c# - 必须在使用DataView之前设置DataTable

当我尝试手动对表格进行排序时，出现以下错误：
必须在使用DataView之前设置DataTable。
代码是：

protected void GridView1_Sorting(object sender, GridViewSortEventArgs e)
    {

        DataTable sourceTable = GridView1.DataSource as DataTable;
        DataView view = new DataView(sourceTable);
        string[] sortData = Session["sortExpression"]!= null ? Session["sortExpression"].ToString().Trim().Split(' ') : null;
        if (sortData != null && e.SortExpression == sortData[0])
        {
            if (sortData[1] == "ASC")
            {
                view.Sort = e.SortExpression + " " + "DESC";
                Session["sortExpression"] = e.SortExpression + " " + "DESC";
            }
            else
            {
                view.Sort = e.SortExpression + " " + "ASC";
                Session["sortExpression"] = e.SortExpression + " " + "ASC";
            }
        }
        else
        {
            view.Sort = e.SortExpression + " " + "ASC";
            Session["sortExpression"] = e.SortExpression + " " + "ASC";
        }

    }

我哪里错了？

最佳答案

很有可能GridView1.DataSource为null。
您可以在此处找到有关Gridview排序的教程：http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.gridview.sorting.aspx