C#WinForm+条形码扫描器输入，TextChanged错误

Question

有一点需要注意，光标位于memberid：00888的末尾

到目前为止一切都很好：

当第2次（如下一个人）发生时

txtBoxCatchScanner.Clear();

txtBoxCatchScanner.Text = "";

但我想它们会触发TextChanged事件

我如何重新聚焦或...清除旧的数字和光标回到txtBox的开始后，之前的滑动完成了它的东西...

我是一个初学者，所以我敢肯定下面的代码是相当垃圾....

if (txtBoxCatchScanner.Text.Length == 5)
{
label1.Text = txtBoxCatchScanner.Text; // just a label for testing .. shows the memmber ID
txtBoxCatchScanner.Select(0, 5);
}

问题：不是所有的条形码都是5位数！！它们是随机长度！！Memeber ID从2位数（如25）到10位数不等，并将在未来增长。

编辑：我发现条形码是按下分叉键读取的。我想这就是为什么下面的答案1不起作用，而大概率：

例如，对于00675，扫描仪的输入（？输出）为：

private void txtBoxCatchScanner_TextChanged(object sender, EventArgs e)
{             
    Member member = new Member();
    member.FirstName = "";
    member.LastName = "";            

    //Get BarCode
    //VALIDATE: Is a Number           
    double numTest = 0;
    if (Double.TryParse(txtBoxCatchScanner.Text, out numTest))
    {
        //IS A NUMBER
        member.MemberID = Convert.ToInt32(txtBoxCatchScanner.Text);

        //SEARCH
        //Search Member by MemberID (barcode)
        List<Member> searchMembers = Search.SearchForMember(member);

        if (searchMembers.Count == 0)
        {
            lblAlert.Text = "No Member Found";
        }
        else
        {
            foreach (Member mem in searchMembers)
            {
                lblMemberStatus.Text = mem.MemberStatus;
                lblMemberName.Text = mem.FirstName + " " + mem.LastName;
                lblMemberID.Text = mem.MemberID.ToString();

                lblMessages.Text = mem.Notes;

                if (mem.MemberStatus == "OVERDUE") // OR .. OR .. OR ...
                {
                    lblAlert.Visible = true;
                    lblAlert.Text = "!! OVERDUE !!";

                    //PLAY SIREN aLERT SOUND
                    //C:\\WORKTEMP\\siren.wav
                    SoundPlayer simpleSound = 
                        new SoundPlayer(@"C:\\WORKTEMP\\siren.wav");
                    simpleSound.Play();
                }
                else
                {
                    lblAlert.Visible = true;
                    lblAlert.Text = mem.MemberStatus;
                }
            }
        }
    }
    else
    {
        //IS NOT A NUMBER
        lblAlert.Text = "INVALID - NOT A NUMBER";                

        ////
        //lblMemberName.Text = "";
        //lblMemberID.Text = "";
        //lblMemberID.Text = "";
    }

系统不会让我再回答我自己的问题3个小时，因为我是一个新手只有1个帖子，所以将在这里：

首先感谢大家的帮助和耐心。

我终于想出了一个孤独，还没有完全测试，因为它是凌晨2点和睡觉时间。

namespace SCAN_TESTING
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void txtBoxCatchScanner_KeyUp(object sender, KeyEventArgs e)
    {
        if (e.KeyValue == (char)Keys.Return)
        {
            e.Handled = true;

            int barcodeLength = txtBoxCatchScanner.TextLength;

            txtBoxCatchScanner.Select(0, barcodeLength);

            //TEST
            label3.Text = barcodeLength.ToString();
            //TEST
            label2.Text = txtBoxCatchScanner.Text;

        }

    }

private void txtBoxCatchScanner_KeyUp(object sender, KeyEventArgs e)
{
   if (e.KeyValue == (char)Keys.Return)
      {
            e.Handled = true;

            int barcodeLength = txtBoxCatchScanner.TextLength;

            txtBoxCatchScanner.Select(0, barcodeLength);

           //
           //INSERT ORGINAL CODE HERE. No Changes were needed.
           //


      }//end of if e.KeyValue ...
}//end txtBoxCatchScanner_KeyUp

再次感谢2个非常好的解决方案，我可以看到他们是如何工作的，并学到了很多。只是在我的情况下不起作用--更有可能是由于我自己或我的错误/不理解，或者扫描仪类型。

Answer 1

我不太确定实际的问题是什么。

txtBoxCatchScanner.Clear();
txtBoxCatchScanner.Text = "";

两者都会触发“已更改”事件。但他们也会清理盒子。所以那应该是你想做的。

您可以在开始时检查该框是否实际上是空的，如果是空的，则返回。比如：

if(txtBoxCatchScanner.Text == "" |txtBoxCatchScanner.Text == string.Empty)
return;

如果我误解了你的问题，请详细说明，我会尽力帮助你。

问候

编辑：

    private void txtBoxCatchScanner_TextChanged(object sender, EventArgs e)
{             
Member member = new Member();
member.FirstName = "";
member.LastName = "";            

if(txtBoxCatchScanner.Text == "" | txtBoxCatchScanner.Text == string.Empty)
return;    // Leave function if the box is empty

//Get BarCode
//VALIDATE: Is a Number           
int numTest = 0;
if (int.TryParse(txtBoxCatchScanner.Text, out numTest))
{
    //IS A NUMBER
    //member.MemberID = Convert.ToInt32(txtBoxCatchScanner.Text);
    member.MemberID = numTest; // you already converted to a number...
    //SEARCH
    //Search Member by MemberID (barcode)
    List<Member> searchMembers = Search.SearchForMember(member);

    if (searchMembers.Count == 0)
    {
        lblAlert.Text = "No Member Found";
    }
    else
    {
        foreach (Member mem in searchMembers)
        {
            lblMemberStatus.Text = mem.MemberStatus;
            lblMemberName.Text = mem.FirstName + " " + mem.LastName;
            lblMemberID.Text = mem.MemberID.ToString();

            lblMessages.Text = mem.Notes;

            if (mem.MemberStatus == "OVERDUE") // OR .. OR .. OR ...
            {
                lblAlert.Visible = true;
                lblAlert.Text = "!! OVERDUE !!";

                //PLAY SIREN aLERT SOUND
                //C:\\WORKTEMP\\siren.wav
                SoundPlayer simpleSound = 
                    new SoundPlayer(@"C:\\WORKTEMP\\siren.wav");
                simpleSound.Play();
            }
            else
            {
                lblAlert.Visible = true;
                lblAlert.Text = mem.MemberStatus;
            }
        }
    }
}
else
{
    //IS NOT A NUMBER
    lblAlert.Text = "INVALID - NOT A NUMBER";                

    ////
    //lblMemberName.Text = "";
    //lblMemberID.Text = "";
    //lblMemberID.Text = "";
}
txtBoxCatchScanner.Clear();
}