如何编写我的更新按钮然后更新的数据将保存在我的数据库中，更新的数据将显示在我的列表视图中？ [英] How I gonna code my update button then the updated data will be saved in my database and also the updated data will appear to my listview?

问题描述

Private Sub Button2_Click（发件人为对象，e为EventArgs）处理Button2.Click

Dim mycomboentry为ComboBox（）= New ComboBox（）{Comboentry1，Comboentry2，Comboentry3，Comboentry4，Comboentry5，Comboentry6 }

Dim mycombotitle As ComboBox（）= New ComboBox（）{Combotitle1，Combotitle2，Combotitle3，Combotitle4，Combotitle5，Combotitle6}

Dim mytxtquan As TextBox（）= New TextBox （）{txtquan1，txtquan2，txtquan3，txtquan4，txtquan5，txtquan6}

Dim mytxtprice As TextBox（）= New TextBox（）{txtprice1，txtprice2，txtprice3，txtprice4，txtprice5，txtprice6}
Dim mytxtamount As TextBox（）= New TextBox（）{txtamount1，txtamount2，txtamount3，txtamount4，txtamount5，txtamount6}

Dim result As Integer = MessageBox.Show（你确定吗？你想要更新？，Salesbook，MessageBoxButtons.YesNoCancel）

ListView1.SelectedItems.Clear（）

connect（）

如果result = DialogResult.Cancel然后

MessageBox.Show（取消按下）

ElseIf result = DialogResult.No然后

MessageBox.Show （没有按下）



ElseIf结果= DialogResult.Yes然后

尝试



command = New MySqlCommand（UPDATE tblsalesbook SET Date_Ordered ='& DateTimePicker1.Text& '，Customer_Name ='& TextBox1.Text& '，Entry ='& mycomboentry（counter）.Text& '，Account_Title ='& mycombotitle（counter）.Text& '，Quantity ='& mytxtquan（counter）.Text& '，Unit_Price ='& mytxtprice（counter）.Text& '，Amount ='& mytxtamount（counter）.Text& 'WHERE Sales_Invoice ='& TextBox2.Text& '），连接字符串）

command.ExecuteReader（）

fillListview（）



Catch ex As例外

断开连接（）



结束尝试

MessageBox.Show（成功更新！）

结束如果





结束次级



我尝试过：

 私人  Sub  Button2_Click（发件人作为 对象， e  As  EventArgs）句柄 Button2.Click 
  Dim  mycomboentry  As  ComboBox（）= 新 ComboBox（）{Comboentry1，Comboentry2，Comboentry3， Comboentry4，Comboentry5，Combo entry6} 
  Dim  mycombotitle  As  ComboBox（）= 新 ComboBox（）{Combotitle1，Combotitle2，Combotitle3，Combotitle4，Combotitle5，Combotitle6} 
  Dim  mytxtquan  As  TextBox（）= 新 TextBox（）{txtquan1，txtquan2，txtquan3，txtquan4，txtquan5，txtquan6} 
  Dim  mytxtprice  As  TextBox（）= 新 TextBox（）{ txtprice1，txtprice2，txtprice3，txtprice4，txtprice5，txtprice6} 
  Dim  mytxtamount  As  TextBox（） = 新 TextBox（）{txtamount1，txtamount2，txtamount3，txtamount4，txtamount5，txtamount6} 
  Dim 结果作为 整数 = MessageBox.Show（ 您确定要更新吗？，  Salesbook，MessageBoxButtons .YesNoCancel）
 ListView1.SelectedItems.Clear（）
 connect（）
 如果 result = DialogResult.Cancel 然后 
 MessageBox.Show（ 取消按下 ）
  ElseIf  result = DialogResult.No 然后 
 MessageBox.Show（ 没有按）
 
  ElseIf  result = DialogResult.Yes 然后 
 尝试 
 
 command = 新 MySqlCommand（  UPDATE tblsalesbook SET Date_Ordered ='& DateTimePicker1.Text&  '，Customer_Name ='& TextBox1.Text&  '，Entry ='& mycomboentry（counter）.Text&  '，Account_Title ='& mycombotitle（counter）.Text&  '，Quantity ='& mytxtquan（counter）.Text&  '，Unit_Price ='& mytxtprice（counter）.Text&  '，Amount ='& mytxtamount（counter）.Text&  'WHERE Sales_Invoice ='& TextBox2.Text&  '），连接字符串）
 command.ExecuteReader（）
 fillListview（ ）
 
  Catch  ex  As 例外
 disconnect（）
 
 结束 尝试 
 MessageBox.Show（ 已成功更新！）
 结束 如果 
 
 
 结束  Sub  
 

解决方案

 command = 新 MySqlCommand（  UPDATE tblsalesbook SET Date_Ordered ='& DateTimePicker1.Text &  '，Customer_Name ='& TextBox1.Text&  '，Entry ='& mycomboentry（counter）.Text&  '，Account_Title ='& mycombotitle（counter）.Text&  '，Quantity ='& mytxtquan（counter）.Text&  '，Unit_Price ='& mytxtprice（counter）.Text&  '，Amount ='& mytxtamount（counter）.Text&  'WHERE Sales_Invoice ='& TextBox2.Text&  '），connectedtring）

不是你问题的解决方案，而是你遇到的另一个问题。

永远不要通过连接字符串来构建SQL查询。迟早，您将使用用户输入来执行此操作，这会打开一个名为SQL注入的漏洞，这对您的数据库很容易并且容易出错。

名称中的单引号你的程序崩溃。如果用户输入像Brian O'Conner这样的名称可能会使您的应用程序崩溃，那么这是一个SQL注入漏洞，崩溃是最少的问题，恶意用户输入，并且它被提升为具有所有凭据的SQL命令。

SQL注入 - 维基百科 [ ^ ]

SQL注入 [ ^ ]

按示例进行SQL注入攻击 [ ^ ]

PHP：SQL注入 - 手册 [ ^ ]

SQL注入预防备忘单 - OWASP [ ^ ]

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim mycomboentry As ComboBox() = New ComboBox() {Comboentry1, Comboentry2, Comboentry3, Comboentry4, Comboentry5, Comboentry6}
Dim mycombotitle As ComboBox() = New ComboBox() {Combotitle1, Combotitle2, Combotitle3, Combotitle4, Combotitle5, Combotitle6}
Dim mytxtquan As TextBox() = New TextBox() {txtquan1, txtquan2, txtquan3, txtquan4, txtquan5, txtquan6}
Dim mytxtprice As TextBox() = New TextBox() {txtprice1, txtprice2, txtprice3, txtprice4, txtprice5, txtprice6}
Dim mytxtamount As TextBox() = New TextBox() {txtamount1, txtamount2, txtamount3, txtamount4, txtamount5, txtamount6}
Dim result As Integer = MessageBox.Show("Are you sure you want to update?", "Salesbook", MessageBoxButtons.YesNoCancel)
ListView1.SelectedItems.Clear()
connect()
If result = DialogResult.Cancel Then
MessageBox.Show("Cancel pressed")
ElseIf result = DialogResult.No Then
MessageBox.Show("No pressed")

ElseIf result = DialogResult.Yes Then
Try

command = New MySqlCommand("UPDATE tblsalesbook SET Date_Ordered='" & DateTimePicker1.Text & "', Customer_Name='" & TextBox1.Text & "' , Entry='" & mycomboentry(counter).Text & "', Account_Title='" & mycombotitle(counter).Text & "', Quantity='" & mytxtquan(counter).Text & "', Unit_Price='" & mytxtprice(counter).Text & "', Amount='" & mytxtamount(counter).Text & "' WHERE Sales_Invoice='" & TextBox2.Text & "' )", connectstring)
command.ExecuteReader()
fillListview()

Catch ex As Exception
disconnect()

End Try
MessageBox.Show("Successfully updated!")
End If


End Sub

What I have tried:

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
       Dim mycomboentry As ComboBox() = New ComboBox() {Comboentry1, Comboentry2, Comboentry3, Comboentry4, Comboentry5, Comboentry6}
       Dim mycombotitle As ComboBox() = New ComboBox() {Combotitle1, Combotitle2, Combotitle3, Combotitle4, Combotitle5, Combotitle6}
       Dim mytxtquan As TextBox() = New TextBox() {txtquan1, txtquan2, txtquan3, txtquan4, txtquan5, txtquan6}
       Dim mytxtprice As TextBox() = New TextBox() {txtprice1, txtprice2, txtprice3, txtprice4, txtprice5, txtprice6}
       Dim mytxtamount As TextBox() = New TextBox() {txtamount1, txtamount2, txtamount3, txtamount4, txtamount5, txtamount6}
       Dim result As Integer = MessageBox.Show("Are you sure you want to update?", "Salesbook", MessageBoxButtons.YesNoCancel)
       ListView1.SelectedItems.Clear()
       connect()
       If result = DialogResult.Cancel Then
           MessageBox.Show("Cancel pressed")
       ElseIf result = DialogResult.No Then
           MessageBox.Show("No pressed")

       ElseIf result = DialogResult.Yes Then
           Try

               command = New MySqlCommand("UPDATE tblsalesbook SET Date_Ordered='" & DateTimePicker1.Text & "', Customer_Name='" & TextBox1.Text & "' , Entry='" & mycomboentry(counter).Text & "', Account_Title='" & mycombotitle(counter).Text & "', Quantity='" & mytxtquan(counter).Text & "', Unit_Price='" & mytxtprice(counter).Text & "', Amount='" & mytxtamount(counter).Text & "' WHERE Sales_Invoice='" & TextBox2.Text & "' )", connectstring)
               command.ExecuteReader()
               fillListview()

           Catch ex As Exception
               disconnect()

           End Try
           MessageBox.Show("Successfully updated!")
       End If


   End Sub

解决方案

command = New MySqlCommand("UPDATE tblsalesbook SET Date_Ordered='" & DateTimePicker1.Text & "', Customer_Name='" & TextBox1.Text & "' , Entry='" & mycomboentry(counter).Text & "', Account_Title='" & mycombotitle(counter).Text & "', Quantity='" & mytxtquan(counter).Text & "', Unit_Price='" & mytxtprice(counter).Text & "', Amount='" & mytxtamount(counter).Text & "' WHERE Sales_Invoice='" & TextBox2.Text & "' )", connectstring)

Not a solution to your question, but another problem you have.
Never build an SQL query by concatenating strings. Sooner or later, you will do it with user inputs, and this opens door to a vulnerability named "SQL injection", it is dangerous for your database and error prone.
A single quote in a name and your program crash. If a user input a name like "Brian O'Conner" can crash your app, it is an SQL injection vulnerability, and the crash is the least of the problems, a malicious user input and it is promoted to SQL commands with all credentials.
SQL injection - Wikipedia[^]
SQL Injection[^]
SQL Injection Attacks by Example[^]
PHP: SQL Injection - Manual[^]
SQL Injection Prevention Cheat Sheet - OWASP[^]

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