The original question came from someone who wanted to stop text objects from being highlighted when selected. I’ve extended the mechanism to make it a little more flexible: it now maintains a list of object types (their DXF names) of objects that should not be highlighted, when selected.
Balaji implemented a HighlightOverrule to control the highlighting. This doesn’t stop the objects from actually being selected, however: in the next post I’ll add some additional code from Balaji’s implementation that also stops the objects from being selected.
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Runtime;
using System.Collections.Generic;
using System.Text;
namespace PreventSelectionHighlight
{
public class Test : IExtensionApplication
{
static UnhighlightOverrule _ho = new UnhighlightOverrule();
[CommandMethod("UH")]
public static void Unhighlight()
{
Document doc = Application.DocumentManager.MdiActiveDocument;
Editor ed = doc.Editor;
// Print the list of currently unhighlighted classes
ed.WriteMessage(_ho.ListToPrint());
// Get the type to add to the list
PromptResult pr =
ed.GetString(
"\nEnter the type of object to stop from " +
"being highlighted: "
);
if (pr.Status != PromptStatus.OK)
return;
if (_ho.IsInList(pr.StringResult))
{
ed.WriteMessage("\nItem already in the list.");
}
else
{
_ho.AddToList(pr.StringResult);
ed.WriteMessage("\nItem added to the list.");
}
}
[CommandMethod("RH")]
public static void Rehighlight()
{
Document doc = Application.DocumentManager.MdiActiveDocument;
Editor ed = doc.Editor;
// Print the list of currently unhighlighted classes
ed.WriteMessage(_ho.ListToPrint());
// Get the type to remove from the list
PromptResult pr =
ed.GetString(
"\nEnter the type of object to remove from the " +
"list: "
);
if (pr.Status != PromptStatus.OK)
return;
if (!_ho.IsInList(pr.StringResult))
{
ed.WriteMessage("\nItem not currently in the list.");
}
else
{
_ho.RemoveFromList(pr.StringResult);
ed.WriteMessage("\nItem removed from the list.");
}
}
void IExtensionApplication.Initialize()
{
// Add our overrule
Overrule.AddOverrule(
RXObject.GetClass(typeof(Entity)), _ho, false
);
Overrule.Overruling = true;
}
void IExtensionApplication.Terminate()
{
// Remove our overrule
Overrule.RemoveOverrule(
RXObject.GetClass(typeof(Entity)), _ho
);
Overrule.Overruling = false;
}
}
class UnhighlightOverrule : HighlightOverrule
{
// The list of types to unhighlight
List<string> _unhighlighted = new List<string>();
// Add a type to the list
public void AddToList(string name)
{
string upper = name.ToUpper();
if (!_unhighlighted.Contains(upper))
{
_unhighlighted.Add(upper);
}
}
// Remove a type from the list
public void RemoveFromList(string name)
{
string upper = name.ToUpper();
if (_unhighlighted.Contains(upper))
{
_unhighlighted.Remove(upper);
}
}
// Check whether the list contains a type
public bool IsInList(string name)
{
return _unhighlighted.Contains(name.ToUpper());
}
// Get a string printing the contents of the list
public string ListToPrint()
{
string toPrint;
if (_unhighlighted.Count == 0)
{
toPrint =
"\nThere are currently no objects in the list " +
"to stop from being highlighted.";
}
else
{
StringBuilder sb =
new StringBuilder(
"\nObjects of these types will not be highlighted " +
"during selection:"
);
foreach (string name in _unhighlighted)
{
sb.Append(" " + name);
}
toPrint = sb.ToString();
}
return toPrint;
}
// Called when an entity is highlighted
public override void Highlight(
Entity entity, FullSubentityPath subId, bool highlightAll
)
{
// If our object's type is in the list, return
// without calling the base implementation
if (IsInList(entity.GetRXClass().DxfName))
return;
base.Highlight(entity, subId, highlightAll);
}
// Called when an entity is unhighlighted
public override void Unhighlight(
Entity entity, FullSubentityPath subId, bool highlightAll
)
{
base.Unhighlight(entity, subId, highlightAll);
}
}
}
You can use the UH command to “unhighlight” objects via their type’s DXF name and RH to re-highlight them.
Let’s draw some simple geometry – lines, arcs and circles.
When we select them, they all get highlighted (see? nothing up my sleeves. ;-)
Next time we’ll take a look at ways to stop objects from being selected, not just highlighted.
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