c#登陆问题求解!!!!!

Question

代码如下
        private void UserCheck() 
        {
            string sql = string.Format("select count(*) from Admin where LoginId={0} and LoginPwd={1}", TxtName.Text.Trim(), TxtPwd.Text.Trim());
            bool result = DBHelpe.Execulse(sql);
            if (result)
            {
                admin dm = new admin();
                dm.Show();
            }
namespace WindowsApplication1
{
class DBHelpe
    {
        public static string connction = "Data Source=.;Initial Catalog=MySchool;User ID=sa;pwd=123456";
        public static SqlConnection coon = new SqlConnection(connction);
        public static bool Execulse(string sql)
        {
            coon.Open();
            SqlCommand cmd = new SqlCommand(sql,coon);
            int result = (int)cmd.ExecuteScalar();
            if (result > 0)
            {
                return true;
            }
            else
            {
                return false;
            }        }
    }
}
连接了数据库,为什么运行输入账号密码,点击登陆 也不提示出错,什么反应也没,卡住了!  到底怎么回事求解!!!! 

Answer 1

        private void button2_Click(object sender, EventArgs e)
        {
            if (Input())
            {
                UserCheck();
            }
登陆语句        

Answer 2

select count(*) from Admin where LoginId={0} and LoginPwd={1}
int result = (int)cmd.ExecuteScalar();
---------------
这个结果无论神马时候都返回1啊
应该改成select * from Admin where LoginId={0} and LoginPwd={1}

Answer 3

       public bool UserCheck() 
        {
            string connction = "Data Source=.;Initial Catalog=MySchool;User ID=sa;pwd=123456";
            SqlConnection coon = new SqlConnection(connction);
            try
            {
                coon.Open();
                string sql = string.Format("select count(*) from Admin where LoginId='{0}' and LoginPwd='{1}'", TxtName.Text.Trim(), TxtPwd.Text.Trim());
                SqlCommand cmd = new SqlCommand(sql, coon);
                int result = (int)cmd.ExecuteScalar();
                if (result > 0)
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                coon.Close();
            }
}
提示出错,并非所有的代码路径都有返回值!  哪出错了?

Answer 4

修改如下 public bool UserCheck()
        {
            bool flag = false;
            string connction = "Data Source=.;Initial Catalog=MySchool;User ID=sa;pwd=123456";
            SqlConnection coon = new SqlConnection(connction);
            try
            {
                coon.Open();
                string sql = string.Format("select count(*) from Admin where LoginId='{0}' and LoginPwd='{1}'", TxtName.Text.Trim(), TxtPwd.Text.Trim());
                SqlCommand cmd = new SqlCommand(sql, coon);
                int result = (int)cmd.ExecuteScalar();
                if (result > 0)
                {
                    flag= true;
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                coon.Close();
            }
            return flag;
        }

Answer 5

你开了无数次con.open,又不关，不卡才怪啊