WPF：如何使数据网格与动态列可编辑绑定？

问题描述：

我需要一些数据绑定到的列的数目可变的一个DataGrid。我做了它的工作用以下code：

I need to bind some data to a DataGrid with variable number of columns. I made it work using following code:

int n = 0;
foreach (string title in TitleList)
{
    DataGridTextColumn col = new DataGridTextColumn();
    col.Header = title;
    Binding binding = new Binding(string.Format("DataList[{0}]", n++));
    binding.Mode = BindingMode.TwoWay;
    col.Binding = binding;
    grid.Columns.Add(col);
}

在这里DataList的声明为：

where DataList is declared as:

public ObservableCollection<double> DataList { get; set; }

和TitleList声明为：

and TitleList is declared as:

public ObservableCollection<string> TitleList { get; set; }

问题是，即使我指定的双向绑定，实在是单向的。当我点击一个单元格尝试编辑，我得到了一个异常'EditItem'不允许这种观点。难道我只是想念在绑定前pression的东西吗？

The problem is that, even though I specified TwoWay binding, it is really one-way. When I click a cell to try to edit, I got an exception "'EditItem' is not allowed for this view". Did I just miss something in the binding expression?

P.S。我发现从德博拉使用MVVM填充与动态列一个DataGrid的Silverlight应用程序。不过，我有困难时期，使之成为我的情况下工作（具体地讲，我不能让头绑定工作）。即使它的工作，我仍然面临着像不一致的单元格样式的问题。这就是为什么我想知道如果我可以让我的上述code的工作 - 一个小调整？

P.S. I found an article from Deborah "Populating a DataGrid with Dynamic Columns in a Silverlight Application using MVVM". However, I had hard time to make it work for my case (specifically, I can't make the header binding work). Even if it worked, I'm still facing issues like inconsistent cell styles. That's why I'm wondering if I could make my above code work - with a little tweak?

编辑：我发现了另一个帖子里面可能与我的问题：的隐式双向绑定。看起来如果使用绑定到字符串的列表，以一个TextBox

I found another post which might be related to my problem: Implicit Two Way binding. It looks if you bind to a list of string to a TextBox using

<TextBox Text="{Binding}"/>

您会得到像双向绑定需要路径或XPath错误。但问题可以很容易地通过使用固定

You will get an error like "Two-way binding requires Path or XPath". But the problem can easily be fixed by using

<TextBox Text="{Binding Path=DataContext, RelativeSource={RelativeSource Self}}"/>

或

<TextBox Text="{Binding .}"/>

任何人都可以给我一个提示，如果我的问题可以用类似的方式来解决？

Can anybody give me a hint if my problem can be solved in a similar way?

答

你绑定到一个索引？你能告诉我们你的DataList控件属性怎么样子？

Do you bind to an indexer?. can you show us how your DataList Property looks like?

我做了同样的前一段时间有一个索引属性。

i did the same a while ago with an indexed property.

 public SomeObjectWithIndexer DataList
 {get; set;}


 public class SomeObjectWithIndexer 
 {
      public string this
      {
          get { ... }
          set { ... }//<-- you need this one for TwoWay
      }
 }

编辑：你不能编辑属性的原因，是你尝试编辑双田。
一个解决办法将是包装你的双与INotifyPropertyChanged的一类。

the reason that you cant edit your Property, is that you try to edit a "double field". one workaround would be to wrap your double into a class with INotifyPropertyChanged.

public class DataListItem
{
    public double MyValue { get; set;}//with OnPropertyChanged() and stuff
}

那么你可以使用

ObservableCollection<DataListItem>

您可以编辑你的价值。阉指数的问题都是一样的住宿仍然存在：）

and you can edit your value. the question wether the index are always the same stay still around :)

Binding binding = new Binding(string.Format("DataList[{0}].MyValue", n++));

EDIT2：工作示例：只是为了显示双向正在

working example: just to show twoway is working

public class DataItem
{
    public string Name { get; set; }
    public ObservableCollection<DataListItem> DataList { get; set; }

    public DataItem()
    {
        this.DataList = new ObservableCollection<DataListItem>();
    }
}

包装双：

public class DataListItem
{
    private double myValue;
    public double MyValue
    {
        get { return myValue; }
        set { myValue = value; }//<-- set breakpoint here to see that edit is working
    }
}

用户控件与一个DataGrid

usercontrol with a datagrid

<UserControl x:Class="WpfStackoverflow.IndexCollectionDataGrid"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300">
<DataGrid ItemsSource="{Binding MyList}" AutoGenerateColumns="False">
    <DataGrid.Columns>
        <DataGridTextColumn Header="Name" Binding="{Binding Path=Name}" />
        <DataGridTextColumn Header="Index1" Binding="{Binding Path=DataList[0].MyValue, Mode=TwoWay}" />
        <DataGridTextColumn Header="Index2" Binding="{Binding Path=DataList[1].MyValue, Mode=TwoWay}" />
    </DataGrid.Columns>
</DataGrid>
</UserControl>

的.cs

public partial class IndexCollectionDataGrid : UserControl
{
    public IndexCollectionDataGrid()
    {
        InitializeComponent();
        this.MyList = new ObservableCollection<DataItem>();

        var m1 = new DataItem() {Name = "test1"};
        m1.DataList.Add(new DataListItem() { MyValue = 10 });
        m1.DataList.Add(new DataListItem() { MyValue = 20 });

        var m2 = new DataItem() { Name = "test2" };
        m2.DataList.Add(new DataListItem() { MyValue = 100 });
        m2.DataList.Add(new DataListItem() { MyValue = 200 });

        this.MyList.Add(m1);
        this.MyList.Add(m2);

        this.DataContext = this;
    }

    public ObservableCollection<DataItem> MyList { get; set; }
}

我希望你在这个例子中，正确的方向得到。

i hope you get in the right direction with this example.

WPF：如何使数据网格与动态列可编辑绑定？

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