从GridView生成DataTable

DataTable与GridView从数据结构上来看都是一个由row和column组成表的结构,我们大部分时间是将DataTable绑定到GridView中,但web中当页面回传的时候,传递给GridView的数据源却再也找不到了,这是一件很郁闷的事情,下面我们根据两者的相似性,实现从GridView生成DataTable的方法,不管原来的GridView数据源是否是DataTable,都能使用该方法 

/*----------------------------------------------------------------
// Copyright (C) 2007 jillzhang 版权所有。 
//  
// 文件名:GridView.cs
// 文件功能描述:
// 
// 创建标识:jillzhang 
// 修改标识:
// 修改描述:
//
// 修改标识:
// 修改描述:
//----------------------------------------------------------------
*/


using System;
using System.Collections.Generic;
using System.Text;
using System.Web.UI.WebControls;
using System.Data;
using System.Web.UI;


namespace jzlib.Common
{
    
public class GridViewHelper
    
{
        
public 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>
        
/// 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[i]);
                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[i]);
                        
if (!String.IsNullOrEmpty(text))
                        
{
                            
if (rowIndex == 0)
                            
{
                               
string columnName = cols[i];
                                
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;
        }

    }

}

使用这个函数,您可以得到GridView当前页面的数据,当然如果您在GridView中添加了复杂的控件,我们将略过这些内容,我们只从显示文本的列中导出数据到DataTable,如果您想导出GridView的全部数据,请在绑定前设置AllowPaging=false;
当然大家会问这样做有什么用呢?这个函数是我在开发将GridView导出Excel的时候想到的,类似于这种应用情形,我想还有很多。
下面是一个示例,通过从上面的GridView导出DataTable,然后再绑定到下面的GridView中


示例代码:
/Files/jillzhang/gv2dtdemo.rar

更新标识:
1. 2007-10-12 日 更新,添加对IButtonControl列的支持,修正了有时出现索引超出的异常

posted @ 2007-10-11 15:01 Robin Zhang 阅读(...) 评论(...) 编辑 收藏