SqlConnection con = new SqlConnection();
con.Open();
SqlCommand cmd = new SqlCommand("select count(*) from [User] where [Name]='" + TxtName.Text.Trim() + "'", con);
int count = (int)cmd.ExecuteScalar();
con.Close();
if (count >= 1)
{
this.cue.Text = "用户已经被注册";
}
else
{
this.cue.Text = "用户未被注册";
}