About Enter key in vb.net code behind

[s2008]

Hi,
I'm using vb.net 2005. In my code behind i wrote like this code..

Partial Class SearchTxt
    Inherits System.Web.UI.Page
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
 
    End Sub
    Protected Sub TextBox1_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
        If Not TextBox1.Text = "" Then
            Response.Redirect("Page2.aspx?txt=" & TextBox1.Text)
        End If
    End Sub
End Class
 

Now what i want is i want the page to redirect only if the enter key is pressed inside the textbox...Please tell me how to write the code inside TextBox1_TextChanged..

[Frinavale]

You can only check which key is pressed in client side code.
So you're going to have to write JavaScript that checks to see if the enter key is pressed when the user is in the text box. You're going to have to write JavaScript functions that handle the OnBlur, and OnChange events to do this:

OnChange event: you should check to see which key the user's entered...if the user's hit the enter key, store a "True" value in a hidden field that you can then retrieve in the server code so that you can determine what to do.

OnBlur event: store a "False" value in the hidden field in order to indicate that you are no longer in the text box.

-Frinny

[Plater]

Pressing enter on an input field just fires a postback. None of your specific button events should fire (unless there is a default button assigned to the form)

[Frinavale]

@Plater
If you set the function that handles OnChange event to return False... and in that function catch the case when the enter key is hit I think it should prevent it from firing....regardless I think the OnChange event happens before the enter key gets to submit the forum.

I'm going to try it now.

[Frinavale]

The following JavaScript checks if the user pressed Enter:

 function checkEnter(e)
       {
         var unicode;
         try
         {   /*IE*/
             unicode = e.keyCode; 
         }
        catch(err)
         {   
             try
             { /*Netscape, Mozilla, FireFox...*/
                  unicode = window.event.keyCode;
 
             }
             catch(error)
             {  /*Other*/
                 unicode = e.which;
              }
          }
          //displays an alert  and returns false
         //if enter is pressed
         if(unicode == 13)
         { alert("enter pressed");
           return false;
         } 
         return true;
       }

In my ASP code I created a TextBox

  <asp:TextBox ID="testTextBox" runat="server"></asp:TextBox>

And in my PageLoad event I set the TextBox to execute the function every time a key's pressed:

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If IsPostBack = False Then
            testTextBox.Attributes.Add("onkeypress", "return checkEnter(event);")
        End If
End Sub
 

Note that I set the "onkeypress" event to return the function call. The enter action is cancelled because I'm returning false here...

So this suggests that the JavaScript is executed before the page is sent to the server....
-Frinny

[Plater]

isn't window.event just IE?
Javascript - Event accessing

[Frinavale]

@Plater
Hmmm....
Apparently not because I tested that in FireFox.

[Plater]

Hmm everything I read about event handling says mozilla based uses the "e" but in IE you could use window.event

function OnlyNumbers(e)
{
    var keynum;   
    if(window.event) // IE
    {
        keynum = e.keyCode;
    }
    else if(e.which) // Netscape/Firefox/Opera
    {
        keynum = e.which;   
    }
//...
}
 

Although I am sure they have unified somewhat in their behavior