当读取器对标签执行数据时,显示这样的错误,我该怎么办
我在这里给出了错误图像的链接: https://ibb.co/MMKchWC
private void balance_enery_Load(object sender, EventArgs e)
{
label3.Visible = false;
con.Open();
SqlCommand cmd = new SqlCommand("select * from transactions where account_no='" + label3.Text + "'", con);
SqlDataReader rdr = cmd.ExecuteReader();
if (rdr.Read())
{
label2.Text = rdr["total"].ToString();
}
rdr.Close();
rdr.Dispose();
con.Close();
}