How to solve error Unable to cast object of type 'System.Web.UI.WebControls.DataContr

[sana krishna]

Hai,
Pls anyone help me...........................
I am using ASP.NET(C#).
I want to display the data in a gridview and make the gridview to become editable and insert and delete.
But i can't perform edit .
when i click update button
It display a error message like this......

Unable to cast object of type 'System.Web.UI.WebControls.DataControlLinkButton' to type 'System.Web.UI.WebControls.TextBox'.

My code is
protected void grdvwteleno_RowEditing(object sender, GridViewEditEventArgs e)
{
grdvwteleno.EditIndex = e.NewEditIndex;
BindData();
}
protected void grdvwteleno_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
DataTable dt = (DataTable)Session["dt"];

GridViewRow row = grdvwteleno.Rows[e.RowIndex];
dt.Rows[grdvwteleno.EditIndex]["SL"] = ((TextBox)(row.Cells[1].Controls[0])).Text.ToString();
dt.Rows[grdvwteleno.EditIndex]["Name"] = ((TextBox)(row.Cells[2].Controls[0])).Text.ToString();
dt.Rows[grdvwteleno.EditIndex]["Id"] = ((TextBox)(row.Cells[3].Controls[0])).Text.ToString();

[Plater]

Sometimes I wonder about the language barrier.
That error message is very clear. One of those things you think is a TextBox, is really a DataControlLinkButton. Figure out which one (it probably pointed to the offending line number in the error message) and correct your mistake.