Capturing the Enter key to cause a button click

• Download source files - 7.5 KB

Introduction

Have you ever wanted to trap the Enter key press event in ASP.NET and have it click a button for you? This article describes two options for capturing the Enter key press event and then clicking a button. One solution uses JavaScript, the other uses a Panel control.

Background

Most people like things to work a certain way. Consider a search engine text box. After you type in your search text, most people just want to push the Enter key and have the search start. It is a pain when you have to grab the mouse and move the cursor to the Search button and click it. The article describes two solutions to this problem.

The problem

Web pages have text boxes, text areas, etc., where users enter text. Often, after the text is entered, the user needs to click a button. It may be a search button, or a submit button, or some other sort of button. The problem is how to trap the Enter key press event so that the correct button can be clicked.

The solution

Let's explore two solutions to this problem. First, let us look at using JavaScript. With this solution, each textbox needs to have some JavaScript attached to the onKeyPress JavaScript event. I usually do this in the pageload method in the code-behind.

//Add the javascript so we know where we want the enter key press to go
if (!IsPostBack)
{
   txtboxFirstName.Attributes.Add("onKeyPress", 
                   "doClick('" + btnSearch.ClientID + "',event)");
   txtboxLastName.Attributes.Add("onKeyPress", 
                  "doClick('" + btnSearch.ClientID + "',event)");
   txtboxAddress1.Attributes.Add("onKeyPress", 
                  "doClick('" + btnSearch.ClientID + "',event)");
   txtboxAddress2.Attributes.Add("onKeyPress", 
                  "doClick('" + btnSearch.ClientID + "',event)");
   txtboxCity.Attributes.Add("onKeyPress", 
              "doClick('" + btnSearch.ClientID + "',event)");
   txtboxState.Attributes.Add("onKeyPress", 
               "doClick('" + btnSearch.ClientID + "',event)");
   txtboxZipcode.Attributes.Add("onKeyPress", 
                 "doClick('" + btnSearch.ClientID + "',event)");
}

Note: You pass into the JavaScript method the button's ClientID so that the JavaScript method can find the button and call its Click method.

Next, we need a JavaScript method called doClick in the ASP.NET form.

<SCRIPT type=text/javascript>
    function doClick(buttonName,e)
    {
        //the purpose of this function is to allow the enter key to 
        //point to the correct button to click.
        var key;

         if(window.event)
              key = window.event.keyCode;     //IE
         else
              key = e.which;     //firefox
    
        if (key == 13)
        {
            //Get the button the user wants to have clicked
            var btn = document.getElementById(buttonName);
            if (btn != null)
            { //If we find the button click it
                btn.click();
                event.keyCode = 0
            }
        }
   }
</SCRIPT>

The next solution is using a Panel control. In this case, the panel is doing all the work.

<asp:Panel ID="panSearch" runat="server" 
       DefaultButton="btnSearch2" Width="100%" >
    <table width="100%">
    
    <tr>
     <td>First Name</td>
     <td ><asp:TextBox ID="txtboxFirstName2" 
           runat="server" ></asp:TextBox></td>
    </tr>
    ...

Notice that the Panel tag has a property called DefaultButton. You set this property to the button ID of the button you want to be clicked on an Enter key press event. So any text box inside of the Panel will direct its Enter key press to the button set in the DefaultButton property of the Panel.

Which one is better?

I suppose we could spend a lot of time arguing about which method is better. Some people like JavaScript, so that might be the better one. Others hate JavaScript and prefer writing less code, so they would choose the Panel solution. One thing I would note is that if you have several buttons and need to have different text boxes click different buttons, then you have to go with the JavaScript solution since it gives you that flexibility. I guess I will let you decide which solution best fits your needs.

Conclusion

Hopefully, this article demonstrates two useful techniques to capture the Enter key press event and directing it to click the correct button. Let me know which method you prefer.