DataGrid 列宽不会自动更新 [英] DataGrid column width doesn't auto-update

问题描述

<DataGridTextColumn Binding="{Binding Name}" Width="*"/>
<DataGridTextColumn Binding="{Binding Change}" Width="Auto"/>

当Change 的值更新时，其列不会更新以适应新值.所以列太小，值被剪掉了.
有什么想法吗?

When the value of Change updates, its column doesn't update to fit the new value. So the column stays too small and the value is clipped.
Any ideas?

推荐答案

DataGrid 会随着数据变长而增加列大小以适应，但不会在数据长度减少时自动减小列大小.在您的示例中，您正确对齐更改"列，并将其余空间用于名称"列.

The DataGrid will increase column sizes to fit as the data becomes longer, but it does not automatically decrease column sizes when the length of the data decreases. In your example, you're right aligning the 'Change' column, and using the rest of the space for the 'Name' column.

现在，当Change"属性增长到足以增加列的宽度时，Name"列拒绝缩小以适应，因此您必须自己强制刷新.

Now, when a 'Change' property grows large enough that it should increase the column's width, the 'Name' column is refusing to shrink to accommodate, so you have to force a refresh yourself.

以下步骤应该为您完成(我已经包含了一个示例应用程序来演示):

1) 在您的 DataGridTextColumn 绑定中(除 * 大小的列之外的所有内容)设置 NotifyTargetUpdated=True.
2) 在您的 DataGrid 上，向 TargetUpdated 事件添加一个处理程序.
3) 在您的 TargetUpdated 事件处理程序中:
-- a) 将 DataGrid 的 * 大小列的宽度设置为 0.
-- b) 在 DataGrid 上调用 UpdateLayout() 方法.
-- c) 将 DataGrid 的 * 大小列的宽度设置回 new DataGridLength(1, DataGridLengthUnitType.Star)

1) In your DataGridTextColumn Bindings (all except your * sized column) set NotifyTargetUpdated=True.
2) On your DataGrid, add a handler to the TargetUpdated event.
3) In your TargetUpdated event handler:
-- a) Set the DataGrid's * sized column's width to 0.
-- b) Call the UpdateLayout() method on the DataGrid.
-- c) Set the DataGrid's * sized column's width back to new DataGridLength(1, DataGridLengthUnitType.Star)

示例 XAML:

<Window x:Class="DataGridTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <CollectionViewSource x:Key="MyObjectCollection" />
    </Window.Resources>
    <DockPanel>
        <Button DockPanel.Dock="Bottom" Content="Click to Make Item 1s Text Longer" Click="Button_Click" />
        <Grid>
            <DataGrid x:Name="dg" ItemsSource="{Binding Source={StaticResource MyObjectCollection}}" AutoGenerateColumns="False" TargetUpdated="dg_TargetUpdated">
                <DataGrid.Columns>
                    <DataGridTextColumn Binding="{Binding First}" Width="1*"/>
                    <DataGridTextColumn Binding="{Binding Last, NotifyOnTargetUpdated=True}"  Width="Auto" />
                </DataGrid.Columns>
            </DataGrid>
        </Grid>

    </DockPanel>
</Window>

背后的示例代码:

using System;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.ComponentModel;

namespace DataGridTest
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private ObservableCollection<MyObject> myObjectList = new ObservableCollection<MyObject>();

        public MainWindow()
        {
            InitializeComponent();
            (this.FindResource("MyObjectCollection") as CollectionViewSource).Source = this.myObjectList;
            this.myObjectList.Add(new MyObject() { First = "Bob", Last = "Jones" });
            this.myObjectList.Add(new MyObject() { First = "Jane", Last = "Doe" });
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            this.myObjectList[0].Last = "BillyOBrian";
        }

        private void dg_TargetUpdated(object sender, DataTransferEventArgs e)
        {
            dg.Columns[0].Width = 0;
            dg.UpdateLayout();
            dg.Columns[0].Width = new DataGridLength(1, DataGridLengthUnitType.Star);
        }
    }

    public class MyObject : INotifyPropertyChanged
    {
        private string firstName;
        public string First
        {
            get { return this.firstName; }
            set
            {
                if (this.firstName != value)
                {
                    this.firstName = value;
                    NotifyPropertyChanged("First");
                }
            }
        }

        private string lastName;
        public string Last
        {
            get { return this.lastName; }
            set
            {
                if (this.lastName != value)
                {
                    this.lastName = value;
                    NotifyPropertyChanged("Last");
                }
            }
        }

        public MyObject() { }

        #region -- INotifyPropertyChanged Contract --

        public event PropertyChangedEventHandler PropertyChanged;

        private void NotifyPropertyChanged(String info)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(info));
            }
        }

        #endregion INotifyPropertyChanged Contract
    }
}

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