Keydown + Enter event. Clear keyboard buffer

Asked

Viewed 858 times

3

I created an example Winform C# . net containing textbox1, textbox2 and button1 to simulate the following situation:

When starting the application, the textbox1 gets the focus and when we press Enter, your event was scheduled KeyDown so that the focus goes to the textbox2.

It also happens that within it KeyDown of textbox1 some kind of processing must be performed, which in my example is represented by a Thread.Slepp(5000).

The problem occurs when we press several times the Enter in the textbox1. It performs several times the processing of this KeyDown when it was expected that textbox1 and focus on the textbox2.

Apparently it stores some kind of buffer keyboard, firing several times the event of the textbox selected.

any suggestions as to how such a situation might be dealt with, so that once the textbox1 has the focus regardless of how many times it is pressed Enter, he perform only once the event KeyDown and focus on the textbox2?

Code used for example: 

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

    private void textBox1_KeyDown(object sender, KeyEventArgs e)
    {               
        if (e.KeyCode == Keys.Enter)
        {
            Thread.Sleep(5000);
            SendKeys.Send("{TAB}");               
        }
    }        

    private void textBox2_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.KeyCode == Keys.Enter)
        {
            Thread.Sleep(5000);                
            SendKeys.Send("{TAB}");                    
        }           
    }
}
c# buffer

  • Have you ever tried to put the following line textbox2.Focus(); instead of SendKeys.Send("{TAB}"); ? Maybe it works.

  • Yes @Érikthiago, the problem is the various executions of Keydown of textbox1. Another situation is also that this was just an example, and I will not know what will be the next component to receive the focus, the use of SendKeys.Send("{TAB}") leaves it to the application by Tabindex, thus being mandatory.

  • Place SendKeys.Send("{TAB}"); before Thread.Sleep(5000);

  • He continues with the "buffer of Enter" and so he executes SendKeys.Send("{TAB}"); and Thread.Sleep(5000); several times, both of the textbox1 how much of textbox2

  • Yes will continue with buffer, but you should be running textbox1 once and then jump to textbox2, right?

  • Yeah, except by jumping into the textbox2, as we have several Enter in the buffer he executes the Keydown of textbox2 also, and several times, soon the focus does not necessarily stay on the desired textbox.

  • Yes, but that’s the expected behavior. Maybe there’s a possibility to get around that but it’s not much "beautiful". I’ll put an answer for you to test.

  • On second thought I see no way to distinguish one enter which must be accepted by one or more others who must not be accepted.

Show 3 more comments

2 answers

1

Why don’t you try to encapsulate like objects, you put the sendKeys.send("{TAB}") and Thread.Sleep as properties of each textbox.

This way you can call the event independently, at the time you want and in the order you want.

0

Why not just put a control variable? Something like:

int ok1 = 0;
private void textBox1_KeyDown(object sender, KeyEventArgs e)
{

    if (e.KeyCode == Keys.Enter)
    {
        if (ok1 > 0) return;
        ok1++;
        Thread.Sleep(5000);
        SendKeys.Send("{TAB}");
        ok2 = 0;
    }
}

int ok2 = 0;
private void textBox2_KeyDown(object sender, KeyEventArgs e)
{

    if (e.KeyCode == Keys.Enter)
    {
        if (ok2 > 0)
        {
            return;
        }
        ok2++;
        Thread.Sleep(5000);
        SendKeys.Send("{TAB}");
        ok1 = 0;
    }
}

Browser other questions tagged c# buffer

You are not signed in. Login or sign up in order to post.