protected void btnview_Click(object sender, EventArgs e)
{
GridView1.Visible = true;
BindGridView();//Function to bind the gridview
}

protected void btnview_Click(object sender, EventArgs e)
{
GridView1.Visible = true;
GridData();
}

//here i write common method call again wherever i required
void GridData()
{
        sqlcmd = new SqlCommand("select * from emp", sqlcon);
        sqlcon.Open();
        da = new SqlDataAdapter(sqlcmd);
        dt.Clear();
        da.Fill(dt);
        GridView1.DataSource = dt;
        GridView1.DataBind();
        sqlcon.Close();
}