = 0; columnNumber < columnsRequired; columnNumber++)
        {
            DataGridTextColumn column = new DataGridTextColumn()
            {
                Header = formatHeader(columnNumber),
                Binding = new Binding(String.Format("{0}[{1}]",
                    propertyName,
                    columnNumber))
            };

            dataGrid.Columns.Add(column);
        }
    }


    private static Func<TItem, Int32> GetCountGetter<TItem, TPropertyCollectionItem>(
        Func<TItem, IEnumerable<TPropertyCollectionItem>> getCollection,
        PropertyInfo propInfo)
    {
        if (getCollection == null)
            throw new ArgumentNullException("getCollection");
        if (propInfo == null)
            throw new ArgumentNullException("propInfo");

        var collectionType = propInfo.PropertyType;

        var countGetter = collectionType.GetInterfaceProperty("Count",
            typeof(Int32));

        if (countGetter != null)
        {
            return (item) =>
                (Int32)countGetter.GetMethod.Invoke(getCollection(item), null);
        }

        throw new NotImplementedException("Not implemented: For simple IEnumerables the use of Enumerable.Count() method shall be considered.");
    }


    private static PropertyInfo GetCollectionPropertyInfoFor<TItem, TPropertyCollectionItem>(
        Expressions.Expression<Func<TItem, 
        IEnumerable<TPropertyCollectionItem>>> propertyExpression)
    {
        if (propertyExpression == null)
            throw new ArgumentNullException("propertyExpression");

        var memberExp = propertyExpression.Body as Expressions.MemberExpression;
        if (memberExp == null)
            throw new ArgumentNullException("propertyExpression");

        var propInfo = memberExp.Member as PropertyInfo;
        if (propInfo == null)
            throw new ArgumentNullException("propertyExpression");

        if (!propInfo.DeclaringType.IsAssignableFrom(typeof(TItem)))
            throw new ArgumentException("propertyExpression");

        return propInfo;
    }
}

这是XAML：

    <DataGrid ItemsSource="{Binding Items}" AutoGenerateColumns="False" Name="dataGrid">
        <DataGrid.Columns>
            <DataGridTextColumn Header="Quarter" Binding="{Binding Quarter}"/>
        </DataGrid.Columns>
    </DataGrid>

这就是代码隐藏：

using Expressions = System.Linq.Expressions

public class Item
{
    public Item(Int32 quarter, Int32 repeatColumns)
    {
        this.Quarter = quarter;
        this.MyColumns = Enumerable
            .Range(1, repeatColumns)
            .ToList();
    }

    public Int32 Quarter
    {
        get; set;
    }

    public IList<Int32> MyColumns
    {
        get; set;
    }
}


/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        this.Items = GetOriginalItems();

        this.DataContext = this;

        this.ReinitializeColumns();
    }

    private void ReinitializeColumns()
    {
        Expressions.Expression<Func<Item, IEnumerable<Int32>>> exp = 
            obj => 
                obj.MyColumns;

        this.dataGrid.RegenerateColumns(exp,
            this.Items);
    }

    public IEnumerable<Item> Items
    {
        get;
        private set;
    }

    public IEnumerable<Item> GetOriginalItems()
    {
        return new Item[] 
        {
            new Item(1, 3),
            new Item(2, 2),
            new Item(3, 5),
            new Item(4, 2),
        };
    }
}

设定长度

这是将创建指定数量的列的代码（您可以将它放到某个独立类中，因为它完全是自包含的，或者是使用任意长度方法的同一个类（在这种情况下只是不要忘记）删除重复生成方法））。它有点简单，直接适合您的需求：

    public static void RegenerateColumns<TItem, TPropertyCollectionItem>(
       this DataGrid dataGrid,
       String propertyName,
       Int32 columnsRequired)
    {
        dataGrid.RegenerateColumns<TItem, TPropertyCollectionItem>(propertyName,
            columnsRequired,
            index => String.Format("Column - {0}",
                index));
    }


    public static void RegenerateColumns<TItem, TPropertyCollectionItem>(
        this DataGrid dataGrid,
        String propertyName,
        Int32 columnsRequired,
        Func<Int32, String> formatHeader)
    {
        if (dataGrid == null)
            throw new ArgumentNullException("dataGrid");
        if (propertyName == null)
            throw new ArgumentNullException("propertyName");
        if (columnsRequired < 0)
            throw new ArgumentOutOfRangeException("columnsRequired");
        if (formatHeader == null)
            throw new ArgumentNullException("formatHeader");

        // Remove old autocolumns
        dataGrid.RemoveAutoGeneratedColumns(propertyName);

        GenerateColumns(dataGrid,
            formatHeader,
            propertyName,
            columnsRequired);
    }


    private static void GenerateColumns(DataGrid dataGrid,
        Func<Int32, String> formatHeader,
        String propertyName,
        Int32 columnsRequired)
    {
        for (int columnNumber = 0; columnNumber < columnsRequired; columnNumber++)
        {
            DataGridTextColumn column = new DataGridTextColumn()
            {
                Header = formatHeader(columnNumber),
                Binding = new Binding(String.Format("{0}[{1}]",
                    propertyName,
                    columnNumber))
            };

            dataGrid.Columns.Add(column);
        }
    }

使用它的是代码隐藏：

    public MainWindow()
    {
        InitializeComponent();

        this.Items = GetOriginalItems();

        this.DataContext = this;

        this.ReinitializeColumns(2);
    }

    private void ReinitializeColumns(Int32 columnsCount)
    {
        this.dataGrid.RegenerateColumns<Item, Int32>("MyColumns",
            columnsCount);
    }

Answer 2

通过Eugene对动态和expandoObject的见解，这就是我为解决当前问题而实施的。

这是我的解决方案 -

我们收集来自模型，其结构相当严格。因此，要将其绑定到UI网格，我们需要另一个以视觉上不同的方式映射当前列表的对象。

- 使用Expando对象 -

您可以创建ExpandoObjects的集合，并将其动态属性映射到集合的属性。

Dim pivotItems As Object = New ExpandoObject()
    ' set properties for object'
     pivotItems.Quarter = developmentQuarters.Key
     pivotItems.Name = developmentQuarters.Key.Name

     ' since expando obj is a dictionary for prop name and its value we can set property names dynamically like this'
     For Each developmentModel As DevelopmentModel In developmentModels
         Dim pivotAsDict As IDictionary(Of String, Object) = pivotItems
         pivotAsDict.Add(developmentModel.BusinessGroupName + " " + developmentModel.Currency.Code, developmentModel.DevelopmentPercentage)
      Next
      ReModelledItems.Add(pivotItems)

所以现在我们将一个嵌套对象展平为一个简单的集合，它具有基于初始集合中的值生成的动态列/属性。

我们现在可以简单地绑定此ExpandoObjects集合

如何为用作DataGrid的ItemsSource的项的集合属性中的每个项生成和绑定列

2 个答案:

任意长度

设定长度