相关疑难解决方法(0)

看看下表:

Item          Value
A                10
b                50
c                90

我想找到这个项目maximum value.我可以通过使用group by或得到它orderding,但不知何故,我有一种感觉,应该有一个更直接的方式.我对吗？

我有一个DataGrid(称为TheGrid),我想在其上实现复制和粘贴功能.复制功能很好但我不知道如何实现粘贴.我只需要从剪贴板中获取数据并自己解析吗？

命令绑定:

<Window.CommandBindings>
    <CommandBinding Command="Copy" Executed="CommandBinding_Executed" CanExecute="CommandBinding_CanExecute" />
    <CommandBinding Command="Paste" Executed="CommandBinding_Executed" CanExecute="CommandBinding_CanExecute" />
</Window.CommandBindings>

菜单项:

<MenuItem Header="{x:Static culture:TextResource.CopyMenuItem}" Command="Copy"/>
<MenuItem Header="{x:Static culture:TextResource.PasteMenuItem}" Command="Paste"/>

CommandBinding_Executed背后的代码:

private void CommandBinding_Executed(object sender, ExecutedRoutedEventArgs e)
{
    if(e.Command.Equals(ApplicationCommands.Copy))
    {
        // This works great, wow that was easy!
        ApplicationCommands.Copy.Execute(null, TheGrid);
    }
    else if (e.Command.Equals(ApplicationCommands.Paste))
    {
        //What do I do here? Is there an easy way to paste like there was for copy?
        // Or do I need to grab data using Clipboard.GetData and parse it myself?
    } …

我需要为WPF应用程序中的网格之间的数据实现数据(非文本或CSV)的自定义复制+剪切+粘贴.使用标准ApplicationCommands并定义CommandBinding非常有效,但前提是DataGrid包含至少1行数据以及何时选择.当没有行或焦点不在任何行上时,所有命令都被禁用.

为了解决这个问题,我尝试在DataGrid上调用CommandManager.InvalidateRequerySuggested()并设置Focusable = true和/或FocusManager.IsFocusScope = true,但似乎内部DataGrid作为一个整体在处理复制/粘贴操作时"不感兴趣",只有它的行正在重新查询命令CanExecute状态并相应地调用Execute.它也忽略了KeyBindings.

如何让DataGrid处理重新查询ApplicationCommands？

请找到我在下面测试问题的示例:

<Window x:Class="WpfApplication1.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">
    <DataGrid x:Name="TheGrid">
        <DataGrid.Columns>
            <DataGridTextColumn Header="Number" Binding="{Binding}"/>
        </DataGrid.Columns>
        <DataGrid.InputBindings>
            <KeyBinding Key="A" Command="{x:Static ApplicationCommands.New}"/>
        </DataGrid.InputBindings>
        <DataGrid.CommandBindings>
            <CommandBinding Command="{x:Static ApplicationCommands.Paste}" CanExecute="CanPaste" Executed="Paste"/>
            <CommandBinding Command="{x:Static ApplicationCommands.Copy}" CanExecute="CanCopy" Executed="Copy"/>
            <CommandBinding Command="{x:Static ApplicationCommands.New}" CanExecute="CanAddNew" Executed="AddNew"/>
        </DataGrid.CommandBindings>
        <DataGrid.ContextMenu>
            <ContextMenu>
                <MenuItem Command="{x:Static ApplicationCommands.Copy}" Header="Copy"/>
                <MenuItem Command="{x:Static ApplicationCommands.Paste}" Header="Paste"/>
                <MenuItem Command="{x:Static ApplicationCommands.New}" Header="New row"/>
            </ContextMenu>
        </DataGrid.ContextMenu>
    </DataGrid>
</Window>

而背后的代码:

using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Input;

namespace WpfApplication1
{
    public partial class MainWindow …