ASP.NET OnTextChanged事件无法立即响应

Question

It is working but it is not responding instantly. When I click somewhere it is working.

I also tried the onkeyPress technique:

<asp:TextBox ID="txtWriter" runat="server" onkeyPress="txtOnKeyPress"  ></asp:TextBox>

But I am receiving a message like:

Attribute 'onkeyPress' is not a valid attribute of element 'TextBox'.

Answer 1

Which version of ASP.NET? The following certainly works for me ^* :

<script>
    function txtOnKeyPress() {
        console.log("txtOnKeyPress");
    }
</script>
<asp:TextBox ID="txtWriter" runat="server" onkeypress="txtOnKeyPress" />

_{^* Although, I did add () to the function name.}

Regardless, if ASP.NET has an issue with that attribute name, you could simply attach a handler on the client-side. Depending upon your needs, the input event may make more sense. It's sort of a live change event which fires as the input value is being edited (via keystroke, cut, paste, etc). Here's a sample:

 document.querySelector("input").addEventListener("input", function(e) { console.log("value: %o", this.value); }); 

 <input autofocus placeholder="type here"></input> 

_{Note browser compatibility here .}

Now, the previous sample fires with every single change to the input value... which can be quite bit, ie: 4 times for simply typing, "test". Since you'd (presumably) like it to trigger your server-side code, we'll want to wait for any changes made in rapid succession before actually posting the form:

 function __doPostBack(name, argument) { // dummy version of ASP.NET's __doPostBack console.log("value: %o", document.getElementsByName(name)[0].value); } var t; // handle for our timeout document.querySelector("input").addEventListener("input", function(e) { // input received... cancel the previous timeout, if any clearTimeout(t); // wait 1000 milliseconds (1 second) for more input before posting t = setTimeout(__doPostBack, 1000, this.name); }); 

 <input autofocus placeholder="type here" name="test-input"></input> 

_{See also: window. setTimeout() window. setTimeout() , document. querySelector() document. querySelector() , document. getElementsByName document. getElementsByName , and EventTarget. addEventListener() EventTarget. addEventListener() .}

In your code behind:

protected void Page_Load(object sender, EventArgs e)
{
    if (IsPostBack && Request.Form["__EVENTTARGET"] == txtWriter.UniqueID) {
        GridView1.DataSource = /* some data source */;
        GridView1.DataBind();
    }
}