如何从数据库中列出已选择项?

 在DataList 列表中,我增加了一个CheckBox控件,勾选后按"确定"按钮后该即把该控件是否选中状态写进数据表的"tuijian"字段中(选中后"tuijian"字段值为"1",未选中为"0"),但我不知道在PageLoad事件中怎样再把该控件是否选中的状态显示出来.我是个菜鸟,大家帮帮我,谢谢大家!!以下是代码:
public partial class Admin_TuiJian_Img : System.Web.UI.Page
{
    protected OleDbDataAdapter da;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            getProduct();
                   }
        }
    }    private void getProduct()
    {        string strLoad = Server.MapPath("~//data//clothes.mdb"); 
        OleDbConnection conn = new OleDbConnection("provider=Microsoft.Jet.OleDb.4.0;Data Source=" + strLoad + ";");
        string sel = "Select * From product" ;
        da = new OleDbDataAdapter();
        DataSet ds = new DataSet();
        da.SelectCommand = new OleDbCommand(sel, conn);
        try
        {
            conn.Open();
            da.Fill(ds, "product");
            DataList1.DataKeyField = "ProductId";
            DataList1.DataSource = ds;
            DataList1.DataBind();
            conn.Close();
        }
        catch (Exception ex)
        {
            Response.Write(ex.ToString());        }
        int cup = Convert.ToInt32(this.lb_CurrentPage.Text);  //显示当前页        
PagedDataSource ps = new PagedDataSource();
        ps.DataSource = ds.Tables["product"].DefaultView;
        ps.AllowPaging = true;
        ps.PageSize = 6;     
        ps.CurrentPageIndex = cup - 1;
        lb_count.Text = ps.DataSourceCount.ToString(); 
        lb_page.Text = ps.PageCount.ToString(); //总页数
        if (!IsPostBack)
        {
            for (int i = 1; i < ps.PageCount + 1; i++)
            {
                this.DropDownList1.Items.Add(i.ToString());            }
            LinkUp.Enabled = true;
            LinkDown.Enabled = true;
        }
        try
        {
            DropDownList1.SelectedItem.Text = cup.ToString();
            DataList1.DataSource = ps;
            DataList1.DataKeyField = "ProductId";
            DataList1.DataBind();
        }
        catch (Exception ex)
        {
            Response.Write(ex.ToString());
        }    }    protected void LinkDown_Click(object sender, EventArgs e)   //下翻一页
    {
        try
        {
            lb_CurrentPage.Text = Convert.ToString(Convert.ToInt32(lb_CurrentPage.Text) + 1);
            DropDownList1.SelectedValue = lb_CurrentPage.Text;
            getProduct();
        }
        catch (Exception)
        {
            Response.Write("<script language=javascript>" + "alert(\"这是最后一页\")" + "</script>");
            lb_CurrentPage.Text = "1";
            getProduct();
        }    }
    protected void LinkUp_Click(object sender, EventArgs e)
    {
        try
        {
            if (Convert.ToInt16(lb_CurrentPage.Text) > 1)
            {
                lb_CurrentPage.Text = Convert.ToString(Convert.ToInt32(lb_CurrentPage.Text) - 1);
                DropDownList1.SelectedValue = lb_CurrentPage.Text;
                getProduct();
            }
            else
            {
                Response.Write("<script language=javascript>" + "alert(\"已经是第一页\")" + "</script>");
            }
        }
        catch (Exception)
        {            Response.Write("<script language=javascript>" + "alert(\"已经是第一页\")" + "</script>");        }    }
    protected void LinkFirst_Click(object sender, EventArgs e)
    {
        if (lb_CurrentPage.Text != "1")
            lb_CurrentPage.Text = "1";
        else
        {
            Response.Write("<script language=javascript>" + "alert(\"已经是第一页\")" + "</script>");
        }
        getProduct();    }
    protected void LinkLast_Click(object sender, EventArgs e)
    {
        if (lb_CurrentPage.Text.ToString() != lb_page.Text.ToString())
            lb_CurrentPage.Text = lb_page.Text.ToString();
        else
        {
            Response.Write("<script language=javascript>" + "alert(\"已经是最后一页\")" + "</script>");
        }
        getProduct();    }  
    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)  //分页列表
    {
        int page = Convert.ToInt16((DropDownList1.SelectedItem.Value));
        lb_CurrentPage.Text = page.ToString();
        getProduct();
    }    protected void Button1_Click(object sender, EventArgs e)    //点击确定后把CheckBox选中的值写进数据表
    {  CheckBox chk;
        for (int i = 0; i < DataList1.Items.Count;i++)
        {
            chk = (CheckBox)DataList1.Items[i].FindControl("checkbox1");
            if (chk.Checked)
            {
                string strLoad = Server.MapPath("~//data//clothes.mdb"); 
                OleDbConnection conn = new OleDbConnection("provider=Microsoft.Jet.OleDb.4.0;Data Source=" + strLoad + ";");
                conn.Open();
             string  strUpdate = "Update Product Set tuijian=1 Where ProductId=" + Convert.ToInt32(DataList1.DataKeys[i].ToString());
                OleDbCommand cmd = new OleDbCommand(strUpdate,conn);
                cmd.ExecuteNonQuery();
                conn.Close();
            }
        }
    }
   
}

解决方案 »

  1.   

    用viewstate保存状态
    选中checkbox后，为viewstate赋值，page load时根据iewstate的值显示控件状态
      

  2.   

    不需要在page_load写，直接在.aspx你新加checkbox那里写就OK了，比如<asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Eval("tuijian") == 1 ? True : False %>' />
      

  3.   

    这样做不行,提示出错:编译错误 
    说明: 在编译向该请求提供服务所需资源的过程中出现错误。请检查下列特定错误详细信息并适当地修改源代码。 编译器错误消息: CS0019: 运算符“==”无法应用于“object”和“int”类型的操作数源错误:行 24:                 <asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Eval("tuijian") == 1 ? True : False %>'/> <asp:Image ID="Image1" runat="server" ImageUrl='<%# Eval("smallImg") %>'   Width="150px" Height="150px"/><br />
     
    以下是我的界面生成代码:<%@ Page Language="C#" AutoEventWireup="true" CodeFile="TuiJian_Img.aspx.cs" Inherits="Admin_TuiJian_Img" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" >
    <head id="Head1" runat="server">
        <title>无标题页</title>
    </head>
    <body>
        <form id="form1" runat="server">
        <div  style="margin-left:auto;margin-right:auto; width:80%;" >
            选择类别:&nbsp;<asp:DropDownList ID="DropDownList2" runat="server" AutoPostBack="True" DataSourceID="AccessDataSource1" DataTextField="Type_Name" DataValueField="id">
            </asp:DropDownList><asp:AccessDataSource ID="AccessDataSource1" runat="server" DataFile="~/data/clothes.mdb"
                SelectCommand="SELECT [Type_Name], [id] FROM [Product_Type]"></asp:AccessDataSource>
            </div>
            <br />
            <br />
         
            <div style="margin-left:auto;margin-right:auto; width:100%; vertical-align:middle;">   
                <asp:DataList ID="DataList1" runat="server" RepeatColumns="3" CellPadding="3" CellSpacing="3" Width="100%"  RepeatDirection="Horizontal"  Height="500px" GridLines="Both" HorizontalAlign="Center">
                <ItemTemplate>
                
                    ID:<asp:Label ID="Label1" runat="server" Text='<%#Eval("ProductId") %>'>'></asp:Label><br />
                    <asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Eval("tuijian") == 1 ? True : False %>'/> <asp:Image ID="Image1" runat="server" ImageUrl='<%# Eval("smallImg") %>'   Width="150px" Height="150px"/><br />
                    产品名称:<asp:Label ID="Label2" runat="server" Text='<%#Eval("Product_Name")%>'>'></asp:Label>
                <br />
                </ItemTemplate>
                    <ItemStyle BorderStyle="Solid" />
                </asp:DataList>
                <asp:Button ID="Button1" runat="server" Text="确定" OnClick="Button1_Click" />
                <br />
                <br />
             共<asp:Label ID="lb_count" runat="server"></asp:Label>条记录
            &nbsp; &nbsp; &nbsp; 共<asp:Label ID="lb_page" runat="server"></asp:Label>页 &nbsp;
            &nbsp; 当前第<asp:Label ID="lb_CurrentPage" runat="server" Text="1"></asp:Label>页&nbsp; &nbsp;
            &nbsp; &nbsp;
            <asp:LinkButton ID="LinkFirst" runat="server" OnClick="LinkFirst_Click">第一页</asp:LinkButton>
            &nbsp; &nbsp;
            <asp:LinkButton ID="LinkUp" runat="server" OnClick="LinkUp_Click">上一页</asp:LinkButton>
            &nbsp; &nbsp;<asp:LinkButton ID="LinkDown" runat="server" OnClick="LinkDown_Click">下一页</asp:LinkButton>
            &nbsp; &nbsp;<asp:LinkButton ID="LinkLast" runat="server" OnClick="LinkLast_Click">最后一页</asp:LinkButton>
            &nbsp; &nbsp;转到第<asp:DropDownList ID="DropDownList1" runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" AutoPostBack="True">
            </asp:DropDownList>页        
             </div>
        </form>
    </body>
    </html>
      

  4.   

    <asp:CheckBox ID="CheckBox1" runat="server" Checked='<%# Eval("tuijian") == "1" ? True : False %>' />
    类型转换