如何在asp.net的键盘上按Tab键时引发事件 [英] how to raise an event when tab key is pressed from key board in asp.net

问题描述

如何在asp.net的键盘上按Tab键时引发事件？



i需要在用户点击键盘上的标签按钮时触发事件？



我怎样才能实现它？



请帮助..

how to raise an event when tab key is pressed from key board in asp.net?

i need to trigger an event when user click tab button from keyboard?

how can i achieve it?

please help..

推荐答案

你必须通过JavaScript来完成它，例如在 this [ ^ ] SO线程。可以在此处 [ ^ ]，请使用此 [ ^ ]测试页面试用。

You would have to do it by JavaScript, for example like it was discussed in this[^] SO thread. An overview of the key press event implementations can be found here[^], use this[^] test page to try it out.

<script language="JavaScript">
init();
</script>

function init()
{
    document.testform.t.value+= '';
    lines= 0;

    if (document.addEventListener)
    {
       document.addEventListener("keydown",keydown,false);
       document.addEventListener("keypress",keypress,false);
       document.addEventListener("keyup",keyup,false);
       document.addEventListener("textInput",textinput,false);
    }
    else if (document.attachEvent)
    {
       document.attachEvent("onkeydown", keydown);
       document.attachEvent("onkeypress", keypress);
       document.attachEvent("onkeyup", keyup);
       document.attachEvent("ontextInput", textinput);
    }
    else
    {
       document.onkeydown= keydown;
       document.onkeypress= keypress;
       document.onkeyup= keyup;
       document.ontextinput= textinput;   // probably doesn't work
    }
}

function showmesg(t)
{
   var old= document.testform.t.value;
   if (lines >= maxlines)
   {
    var i= old.indexOf('\n');
    if (i >= 0)
        old= old.substr(i+1);
   }
   else
    lines++;

   document.testform.t.value= old + t + '\n';
}

function keyval(n)
{
    if (n == null) return 'undefined';
    var s= pad(3,n);
    if (n >= 32 && n < 127) s+= ' (' + String.fromCharCode(n) + ')';
    while (s.length < 9) s+= ' ';
    return s;
}

function keymesg(w,e)
{
    var row= 0;
    var head= [w, '        '];
    if (document.testform.classic.checked)
    {
    showmesg(head[row] +
            ' keyCode=' + keyval(e.keyCode) +
        ' which=' + keyval(e.which) +
            ' charCode=' + keyval(e.charCode));
    row= 1;
    }
    if (document.testform.modifiers.checked)
    {
    showmesg(head[row] +
            ' shiftKey='+pad(5,e.shiftKey) +
        ' ctrlKey='+pad(5,e.ctrlKey) +
        ' altKey='+pad(5,e.altKey) +
        ' metaKey='+pad(5,e.metaKey));
    row= 1;
    }
    if (document.testform.dom3.checked)
    {
    showmesg(head[row] +
        ' key='+e.key +
        ' char='+e.char +
        ' location='+e.location +
        ' repeat='+e.repeat);
    row= 1;
    }
    if (document.testform.olddom3.checked)
    {
    showmesg(head[row] +
        ' keyIdentifier='+ pad(8,e.keyIdentifier)+
        ' keyLocation='+e.keyLocation);
    row= 1;
    }
    if (row == 0)
    showmesg(head[row]);
}

function pad(n,s)
{
   s+= '';
   while (s.length < n) s+= ' ';
   return s;
}

function suppressdefault(e,flag)
{
   if (flag)
   {
       if (e.preventDefault) e.preventDefault();
       if (e.stopPropagation) e.stopPropagation();
   }
   return !flag;
}

function keydown(e)
{
   if (!e) e= event;
   keymesg('keydown ',e);
   return suppressdefault(e,document.testform.keydown.checked);
}

function keyup(e)
{
   if (!e) e= event;
   keymesg('keyup   ',e);
   return suppressdefault(e,document.testform.keyup.checked);
}

function keypress(e)
{
   if (!e) e= event;
   keymesg('keypress',e);
   return suppressdefault(e,document.testform.keypress.checked);
}

function textinput(e)
{
   if (!e) e= event;
   //showmesg('textInput  data=' + e.data);
   showmesg('textInput data='+e.data);
   return suppressdefault(e,document.testform.textinput.checked);
}</pre>

如果您想特别检查Tab按，那么您必须检查 KeyCode 这是9.

参考 - 仅当tab键为时才调用onBlur事件按下 [ ^ ]

If you want to check Tab press in particular, then you have to check the KeyCode which is 9.
Refer - Call onBlur event only when tab key is pressed[^]

if ((e.which || e.keyCode) == 9) {
  // tab key was pressed, do stuff
}

否则，您可以处理onblur事件，该事件在Tab按下以及在元素外部单击时触发。

Otherwise, you can handle onblur event, which is fired on Tab press as well as on clicking outside the element.

尝试这个

Try this

<script type="text/javascript">
       document.onkeyup = PresTab;

       function PresTab(e)
       {
           var keycode = (window.event) ? event.keyCode : e.keyCode;
           if (keycode == 9)
           alert('tab key pressed');
       }

   </script>

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