我有一个DataGrid，每行都有一个删除按钮，挂钩到Delete命令。需要单击两次该按钮才能删除该行，这不是我想要的。
最初根据监听按钮的IsEnabled == false，第一次单击将其启用。这似乎是问题所在，所以如何在用户单击之前使按钮启用？
我尝试使用触发器来更改IsEnabled，在下面的代码中已将其注释掉，但没有用。
Window1.xaml
<Window x:Class="WpfApp1.Window1"
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:local="clr-namespace:WpfApp1"
mc:Ignorable="d"
Title="Window1" Height="450" Width="800">
<Grid>
<DataGrid HorizontalAlignment="Left" Height="399" Margin="10,10,0,0"
VerticalAlignment="Top" Width="772"
x:Name="dataGrid1"
ItemsSource="{Binding ProxyServers}"
CanUserAddRows="True"
CanUserDeleteRows="True"
>
<DataGrid.Columns>
<DataGridTemplateColumn Width="SizeToCells">
<DataGridTemplateColumn.CellStyle>
<Style TargetType="{x:Type DataGridCell}"
BasedOn="{StaticResource {x:Type DataGridCell}}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type DataGridCell}">
<Button Command="DataGrid.DeleteCommand"
IsEnabled="True" x:Name="deleteButton"
Content="X">
<!-- Make the button enable on mouse over?
Didn't work.
<Button.Style>
<Style TargetType="Button">
<Style.Triggers>
<Trigger Property="IsMouseOver"
Value="true">
<Setter Property="IsEnabled"
Value="true" />
</Trigger>
</Style.Triggers>
</Style>
</Button.Style>-->
</Button>
</ControlTemplate>
</Setter.Value>
</Setter>
<Setter Property="IsEnabled" Value="True"/>
</Style>
</DataGridTemplateColumn.CellStyle>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
</Grid>
</Window>
Window1.xaml.cs
using System.ComponentModel;
using System.Windows;
namespace WpfApp1
{
public partial class Window1 : Window
{
BindingList<Proxy> proxyServers;
public Window1()
{
InitializeComponent();
dataGrid1.DataContext = this;
proxyServers = new BindingList<Proxy>();
proxyServers.Add(new Proxy() { LocalURL = "http://localhost" });
}
public BindingList<Proxy> ProxyServers { get => proxyServers; set => proxyServers = value; }
}
public class Proxy
{
string localURL;
public string LocalURL { get => localURL; set => localURL = value; }
}
}
答案 0 :(得分：0)
您是否考虑过类似的内容：
<DataGridTemplateColumn Header="Delete">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Button Command="{Binding Deletecommand}"
如果要在父视图的daracontext中使用命令，则可以使用relativesource。 用commandparameter传递绑定的行对象。
答案 1 :(得分：0)
详细说明@Andy的答案。这就是我要做的。
添加RelayCommand（此实现在Internet上浮动，我相信它来自MVVMLite）：
using System;
using System.Windows.Input;
namespace WpfApp1
{
public class RelayCommand<T> : ICommand
{
#region Fields
readonly Action<T> _execute = null;
readonly Predicate<T> _canExecute = null;
#endregion
#region Constructors
/// <summary>
/// Initializes a new instance of <see cref="DelegateCommand{T}"/>.
/// </summary>
/// <param name="execute">Delegate to execute when Execute is called on the command. This can be null to just hook up a CanExecute delegate.</param>
/// <remarks><seealso cref="CanExecute"/> will always return true.</remarks>
public RelayCommand(Action<T> execute)
: this(execute, null)
{
}
/// <summary>
/// Creates a new command.
/// </summary>
/// <param name="execute">The execution logic.</param>
/// <param name="canExecute">The execution status logic.</param>
public RelayCommand(Action<T> execute, Predicate<T> canExecute)
{
if (execute == null)
throw new ArgumentNullException("execute");
_execute = execute;
_canExecute = canExecute;
}
#endregion
#region ICommand Members
///<summary>
///Defines the method that determines whether the command can execute in its current state.
///</summary>
///<param name="parameter">Data used by the command. If the command does not require data to be passed, this object can be set to null.</param>
///<returns>
///true if this command can be executed; otherwise, false.
///</returns>
public bool CanExecute(object parameter)
{
return _canExecute == null ? true : _canExecute((T)parameter);
}
///<summary>
///Occurs when changes occur that affect whether or not the command should execute.
///</summary>
public event EventHandler CanExecuteChanged
{
add { CommandManager.RequerySuggested += value; }
remove { CommandManager.RequerySuggested -= value; }
}
///<summary>
///Defines the method to be called when the command is invoked.
///</summary>
///<param name="parameter">Data used by the command. If the command does not require data to be passed, this object can be set to <see langword="null" />.</param>
public void Execute(object parameter)
{
_execute((T)parameter);
}
#endregion
}
}
定义我自己的DeleteCommand，而不是使用DataGrid中的内置命令。我是在后台代码中完成此操作的，但在我的实际项目中，它将在视图模型中进行。
private RelayCommand<object> _DeleteCommand;
public RelayCommand<object> DeleteCommand => _DeleteCommand ?? (_DeleteCommand = new RelayCommand<object>((object o) => {
var proxy = o as Proxy;
proxyServers.Remove(proxy);
}, (object o) => {
if (o is Proxy)
{
return true;
}
else
{
return false;
}
}));
我无法使用RelayCommand<Proxy>，因为新项目行不是代理对象。如果没有新的项目行，则可以使用RelayCommand<Proxy>。
在XAML中删除此模板定义（因为它是ControlTemplate而不是DataTemplate，并且如果要传递网格，似乎需要DataTemplate命令中的CommandParameter项）
<DataGridTemplateColumn.CellStyle>
<Style TargetType="{x:Type DataGridCell}" BasedOn="{StaticResource {x:Type DataGridCell}}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate >
<Button Command="{Binding DeleteCommand,RelativeSource={RelativeSource AncestorType={x:Type Window}}}"
CommandParameter="{Binding RelativeSource={RelativeSource AncestorType={x:Type local:Proxy}}}"
IsEnabled="True" x:Name="deleteButton" Content="X">
</Button>
</ControlTemplate>
</Setter.Value>
</Setter>
<Setter Property="IsEnabled" Value="True"/>
</Style>
</DataGridTemplateColumn.CellStyle>
添加此内容
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Button Command="{Binding DeleteCommand,RelativeSource={RelativeSource AncestorType={x:Type Window}}}"
CommandParameter="{Binding}"
IsEnabled="True" x:Name="deleteButton" Content="X">
</Button>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>