.Net GridView 应用：Gridview有一个CheckBox列，在用了分页的情况下，如何取出用户选择的所有记录id

思路一：每次换页时查询数据库，Session 保存已选

首先，分页保持每页先前选择的checkbox   的状态。
写了一个方法，遍历gridview,把选中的checkbox   的值存为arraylist  再保存  Session。在pageIndexChanging   事件里里调用。   （用；号分割，累加起来，样就遇到了一个问题，如果点了下一页，再回到上一页的话，Session   的值会有重复 ）。

 protected void gvFileList_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            RememberOldValues();
            gvFileList.PageIndex = e.NewPageIndex;
            bindData();
            RePopulateValues();
        }

         /*保存分页前选择的值*/
        private void RememberOldValues()
        {
            ArrayList categoryIDList = new ArrayList();
            int index = -1;
            foreach (GridViewRow row in gvFileList.Rows)
            {
                    bool result = ((CheckBox)row.FindControl("chkfile")).Checked;
               
                    string str = returnStrRules(row);
                   
                    // Check in the Session
                    if (Session["CHECKED_ITEMS"] != null)
                        categoryIDList = (ArrayList)Session["CHECKED_ITEMS"];
                    if (result)
                    {
                        if (!categoryIDList.Contains(str))
                            categoryIDList.Add(str);
                    }
                    else
                        categoryIDList.Remove(str);
               
            }
            if (categoryIDList != null && categoryIDList.Count > 0)
                Session["CHECKED_ITEMS"] = categoryIDList;
        }

        /*   取出分页前选择的值 初始选中状态 */
        private void RePopulateValues()
        {
            ArrayList categoryIDList = (ArrayList)Session["CHECKED_ITEMS"];
            if (categoryIDList != null && categoryIDList.Count > 0)
            {
                foreach (GridViewRow row in gvFileList.Rows)
                {
                    string str = returnStrRules(row);
                    if (categoryIDList.Contains(str))
                    {
                        CheckBox myCheckBox = (CheckBox)row.FindControl("chkfile");
                        myCheckBox.Checked = true;
                    }
                }
            }
        }

  // 保存到 arraylist 的stri 的规则

 private string returnStrRules(GridViewRow row)
        {
            string result = null;
            result = gvFileList.DataKeys[row.RowIndex].Value.ToString ();
            //string folio = row.Cells[2].Text.ToString();
            //string processType = row.Cells[6].Text.ToString();    /* albert提醒在修改Sql查询语句后要记得修改processType的Cells属性索引*/
            //bool result = ((CheckBox)row.FindControl("chkfile")).Checked;
            //folio = index + ";" + folio + ";" + processType;

            return result;
       
        }

解析字符串

 public  string setReturnStr()
        {
            ArrayList categoryIDList = (ArrayList)Session["CHECKED_ITEMS"];

            if (categoryIDList != null && categoryIDList.Count > 0)
            {
                string str = null;
                foreach (object index in categoryIDList)
                {
                    str += index.ToString() + ",";
                }
               str=str.Substring(0, str.Length - 1);
                this.txtReturn.Value = str;
            }
            //Session["CHECKED_ITEMS"] = null;
            return true.ToString();
       
        }

js实现当前页全选（gridview->table）

 function selectAll(obj)
    {
       var theTable  = obj.parentElement.parentElement.parentElement;
       var i;
       var j = obj.parentElement.cellIndex;
       
        for(i=0;i<theTable.rows.length;i++)
        {
           var objCheckBox = theTable.rows[i].cells[j].firstChild;
           if(objCheckBox.checked!=null)objCheckBox.checked = obj.checked;
        }
    }

<asp:GridView ID="gvFileList" runat="server" DataKeyNames="ID" AutoGenerateColumns="False"
                            Width="98%" AllowPaging="True" CssClass="tbl_border" OnPageIndexChanging="gvFileList_PageIndexChanging" PageSize="4">
                            <Columns>
                                <asp:TemplateField>
                                    <ItemTemplate>
                                        <asp:CheckBox runat="server"  ID="chkfile"    />
                                      </ItemTemplate>  
                                     <%-- <HeaderTemplate>                   
                                       <input id="CheckAll" type="checkbox" onclick="selectAll(this);" />本页全选
                                      </HeaderTemplate>--%>
                                </asp:TemplateField>                                
                                <asp:BoundField DataField="id" HeaderText="序号">
                                    <ItemStyle Font-Size="Smaller" Width="10%" />
                                    <HeaderStyle Font-Size="Smaller" />
                                </asp:BoundField>
                                 </Columns>
                            <FooterStyle Height="2px" Width="2px" />
                            <PagerStyle Height="1px" Font-Size="Smaller" />
                            <SelectedRowStyle BorderColor="#0066CC" />
                            <HeaderStyle HorizontalAlign="Left" Width="2px" Height="2px" CssClass="tbl_borderTH" />
                            <AlternatingRowStyle CssClass="tbl_borderStripe" />
    </asp:GridView>