RadAlert Dialog
The RadAlert dialog presents a modal message box and displays an "OK" button for the user. This dialog only requires a single parameter: the string to display. This string can also contain HTML markup. Optionally, you can provide additional parameters to supply the dialog width and height, a title string, a callback function and an URL to replace its original image.
In order to use this dialog you need to have a RadWindowManager on the page.
Calling RadAlert via JavaScript
The minimum required to show a RadAlert is the content string:
<button onclick="radalert('An <br /><b>html</b> string.<br />'); return false;"> Alert</button>
The full syntax of the radalert() function is as follows:
var oAlert = radalert(text, oWidth, oHeight, oTitle, callbackFn, imgUrl);
where you can set optional width, height, title, a callback function and an URL to replace the image for the RadAlert dialog.The callback function receives an argument that reflects the user action with the dialog.
This method also returns a reference to the RadAlert object (which is essentially a RadWindow), so you can use the RadWindow's client-side API on it to further change it (titlebar icon, behaviors, etc.)
Calling RadAlert from the code-behind
Since Q1 2011 the RadWindowManager offers a built-in server-side method to call the RadAlert:
<telerik:RadWindowManager RenderMode="Lightweight" runat="server" id="RadWindowManager1"></telerik:RadWindowManager>
<script type="text/javascript">
function callBackFn(arg)
{
alert("this is the client-side callback function. The RadAlert returned: " + arg);
}
</script>
RadWindowManager1.RadAlert("An <br /><b>html</b> string.<br />", 200, 100, "My Alert", "callBackFn", "myAlertImage.png");
RadWindowManager1.RadAlert("An <br /><b>html</b> string.<br />", 200, 100, "My Alert", "callBackFn", "myAlertImage.png")
Strings passed into this method must be properly formatted and escaped for HTML and JavaScript. Please see the related article Calling the Predefined Dialogs from the Server Methods.
The callback function is a client-side JavaScript function which is executed when the dialog is closed.
If you change the default image the new one you provide should be 32px by 32px for best results. The string you pass to change the image URL can be:
- an absolute URL, or a relative URL that can be resolved on the client (i.e. "~/" is not allowed). This will set the image the URL points to.
- an empty string - this will remove the default image and leave the space empty.
- null - the behavior is the same as if no argument is provided - i.e. the default image is kept.
The appearance of the alert dialog is controlled by two things: the Skin property of the RadWindowManager, and the values you pass in as arguments to RadAlert. The arguments can include the HTML string you pass in as a message, the width, the height, and the Title string. The Skin property controls not only the appearance of the popup's title bar, but also the layout of the dialog: its icon, button style, and so on. This dialog layout and appearance is controlled by the alert dialog template associated with the Skin. For details on how to customize the template, see Templates.