asp.net工具类 
using System;
using System.Collections.Generic;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Collections;
using System.Reflection;

public class GridViewHelper
{
    #region 私有方法
    /// <summary>
    /// 截取内容长度
    /// </summary>
    /// <param name="o_Str">原字符串</param>
    /// <param name="len">截取长度</param>
    /// <returns>截取后字符串</returns>
    private static string GetStrPartly(string o_Str, int len)
    {
        if (len == 0)
        {
            return o_Str;
        }
        else
        {
            if (o_Str.Length > len)
            {
                return o_Str.Substring(0, len) + "..";
            }
            else
            {
                return o_Str;
            }
        }
    }

    /// <summary>
    /// 获取单元格内容 www.52mvc.com
    /// </summary>
    /// <param name="cell">TableCell</param>
    /// <returns>内容</returns>
    private static string GetCellText(TableCell cell)
    {
        string text = cell.Text;
        if (!string.IsNullOrEmpty(text))
        {
            return text;
        }
        foreach (Control control in cell.Controls)
        {
            if (control != null && control is IButtonControl)
            {
                IButtonControl btn = control as IButtonControl;
                text = btn.Text.Replace("\r\n", "").Trim();
                break;
            }
            if (control != null && control is ITextControl)
            {
                LiteralControl lc = control as LiteralControl;
                if (lc != null)
                {
                    continue;
                }
                ITextControl l = control as ITextControl;
                text = l.Text.Replace("\r\n", "").Trim();
                break;
            }
        }
        return text;
    }

    /// <summary>
    /// 设置单元格内容 www.52mvc.com 
    /// </summary>
    /// <param name="cell">TableCell</param>
    /// <param name="maxLen">最大长度</param>
    private static void SetCellText(TableCell cell, int maxLen)
    {
        string text = cell.Text;
        if (!string.IsNullOrEmpty(text))
        {
            cell.Text = GetStrPartly(text, maxLen);
        }
        foreach (Control control in cell.Controls)
        {
            if (control != null && control is IButtonControl)
            {
                IButtonControl btn = control as IButtonControl;
                text = btn.Text.Replace("\r\n", "").Trim();
                btn.Text = GetStrPartly(text, maxLen);
                break;
            }
            if (control != null && control is ITextControl)
            {
                LiteralControl lc = control as LiteralControl;
                if (lc != null)
                {
                    continue;
                }
                ITextControl l = control as ITextControl;
                text = l.Text.Replace("\r\n", "").Trim();
                if (l is DataBoundLiteralControl)
                {
                    cell.Text = GetStrPartly(text, maxLen);
                    break;
                }
                else
                {
                    l.Text = GetStrPartly(text, maxLen);
                    break;
                }
            }
        }
    }
    #endregion

    #region 公有方法
    /// <summary>
    /// 从GridView的数据生成DataTable
    /// </summary>
    /// <param name="gv">GridView对象</param>
    public static DataTable GridView2DataTable(GridView gv)
    {
        DataTable table = new DataTable();
        int rowIndex = 0;
        List<string> cols = new List<string>();
        if (!gv.ShowHeader && gv.Columns.Count == 0)
        {
            return table;
        }
        GridViewRow headerRow = gv.HeaderRow;
        int columnCount = headerRow.Cells.Count;
        for (int i = 0; i < columnCount; i++)
        {
            string text = GetCellText(headerRow.Cells);
            cols.Add(text);
        }
        foreach (GridViewRow r in gv.Rows)
        {
            if (r.RowType == DataControlRowType.DataRow)
            {
                DataRow row = table.NewRow();
                int j = 0;
                for (int i = 0; i < columnCount; i++)
                {
                    string text = GetCellText(r.Cells);
                    if (!String.IsNullOrEmpty(text))
                    {
                        if (rowIndex == 0)
                        {
                            string columnName = cols;
                            if (String.IsNullOrEmpty(columnName))
                            {
                                continue;
                            }
                            if (table.Columns.Contains(columnName))
                            {
                                continue;
                            }
                            DataColumn dc = table.Columns.Add();
                            dc.ColumnName = columnName;
                            dc.DataType = typeof(string);
                        }
                        row[j] = text;
                        j++;
                    }
                }
                rowIndex++;
                table.Rows.Add(row);
            }
        }
        return table;
    }

    /// <summary>
    /// 将集合类转换成DataTable
    /// </summary>
    /// <param name="list">集合</param>
    public static DataTable ToDataTable(IList list)
    {
        DataTable result = new DataTable();
        if (list.Count > 0)
        {
            PropertyInfo[] propertys = list[0].GetType().GetProperties();
            foreach (PropertyInfo pi in propertys)
            {
                result.Columns.Add(pi.Name, pi.PropertyType);
            }

            for (int i = 0; i < list.Count; i++)
            {
                ArrayList tempList = new ArrayList();
                foreach (PropertyInfo pi in propertys)
                {
                    object obj = pi.GetValue(list, null);
                    tempList.Add(obj);
                }
                object[] array = tempList.ToArray();
                result.LoadDataRow(array, true);
            }
        }
        return result;
    }

    /// <summary>
    /// 将泛型集合类转换成DataTable
    /// </summary>
    /// <typeparam name="T">集合项类型</typeparam>
    /// <param name="list">集合</param>
    /// <param name="propertyName">需要返回的列的列名</param>
    /// <returns>数据集(表)</returns>
    public static DataTable ToDataTable<T>(IList<T> list, params string[] propertyName)
    {
        List<string> propertyNameList = new List<string>();
        if (propertyName != null) propertyNameList.AddRange(propertyName);

        DataTable result = new DataTable();
        if (list.Count > 0)
        {
            PropertyInfo[] propertys = list[0].GetType().GetProperties();
            foreach (PropertyInfo pi in propertys)
            {
                if (propertyNameList.Count == 0)
                {
                    result.Columns.Add(pi.Name, pi.PropertyType);
                }
                else
                {
                    if (propertyNameList.Contains(pi.Name)) result.Columns.Add(pi.Name, pi.PropertyType);
                }
            }

            for (int i = 0; i < list.Count; i++)
            {
                ArrayList tempList = new ArrayList();
                foreach (PropertyInfo pi in propertys)
                {
                    if (propertyNameList.Count == 0)
                    {
                        object obj = pi.GetValue(list, null);
                        tempList.Add(obj);
                    }
                    else
                    {
                        if (propertyNameList.Contains(pi.Name))
                        {
                            object obj = pi.GetValue(list, null);
                            tempList.Add(obj);
                        }
                    }
                }
                object[] array = tempList.ToArray();
                result.LoadDataRow(array, true);
            }
        }
        return result;
    }
    #endregion
}
更多:http://www.52mvc.com/showtopic-1697.aspx
原文:http://blog.csdn.net/sophia_wjy