string str="";
SqlCommand cmd = new SqlCommand();
cmd.Connection = DB.Create_Connection();//连接数据库的
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "sp_password";
SqlParameter para3 = new SqlParameter("@old", SqlDbType.VarChar);
para3.Value = txt_jiumm.Text.Trim();
cmd.Parameters.Add(para3);
SqlParameter para4 = new SqlParameter("@new", SqlDbType.VarChar);
para4.Value = txt_xinmm.Text.Trim();
cmd.Parameters.Add(para4);
SqlParameter para5 = new SqlParameter("@loginame", SqlDbType.VarChar);
para5.Value = txt_name.Text.Trim();
cmd.Parameters.Add(para5);
str = cmd.ExecuteScalar().ToString();
帮我看看为什么会报“未将对象引用设置为对象的实例”
SqlCommand cmd = new SqlCommand();
cmd.Connection = DB.Create_Connection();//连接数据库的
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "sp_password";
SqlParameter para3 = new SqlParameter("@old", SqlDbType.VarChar);
para3.Value = txt_jiumm.Text.Trim();
cmd.Parameters.Add(para3);
SqlParameter para4 = new SqlParameter("@new", SqlDbType.VarChar);
para4.Value = txt_xinmm.Text.Trim();
cmd.Parameters.Add(para4);
SqlParameter para5 = new SqlParameter("@loginame", SqlDbType.VarChar);
para5.Value = txt_name.Text.Trim();
cmd.Parameters.Add(para5);
str = cmd.ExecuteScalar().ToString();
帮我看看为什么会报“未将对象引用设置为对象的实例”
这行出的问题
SqlCommand cmd = new SqlCommand();
cmd.Connection = DB.Create_Connection();//连接数据库的
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "sp_password";
SqlParameter para3 = new SqlParameter("@old", SqlDbType.VarChar);
para3.Direction = ParameterDirection.Input;
para3.Value = txt_jiumm.Text.Trim();
cmd.Parameters.Add(para3);
SqlParameter para4 = new SqlParameter("@new", SqlDbType.VarChar);
para3.Direction = ParameterDirection.Input;
para4.Value = txt_xinmm.Text.Trim();
cmd.Parameters.Add(para4);
SqlParameter para5 = new SqlParameter("@loginame", SqlDbType.VarChar);
para3.Direction = ParameterDirection.Input;
para5.Value = txt_name.Text.Trim();
cmd.Parameters.Add(para5);
str = cmd.ExecuteScalar().ToString();
para4.Direction = ParameterDirection.Input;
para5.Direction = ParameterDirection.Input;
加这3句看看
cmd.ExecuteScalar() 返回了 null,所以出错了。
SqlCommand cmd = new SqlCommand();
cmd.Connection = DB.Create_Connection();
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "sp_password";
SqlParameter para3 = new SqlParameter("@old", SqlDbType.VarChar);
para3.Value = txt_jiumm.Text.Trim();
cmd.Parameters.Add(para3);
SqlParameter para4 = new SqlParameter("@new", SqlDbType.VarChar);
para4.Value = txt_xinmm.Text.Trim();
cmd.Parameters.Add(para4);
SqlParameter para5 = new SqlParameter("@loginame", SqlDbType.VarChar);
para5.Value = txt_name.Text.Trim();
cmd.Parameters.Add(para5);
SqlParameter para6= new SqlParameter("@Return", SqlDbType.VarChar);
para6.Direction = ParameterDirection.ReturnValue;
cmd.Parameters.Add(para6);
cmd.ExecuteScalar();
str = cmd.Parameters["@Return"].Value.ToString();
// str =cmd.ExecuteScalar() .ToString();这样就可以了