MVVM WPF 动态数据网格

Question

我正在我的视图模型中动态创建两个数据表。 在我在视图中显示它们之前，我将一个 DataTable 中的每个单元格值与第二个 DataTable 中的同一单元格进行比较。 我的问题是我想为不同的单元格提供不同的背景颜色。我怎样才能以编程方式做到这一点？

这是第一个 DataGrid：

 <GroupBox Header="Xml 1 Details" Margin="10,10,10,10" Grid.Row="1" Grid.ColumnSpan="4" Grid.Column="0">
        <ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Disabled">
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*"/>
                </Grid.ColumnDefinitions>
                <Grid.RowDefinitions>
                    <RowDefinition Height="*"/>
                </Grid.RowDefinitions>

                <GroupBox x:Name="GridGroupBox"
                  Grid.Column="0"
                  Header="{Binding TableName}">
                    <DataGrid x:Name="DataGrid" Margin="5,5,5,5"
                      ItemsSource="{Binding GenericDataTable}"
                      attachedBehaviors:DataGridColumnsBehavior.BindableColumns="{Binding GridColumns}"                                 
                      AutoGenerateColumns="False"
                      EnableRowVirtualization="False">                            
                    </DataGrid>
                </GroupBox>
            </Grid>
        </ScrollViewer>
    </GroupBox>

第二个数据网格：

    <GroupBox Header="Xml 2 Details" Margin="10,20,10,10" Grid.Row="2" Grid.ColumnSpan="4" Grid.Column="0">
        <ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Disabled">
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*"/>
                </Grid.ColumnDefinitions>
                <Grid.RowDefinitions>
                    <RowDefinition Height="*"/>
                </Grid.RowDefinitions>


                <GroupBox x:Name="GridGroupBox2" 
                Grid.Column="0"
                Header="{Binding TableName}">

                    <DataGrid x:Name="DataGrid2" Margin="5,5,5,5" 
                    ItemsSource="{Binding GenericDataTable2}"
                    attachedBehaviors:DataGridColumnsBehavior.BindableColumns="{Binding GridColumns2}"                                 
                    AutoGenerateColumns="False"
                    EnableRowVirtualization="False"
                    />                    
                </GroupBox>
            </Grid>
        </ScrollViewer>
    </GroupBox>

以编程方式创建它们：

    private void GenerateFirstXmlDynamicColumns(DataTable dt, List<string> cols)
    {

        GridColumns = new ObservableCollection<DataGridColumn>();

        foreach (DataColumn col in dt.Columns)
        {

            GridColumns.Add(new DataGridTextColumn
            {
                Header = col.ColumnName,
                Binding = new Binding(col.ColumnName)
            });
        }

        RaisePropertyChanged("GridColumns");
        GenericDataTable = dt;
        RaisePropertyChanged("GenericDataTable");
    }

    private void GenerateSecondXmlDynamicColumns(DataTable dt, List<string> cols)
    {
        GridColumns2 = new ObservableCollection<DataGridColumn>();

        foreach (DataColumn col in dt.Columns)
        {

            GridColumns2.Add(new DataGridTextColumn
            {
                Header = col.ColumnName,
                Binding = new Binding(col.ColumnName)
            });
        }

        RaisePropertyChanged("GridColumns2");
        GenericDataTable2 = dt;
        RaisePropertyChanged("GenericDataTable2");
    }

这里我比较单元格，我想改变不同单元格的背景颜色：

private void CompareData()
    {
        for (int i = 0; i < GenericDataTable.Rows.Count; i++)
        {
            for (int j = 0; j < GenericDataTable.Columns.Count; j++)
            {
                if (!GenericDataTable.Rows[i][j].Equals(GenericDataTable2.Rows[i][j]))//if cells are different
                {

                }
            }

        }     
    }

Answer 1

从索引中获取 DataGrid 单元格：

public DataGridCell GetCell(DataGrid dg, int row, int column)
    {
        DataGridRow rowContainer = GetRow(dg, row);
        if (rowContainer != null)
        {
            DataGridCellsPresenter presenter = GetVisualChild<DataGridCellsPresenter>(rowContainer);
            if (presenter == null)
            {
                dg.ScrollIntoView(rowContainer, dg.Columns[column]);
                presenter = GetVisualChild<DataGridCellsPresenter>(rowContainer);
            }
            DataGridCell cell = (DataGridCell)presenter.ItemContainerGenerator.ContainerFromIndex(column);
            return cell;
        }
        return null;
    }

    public static DataGridRow GetRow(DataGrid dg, int index)
    {
        DataGridRow row = (DataGridRow)dg.ItemContainerGenerator.ContainerFromIndex(index);
        if (row == null)
        {
            dg.UpdateLayout();
            dg.ScrollIntoView(dg.Items[index]);
            row = (DataGridRow)dg.ItemContainerGenerator.ContainerFromIndex(index);
        }
        return row;
    }

    public static T GetVisualChild<T>(Visual parent) where T : Visual
    {
        if (parent == null) return null;
        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;
    }

并设置背景：

var cell = GetCell(DataGrid2, i, j);
cell.Background = color;

Answer 2

解决办法如下：

创建一个多转换器：

 public object Convert(object[] values, 
 Type targetType, object parameter,      
 CultureInfo culture)
    {
        var dataContext = values[0];
        var dg = (DataGrid)values[1];
        var i = (DataGridCell)values[2];
        var col = i.Column.DisplayIndex;
        var row = dg.Items.IndexOf(i.DataContext);
        if (row >= 0 && col >= 0)
        {
            DataTable td1 = ((CheckXmlAppWpf.ViewModel.MainWindowViewModel) (dataContext)).GenericDataTable;
            DataTable td2 = ((CheckXmlAppWpf.ViewModel.MainWindowViewModel)(dataContext)).GenericDataTable2;

            if (!td1.Rows[row][col].Equals(td2.Rows[row][col]))
            {
                GetCell(dg, row, col).Background = Brushes.Yellow;
            }
        }

        return SystemColors.AppWorkspaceColor;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new System.NotImplementedException();
    }
}

在 xaml 中使用它：

<DataGrid x:Name="DataGrid" Margin="5,5,5,5" ItemsSource="{Binding GenericDataTable}" attachedBehaviors:DataGridColumnsBehavior.BindableColumns="{Binding GridColumns}" AutoGenerateColumns="False" EnableRowVirtualization="False"> <DataGrid.Resources> <Style TargetType="DataGridCell"> <Setter Property="Background"> <Setter.Value> <MultiBinding Converter="{StaticResource NameToBrushMultiValueConverter}" > <MultiBinding.Bindings> <Binding RelativeSource="{RelativeSource AncestorType=Window}" Path="DataContext" /> <Binding RelativeSource="{RelativeSource AncestorType=DataGrid}"></Binding> <Binding RelativeSource="{RelativeSource Self}"/> </MultiBinding.Bindings> </MultiBinding> </Setter.Value> </Setter> </Style> </DataGrid.Resources> </DataGrid>