ValidationSummary Main Features
The ValidationSummary extension allows you to summarize validation errors from multiple editors and then display these errors in a single block.
Note
The ValidationSummary does not display errors added through the ModelState.AddModelError method when it gets a key that does not match the editor ID.
ValidationSummary provides the following features:
Three Render Modes
Use the ValidationSummarySettings.RenderMode property to specify how the ValidationSummary‘s panel displays validation error texts:
Appearance Affected Properties 
RenderMode=Table 
RenderMode=BulletedList 
RenderMode=OrderedList Show Error Texts as Links
Set the ValidationSummarySettings.ShowErrorAsLink property to true to show validation error texts as links. In this mode, click a link to move focus to a corresponding invalid editor.
Full-Featured Client-Side API
The ASPxClientValidationSummary object is a client-side equivalent of the ValidationSummary extension and can be used to access its client-side API.