ASPxValidationSummary
The ASPxValidationSummary control allows you to summarize validation errors from multiple controls and display them in a single block. This helps to organize screen space more effectively if validation is required for several editors.
Main Features
Three Render Modes
Use the ASPxValidationSummary.RenderMode property to specify the manner in which ASPxValidationSummary displays validation error text within its panel. The following properties allow you to display error text as a table, a bulleted list, or an ordered list:
Appearance Affected Properties 
RenderMode=Table 
RenderMode=BulletedList 
RenderMode=OrderedList Show Error Text as a Link
You can add a link to validation error text. To do this, set the ASPxValidationSummary.ShowErrorAsLink property to true. When a user clicks the link, focus moves to the corresponding invalid editor.
Full-Featured Client-Side API
The ASPxClientValidationSummary object is the client-side equivalent of the ASPxValidationSummary control. This object exposes the control’s comprehensive client-side API.