blocks|key|189090|text|另一种可能的解决方法是处理按键事件以限制用户输入。不允许从键盘直接输入，并保留readonly+false。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|189091|在KeyPress事件处理程序中设置以下内容|189092|Private+Sub+Textbox1_KeyPress(ByVal+sender+As+System.Object,+ByVal+e+As+System.Windows.Forms.KeyPressEventArgs)+Handles+Textbox1.KeyPress
++++++++e.Handled+=+True
End+Sub|code-block|syntax|javascript|189093|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

The other possible workaround is to handle keypress event to restrict user input. Do not allow direct input from keyboard and leave the readonly false.

Set following in KeyPress event handler

<pre><code>Private Sub Textbox1_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles Textbox1.KeyPress
 e.Handled = True
End Sub
</code></pre>

blocks|key|407299|text|无论如何，只要禁用键盘即可。使用条形码时，您可以禁用键盘，而不使用文本框上的只读。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|407300|在按键事件上放入一些代码，即|407301|if+e.keychar+<>+chrw(0)则e.keychar+=+chrw(0)+end+if|407302|当用户键入任何内容时，该条件将自动触发。您将强制禁用任何来自用户的输入，而不是条形码的输入|407303|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|L|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|M|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Just disable the keyboard anyway.. when using barcode you can disable the keyboard without using readonly on the textbox..

on keypress event put some code i.e

if e.keychar &lt;> chrw(0) then
e.keychar = chrw(0)
end if

that condition will automatically be trigged when user type anything.. you will forcibly disable any input from user but not from barcode

blocks|key|189310|text|为什么不在条形码中使用“别名”，比如"123@#$!“(但使其变得愚蠢的长)是"JSMITH“，并将字体颜色设置为与文本框中的背景颜色相同。用户在扫描时看不到他们输入的内容或条形码的值。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|189311|非常简单的方法，除了用户表中的另一个字段外，实际上不需要添加任何东西。|189312|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

why not use an "alias" in the bar code like "123@#$!" (but make it stupid long) is "JSMITH" and set the font color to the same as the background color in the textbox. The user can't see what they're typing or what the bar code value is when it's scanned.

Super simplistic approach that doesn't really require anything added aside from another field in the the user table.

blocks|key|189187|text|这是一个老帖子，但我花了一些时间来找出一个相对干净的方式使用条形码扫描仪和组合框，以便这是为未来的用户。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|189188|条形码扫描仪通常可以配置为将回车符和换行符附加到扫描的末尾。我有一个表单，可以将用户输入或条形码扫描器输入输入到绑定的组合框中，使用_PreviewKeyDown属性并陷井在值"Keys.Enter“上。|189189|示例：|189190|If+((e.KeyCode+=+Keys.Enter)+Then
'do+stuff
Else
'do+other+stuff
End+if|code-block|syntax|javascript|189191|验证数据是否存在于数据源中有点棘手，因为combobox的SelectedValue属性不会更新，因此不会触发该事件。我使用自定义方法来验证所扫描的值是否存在于数据源中。此方法使用组合框的.Text属性。它使用：|189192|Me.combobox.findexactstring(Me.combobox.Text)|189193|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|S|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|T|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|H|7|V|8|@]|9|@]|A|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

This is an old post, but it took me some time to figure out a relatively clean way to use a barcode scanner and combobox so this is for future users.

Barcode scanners can often be configured to append carriage return and line feed to the end of the scan. I have a form that can take user input or barcode scanner input into a bound combobox using the _PreviewKeyDown property and trapping on the value "Keys.Enter".

Example:

<pre><code>If ((e.KeyCode = Keys.Enter) Then
'do stuff
Else
'do other stuff
End if
</code></pre>

Verifying the data exists in the datasource is a bit trickier because the SelectedValue property of the combobox doesn't update so that event doesn't fire. I used a custom method to verify that the value scanned exists in the datasource. This method uses the .Text property of the combo box. It uses:

<pre><code>Me.combobox.findexactstring(Me.combobox.Text)
</code></pre>

blocks|key|189198|text|If+e.KeyCode+=+Keys.Enter+And+txt.Text.Length+>+0+Then
++++'To+Do
Else
++++'To+Do
End+if|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|189199|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>If e.KeyCode = Keys.Enter And txt.Text.Length &gt; 0 Then
 'To Do
Else
 'To Do
End if
</code></pre>

blocks|key|189220|text|我所有的扫描仪输入都会进入一个“隐藏”的文本框中，然后根据输入的内容填充可见的文本框。当然，这意味着你需要跟踪焦点在哪里。任何类型的可以获得焦点的控件都会在这些事件中调用，以将焦点返回到当时的“活动”文本框，通常是隐藏的文本框。例如..。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|189221|Private+Sub+buttons_gotFocus(sender+As+System.Object,+e+As+System.EventArgs)+Handles+btnPrint.GotFocus,+btnInMVPageDown.GotFocus,+btnAdv.GotFocus,+btnManual.GotFocus,+btnResend.GotFocus,+dgvInbound.GotFocus,+dgvOutbound.GotFocus,+TCRole.GotFocus
++++Try
++++++++activeTextbox.Focus()
++++Catch+ex+As+Exception
++++++++'ignore+any+errors
++++End+Try

End+Sub|code-block|syntax|javascript|189222|默认情况下，大多数其他文本框都是禁用的，只有在某些情况下才会启用。一旦该条目完成，它们将被禁用，隐藏的条目将再次获得焦点。就像一种护身符。|189223|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

All of my scanner input goes into a "hidden" textbox, which then fills the visible ones as needed depending on the input. This, of course, means you need to keep track of where the focus is. Any type of control that can get focus will then make a call in those events to return focus to whatever the "active" textbox is at that time, which is normally the hidden one. For example...

<pre><code>Private Sub buttons_gotFocus(sender As System.Object, e As System.EventArgs) Handles btnPrint.GotFocus, btnInMVPageDown.GotFocus, btnAdv.GotFocus, btnManual.GotFocus, btnResend.GotFocus, dgvInbound.GotFocus, dgvOutbound.GotFocus, TCRole.GotFocus
 Try
 activeTextbox.Focus()
 Catch ex As Exception
 'ignore any errors
 End Try

End Sub
</code></pre>

Most other textboxes are disabled by default, and only enabled under certain conditions. Once that entry is done they are disabled and the hidden one will get focus again. Works like a charm.

blocks|key|189240|text|不需要记录以前输入的字符。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|189241|这是我的解决方案：|189242|Private+Sub+TextBox1_TextChanged(sender+As+Object,+e+As+EventArgs)+Handles+TextBox1.TextChanged
++++If+TextBox1.Text.Length+>=+17+Then+'17+or+the+number+of+characters+your+scanner+gets.+
++++++++MsgBox("scanned")
++++++++TextBox1.Clear()
++++Else
++++++++If+TextBox1.Text.Length+<>+0+Then+TextBox1.Clear()
++++End+If
End+Sub|code-block|syntax|javascript|189243|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

There's no need to record previous typed characters.

Here's my solution:

<pre><code>Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
 If TextBox1.Text.Length &gt;= 17 Then '17 or the number of characters your scanner gets. 
 MsgBox("scanned")
 TextBox1.Clear()
 Else
 If TextBox1.Text.Length &lt;&gt; 0 Then TextBox1.Clear()
 End If
End Sub
</code></pre>

blocks|key|407419|text|此答案将处理任何快速键入。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|407420|Dim+scanner_input+As+Boolean+=+False
Dim+start_typing+As+DateTime+

Private+Sub+TextBox_part_number_TextChanged(sender+As+Object,+e+As+EventArgs)+Handles+
+TextBox_part_number.TextChanged
++++If+(TextBox_part_number.Text.Length+=+1)+Then
++++++++start_typing+=+DateTime.Now
++++++++scanner_input+=+False
++++++++''+++MsgBox(start_typing.ToString)
++++ElseIf+(TextBox_part_number.Text.Length+>+7)+Then
++++++++If+(calc_typing_time(start_typing)+<+500)+Then
++++++++++++scanner_input+=+True
++++++++Else
++++++++++++scanner_input+=+False
++++++++End+If
++++End+If
End+Sub
Function+calc_typing_time(time_started+As+DateTime)
++++Dim+time_finished+As+DateTime
++++time_finished+=+DateTime.Now
++++Dim+duration+As+TimeSpan+=+time_finished+-+time_started
++++Dim+time_diff+As+String+=+duration.TotalMilliseconds
++++Return+time_diff
End+Function|code-block|syntax|javascript|407421|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This answer will handle any fast typing.

<pre><code>Dim scanner_input As Boolean = False
Dim start_typing As DateTime 

Private Sub TextBox_part_number_TextChanged(sender As Object, e As EventArgs) Handles 
 TextBox_part_number.TextChanged
 If (TextBox_part_number.Text.Length = 1) Then
 start_typing = DateTime.Now
 scanner_input = False
 '' MsgBox(start_typing.ToString)
 ElseIf (TextBox_part_number.Text.Length &gt; 7) Then
 If (calc_typing_time(start_typing) &lt; 500) Then
 scanner_input = True
 Else
 scanner_input = False
 End If
 End If
End Sub
Function calc_typing_time(time_started As DateTime)
 Dim time_finished As DateTime
 time_finished = DateTime.Now
 Dim duration As TimeSpan = time_finished - time_started
 Dim time_diff As String = duration.TotalMilliseconds
 Return time_diff
End Function
</code></pre>

blocks|key|189358|text|大多数扫描仪都有一个与之通信的驱动程序(Opos)，它有打开扫描仪端口并监听扫描的功能，所以你可以在后台解码结果，然后在文本框中显示结果……你需要做什么来检查你的条形码扫描仪的品牌，去它的网站，下载驱动程序和它的手册。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|189359|entityMap|0|LINK|mutability|MUTABLE|url|https://en.wikipedia.org/wiki/OPOS^0|K|4|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Most of the scanners has a driver to communicate with (<a href="https://en.wikipedia.org/wiki/OPOS" rel="nofollow noreferrer">Opos</a>) it has functions to open the scanner port and listen to the scanning , so you take the result and decode it in the background and then display the result in the Textbox... what you need to do it to check your barcode scanner's brand go to it's website and download the driver and its manual.

blocks|key|189118|text|您应该只将您的文本框标记为只读。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|189119|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

You should just mark your textbox as readonly.

My program is already working fine, I use a TextBox to capture the barcode scanner input. The purpose of my program is for time and attendance monitoring, the problem is I want to prevent users from using the keyboard to type in their ID's as it would render the barcode scanner and their ID's with barcodes useless. 

*I already tried removing the keyboard from the computer and it did work, but the keyboard must not be removed as a requirement...

How to read input from a barcode scanner in vb.net without using a textbox?

Windows

我的程序已经运行良好，我使用TextBox来捕获条形码扫描器输入。我的程序的目的是时间和考勤监控，问题是我想阻止用户使用键盘键入他们的ID，因为这将使条形码扫描仪和他们的条形码ID无用。*我已经尝试从计算机上卸下键盘，它确实起作用了，但键盘不能作为一个要求被卸下...

问如何在不使用文本框的情况下在vb.net中读取条形码扫描仪的输入？
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问如何在不使用文本框的情况下在vb.net中读取条形码扫描仪的输入？
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