更新过程中命令执行过程中遇到致命错误 [英] fatal error encountered during command execution during update

问题描述

我使用此代码更新是在文本框中数据...此代码是在更新按钮，一旦我所做的更改并点击出现错误消息的按钮

 试
 {
的MySqlConnection连接=新的MySqlConnection（MyConnectionString）; 
的MySqlCommand CMD; 
 connection.Open（）; 
 CMD = connection.CreateCommand（）; 
 cmd.CommandText =UPDATE student_info SET SEM = @SEM，STUDENT_NO = @STUDENT_NO，姓氏= @LASTNAME+ 
，名字= @FIRSTNAME，中间名= @MIDDLENAME，CITY = @CITY，街道= @STREET，性别= @GENDER+ 
，当然= @COURSE，YEAR = @YEAR，SECTION = @SECTION，生日= @BIRTHDAY其中STUDENT_NO = @STUDENT_NO; 
 
 cmd.Parameters.AddWithValue（@ SEM，sem_combo.Text）; 
 cmd.Parameters.AddWithValue（@ STUDENT_NO，studentNo_txt.Text）; 
 cmd.Parameters.AddWithValue（@姓氏，lname_txt.Text）; 
 cmd.Parameters.AddWithValue（@名字，fname_txt.Text）; 
 cmd.Parameters.AddWithValue（@中间名，mname_txt.Text）; 
 cmd.Parameters.AddWithValue（@ CITY，address_txt.Text）; 
 cmd.Parameters.AddWithValue（@街，street_txt.Text）; 
 cmd.Parameters.AddWithValue（@性别，gender_combo.Text）; 
 cmd.Parameters.AddWithValue（@课程，program_combo.Text）; 
 cmd.Parameters.AddWithValue（@ YEAR，yr_combo.Text）; 
 cmd.Parameters.AddWithValue（@段，section_combo.Text）; 
 cmd.Parameters.AddWithValue（@你生日快乐，bday.Text）; 
 cmd.ExecuteNonQuery（）; 
 cmd.Parameters.Clear（）; 
 
 cmd.CommandText =UPDATE联系人设置电子邮件= @EMAIL，CELL_NO = @CELL_NO其中STUDENT_NO = @STUDENT_NO; 
 
 cmd.Parameters.AddWithValue（@ EMAIL，email_txt.Text）; 
 cmd.Parameters.AddWithValue（@ CELL_NO，contact_txt.Text）; 
 cmd.ExecuteNonQuery（）; 
 cmd.Parameters.Clear（）; 
} 
赶上（异常前）
 {
 MessageBox.Show（ex.Message）; 
} 
  

解决方案

检查在此行

  cmd.Parameters.Clear（）; 
 
 cmd.CommandText =UPDATE联系人设置电子邮件= @EMAIL，
 CELL_NO = @CELL_NO其中STUDENT_NO = @STUDENT_NO; 
 
 cmd.Parameters.AddWithValue（@ EMAIL，email_txt.Text）; 
 cmd.Parameters.AddWithValue（@ CELL_NO，contact_txt.Text）; 
 cmd.ExecuteNonQuery（）; 
 cmd.Parameters.Clear（）; 
  

更​​改为

  cmd.Parameters.Clear（）; 
 cmd.CommandText =UPDATE联系人设置电子邮件= @EMAIL，
 CELL_NO = @CELL_NO其中STUDENT_NO = @STUDENT_NO; 
 
 cmd.Parameters.AddWithValue（@ EMAIL，email_txt.Text）; 
 cmd.Parameters.AddWithValue（@ CELL_NO，contact_txt.Text）; 
 cmd.Parameters.AddWithValue（@ STUDENT_NOL，studentNo_txt.Text）; 
 cmd.ExecuteNonQuery（）; 
 cmd.Parameters.Clear（）; 
  

您都清楚了参数，但使用后 @STUDENT_NO 参数。清除后疗法参数

此参数不会宣布任何地方

i use this code to update data that are in the textboxes... this code is in the update button and once i made the changes and clicked the button the error message appears

        try
        {
            MySqlConnection connection = new MySqlConnection(MyConnectionString);
            MySqlCommand cmd;
            connection.Open();
            cmd = connection.CreateCommand();
            cmd.CommandText = "UPDATE student_info SET SEM = @SEM, STUDENT_NO = @STUDENT_NO, LASTNAME = @LASTNAME" +
            ", FIRSTNAME = @FIRSTNAME, MIDDLENAME = @MIDDLENAME, CITY = @CITY, STREET = @STREET, GENDER = @GENDER" +
            ", COURSE = @COURSE, YEAR = @YEAR, SECTION = @SECTION, BIRTHDAY = @BIRTHDAY  Where STUDENT_NO = @STUDENT_NO";

            cmd.Parameters.AddWithValue("@SEM", sem_combo.Text);
            cmd.Parameters.AddWithValue("@STUDENT_NO", studentNo_txt.Text);
            cmd.Parameters.AddWithValue("@LASTNAME", lname_txt.Text);
            cmd.Parameters.AddWithValue("@FIRSTNAME", fname_txt.Text);
            cmd.Parameters.AddWithValue("@MIDDLENAME", mname_txt.Text);
            cmd.Parameters.AddWithValue("@CITY", address_txt.Text);
            cmd.Parameters.AddWithValue("@STREET", street_txt.Text);
            cmd.Parameters.AddWithValue("@GENDER", gender_combo.Text);
            cmd.Parameters.AddWithValue("@COURSE", program_combo.Text);
            cmd.Parameters.AddWithValue("@YEAR", yr_combo.Text);
            cmd.Parameters.AddWithValue("@SECTION", section_combo.Text);
            cmd.Parameters.AddWithValue("@BIRTHDAY", bday.Text);
            cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();

            cmd.CommandText = "UPDATE contacts SET EMAIL = @EMAIL, CELL_NO = @CELL_NO Where STUDENT_NO = @STUDENT_NO";

            cmd.Parameters.AddWithValue("@EMAIL", email_txt.Text);
            cmd.Parameters.AddWithValue("@CELL_NO", contact_txt.Text);
            cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
        }
        catch(Exception ex)
        {
            MessageBox.Show(ex.Message);
        }

解决方案

Check in This Line

            cmd.Parameters.Clear();

            cmd.CommandText = "UPDATE contacts SET EMAIL = @EMAIL,
            CELL_NO = @CELL_NO Where STUDENT_NO = @STUDENT_NO";

            cmd.Parameters.AddWithValue("@EMAIL", email_txt.Text);
            cmd.Parameters.AddWithValue("@CELL_NO", contact_txt.Text);
            cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();

Change To

            cmd.Parameters.Clear();
            cmd.CommandText = "UPDATE contacts SET EMAIL = @EMAIL,
            CELL_NO = @CELL_NO Where STUDENT_NO = @STUDENT_NO";

            cmd.Parameters.AddWithValue("@EMAIL", email_txt.Text);
            cmd.Parameters.AddWithValue("@CELL_NO", contact_txt.Text);
            cmd.Parameters.AddWithValue("@STUDENT_NOL",studentNo_txt.Text);
            cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();

you are clear the parameters, but after that use @STUDENT_NO parameter. This parameter is not declare any where after clear ther parameters

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