Window.Resources中的WPF DataTemplate绑定参数 [英] WPF DataTemplate binding parameter in Window.Resources

问题描述

我正在创建一个数据网格，列标题中有过滤器。它有效，但我认为这不是一个好办法。让我看看你的代码，非常简单的例子：

视图

 < Window x：Class =TestDataGridApp.Views.MainWindow
 xmlns =http://schemas.microsoft.com/winfx/2006/xaml/presentation
 xmlns：x =http://schemas.microsoft.com/winfx/2006/xaml
 xmlns：d =http://schemas.microsoft.com/expression/blend/2008
 xmlns：mc =http://schemas.openxmlformats.org/markup-compatibility/2006
 xmlns：viewModels =clr-namespace：TestDataGridApp.ViewModels
 mc：Ignorable =d 
 Title =MainWindowHeight =300Width =300> 
< Window.DataContext> 
< viewModels：MainWindowViewModel /> 
< /Window.DataContext> 
< Window.Resources> 
< DataTemplate x：Key =DataGridHeader> 
& DockPanel> 
< TextBlock DockPanel.Dock =TopTextAlignment =LeftText ={Binding Content，RelativeSource = {RelativeSource Mode = TemplatedParent}}/> 
< TextBox DockPanel.Dock =TopText ={Binding DataContext.FilterName，RelativeSource = {RelativeSource AncestorType = Window}，UpdateSourceTrigger = LostFocus}/> 
< / DockPanel> 
< / DataTemplate> 
< /Window.Resources> 
< Grid> 
< DataGrid ItemsSource ={Binding ItemCollection}AutoGenerateColumns =False> 
< DataGrid.ColumnHeaderStyle> 
< Style TargetType ={x：Type DataGridColumnHeader}> 
< Setter Property =Horizo​​ntalContentAlignmentValue =Stretch/> 
< / Style> 
< /DataGrid.ColumnHeaderStyle> 
 
< DataGrid.Columns> 
< DataGridTextColumn Header =IdBinding ={Binding Path = Id}Width =60MinWidth =60MaxWidth =60HeaderTemplate ={StaticResource DataGridHeader}/> 
< DataGridTextColumn Header =NameBinding ={Binding Path = Name}Width =60MinWidth =60MaxWidth =60HeaderTemplate ={StaticResource DataGridHeader}/> 
< /DataGrid.Columns> 
< / DataGrid> 
< / Grid> 
< / Window> 
  

ViewModel

 命名空间TestDataGridApp.ViewModels 
 {
 using System; 
使用System.Collections.ObjectModel; 
使用System.ComponentModel; 
使用System.Windows.Data; 
使用TestDataGridApp.Entities; 
使用Prism.Mvvm; 
 public class MainWindowViewModel：BindableBase 
 {
 private string _filterId; 
 private string _filterName; 
 private ObservableCollection< Item> _items = new ObservableCollection< Item>（）; 
 
 public MainWindowViewModel（）
 {
 for（int i = 1; i< = 100; ++ i）
 {
 Items.Add （new Item（）{Id = i，Name = $Item {i}}）; 
} 
} 
 public string FilterId 
 {
 get {return _filterId; } 
 set 
 {
 SetProperty（ref _filterId，value）; 
 TriggerFilters（）; 
} 
} 
 public string FilterName 
 {
 get {return _filterName; } 
 set 
 {
 SetProperty（ref _filterName，value）; 
 TriggerFilters（）; 
} 
} 
 public ObservableCollection< Item>项目
 {
 get {return _items; } 
 set {SetProperty（ref _items，value）; } 
} 
 public ICollectionView ItemCollection => CollectionViewSource.GetDefaultView（Items）; 
 
 private void TriggerFilters（）
 {
 ItemCollection.Filter = o => FilterItem（（Item）o）; 
} 
 private bool FilterItem（Item item）
 {
 try 
 {
 bool checkId = false; 
 bool checkName = false; 
 
 int itemId = 0; 
 if（！string.IsNullOrEmpty（FilterId）&& int.TryParse（FilterId，out itemId））checkId = true; 
 if（！string.IsNullOrEmpty（FilterName））checkName = true; 
 
 if（！checkId&&！checkName）返回true; 
 if（item == null）return false; 
 
 bool checkIdIsOk =（checkId&& item.Id == int.Parse（FilterId）||！checkId）; 
 bool checkNameIsOk =（checkName&& item.Name.ToUpper（）。包含（FilterName.ToUpper（））||！checkName）; 
 if（checkIdIsOk&& checkNameIsOk）返回true; 
} 
 catch（异常e）
 {
 Console.WriteLine（e）; 
} 
返回false; 
} 
} 
} 
  

/ strong>

  public class Item 
 {
 public int Id {get;组; } 
 public string Name {get;组; } 
} 
  

基本上简单的datagrid，2列。在每列中有一个带有绑定过滤器的 TextBox 。每个过滤器都有自己的字段，所以在焦点丢失后，我可以通过所有过滤器过滤网格。

我的问题是..我有很多列。这是定制的datagrid，因此您可以随时添加和删除列，并且有很多重复的代码。基本上这是重复的：

 < DataGridTextColumn.HeaderTemplate> 
< DataTemplate> 
& DockPanel> 
< TextBlock DockPanel.Dock =TopTextAlignment =LeftText ={Binding Content，RelativeSource = {RelativeSource Mode = TemplatedParent}}/> 
< TextBox DockPanel.Dock =Top
 Text ={Binding DataContext.FilterId，RelativeSource = {RelativeSource AncestorType = Window}，UpdateSourceTrigger = LostFocus}/> 
< / DockPanel> 
< / DataTemplate> 
< /DataGridTextColumn.HeaderTemplate> 
  

只有这个< TextBox DockPanel.Dock =Top Text ={Binding DataContext.FilterId，... 正在改变不同的列。

所以，我想，我可以很容易地替换它使用这个解决方案，但现在..我失去了对ViewModel中的过滤器字段的绑定：

 < Window.Resources> 
< DataTemplate x：Key =DataGridHeader> 
< DockPanel> 
< TextBlock DockPanel.Dock =TopTextAlignment =LeftText ={Binding Content，RelativeSource = {RelativeSource Mode = TemplatedParent}}/> 
< TextBox DockPanel.Dock =TopText ={Binding DataContext.FilterName，RelativeSource = {RelativeSource AncestorType = Window}，UpdateSourceTrigger = LostFocus}/ > 
< / DockPanel> 
< / DataTemplate> 
< /Window.Resources> 
< Grid> 
< DataGrid ItemsSource =绑定ItemCollection}AutoGenerateColumns =False> 
 < DataGrid.ColumnHeaderStyle> 
< Style TargetType ={x：Type DataGridColumnHeader}> 
< Setter Property =Horizo​​ntalContentAlignmentValue =Stretch/> 
< / Style> 
< /DataGrid.ColumnHeaderStyle> 
< DataGrid.Columns> 
< DataGridTextColumn Header =IdBinding ={Binding Path = Id}Width =60MinWidth =60MaxWidth =60HeaderTemplate ={StaticResource DataGridHeader}/> 
< DataGridTextColumn Header =NameBinding ={Binding Path = Name}Width =60MinWidth =60MaxWidth =60HeaderTemplate ={StaticResource DataGridHeader}/> 
< /DataGrid.Columns> 
< / DataGrid> 
< / Grid> 
  

SOO ..我在想，要创建一个字典用于过滤器，其中key将是列的名称，而在值中，我将存储当前过滤器（如果该列目前没有过滤器，则为null）。一些东西像..

 < TextBox x：Name =FooDockPanel.Dock =TopText ={Binding DataContext.FiltersDictionary [Foo]，RelativeSource = {RelativeSource AncestorType = Window}，UpdateSourceTrigger = LostFocus}/> 
  

但是我必须为一个TextBox Biding上下文..我真的不知道这个解决方案。

我的问题是，如何在上述方案中为DataTemplate创建一个参数？感谢您的帮助！

这不是重复的。这个问题是关于如何为DataTemplate创建一个参数。 重复的问题是关于字典作为一个绑定 - 这个问题的潜在解决方案..虽然可能不是。另一位用户建议，解决这个问题可能会有完全不同的更好的解决方案。两个不同的东西我很震惊，我必须解释这个

解决方案

最简单的方法是不要仅依靠xaml并添加一些代码来帮助。例如使用加载的 TextBox 事件，如下所示：

 < DataTemplate x：Key =DataGridHeader> 
& DockPanel> 
< TextBlock DockPanel.Dock =TopTextAlignment =LeftText ={Binding Content，RelativeSource = {RelativeSource Mode = TemplatedParent}}/> 
< TextBox DockPanel.Dock =TopLoaded =OnFilterBoxLoaded/> 
< / DockPanel> 
< / DataTemplate> 
  

加载时设置绑定：

  private void OnFilterBoxLoaded（object sender，RoutedEventArgs e）{
 var tb =（TextBox）sender; 
 //查找列
 DataGridColumnHeader parent = null; 
 DependencyObject current = tb; 
 do {
 current = VisualTreeHelper.GetParent（current）; 
 parent =当前为DataGridColumnHeader; 
} 
 while（parent == null）; 
 //设置绑定
 var binding = new Binding（）; 
 //使用父列标题作为过滤器属性的名称
 binding.Path = new PropertyPath（DataContext.Filter+ parent.Column.Header）; 
 binding.Source = this; 
 binding.UpdateSourceTrigger = UpdateSourceTrigger.LostFocus; 
 tb.SetBinding（TextBox.TextProperty，binding）; 
} 
  

您可以使用附加属性来实现相同的，但我不认为在这种情况下需要。

I'm creating a datagrid, with filters in the column headers. It works, but I don't think it's a good approach. Let me show you the code, very simple example:

The View

<Window x:Class="TestDataGridApp.Views.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:viewModels="clr-namespace:TestDataGridApp.ViewModels"
        mc:Ignorable="d"
        Title="MainWindow" Height="300" Width="300">
    <Window.DataContext>
        <viewModels:MainWindowViewModel />
    </Window.DataContext>
    <Window.Resources>
        <DataTemplate x:Key="DataGridHeader">
            <DockPanel>
                <TextBlock DockPanel.Dock="Top" TextAlignment="Left" Text="{Binding Content, RelativeSource={RelativeSource Mode=TemplatedParent}}" />
                <TextBox DockPanel.Dock="Top" Text="{Binding DataContext.FilterName, RelativeSource={RelativeSource AncestorType=Window}, UpdateSourceTrigger=LostFocus}"/>
            </DockPanel>
        </DataTemplate>
    </Window.Resources>
    <Grid>
        <DataGrid ItemsSource="{Binding ItemCollection}" AutoGenerateColumns="False">
            <DataGrid.ColumnHeaderStyle>
                <Style TargetType="{x:Type DataGridColumnHeader}">
                    <Setter Property="HorizontalContentAlignment" Value="Stretch" />
                </Style>
            </DataGrid.ColumnHeaderStyle>

            <DataGrid.Columns>
                <DataGridTextColumn Header="Id" Binding="{Binding Path=Id}" Width="60" MinWidth="60" MaxWidth="60" HeaderTemplate="{StaticResource DataGridHeader}"/>
                <DataGridTextColumn Header="Name" Binding="{Binding Path=Name}" Width="60" MinWidth="60" MaxWidth="60" HeaderTemplate="{StaticResource DataGridHeader}"/>
            </DataGrid.Columns>
        </DataGrid>
    </Grid>
</Window>

ViewModel

namespace TestDataGridApp.ViewModels
{
    using System;
    using System.Collections.ObjectModel;
    using System.ComponentModel;
    using System.Windows.Data;
    using TestDataGridApp.Entities;
    using Prism.Mvvm;
    public class MainWindowViewModel : BindableBase
    {
        private string _filterId;
        private string _filterName;
        private ObservableCollection<Item> _items = new ObservableCollection<Item>();

        public MainWindowViewModel()
        {
            for (int i = 1; i <= 100; ++i)
            {
                Items.Add(new Item() {Id = i, Name = $"Item{i}"});
            }
        }
        public string FilterId
        {
            get { return _filterId; }
            set
            {
                SetProperty(ref _filterId, value);
                TriggerFilters();
            }
        }
        public string FilterName
        {
            get { return _filterName; }
            set
            {
                SetProperty(ref _filterName, value);
                TriggerFilters();
            }
        }
        public ObservableCollection<Item> Items
        {
            get { return _items; }
            set { SetProperty(ref _items, value); }
        }
        public ICollectionView ItemCollection => CollectionViewSource.GetDefaultView(Items);

        private void TriggerFilters()
        {
            ItemCollection.Filter = o => FilterItem((Item)o);
        }
        private bool FilterItem(Item item)
        {
            try
            {
                bool checkId = false;
                bool checkName = false;

                int itemId = 0;
                if (!string.IsNullOrEmpty(FilterId) && int.TryParse(FilterId, out itemId)) checkId = true;
                if (!string.IsNullOrEmpty(FilterName)) checkName = true;

                if (!checkId && !checkName) return true;
                if (item == null) return false;

                bool checkIdIsOk = (checkId && item.Id == int.Parse(FilterId) || !checkId);
                bool checkNameIsOk = (checkName && item.Name.ToUpper().Contains(FilterName.ToUpper()) || !checkName);
                if (checkIdIsOk && checkNameIsOk) return true;
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }
            return false;
        }
    }
}

The Item

public class Item
{
    public int Id { get; set; }
    public string Name { get; set; }
}

Basically simple datagrid, 2 columns. In each column there is a TextBox with binded filter. Each filter has its own field, so after the focus is lost, I can filter the grid by all filters.

My issue is.. I have a lot of columns. This is customized datagrid, so you can add and remove columns on the fly and there's a lot of duplicated code. Basically this is duplicated:

                <DataGridTextColumn.HeaderTemplate>
                    <DataTemplate>
                        <DockPanel>
                            <TextBlock DockPanel.Dock="Top" TextAlignment="Left" Text="{Binding Content, RelativeSource={RelativeSource Mode=TemplatedParent}}" />
                            <TextBox DockPanel.Dock="Top"
                                     Text="{Binding DataContext.FilterId, RelativeSource={RelativeSource AncestorType=Window}, UpdateSourceTrigger=LostFocus}"/>
                        </DockPanel>
                    </DataTemplate>
                </DataGridTextColumn.HeaderTemplate>

... only this <TextBox DockPanel.Dock="Top" Text="{Binding DataContext.FilterId, ... is changing for different columns.

So, I thought, I can easily replace it with this solution, but now.. I lost binding to my filter fields in the ViewModel:

<Window.Resources>
    <DataTemplate x:Key="DataGridHeader">
        <DockPanel>
            <TextBlock DockPanel.Dock="Top" TextAlignment="Left" Text="{Binding Content, RelativeSource={RelativeSource Mode=TemplatedParent}}" />
            <TextBox DockPanel.Dock="Top" Text="{Binding DataContext.FilterName, RelativeSource={RelativeSource AncestorType=Window}, UpdateSourceTrigger=LostFocus}"/>
        </DockPanel>
    </DataTemplate>
</Window.Resources>
<Grid>
    <DataGrid ItemsSource="{Binding ItemCollection}" AutoGenerateColumns="False">
        <DataGrid.ColumnHeaderStyle>
            <Style TargetType="{x:Type DataGridColumnHeader}">
                <Setter Property="HorizontalContentAlignment" Value="Stretch" />
            </Style>
        </DataGrid.ColumnHeaderStyle>
        <DataGrid.Columns>
            <DataGridTextColumn Header="Id" Binding="{Binding Path=Id}" Width="60" MinWidth="60" MaxWidth="60" HeaderTemplate="{StaticResource DataGridHeader}"/>
            <DataGridTextColumn Header="Name" Binding="{Binding Path=Name}" Width="60" MinWidth="60" MaxWidth="60" HeaderTemplate="{StaticResource DataGridHeader}"/>
        </DataGrid.Columns>
    </DataGrid>
</Grid>

SOO.. I was thinking, to create a Dictionary for filters, where key would be the name of the column and in value I will store current filter (or null, if there's no filter at the moment for this column). Something like..

<TextBox x:Name="Foo" DockPanel.Dock="Top" Text="{Binding DataContext.FiltersDictionary[Foo], RelativeSource={RelativeSource AncestorType=Window}, UpdateSourceTrigger=LostFocus}"/>

But then I have to Biding contexts.. for one TextBox. I'm really not sure about this solution..

My question will be, how to create a parameter for DataTemplate in the above scenario?

Thanks for help!

PS. It's not a duplicate. This question is about "how to create a parameter for DataTemplate". The "duplicated" question is about dictionary as a binding - a potential solution for this question.. although probably NOT. As another user suggested there might be totally different, better solution to solve this problem. Two different things. I'm shocked that I have to explain this

解决方案

Easiest way is to not rely only on xaml and add some code to help. For example use Loaded event of your TextBox like this:

<DataTemplate x:Key="DataGridHeader">
    <DockPanel>
        <TextBlock DockPanel.Dock="Top" TextAlignment="Left" Text="{Binding Content, RelativeSource={RelativeSource Mode=TemplatedParent}}" />
        <TextBox DockPanel.Dock="Top" Loaded="OnFilterBoxLoaded" />
    </DockPanel>
</DataTemplate>

And setup binding when it is loaded:

private void OnFilterBoxLoaded(object sender, RoutedEventArgs e) {
    var tb = (TextBox)sender;
    // find column
    DataGridColumnHeader parent = null;
    DependencyObject current = tb;
    do {
        current = VisualTreeHelper.GetParent(current);
        parent = current as DataGridColumnHeader;
    }
    while (parent == null);
    // setup binding
    var binding = new Binding();
    // use parent column header as name of the filter property
    binding.Path = new PropertyPath("DataContext.Filter" + parent.Column.Header);
    binding.Source = this;
    binding.UpdateSourceTrigger = UpdateSourceTrigger.LostFocus;
    tb.SetBinding(TextBox.TextProperty, binding);
}

You can use attached property to achieve the same, but I don't think it's needed in this case.

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