WPF中DataGrid设置默认选中行

1、DataGrid命名为planDataGrid

<DataGrid ItemsSource="{Binding PlanList}" SelectedItem="{Binding SelectedItem}" x:Name="planDataGrid" AutoGenerateColumns="False" CanUserAddRows="False"
GridLinesVisibility="All" FontSize="12" ColumnHeaderHeight="42" RowHeaderWidth="0" EnableRowVirtualization="False" VirtualizingPanel.IsVirtualizing="False">

</DataGrid>

2、  SetSelectedItemFirstRow(page.planDataGrid);调用方法，获取到前端界面的DataGrid，传给后端使用。

 void SetSelectedItemFirstRow(object dataGrid)
 {
     //若目标datagrid为空，抛出异常
     if (dataGrid == null)
     {
         throw new ArgumentNullException("目标无" + dataGrid + "无法转换为DataGrid");
     }
     //获取目标DataGrid，为空则抛出异常
     System.Windows.Controls.DataGrid dg = dataGrid as System.Windows.Controls.DataGrid;
     if (dg == null)
     {
         throw new ArgumentNullException("目标无" + dataGrid + "无法转换为DataGrid");
     }
     //数据源为空则返回
     if (dg.Items == null || dg.Items.Count < 1)
     {
         return;
     }

     dg.SelectedItem = dg.Items[0];
     dg.CurrentColumn = dg.Columns[0];
     dg.ScrollIntoView(dg.SelectedItem, dg.CurrentColumn);
     //获取焦点，滚动为目标行
     dg.Focus();
     dg.SelectedItem = selectedItem;//设置选中行
     dg.CurrentColumn = dg.Columns[0];
     dg.ScrollIntoView(dg.SelectedItem, dg.CurrentColumn);
     var item = dg.SelectedItem as PlanDataModel;
     ObservableCollection<CoilListModel> clm = new ObservableCollection<CoilListModel>();
     DBHandle.GetCoilsByJobId(item, ref clm);

     CoilList = clm;
     page.coilDataGrid.ItemsSource = CoilList;
 }