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Render Modes

RadWindow and RadWindowManager has different render modes that can change the actual HTML markup that is rendered. They are exposed via the RenderMode property that can have four possible values - Classic, Lightweight, Mobile and Auto. This functionality was introduced in the Q2 2013 version.

The possible options are:

  • Classic—this mode is the rendering that has been used before. It remains without changes and it is the default value of the property. In this mode tables and background images (in several sprites) are used to create the layout (including rounded corners and shadows).

  • Lightweight—this mode emphasizes on semantic HTML and CSS3. It reduces the amount of markup the control renders and makes it easier to customize. This also reduces the number of image sprites required by the control. All of this decreases the overall size and complexity of each skin, including custom ones.

  • Mobile—this mode is currently not supported. If you set it, the mode will fall back automatically to Lightweight.

  • Auto—this mode makes each control choose the appropriate rendering mode according to the used browser—Classic or Lightweight. This functionality was added in Q3 2013.

RadWindow and RadWindowManager, as well as the other Telerik controls that utilize render modes, supports only one type of render mode per page. This includes mode being set for a standalone instance(s), and a programmatically created instance(s). All such controls must have the same RenderMode on a given page.This also includes instances from user controls and master pages.

A RadWindow that is inside the Windows collection of a RadWindowManager will inherit the manager's render mode, unless explicitly specified in the RadWindow instance.

Setting Render Mode

There are two ways to configure the rendering mode of the controls:

  • The RenderMode property in the markup or in the code-behind that can be used for a particular instance:
<telerik:RadWindow ID="RadWindow1" runat="server" RenderMode="Lightweight">
<telerik:RadWindowManager ID="RadWindowManager1" runat="server" RenderMode="Lightweight">
RadWindow1.RenderMode = Telerik.Web.UI.RenderMode.Lightweight;
RadWindowManager1.RenderMode = Telerik.Web.UI.RenderMode.Lightweight;
RadWindow1.RenderMode = Telerik.Web.UI.RenderMode.Lightweight
RadWindowManager1.RenderMode = Telerik.Web.UI.RenderMode.Lightweight
  • A global setting in the web.config file that will affect the entire application, unless a concrete value is specified for a given control instance:
    <add key="Telerik.Web.UI.Window.RenderMode" value="lightweight" />
    <add key="Telerik.Web.UI.WindowManager.RenderMode" value="lightweight" />
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