如何使用C#语言在数据库中插入记录? [英] How to insert Records in Database using C# language?

问题描述

我只是 C# 的初学者，所以我需要太多帮助.现在的问题是我设计了一个 windows 窗体，其中有很多字段，如名字、姓氏、地址等.现在我想做的是，当我填写表格并单击插入按钮时，所有信息都会进入数据库.有人知道怎么做吗?

I am just a begginer on C# so i need too much help. Now the problem is that i have designed a windows form in which there are many fields like first name, last name, address etc. Now i want to do is that when i fill the form and click insert button all the information goes into database. Does anyone know how to do that?

private void button1_Click(object sender, System.EventArgs e)
{
    string connetionString = null;
    SqlConnection cnn ;
    SqlDataAdapter adapter = new SqlDataAdapter();
    string sql = null;
    connetionString = "Data Source=UMAIR;Initial Catalog=Air; Trusted_Connection=True;" ;

    cnn = new SqlConnection(connetionString);
    sql = "insert into Main (Firt Name, Last Name) values(textbox2.Text,textbox3.Text)";

    try
    {
        cnn.Open();
        adapter.InsertCommand = new SqlCommand(sql, cnn);
        adapter.InsertCommand.ExecuteNonQuery();
         MessageBox.Show ("Row inserted !! ");
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.ToString());
    }
}

推荐答案

您的查询有很多问题.
这是您代码的修改版本

There are many problems in your query.
This is a modified version of your code

string connetionString = null;
string sql = null;

// All the info required to reach your db. See connectionstrings.com
connetionString = "Data Source=UMAIR;Initial Catalog=Air; Trusted_Connection=True;" ;

// Prepare a proper parameterized query 
sql = "insert into Main ([Firt Name], [Last Name]) values(@first,@last)";

// Create the connection (and be sure to dispose it at the end)
using(SqlConnection cnn = new SqlConnection(connetionString))
{
    try
    {
       // Open the connection to the database. 
       // This is the first critical step in the process.
       // If we cannot reach the db then we have connectivity problems
       cnn.Open();

       // Prepare the command to be executed on the db
       using(SqlCommand cmd = new SqlCommand(sql, cnn))
       {
           // Create and set the parameters values 
           cmd.Parameters.Add("@first", SqlDbType.NVarChar).Value = textbox2.text;
           cmd.Parameters.Add("@last", SqlDbType.NVarChar).Value = textbox3.text;

           // Let's ask the db to execute the query
           int rowsAdded = cmd.ExecuteNonQuery();
           if(rowsAdded > 0) 
              MessageBox.Show ("Row inserted!!" + );
           else
              // Well this should never really happen
              MessageBox.Show ("No row inserted");

       }
    }
    catch(Exception ex)
    {
        // We should log the error somewhere, 
        // for this example let's just show a message
        MessageBox.Show("ERROR:" + ex.Message);
    }
}

• 列名包含空格(应该避免)，因此您需要方括号括起来
• 您需要使用 using 语句来确保连接将被关闭并释放资源
• 您将控件直接放在字符串中，但这不起作用
• 您需要使用参数化查询来避免引用问题和sqlinjiection 攻击
• 无需为简单的插入查询使用 DataAdapter
• 不要使用 AddWithValue，因为它可能是错误的来源(见下面的链接)
• The column names contain spaces (this should be avoided) thus you need square brackets around them
• You need to use the using statement to be sure that the connection will be closed and resources released
• You put the controls directly in the string, but this don't work
• You need to use a parametrized query to avoid quoting problems and sqlinjiection attacks
• No need to use a DataAdapter for a simple insert query
• Do not use AddWithValue because it could be a source of bugs (See link below)

除此之外，还有其他潜在的问题.如果用户没有在文本框控件中输入任何内容怎么办?在尝试插入之前，您是否对此进行了任何检查?正如我所说，字段名称包含空格，这会给您的代码带来不便.尝试更改这些字段名称.

Apart from this, there are other potential problems. What if the user doesn't input anything in the textbox controls? Do you have done any checking on this before trying to insert? As I have said the fields names contain spaces and this will cause inconveniences in your code. Try to change those field names.

此代码假定您的数据库列是 NVARCHAR 类型，如果不是，则使用适当的 SqlDbType 枚举 值.

This code assumes that your database columns are of type NVARCHAR, if not, then use the appropriate SqlDbType enum value.

请计划尽快切换到更新版本的 NET Framework.1.1 现在真的过时了.

Please plan to switch to a more recent version of NET Framework as soon as possible. The 1.1 is really obsolete now.

而且，关于 AddWithValue 问题，这篇文章解释了为什么我们应该避免它.我们可以停止使用 AddWithValue() 已经?

And, about AddWithValue problems, this article explain why we should avoid it. Can we stop using AddWithValue() already?

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