有没有办法从USB条形码阅读器读取而忽略键盘而不知道USB扫描仪的PID或VID？我知道有一种方法可以通过使用USB扫描仪的VID和/或PID来区分USB扫描仪输入和键盘输入;这是使用来自的代码完成的 http://nicholas.piasecki.name/blog/2009/02/distinguishing-barcode-scanners-from-the-keyboard-in-winforms/ 但是，如果没有将扫描仪的VID或PID放在配置文件（或源代码）中，是否存在区分键盘和USB扫描仪的另一种解决方案？不想在配置文件中放置各种VID或PID的原因是，正在开发的应用程序将部署在众多笔记本电脑上，并且附加了任意类型的扫描仪。
此外，我不想配置扫描仪的输出开始和结束序列，因为扫描仪也被同一台机器上的其他软件使用，我不想更改代码在其他软件上。出于与前面提到的相同的原因，我不想将条形码阅读器编程为串行模式。
有一种方法可以区分键盘和USB条形码阅读器
你可以依赖这些事实：
这是一个使用VS2005 VB的简单表格包含：
Public Class Form1
Dim BarcodeStr As String = ""
Dim IsBarcodeTaken As Boolean = False
Dim Str As String = ""
Dim str3 As String = ""
Private Sub Form1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
If Timer1.Enabled = False Then
Str = TextBox1.Text
str3 = TextBox3.Text
End If
End Sub
Private Sub Form1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles Me.KeyPress
If Timer1.Enabled = False Then
Timer1.Enabled = True
End If
BarcodeStr = BarcodeStr & e.KeyChar
If Asc(e.KeyChar) = 13 And Len(BarcodeStr) >= 4 Then
IsBarcodeTaken = True
TextBox2.Text = BarcodeStr
End If
End Sub
Private Sub Form1_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyUp
If IsBarcodeTaken = True Then
TextBox1.Text = Str
TextBox1.Select(Len(TextBox1.Text), 0)
Str = ""
TextBox3.Text = str3
TextBox3.Select(Len(TextBox3.Text), 0)
str3 = ""
End If
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
BarcodeStr = ""
IsBarcodeTaken = False
Timer1.Enabled = False
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
TextBox2.Text = ""
End Sub
End Class
有一种方法可以区分键盘和USB条形码阅读器
你可以依赖这些事实：
这是一个使用VS2005 VB的简单表格包含：
Public Class Form1
Dim BarcodeStr As String = ""
Dim IsBarcodeTaken As Boolean = False
Dim Str As String = ""
Dim str3 As String = ""
Private Sub Form1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
If Timer1.Enabled = False Then
Str = TextBox1.Text
str3 = TextBox3.Text
End If
End Sub
Private Sub Form1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles Me.KeyPress
If Timer1.Enabled = False Then
Timer1.Enabled = True
End If
BarcodeStr = BarcodeStr & e.KeyChar
If Asc(e.KeyChar) = 13 And Len(BarcodeStr) >= 4 Then
IsBarcodeTaken = True
TextBox2.Text = BarcodeStr
End If
End Sub
Private Sub Form1_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyUp
If IsBarcodeTaken = True Then
TextBox1.Text = Str
TextBox1.Select(Len(TextBox1.Text), 0)
Str = ""
TextBox3.Text = str3
TextBox3.Select(Len(TextBox3.Text), 0)
str3 = ""
End If
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
BarcodeStr = ""
IsBarcodeTaken = False
Timer1.Enabled = False
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
TextBox2.Text = ""
End Sub
End Class
好吧，我使用的解决方案非常类似于Ehab的解决方案 - 我只是为我的应用程序清理了一些代码。我正在为我的编辑控件使用自定义类（它也在做其他一些事情） - 但这些是这个的重要部分：＃
public class ScannerTextBox : TextBox
{
public bool BarcodeOnly { get; set; }
Timer timer;
private void InitializeComponent()
{
this.SuspendLayout();
this.ResumeLayout(false);
}
void timer_Tick(object sender, EventArgs e)
{
if (BarcodeOnly == true)
{
Text = "";
}
timer.Enabled = false;
}
protected override void OnKeyPress(KeyPressEventArgs e)
{
base.OnKeyPress(e);
if (BarcodeOnly == true)
{
if (timer == null)
{
timer = new Timer();
timer.Interval = 200;
timer.Tick += new EventHandler(timer_Tick);
timer.Enabled = false;
}
timer.Enabled = true;
}
if (e.KeyChar == '\r')
{
if (BarcodeOnly == true && timer != null)
{
timer.Enabled = false;
}
}
}
}
还有一个关于条形码的问题 这里，该链接将向您发送通过串行端口使用条形码的答案。也许那是你的解决方案？
恕我直言：最简单的解决方案是接受键盘的输入。
也许这是一个过于简单的解决方案，但你能捕获按键事件并简单地阻止键盘输入吗？