Textbox disappers due to post back and showed Error:Object reference not set to an in

[pen2satya]

I have a Gridview having 3 columns in which i took checkbox,label and label as item templates for columns select,code,name respectively.
ecode column is not editable.Button edit and update are present outside of gridview.

i can edit multiple rows like this...

when i select checkbox in 1st row of gridview then in ename column of that row i added textbox by this code

protected void btnEdit_Click(object sender, EventArgs e)
    {
        
        for (int i = 0; i < GridView1.Rows.Count; i++)
        {
            txteditEname = new TextBox();       
            CheckBox chkDelete = (CheckBox)GridView1.Rows[i].Cells[0].FindControl("chkSelect");
            Label lblEname = (Label)GridView1.Rows[i].Cells[0].FindControl("lblEname");
           
            if (chkDelete.Checked)
            {
                GridView1.Rows[i].Cells[2].Controls.Add(txteditEname);
                txteditEname.Text = lblEname.Text;
                lblEname.Visible = false;
            }

        }
    }

protected void btnUpdate_Click(object sender, EventArgs e)
    {
        ArrayList al = new ArrayList();

        for (int i = 0; i < GridView1.Rows.Count; i++)
        {

            CheckBox chkDelete = (CheckBox)GridView1.Rows[i].Cells[0].FindControl("chkSelect");
            txteditEname = (TextBox)GridView1.Rows[i].Cells[2].FindControl("txteditEname");
            string str=txteditEname.Text;//error

//here i set breakpoint and wanted to retrieve txteditEname but error comes...
then thinking that there is no such textbox when i press Update button as autopost back then
i saved the txteditEname 's value in Viewstate but when i retrieved viewstate it showed me the textbox's value before page is posted back.
But the current txteditEname's value is different which i want to update.Please tell me how to get curret txteditEname's value.
But before that i wonder if this textbox is not available then i'll surely get null value.

[kvprajapati]

Please refer the ASP.NET Page life cycle topic at MSDN. ASP.NET page and control objects are created on each post back.

[dnanetwork]

your code will never work..

you need to iterate through Gridview rows..

Checking should be done on RowDataBound Event..

foreach(GridviewRows Gvr in Gridview1.rows)
{
  Checkbox chk = (CheckBox)e.row.FindControl("Name Of Your Checkbox");

if(chk.checked == true)
{
 // carry out rest of the operation...
}
}