当我向下和向上滚动时，正在清除WPF项目中DataGrid的单元格文本 [英] Cells text of DataGrid in a WPF project is being cleared when I scroll down and up

问题描述

我有一个包含DataGrid的WPF项目，我在程序启动时用很多行填充它，然后在每个按钮上单击我设置它的单元格的内容。问题是如果我在DG中向下和向上滚动，细胞的内容似乎消失了！请帮我确定问题以及如何解决问题。



XAML：

I have a WPF project containing a DataGrid, I fill it with many rows when the program starts, then on each button click I set the content of a cell of it. The problem is if I scroll down and up in the DG, the content of the cells seems to be gone! Please help me identify the problem and what to do to solve it.

The XAML:

<Window x:Class="WpfTest1.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">
    <Grid>
        <DockPanel Grid.Column="1" Margin="0,10,1,0" Panel.ZIndex="10" MinWidth="437" MinHeight="38" VerticalAlignment="Top" HorizontalAlignment="Right">
            <DataGrid x:Name="DGV" HorizontalAlignment="Stretch" VerticalAlignment="Top" Height="103" Panel.ZIndex="1" RowBackground="#FFC6C6C6" FontWeight="Bold" CanUserSortColumns="False" CanUserResizeColumns="False" CanUserReorderColumns="False" MinColumnWidth="0" IsReadOnly="False" AlternatingRowremoved="Gainsboro"  AlternationCount="2">
                <DataGrid.Columns>
                    <DataGridTextColumn Header=" "/>
                    <DataGridHyperlinkColumn Header="URL" Width="295" Binding="{Binding url}"/>
                    <DataGridTextColumn Header="Ahrefs(http)" Width="79" Binding="{Binding AhrefsHttp}"/>
                    <DataGridTextColumn Header="Ahrefs(www)" Width="83" Binding="{Binding AhrefsWww}"/>
                    <DataGridTextColumn Header="Archive" Width="79" Binding="{Binding Archive}"/>
                    <DataGridTextColumn Header="Majesticseo" Width="79" Binding="{Binding Majesticseo}"/>
                    <DataGridTextColumn Header="Majesticseo(anch historic)" Width="79" Binding="{Binding Majesticseo}"/>
                    <DataGridTextColumn Header="Majesticseo(ref historic)" Width="79" Binding="{Binding Majesticseo}"/>
                </DataGrid.Columns>
            </DataGrid>

        </DockPanel>
        <Button Content="Button" HorizontalAlignment="Left" Margin="0,118,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click"/>
    </Grid>
</Window>

这是完整的代码：

And this is the complete code:

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;

namespace WpfTest1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        int selectedIndex;

       public class myLink
        {
            private string Url;
            public string url
            {
                get { return Url; }
                set { Url = value; }
            }

            private string ahrefsHttp;
            public string AhrefsHttp
            {
                get { return ahrefsHttp; }
                set { ahrefsHttp = value; }
            }

            private string ahrefsWww;
            public string AhrefsWww
            {
                get { return ahrefsWww; }
                set { ahrefsWww = value; }
            }

            private string archive;
            public string Archive
            {
                get { return archive; }
                set { archive = value; }
            }

            private string majesticseo;
            public string Majesticseo
            {
                get { return majesticseo; }
                set { majesticseo = value; }
            }

            private string majesticseoAnchorHistoric;
            public string MajesticseoAnchorHistoric
            {
                get { return majesticseoAnchorHistoric; }
                set { majesticseoAnchorHistoric = value; }
            }

            private string majesticseoReferringHistoric;
            public string MajesticseoReferringHistoric
            {
                get { return majesticseoReferringHistoric; }
                set { majesticseoReferringHistoric = value; }
            }
        }

       public MainWindow()
       {
           InitializeComponent();

           for (int i = 1; i <= 10; i++)
               AddNewRow("test");
       }

        private void AddNewRow(string txt)
        {
            myLink dm = new myLink { url = txt, AhrefsHttp = "", AhrefsWww = "", Archive = "", Majesticseo = "" };

            DGV.Items.Add(dm);
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            SetLinkStateInDG("Good");
        }

        private void SetLinkStateInDG(string state)
        {

            DGV.SelectedItem = DGV.Items[selectedIndex++];

            if (state != "")
            {
                string cmt = Microsoft.VisualBasic.Interaction.InputBox("Any comment?", "Comment", "", -1, -1);
                if (cmt != "")
                    state = state + " (" + cmt + ")";
            }

            foreach (DataGridCellInfo cellInfo in DGV.SelectedCells)
            {
                // this changes the cell's content not the data item behind it
                if (cellInfo.Column.Header.ToString() == "Majesticseo(anch historic)")
                {
                    DataGridCell gridCell = TryToFindGridCell(DGV, cellInfo);
                    if (gridCell != null) gridCell.Content = state;
                    break;
                }
            }


            DGV.SelectedItem = DGV.Items[selectedIndex];
        }

        static DataGridCell TryToFindGridCell(DataGrid grid, DataGridCellInfo cellInfo)
        {
            DataGridCell result = null;
            DataGridRow row = (DataGridRow)grid.ItemContainerGenerator.ContainerFromItem(cellInfo.Item);
            if (row != null)
            {
                int columnIndex = grid.Columns.IndexOf(cellInfo.Column);
                if (columnIndex > -1)
                {
                    System.Windows.Controls.Primitives.DataGridCellsPresenter presenter = GetVisualChild<System.Windows.Controls.Primitives.DataGridCellsPresenter>(row);
                    result = presenter.ItemContainerGenerator.ContainerFromIndex(columnIndex) as DataGridCell;
                }
            }
            return result;
        }

        static T GetVisualChild<T>(Visual parent) where T : Visual
        {
            T child = default(T);
            int numVisuals = VisualTreeHelper.GetChildrenCount(parent);
            for (int i = 0; i < numVisuals; i++)
            {
                Visual v = (Visual)VisualTreeHelper.GetChild(parent, i);
                child = v as T;
                if (child == null)
                {
                    child = GetVisualChild<T>(v);
                }
                if (child != null)
                {
                    break;
                }
            }
            return child;
        }
    }
}

推荐答案

修正了它！

我似乎必须为DataGrid设置一个属性来修复它：

Fixed it!
IT appeared that I have to set a property for the DataGrid to fix it:

ScrollViewer.CanContentScroll="False"

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