如果选中gridview内的复选框，如何在数据库字段中插入0或1？

Question

I have a gridview on my web form and I have taken checkbox in the template field of my gridview. I want that if the checkbox is checked inside the gridview, it will insert 1 in my database column and if it is unchecked then it should insert 0 ie by default the field should be inserted with 0. I have tried doing this- My aspx page-

<asp:GridView ID="GridMain" runat="server" Width="1000px" 
        AutoGenerateColumns="False">
        <Columns>
            <asp:TemplateField HeaderText="Student Name">
                <ItemTemplate>
                    <asp:Label ID="lblname" runat="server" Text='<%# Eval("name") %>'></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField HeaderText="Enable/Disable">
                <ItemTemplate>
                    <asp:CheckBox ID="chkenbl" runat="server" AutoPostBack="True" 
                        oncheckedchanged="chkenbl_CheckedChanged" />
                    <br />
                    <asp:Label ID="Label1" runat="server" Text='<%# Eval("id") %>' Visible="False"></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>

My cs page-

public void show()
{
    try
    {
        dt = g1.return_dt("select id,name from tbl_data_show where en_dis='0' order by name");
        if (dt.Rows.Count > 0)
        {
            adsource = new PagedDataSource();
            adsource.DataSource = dt.DefaultView;
            adsource.PageSize = 5;
            GridMain.DataSource = adsource;
            GridMain.DataBind();
        }
    }
    catch (Exception ex)
    {
        Response.Write(ex.ToString());
    }
}
protected void chkenbl_CheckedChanged(object sender, EventArgs e)
{
    foreach (GridViewRow row in GridMain.Rows)
    {
        CheckBox chk = sender as CheckBox;
        if (chk.Checked)
        {
            try
            {
                //Label lblid = (Label)GridMain.FindControl("Label1");
                Label lblid = new Label();
                lblid.Text = GridMain.FindControl("Label1").ToString();
                rows=g1.ExecDB("insert into tbl_data_show(en_dis) values('1') where id="+lblid.Text);
                if (rows > 0)
                {
                    Response.Write("Rows Effected Successfull.");
                }
            }
            catch (Exception ex)
            {
                Response.Write(ex.ToString());
            }
        }
        else
        {
            //Label lblid1 = (Label)GridMain.FindControl("Label1");
            Label lblid1 = new Label();
            lblid1.Text = GridMain.FindControl("Label1").ToString();
            rows=g1.ExecDB("insert into tbl_data_show(en_dis) values('0') where id="+lblid1.Text);
            if (rows > 0)
            {
                Response.Write("Rows Effected Successfull.");
            }
        }
    }
}

Please guide me where I am going wrong. I am getting this exception "Object reference not set to an instance of an object.".

Answer 1

Well, now after getting some details I can tell that: 1) Your checkbox has autopostback=true which will cause post back on every checkbox click. In the code-behind cycle throw all rows and update, therefore you'll update all rows every time you click any checkbox. 2) For getting the Label.Text value you could try something like this:

CheckBox chkStatus = (CheckBox)sender;
GridViewRow row = (GridViewRow)chkStatus.NamingContainer;
Label lbl = (Label)row.FindControl("Label1");
string lblTxt = lbl.Text;

Or you could add custom attribute to your checkbox (rid="<%# Eval("id") %>") and to get its value instead of having hidden label:

string id = ((CheckBox)sender).Attributes["rid"].ToString();

Answer 2

if(chkenbl.IsChecked)
{
  insert 1..
}
else
{
   insert 0..
}