Question

我是C＃的新手，需要一些帮助来验证可以在插入之前添加到访问数据库的输入。

如果没有输入某些内容，那么大多数验证将会出现一个消息框，显示“没有输入任何内容”或者某些内容需要更多字符，然后“长度太短”。我怎么能实现这样的目标？

这是我的代码：

using System;
using System.Collections.Generic;
using System.Data.OleDb;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using ClassLibrary;
using System.Data;

namespace ClassLibrary2
{
    public class Class1
    {
        OleDbConnection connection;
        OleDbCommand command;

        private void ConnectTo()
        {
            connection = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=F:\CMS\CustomerDatabase.accdb;Persist Security Info=False");
            command = connection.CreateCommand();
        }
        public Class1()
        {
            ConnectTo();
        }

        public void Insert(Customer p)
        {
            try
            {
                command.CommandText = "INSERT INTO CustomerData ([Forename], [Surname], [Email Address], [Home Phone Number], [Mobile Phone Number], [Address], [AreaTown], [County], [Postcode]) VALUES('" + p.Forename1 + "', '" + p.Surname1 + "', '" + p.EAddress1 + "', '" + p.HomePhone1 + "' , '" + p.MobNum1 + "' , '" + p.Address1 + "', '" + p.AreaTown1 + "', '" + p.County1 + "', '" + p.Postcode1 + "')";
                command.CommandType = CommandType.Text;
                connection.Open();

                command.ExecuteNonQuery();
            }
            catch (Exception)
            {
                throw;
            }
            finally
            {
                if (connection != null)
                {
                    connection.Close();
                }
            }
        }

        public List<Customer> FillComboBox()
        {
            List<Customer> CustomersList = new List<Customer>();
            try
            {
                command.CommandText = "SELECT * FROM CustomerData";
                command.CommandType = CommandType.Text;
                connection.Open();

                OleDbDataReader reader = command.ExecuteReader();

                while (reader.Read())
                {
                    Customer p = new Customer();

                    p.Id = Convert.ToInt32(reader["ID"].ToString());
                    p.Forename1 = reader["Forename"].ToString();
                    p.Surname1 = reader["Surname"].ToString();
                    p.EAddress1 = reader["Email Address"].ToString();
                    p.HomePhone1 = reader["Home Phone Number"].ToString();
                    p.MobNum1 = reader["Mobile Phone Number"].ToString();
                    p.Address1 = reader["Address"].ToString();
                    p.AreaTown1 = reader["AreaTown"].ToString();
                    p.County1 = reader["County"].ToString();
                    p.Postcode1 = reader["Postcode"].ToString();

                    CustomersList.Add(p);
                }
                 return CustomersList;
            }
            catch (Exception)
            {
                throw;
            }
            finally
            {
                if (connection != null)
                {
                    connection.Close();
                }
            }    
        }

        public void Update(Customer oldCustomer, Customer newCustomer)
        {
            try
            {
                command.CommandText = "UPDATE CustomerData SET [Forename] = @newCustomer.Forename1, [Surname] = @newCustomer.Surname1, [Email Address] = @newCustomer.EAddress1, [Home Phone Number]= @newCustomer.HomePhone1, [Mobile Phone Number] = @newCustomer.MobNum1, [Address]= @newCustomer.Address1, [AreaTown] = @newCustomer.AreaTown1, [County]= @newCustomer.County1, [Postcode]= @newCustomer.Postcode1 WHERE [ID] = @oldCustomer.Id";
                command.Parameters.AddWithValue("@Forename", newCustomer.Forename1);
                command.Parameters.AddWithValue("@Surname", newCustomer.Surname1);
                command.Parameters.AddWithValue("@Email Address", newCustomer.EAddress1);
                command.Parameters.AddWithValue("@Home Phone Number", newCustomer.HomePhone1);
                command.Parameters.AddWithValue("@Mobile Phone Number", newCustomer.MobNum1);
                command.Parameters.AddWithValue("@Address", newCustomer.Address1);
                command.Parameters.AddWithValue("@AreaTown", newCustomer.AreaTown1);
                command.Parameters.AddWithValue("@County", newCustomer.County1);
                command.Parameters.AddWithValue("@Postcode", newCustomer.Postcode1);
                command.Parameters.AddWithValue("@ID", oldCustomer.Id);

                command.CommandType = CommandType.Text;
                connection.Open();

                command.ExecuteNonQuery();
            }
            catch (Exception)
            {
                throw;
            }
            finally
            {
                 if (connection != null)
                {
                   connection.Close();
                }
            }
        }

感谢您的帮助，我真的很挣扎

Answer 1

如果要存档，请尝试在执行保存功能之前实现检查每个验证的函数希望以下示例函数能给你一个想法

      private bool CheckValidation(  )
      {

            bool returnBool = true;

            if ( string.IsNullOrWhiteSpace(txtName.txt) )
            {
                 //Show a label next to you text box

                 returnBool = false;
            }


            return returnBool;

      }

如果返回值为true，请使用SP将数据保存到数据库希望这会指导你。有关额外信息，您了解SQLHelper类。它将使您的生活更轻松，因此您无需在每个地方实施连接和SP呼叫。如果没有让我知道将发送给你样品项目。

欢迎来到.NET世界

的问候， Pubudu

Answer 2

using System.Linq;
using System.Text;
using System.Threading.Tasks;
using ClassLibrary;
using System.Data;

namespace DAL
{
    public static class CustomerDAL
    {
     public static void Insert(Customer p){.......}
     public static List<Customer> FillComboBox(){......}
     public void Update(Customer oldCustomer, Customer newCustomer){.......}
    }
}
----------------------------------------------------
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using ClassLibrary;
using System.Data;

namespace BAL
{
    public class Customer
    {
     public int Id {get;set;}
     public string Name {get;set;}
     .......................
     .......................
    }
}
------------------------------------------------------
In UI Create a Windows or Web Form and add buttons and textbox and on buttonSave_Click event 
If(txtName.Text=="")
{
MessageBox.Show("Some text", "Some title", 
    MessageBoxButtons.OK, MessageBoxIcon.Error);
    txtName.Focus();
}
else
{
//calling BAL
var cus=new Customer{
Name=txtName.Text
}
//Calling DAL
CustomerDAL.Insert(cus);
MessageBox.Show("Information", "Record saved successfully inti the database.", 
    MessageBoxButtons.OK, MessageBoxIcon.Information);
    txtName.tex="";

}

Hope this will help you.

创建一个解决方案，给它一个正确的名称。然后在解决方案中创建两个组件项目BAL和DAL。如果你仍然对组件感到困惑，那么避免创建程序集和后续链接可能会帮助你。 http://www.tutorialized.com/tutorial/3-Tier-Architecture-in-asp.net-using-c/67931

Answer 3

应在代码接近数据层之前验证用户输入的长度，模式，文本与数字等。这就是正则表达式擅长的。关于使用它们的信息很多，所以我不打算在这里重复一遍。只需使用bingoogle正则表达式，您就会发现大量信息。

验证数据库输入C＃访问Oledb

3 个答案: