i have select for gridview data showing textbox.

protected void Button5_Click(object sender, EventArgs e)

{

SqlConnection con = new SqlConnection();

int cmy_id = 0;

cmy_id = Convert.ToInt32(Request.QueryString["@cmy_id"].ToString());//Object reference not set to an instance of an object. error are display

if (!IsPostBack)

{

sel();

}

}

void sel()

{

string select = "select * from companydetail";

SqlCommand cmd = new SqlCommand(select, con);

SqlDataAdapter da = new SqlDataAdapter(cmd);

con.Close();

DataSet ds = new DataSet();

da.Fill(ds);

foreach (GridViewRow gvrow in GridView1.Rows)

{

CheckBox chck = gvrow.FindControl("CheckBox1") as CheckBox;

if (chck.Checked)

{

TextBox6.Text = ds.Tables[0].Rows[0][1].ToString();

}

}