WPF:如何使用可编辑的动态列进行 DataGrid 绑定? [英] WPF: How to make DataGrid binding with dynamic columns editable?

问题描述

我需要将一些数据绑定到列数可变的 DataGrid.我使用以下代码使其工作:

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);
}

DataList 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; }

问题在于，即使我指定了 TwoWay 绑定，它也确实是单向的.当我单击单元格尝试编辑时，出现异常此视图不允许使用‘EditItem’".我是否只是错过了绑定表达式中的某些内容?

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?

附言我发现了一篇来自 Deborah "使用 MVVM 在 Silverlight 应用程序中使用动态列填充 DataGrid".但是，我很难让它适用于我的案例(具体来说，我无法使标头绑定工作).即使它有效，我仍然面临着单元格样式不一致等问题.这就是为什么我想知道我是否可以让我上面的代码工作 - 稍微调整一下?

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?

我发现了另一篇可能与我的问题有关的帖子:隐式双向绑定.看起来是否使用

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}"/>

您将收到类似双向绑定需要 Path 或 XPath"的错误消息.但是这个问题可以很容易地通过使用

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 .}"/>

如果我的问题可以用类似的方式解决，有人可以给我一个提示吗?

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

推荐答案

您是否绑定到索引器?.你能告诉我们你的 DataList 属性是什么样的吗?

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

我不久前对索引属性做了同样的事情.

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
      }
 }

您无法编辑属性的原因是您尝试编辑双字段".一种解决方法是使用 INotifyPropertyChanged 将您的 double 包装到一个类中.

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
}

然后你可以使用一个

ObservableCollection<DataListItem>

并且您可以编辑您的值.索引是否总是相同的问题仍然存在:)

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++));

工作示例:只是为了显示双向工作

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>();
    }
}

双重包装:

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

带有数据网格的用户控件

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>

.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; }
}

我希望你通过这个例子找到了正确的方向.

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

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