用户对列进行排序时排序不起作用答案

【问题标题】：Sorting not working when User sort columns用户对列进行排序时排序不起作用
【发布时间】：2021-02-25 10:23:16
【问题描述】：

出于培训目的，我使用 C# 在 WPF 中创建了一个笔记应用程序。
我放入了一些数据并将其保存在数据表中，该数据表是 WPF 中的数据网格视图。数据由您放入文本框“标题”的标题和放入文本框“消息”的消息组成。现在我想读出我输入的数据。所以，当我选择第一行并按“读取”时，“1”出现在标题文本框中，“a”出现在“消息”文本框中，当我选择时同样适用第 2 行和第 3 行。

现在，我按“标题”对数据网格视图进行排序，然后再次选择第三行，它在 datagridview 中显示为“1”，然后按“读取”。好吧，如您所见，出现了数字“3”而不是“1”...因此，似乎 datagridview 已排序，但保存值的数据表未排序...

我不知道如何解决这个问题，因为寻找解决方案对我没有帮助...我想我只是不太了解 Microsoft Docs...所以我想您可以帮帮我吗？

提前致谢，这里是 cs 和 xaml 代码：

cs代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Data;
using System.ComponentModel;

namespace NoteTaking_App
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
    DataTable table;
    int indexSelected; //Index of selected row
    //indexSelected = dgrid_data.SelectedIndex;
  
    
    private void MB(string text, string title)
    {
        MessageBox.Show(text, title, MessageBoxButton.OK, MessageBoxImage.Information);
    }


    public MainWindow()
    {
        InitializeComponent();
        

    }

    private void form_Main_Loaded(object sender, RoutedEventArgs e)
    {
        table = new DataTable();
        table.Columns.Add("Title", typeof(String));
        table.Columns.Add("Message", typeof(String));
        dgrid_data.ItemsSource = table.DefaultView;
        

        dgrid_data.Columns[1].Visibility = Visibility.Collapsed;                



    }


    private void bttn_new_Click(object sender, RoutedEventArgs e)
    {
        txt_message.Clear();
        txt_title.Clear();
    }

    private void bttn_save_Click(object sender, RoutedEventArgs e)
    {
        if (String.IsNullOrWhiteSpace(txt_title.Text))
        {
            MB("Please put in a Title", "title missing");
        }

        else
        {
            table.Rows.Add(txt_title.Text, txt_message.Text);
            txt_message.Clear();
            txt_title.Clear();
        }
        
    }

    private void bttn_read_Click(object sender, RoutedEventArgs e)
    {
        indexSelected = dgrid_data.SelectedIndex;

        if (indexSelected > -1)
        {
            txt_title.Text = table.Rows[indexSelected].ItemArray[0].ToString();
            txt_message.Text = table.Rows[indexSelected].ItemArray[1].ToString();
        }

        else if (table.Rows.Count ==0) 
        {
            MB("There are no saved rows to read", "Selection missing");
        }

        else
        {
            MB("Please select a row", "Selection missing");
        }


    }


    private void bttn_delete_Click(object sender, RoutedEventArgs e)
    {
        indexSelected = dgrid_data.SelectedIndex;
        
        if (indexSelected > -1)
        {
            this.table.Rows[indexSelected].Delete();
        }

        else if (table.Rows.Count == 0)
        {
            MB("There are no saved rows to delete", "Selection missing");
        }

        else
        {
            MB("Please select a row", "Selection missing");
        }

    }

    

       
    }
}

xaml 代码

<Window x:Class="NoteTaking_App.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:local="clr-namespace:NoteTaking_App"
    mc:Ignorable="d"
    Title="Note Taking" Height="450" Width="800">
<Grid x:Name="form_Main" Loaded="form_Main_Loaded">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="117*"/>
        <ColumnDefinition Width="220*"/>
        <ColumnDefinition Width="63*"/>
    </Grid.ColumnDefinitions>
    <DataGrid x:Name="dgrid_data" Grid.Column="1" HorizontalAlignment="Left" Height="263" Margin="192,36,0,0" VerticalAlignment="Top" Width="372"  RenderTransformOrigin="0.554,0.552" Grid.ColumnSpan="2" HeadersVisibility="Column" HorizontalScrollBarVisibility="Disabled" UseLayoutRounding="True" CanUserReorderColumns="False" ColumnWidth="*" IsReadOnly="True" IsSynchronizedWithCurrentItem="False" >
        <DataGrid.RowHeaderStyle>
            <Style/>
        </DataGrid.RowHeaderStyle>
        <DataGrid.ColumnHeaderStyle>
            <Style/>
        </DataGrid.ColumnHeaderStyle>
    </DataGrid>
    <TextBox x:Name="txt_message" Grid.ColumnSpan="2" HorizontalAlignment="Left" Height="183" Margin="109,116,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="275" RenderTransformOrigin="0.5,0.5" AcceptsReturn="True" AcceptsTab="True">
        <TextBox.RenderTransform>
            <TransformGroup>
                <ScaleTransform/>
                <SkewTransform/>
                <RotateTransform Angle="0"/>
                <TranslateTransform/>
            </TransformGroup>
        </TextBox.RenderTransform>
    </TextBox>
    <Button x:Name="bttn_new" Content="New" HorizontalAlignment="Left" Height="31" Margin="109,352,0,0" VerticalAlignment="Top" Width="102" Click="bttn_new_Click"/>
    <Button x:Name="bttn_save" Content="Save" HorizontalAlignment="Left" Height="31" Margin="48,352,0,0" VerticalAlignment="Top" Width="102" Grid.Column="1" Click="bttn_save_Click"/>
    <Button x:Name="bttn_read" Content="Read" HorizontalAlignment="Left" Height="31" Margin="246,352,0,0" VerticalAlignment="Top" Width="102" Grid.Column="1" Click="bttn_read_Click"/>
    <Button x:Name="bttn_delete" Content="Delete" HorizontalAlignment="Left" Height="31" Margin="402,352,0,0" VerticalAlignment="Top" Width="102" Grid.Column="1" Click="bttn_delete_Click" Grid.ColumnSpan="2"/>
    <Label x:Name="lbl_titel" Content="Title" HorizontalAlignment="Left" Height="48" Margin="12,41,0,0" VerticalAlignment="Top" Width="89" AutomationProperties.Name="Titel"/>
    <Label x:Name="lbl_message" Content="Message" HorizontalAlignment="Left" Height="44" Margin="12,109,0,0" VerticalAlignment="Top" Width="89"/>
    <TextBox x:Name="txt_title" Grid.ColumnSpan="2" HorizontalAlignment="Left" Height="41" Margin="108,35,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="275"/>

</Grid>

答案实现后的最终代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Data;
using System.ComponentModel;

namespace NoteTaking_App
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        DataTable table;       
        

        private void MB(string text, string title)
        {
            MessageBox.Show(text, title, MessageBoxButton.OK, MessageBoxImage.Information);
        }


        public MainWindow()
        {
            InitializeComponent();
            DataRowView dataRowView = (DataRowView)dgrid_data.SelectedItem;

        }

        private void form_Main_Loaded(object sender, RoutedEventArgs e)
        {
            table = new DataTable();
            table.Columns.Add("Title", typeof(String));
            table.Columns.Add("Message", typeof(String));
            dgrid_data.ItemsSource = table.DefaultView;            

            dgrid_data.Columns[1].Visibility = Visibility.Collapsed;          
        }


        private void bttn_new_Click(object sender, RoutedEventArgs e)
        {
            txt_message.Clear();
            txt_title.Clear();
        }

        private void bttn_save_Click(object sender, RoutedEventArgs e)
        {
            if (String.IsNullOrWhiteSpace(txt_title.Text))
            {
                MB("Please put in a Title", "title missing");
            }

            else
            {
                table.Rows.Add(txt_title.Text, txt_message.Text);
                txt_message.Clear();
                txt_title.Clear();
            }
            
        }


        private void bttn_read_Click(object sender, RoutedEventArgs e)
        {         
            DataRowView dataRowView = (DataRowView)dgrid_data.SelectedItem;

            if (dataRowView!=null)
            {
                txt_title.Text = dataRowView[0].ToString();
                txt_message.Text = dataRowView[1].ToString();
            }
            else if (table.Rows.Count == 0)
            {
                MB("There are no saved rows to read", "Selection missing");
            }
            else
            {
                MB("Please select a row", "Selection missing");
            }       
        }


        private void bttn_delete_Click(object sender, RoutedEventArgs e)
        {
            DataRowView dataRowView = (DataRowView)dgrid_data.SelectedItem;

            if (dataRowView!=null)
            {
                dataRowView.Delete();
            }                             
            else if (table.Rows.Count == 0)
            {
                MB("There are no saved rows to delete", "Selection missing");
            }

            else
            {
                MB("Please select a row", "Selection missing");
            }

        }
      
    }
}

【问题讨论】：

您已对收藏进行排序，但尚未更改所选项目
我不明白你在说什么..我不是通过点击不同的行来做到这一点的吗？

标签： c# wpf sorting datatable datagridview

【解决方案1】：

将SelectedItem 转换为DataRowView 并从那里获取列值：

private void bttn_read_Click(object sender, RoutedEventArgs e)
{
    DataRowView drv = dgrid_data.SelectedItem as DataRowView;

    if (drv != null)
    {
        txt_title.Text = drv[0].ToString();
        txt_message.Text = drv[0].ToString();
    }

    else if (table.Rows.Count == 0)
    {
        MB("There are no saved rows to read", "Selection missing");
    }

    else
    {
        MB("Please select a row", "Selection missing");
    }
}

删除时也是如此，即使用DataGrid 的SelectedItem 属性。

【讨论】：

非常感谢，工作就像一个魅力！我还有 3 件事情/问题想要解决（因为每条评论都可以更好地概述）
txt_message.Text = drv[0].ToString();需要是 txt_message.Text = drv[1].ToString();我知道你只是忘了改变......
因为我们需要使用 DataRowView drv = dgrid_data.SelectedItem 作为 DataRowView;对于 bttn_delete_Click，是否有更好的方法在 bttn_read_Click 方法之外定义它？我试过了，但它没有奏效，这是我所期望的......但是，也许我做错了什么......
写DataRowView drv = dgrid_data.SelectedItem as DataRowView; 有没有更深层次的目的？而不是 DataRowView drv = (DataRowView)dgrid_data.SelectedItem; ?我的意思是两者都可以，因为我已经尝试过了，但我更喜欢 (DataRowView)dgrid_data.SelectedItem;因为如果出现问题，它会抛出异常错误......

【解决方案2】：

在 UI 中排序不会更改索引。使用 SelectedItem 而不是 SelectedIndex

【讨论】：

对不起，但我的知识有限：从以下代码部分，我如何正确显示标题和消息：txt_title.Text = table.Rows[indexSelected].ItemArray[0].ToString() ; （这是来自 bttn_read_Click 事件）
我的意思是 dgrid_data.SelectedItem
它不是那么简单：SelectedItem 是一个对象而不是一个 int - 这导致了我如何访问我的 datagridview 中的“标题”和“消息”并将它们放在文本框中的问题？跨度>