如何为用作DataGrid的ItemsSource的项目的collection属性中的每个项目生成和绑定列

问题描述

我的数据网格的项目来源是一组对象，如：

The items source of my data grid is a collection of objects like:

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

现在我想要一个网格绑定一种我生成的网格看起来像

Now I want to have a grid binding in a way that my resulting grid looks like

数据源中的所有项目将具有相同的MyColumns。

All items in datasource will have same MyColumns.

有没有办法我可以将集合绑定到网格列？

Is there a way by which I can bind a collection to grid columns ?

推荐答案

这是解决方案。它不是最漂亮或最简单，但它是可配置的。它主要基于中，只是变成了一个更广泛的版本，具有一些表达和反思。

Here is the solution. It is not the prettiest or the easiest but it is quite configurable. It is based mostly on the idea from the post WPF: Dictionary<int, List<string>> in DataGrid, just turned into a more generalized version with a bit of Expressions and Reflection.

它将用于 ItemsSource 在相应的集合属性中包含相同或不同数量的项目。

It will work whether items used as ItemsSource have the same or different amount of items contained in the respective collection property.

以下是必需的组件：

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

// See - http://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：

---

Here is the XAML:

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

这是代码隐藏：

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),
        };
    }
}

---

设置长度

这里是将创建指定数量的列的代码（您可以将其放在一些独立的类中，因为它完全独立，或者是同一类具有任意长度的方法（在这种情况下只要不要忘记删除重复的生成方法））。这是一个更简单，直接适合您的需求：

---

Set length

Here is the code that will create the specified amount of columns(you can put it to some standalone class because it is completely self-contained, or to the same class with arbitrary-length methods(in this case just do not forget to remove the duplicate generate methods)). It is a bit simpler and directly suits your needs:

    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);
        }
    }

它是使用它的代码隐藏：

And it is the code-behind that uses it:

    public MainWindow()
    {
        InitializeComponent();

        this.Items = GetOriginalItems();

        this.DataContext = this;

        this.ReinitializeColumns(2);
    }

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

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