You must Sign In to post a response.
  • Category: .NET

    How to get rid of the problem occured when inserting dynamic control values "

    hi all i am creating a table with controls when i enter value 1 in textbox and click submit button
    1 table with controls should be created so if i enter value 2 in textbox and click on submit button
    2 tables with controls should be displayed,,,,,up to this ok
    when i am inserting this dynamic controls values to database then error coming like object reference not set to an instance of object
    so below is the code where i am wrong plz suggest me
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Web;
    using System.Web.UI;
    using System.Web.UI.WebControls;
    using System.Data;
    using System.Data.SqlClient;

    public partial class dynamic2 : System.Web.UI.Page
    {
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {

    int rowCount = Convert.ToInt32(TextBox1.Text);
    Table tbldynamic = new Table();
    //Table tblanother = new Table();
    //Table tba = new Table();
    //Table per = new Table();
    //Table ing = new Table();
    tbldynamic.ID = "table1";
    //tblanother.ID = "table 2";
    //tba.ID = "table3";
    //per.ID = "table4";
    //ing.ID = "table5";
    TableCell tc = new TableCell();
    TableRow tr1 = new TableRow();

    TableCell tc1 = new TableCell();
    TableRow tr2 = new TableRow();
    TableCell tc2 = new TableCell();
    TableRow tr3 = new TableRow();
    TableCell tc3 = new TableCell();
    TableRow tr4 = new TableRow();
    TableCell tc4 = new TableCell();
    TableRow tr5 = new TableRow();


    for (int i = 0; i < rowCount; i++)
    {


    TextBox TxtBoxU = new TextBox();

    TextBox TxtBoxE = new TextBox();
    TextBox txt = new TextBox();
    CheckBox chk = new CheckBox();

    CheckBox chka = new CheckBox();
    Label lblU = new Label();
    Label lblE = new Label();
    Label lbh = new Label();
    Label lba = new Label();
    Label grade = new Label();
    DropDownList dd = new DropDownList();
    ListItem[] items = new ListItem[3];
    items[0] = new ListItem("A Grade", "1");
    items[1] = new ListItem("B Grade", "2");

    items[2] = new ListItem("C Grade", "3");
    dd.Items.AddRange(items);
    dd.DataBind();
    TxtBoxU.ID = "TextBoxU" + i.ToString();
    TxtBoxE.ID = "TextBoxE" + i.ToString();
    txt.ID = "txt" + i.ToString();
    chk.ID = "chk" + i.ToString();
    chka.ID = "chka" + i.ToString();
    lblU.ID = "LabelU" + i.ToString();
    lblE.ID = "LabelE" + i.ToString();
    lbh.ID = "label h" + i.ToString();
    lba.ID = "labela" + i.ToString();
    grade.ID = "labelb" + i.ToString();
    dd.ID = "da" + i.ToString();
    lblU.Text = "Children firstname: ";
    Panel1.Controls.Add(lblU);
    Panel1.Controls.Add(TxtBoxU);
    lblE.Text = "children lastname : ";
    Panel1.Controls.Add(lblE);
    Panel1.Controls.Add(TxtBoxE);
    lbh.Text = "Going to school?:";
    Panel1.Controls.Add(lbh);
    Panel1.Controls.Add(chk);
    Panel1.Controls.Add(chka);
    lba.Text = "school name:";
    grade.Text = "Grade:";
    Panel1.Controls.Add(lba);
    Panel1.Controls.Add(txt);
    Panel1.Controls.Add(grade);
    Panel1.Controls.Add(dd);

    tc.Controls.Add(lblU);
    tc.Controls.Add(TxtBoxU);
    chk.Text = "yes";
    chka.Text = "no";
    tc4.Controls.Add(grade);
    tc4.Controls.Add(dd);
    tr1.Cells.Add(tc);
    tr1.Cells.Add(tc);
    tc1.Controls.Add(lblU);
    tc1.Controls.Add(TxtBoxU);
    tc2.Controls.Add(lbh);
    tc2.Controls.Add(chk);
    tc2.Controls.Add(chka);
    tc3.Controls.Add(lba);
    tc3.Controls.Add(txt);
    tr4.Cells.Add(tc3);
    tr4.Cells.Add(tc3);
    tr3.Cells.Add(tc2);
    tr3.Cells.Add(tc2);
    tr3.Cells.Add(tc2);
    tr2.Cells.Add(tc1);
    tr2.Cells.Add(tc1);
    tr5.Cells.Add(tc4);
    tr5.Cells.Add(tc4);
    tbldynamic.Controls.Add(tr1);
    tbldynamic.Controls.Add(tr1);
    //tbldynamic.Controls.Add(tr2);
    //tbldynamic.Controls.Add(tr2);
    //tbldynamic.Controls.Add(tr3);
    //tbldynamic.Controls.Add(tr3);
    //tbldynamic.Controls.Add(tr3);

    //tbldynamic.Controls.Add(tr4);
    //tbldynamic.Controls.Add(tr4);
    //tbldynamic.Controls.Add(tr5);
    //tbldynamic.Controls.Add(tr5);
    tbldynamic.Controls.Add(tr2);
    tbldynamic.Controls.Add(tr2);
    tbldynamic.Controls.Add(tr3);
    tbldynamic.Controls.Add(tr3);
    tbldynamic.Controls.Add(tr3);
    tbldynamic.Controls.Add(tr4);
    tbldynamic.Controls.Add(tr4);
    tbldynamic.Controls.Add(tr5);
    tbldynamic.Controls.Add(tr5);


    Panel1.Controls.Add(tbldynamic);


    //Panel1.Controls.Add(tblanother);
    //Panel1.Controls.Add(tba);
    //Panel1.Controls.Add(per);
    //Panel1.Controls.Add(ing);


    }
    }

    protected void Button2_Click(object sender, EventArgs e)
    {
    String str = string.Empty;
    TextBox firstname = (TextBox)Panel1.FindControl("TxtBoxU");
    // str = txtUserName.Text;
    TextBox lastname = (TextBox)Panel1.FindControl("txtEmail");
    CheckBox chkk = (CheckBox)Panel1.FindControl("chk");
    TextBox txttt = (TextBox)Panel1.FindControl("txt");
    DropDownList dda = (DropDownList)Panel1.FindControl("dd");
    using (SqlConnection con = new SqlConnection("Data Source=HOME;Initial Catalog=login;Integrated Security=True"))
    {
    using (SqlCommand cmd = new SqlCommand("INSERT INTO studentdetails(sname,slname,gsch,ssname,sgr) VALUES(@sname,@slname,@gsch,@ssname,@sgr)", con))
    {
    con.Open();
    cmd.Parameters.AddWithValue("@sname", firstname.Text);
    cmd.Parameters.AddWithValue("@slname", lastname.Text);
    cmd.Parameters.AddWithValue("@gsch", chkk.Text);
    cmd.Parameters.AddWithValue("@ssname", txttt.Text);
    cmd.Parameters.AddWithValue("@sgr", dda.SelectedItem.Text);
    cmd.ExecuteNonQuery();
    firstname.Text = string.Empty;
    lastname.Text = string.Empty;
    chkk.Text = string.Empty;
    txttt.Text = string.Empty;
    dda.SelectedItem.Text = string.Empty;
    //lastname.Text = string.Empty;
    }
    }
    }
    }
  • #762892
    Hello Velidi Viram,

    object reference not set to an instance of object means the control's value you want to pass its's values is null which can not passed.

    I suggest you to put the breakpoint in your code and check whether the values you are passing with your dynamic control. do they have values or not.

    So it will help you to understand that where you are wrong.

    Hope you understand.

    Regards,
    Nirav Lalan
    DNS Gold Member
    "Failure is the path of least persistence"

  • #762896
    Hi

    Don't post the same thread again and again repeatedly.
    If you don't get answer then post as comment under your previous thread.
    Duplicate thread, hence closing.

    Sridhar Thota.
    Editor: DNS Forum.


This thread is locked for new responses. Please post your comments and questions as a separate thread.
If required, refer to the URL of this page in your new post.