WPF DataGrid Selected Cell Changed 获取“父 DataGrid 上的 SelectionUnit 属性的当前值阻止选择行。”答案

【问题标题】：WPF DataGrid SelectedCellsChanged geting "The current value of the SelectionUnit property on the parent DataGrid prevents rows from being selected."WPF DataGrid Selected Cell Changed 获取“父 DataGrid 上的 SelectionUnit 属性的当前值阻止选择行。”
【发布时间】：2012-10-05 00:07:59
【问题描述】：

请帮助我，我正在使用“WPF Application Framework”和 EF Code First 编写应用程序。我正在尝试将选定的行设置为绑定到 DataGrids SelectedItem 的 ViewModels 变量“SelectedRawMaterial”，并引发异常：“父 DataGrid 上的 SelectionUnit 属性的当前值阻止选择行。”

private void rawMaterialTable_SelectedCellsChanged(object sender, SelectedCellsChangedEventArgs e)
    {
        DataGridCell cell = null;
        try
        {
            cell = DataGridHelper.GetCell(rawMaterialTable.SelectedCells[0]);
        }
        catch (Exception)
        { }

        if (cell != null)
        {
            int i = DataGridHelper.GetRowIndex(cell);
            try
            {

                RawMaterial rm = (RawMaterial)rawMaterialTable.Items[i];
                ViewModel.SelectedRawMaterial = rm;
            }
            catch (Exception) { }
        }
    }



public static class DataGridHelper
{
    public static DataGridCell GetCell(DataGridCellInfo dataGridCellInfo)
    {
        if (!dataGridCellInfo.IsValid)
        {
            return null;
        }

        var cellContent = dataGridCellInfo.Column.GetCellContent(dataGridCellInfo.Item);
        if (cellContent != null)
        {
            return (DataGridCell)cellContent.Parent;
        }
        else
        {
            return null;
        }
    }

    public static int GetRowIndex(DataGridCell dataGridCell)
    {
        // Use reflection to get DataGridCell.RowDataItem property value.
        PropertyInfo rowDataItemProperty = dataGridCell.GetType().GetProperty("RowDataItem",
                                                                              BindingFlags.Instance |
                                                                              BindingFlags.NonPublic);

        DataGrid dataGrid = GetDataGridFromChild(dataGridCell);

        return dataGrid.Items.IndexOf(rowDataItemProperty.GetValue(dataGridCell, null));
    }

    public static DataGrid GetDataGridFromChild(DependencyObject dataGridPart)
    {
        if (VisualTreeHelper.GetParent(dataGridPart) == null)
        {
            throw new NullReferenceException("Control is null.");
        }
        if (VisualTreeHelper.GetParent(dataGridPart) is DataGrid)
        {
            return (DataGrid)VisualTreeHelper.GetParent(dataGridPart);
        }
        else
        {
            return GetDataGridFromChild(VisualTreeHelper.GetParent(dataGridPart));
        }
    }
}

在这个地方它会引发异常。

ViewModel.SelectedRawMaterial = rm;

数据网格代码

<DataGrid x:Name="rawMaterialTable" ItemsSource="{Binding RawMaterials}" SelectedItem="{Binding SelectedRawMaterial}" 
              CanUserDeleteRows="False" BorderThickness="0" SelectionMode="Single" SelectionUnit="Cell" IsReadOnly="false"
              Grid.Row="1" Grid.Column="1" Margin="1,1,1,1" PreviewKeyDown="rawMaterialTable_PreviewKeyDown" SelectedCellsChanged="rawMaterialTable_SelectedCellsChanged" >
            <DataGrid.InputBindings>
                <KeyBinding Command="{Binding RemoveCommand}" Key="Del"/>
                <KeyBinding Command="{Binding AddCommand}" Key="Insert"/>
                <KeyBinding Command="{Binding EditCommand}" Key="F3"/>
            </DataGrid.InputBindings>

            <DataGrid.Columns>
                <DataGridTextColumn Binding="{Binding Code, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True, 
                                  ValidatesOnExceptions=True, NotifyOnValidationError=True}" 
                                Header="{x:Static p:Resources.Code}" Width="60" ElementStyle="{StaticResource TextCellElementStyle}"
                                EditingElementStyle="{StaticResource TextCellEditingStyle}" DisplayIndex="0"/>


            </DataGrid.Columns>
        </DataGrid>

我添加了 SelectionUnit="Cell" 因为我也想处理 CellKeyDown。

【问题讨论】：

标签： c# wpf datagrid

【解决方案1】：

这是因为您将数据网格的SelectionUnit(see the definition of the property) 属性设置为Cell，我相信您正在尝试一次选择一行。

已编辑：如果您将SelectionUnit 更改为CellOrRowHeader 以允许选择单元格但绑定选择整行

【讨论】：

我添加了 SelectionUnit="Cell" 因为我也想处理 CellKeyDown。