界面输入值和数据库值进行比较

protected void Button1_Click(object sender, EventArgs e)
{
if (TextBox1.Text != "")
{
string strConnection = "server=.;database=colorring;uid=sa;pwd=";
string strSql = "select top 1 ringid from s50usersysringgrp where ringid=@ringid";
SqlConnection con = new SqlConnection(strConnection);
SqlCommand com = new SqlCommand(strSql, con);
con.Open();

com.Parameters.Add("@ringid", SqlDbType.Char, 12).Value = TextBox1.Text;
SqlDataReader dr = com.ExecuteReader();
if (dr.Read())
{
TextBox2.Text = "数据库中有该ringid";
}
else
{
TextBox2.Text = "数据库中没有该ringid";
}
dr.Close();
con.Close();
}
else
{
TextBox2.Text = "你没有输入任何值";
}

}