Rather than starting from scratch, I chose to start my control inheriting from the Panel control. This allows you to add any arbitrary content to the "draggable" item control, as it is translated to a span tag in HTML. In order to make the control "ATLAS-enabled" you need to implement the IScriptControl interface. The control's class declaration should be something similar to this:
public class DraggablePanel : System.Web.UI.WebControls.Panel, IScriptControl
Next you need to make sure to get a reference of the page's ScriptManager and register the control, and optionally you may want to add a reference to the AtlasUIDragDrop library to save you from doing that in the main page:
protected override void OnInit(EventArgs e)
{
base.OnInit(e);
if (!DesignMode)
{
ScriptManager scriptManager = ScriptManager.GetCurrent(Page);
if (scriptManager != null)
{
scriptManager.RegisterControl(this);
scriptManager.RegisterScriptReference(
FrameworkScript.AtlasUIDragDrop);
}
}
}
Next, the only method from the IScriptControl interface that must be implemented is the RenderScript method. The goal of the custom control is to output the following XML-Script:
<control id="webPart1">
<behaviors>
<draggablelistitem handle="webPart1Title">
</behaviors>
</control>
The RenderScript implementation will output the XML-Script above, using the control's id and the panel control's id as the handle:
public void RenderScript(ScriptTextWriter writer)
{
//Outputs control tag
GenericScriptComponent gsc = new GenericScriptComponent(
new ScriptTypeDescriptor("control",
ScriptNamespace.Default));
//Outputs behaviors tag
gsc.ID = this.ClientID;
GenericScriptComponent draggableBehavior =
new GenericScriptComponent(
new ScriptTypeDescriptor("draggableListItem",
ScriptNamespace.Default));
draggableBehavior.AddValueProperty("handle", this.ClientID);
gsc.AddCollectionItem("behaviors", draggableBehavior);
((IScriptObject)gsc).RenderScript(writer);
}
