根据 DataTable 值为 DataGrid 行着色

Question

我从 CSV 文件中提取数据，在 DataTable 中对其进行解析，然后将此 DataTable 设置为 DataGrid 的 ItemsSource。然后，我循环 DataTable 以对数据进行一些验证，并且我想相应地为 DataGrid 行着色。

问题是，我无法根据DataTable行找到对应的DataGrid行。

这是我的代码：

Dim dg As New DataGrid
Dim dataTable as DataTable = ParseFile(filePath)
Dim statutList() As String = {"Saisi", "Validé", "Suspendu", "Annulé"}

dg.ItemsSource = dataTable.DefaultView

For Each row As DataRow In dataTable.Rows
    'This line is what I tried, but it always returns nothing
    Dim dgrow As DataGridRow = dg.ItemContainerGenerator.ContainerFromItem(row)
    If Not statutList.Contains(row("Statut").ToString) Then
        dgrow.Background = Brushes.Red
    End If
Next

问题来自这一行，它不起作用：

Dim dgrow As DataGridRow = dg.ItemContainerGenerator.ContainerFromItem(row)

解决方案：

两种 mm8 解决方案都有效。就我而言，我使用了：

dg.UpdateLayout()
For Each row As DataRowView In dg.Items.OfType(Of DataRowView)
    Dim dgrow As DataGridRow = dg.ItemContainerGenerator.ContainerFromItem(row)
    If Not statutList.Contains(row("Statut").ToString) Then
        dgrow.Background = Brushes.Red
    End If
Next

Answer 1

正确的“WPF”方法是定义一个 RowStyle，其中包含一个或多个数据触发器，当该特定行的“Statut”列返回任何特定值时，设置该行的背景颜色，例如：

<DataGrid x:Name="dg">
    <DataGrid.Resources>
        <SolidColorBrush x:Key="color" Color="Red" />
    </DataGrid.Resources>
    <DataGrid.RowStyle>
        <Style TargetType="DataGridRow">
            <Style.Triggers>
                <DataTrigger Binding="{Binding Statut}" Value="Saisi">
                    <Setter Property="Background" Value="{StaticResource color}" />
                </DataTrigger>
                <DataTrigger Binding="{Binding Statut}" Value="Validé">
                    <Setter Property="Background" Value="{StaticResource color}" />
                </DataTrigger>
                <DataTrigger Binding="{Binding Statut}" Value="Suspendu">
                    <Setter Property="Background" Value="{StaticResource color}" />
                </DataTrigger>
                <DataTrigger Binding="{Binding Statut}" Value="Annulé">
                    <Setter Property="Background" Value="{StaticResource color}" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </DataGrid.RowStyle>
</DataGrid>

如果您稍微修改一下，您当前的代码隐藏方法将可以正常工作：

    For Each row As DataRowView In dg.Items.OfType(Of DataRowView)
        Dim dgrow As DataGridRow = dg.ItemContainerGenerator.ContainerFromItem(row)
        If Not statutList.Contains(row("Statut").ToString) Then
            dgrow.Background = Brushes.Red
        End If
    Next

请注意，如果 DataTable 包含大量行并且您没有禁用 UI 虚拟化，则 ItemContainerGenerator.ContainerFromItem 方法实际上不会为可能已被虚拟化掉的项目返回 DataGridRow 容器：

<DataGrid x:Name="dg" VirtualizingPanel.IsVirtualizing="False">.

如果您的 DataTable 包含很多行，显然禁用虚拟化可能会导致性能问题。

还要注意，一旦真正创建了容器，就需要执行代码，例如当窗口的 Loaded 事件发生时。

Class MainWindow
    Dim statutList() As String = {"Saisi", "Validé", "Suspendu", "Annulé"}

    Public Sub New()

        ' This call is required by the designer.
        InitializeComponent()

        ' Add any initialization after the InitializeComponent() call.
        Dim dg As New DataGrid
        Dim dataTable As DataTable = ParseFile(filePath)

        dg.ItemsSource = dataTable.DefaultView
    End Sub

    Private Sub Window_Loaded(sender As Object, e As RoutedEventArgs) Handles Me.Loaded
        For Each row As DataRowView In dg.Items.OfType(Of DataRowView)
            Dim dgrow As DataGridRow = dg.ItemContainerGenerator.ContainerFromItem(row)
            If Not statutList.Contains(row("Statut").ToString) Then
                dgrow.Background = Brushes.Red
            End If
        Next
    End Sub
    ...
End Class