DataGrid 得到DataGridRow 和DataGridColumn

/* ----------------------------------------------------------
文件名称：DataGridPlus.cs

作者：秦建辉

MSN：splashcn@msn.com
QQ：36748897

博客：http://blog.csdn.net/jhqin

开发环境：
    Visual Studio V2010
    .NET Framework 4 Client Profile

版本历史：
    V1.0    2012年06月07日
            WPF DataGrid控件扩展方法

参考资料：
    http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/b7299e55-92e2-4a6b-8987-869fef8f22eb/
------------------------------------------------------------ */
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Media;

namespace Splash.WPF
{
    public static class DataGridPlus
    {
        /// <summary>
        /// 获取DataGrid控件单元格
        /// </summary>
        /// <param name="dataGrid">DataGrid控件</param>
        /// <param name="rowIndex">单元格所在的行号</param>
        /// <param name="columnIndex">单元格所在的列号</param>
        /// <returns>指定的单元格</returns>
        public static DataGridCell GetCell(this DataGrid dataGrid, int rowIndex, int columnIndex)        
        {
            DataGridRow rowContainer = dataGrid.GetRow(rowIndex);
            if (rowContainer != null)
            {
                DataGridCellsPresenter presenter = GetVisualChild<DataGridCellsPresenter>(rowContainer);
                DataGridCell cell = (DataGridCell)presenter.ItemContainerGenerator.ContainerFromIndex(columnIndex);
                if (cell == null)
                {
                    dataGrid.ScrollIntoView(rowContainer, dataGrid.Columns[columnIndex]);
                    cell = (DataGridCell)presenter.ItemContainerGenerator.ContainerFromIndex(columnIndex);
                }
                return cell;
            }
            return null;
        }

        /// <summary>
        /// 获取DataGrid的行
        /// </summary>
        /// <param name="dataGrid">DataGrid控件</param>
        /// <param name="rowIndex">DataGrid行号</param>
        /// <returns>指定的行号</returns>
        public static DataGridRow GetRow(this DataGrid dataGrid, int rowIndex)        
        {
            DataGridRow rowContainer = (DataGridRow)dataGrid.ItemContainerGenerator.ContainerFromIndex(rowIndex);
            if (rowContainer == null)
            {
                dataGrid.UpdateLayout();
                dataGrid.ScrollIntoView(dataGrid.Items[rowIndex]);
                rowContainer = (DataGridRow)dataGrid.ItemContainerGenerator.ContainerFromIndex(rowIndex);
            }
            return rowContainer;
        }

        /// <summary>
        /// 获取父可视对象中第一个指定类型的子可视对象
        /// </summary>
        /// <typeparam name="T">可视对象类型</typeparam>
        /// <param name="parent">父可视对象</param>
        /// <returns>第一个指定类型的子可视对象</returns>
        public 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;
        }
    }
}