November 01, 2003
Create Binary Behaviors for IE with .NET
Create Binary Behaviors for IE with .NET
Listing 1 Implementing IElementBehavior
namespace BinBehaviors
{
[
ComVisible(true),
IElementBehaviorSiteOM bsiteOM;
IHTMLPaintSite paintsite;
IHTMLDocument2 document;
IHTMLWindow2 parwindow;
IHTMLElement element;
HTMLElementEvents_Event events;
Point point1, point2;
float penwidth;
Color pencolor;
int xoffset, yoffset;
Bitmap bitmap;
/// <summary>
/// A default constructor (no parameters) is necessary for COM instantiation
/// </summary>
public Line()
{
point1 = new Point(0, 0);
point2= new Point(0, 0);
penwidth = 1;
pencolor = Color.Black;
xoffset = yoffset = (int) this.penwidth + 1;
}
~Line()
{
}
/// <summary>
/// Gets or sets the end points of the line as a single string.
/// </summary>
public string coords
{
get
{
return String.Format("{0} {1} {2} {3}",
point1.X, point1.Y, point2.X, point2.Y);
}
set
{
UpdateCoords(value);
DoLineDraw();
}
}
// IElementBehavior method.
void mshtml2.IElementBehavior.Init(IElementBehaviorSite behavsite)
{
try
{
this.bsite = behavsite;
if (behavsite is IElementBehaviorSiteOM)
this.bsiteOM = (IElementBehaviorSiteOM) behavsite;
if (behavsite is mshtml.IHTMLPaintSite)
this.paintsite = (mshtml.IHTMLPaintSite) behavsite;
}
catch (System.ExecutionEngineException e)
{
MessageBox.Show(e.Message);
}
}
// IElementBehavior method.
void mshtml2.IElementBehavior.Notify(int lEvent, System.IntPtr pVar)
{
try
{
switch ((_BEHAVIOR_EVENT)lEvent)
{
case _BEHAVIOR_EVENT.BEHAVIOREVENT_DOCUMENTREADY:
if (this.bsite == null)
return;
this.element = this.bsite.GetElement(); // Cache the HTML element.
this.document = (IHTMLDocument2) this.element.document;
this.parwindow = (IHTMLWindow2) document.parentWindow;
// Drawing to absolute point locations
// requires absolute position style.
element.style.setAttribute("position", "absolute", 0);
// Hook up event handlers.
if (element is mshtml.HTMLElementEvents_Event)
{
this.events = (HTMLElementEvents_Event) this.element;
events.onpropertychange +=
new mshtml.HTMLElementEvents_onpropertychangeEventHandler(
HTMLElement_OnPropertyChange);
}
// Initial attribute values.
// All HTML attributes come in as strings (or null, if not present).
// "coords" property is ONLY a property, not an attribute.
string x1 = element.getAttribute("x1", 0) as string;
string y1 = element.getAttribute("y1", 0) as string;
string x2 = element.getAttribute("x2", 0) as string;
string y2 = element.getAttribute("y2", 0) as string;
if (x1 != null)
point1.X = Convert.ToInt32(x1);
if (y1 != null)
point1.Y = Convert.ToInt32(y1);
if (x2 != null)
point2.X = Convert.ToInt32(x2);
if (y2 != null)
point2.Y = Convert.ToInt32(y2);
// ARGB must come in hexadecimal form.
string argbstring = element.getAttribute("argb", 0) as string;
if (argbstring != null)
this.pencolor = Color.FromArgb(
(int) Convert.ToUInt32(argbstring, 16));
// Width must be base 10.
string widthstring =
(string) element.getAttribute("width", 0) as string;
if (widthstring != null)
{
this.penwidth = Convert.ToSingle(widthstring);
xoffset = yoffset = (int) this.penwidth + 1;
}
DoLineDraw();
break;
case _BEHAVIOR_EVENT.BEHAVIOREVENT_FIRST:
//MessageBox.Show("event: first");
break;
case _BEHAVIOR_EVENT.BEHAVIOREVENT_LAST:
MessageBox.Show("event: last");
break;
case _BEHAVIOR_EVENT.BEHAVIOREVENT_APPLYSTYLE:
MessageBox.Show("event: apply style");
break;
default:
MessageBox.Show("event: (default)");
break;
}
}
catch (System.ExecutionEngineException e)
{
MessageBox.Show(e.Message);
}
}
// IElementBehavior method.
void mshtml2.IElementBehavior.Detach()
{
}
/// <summary>
/// Handle the element's OnPropertyChange event.
/// Update the drawing to reflect the new property values.
/// </summary>
public void HTMLElement_OnPropertyChange()
{
IHTMLEventObj2 evo = (IHTMLEventObj2) parwindow.@event;
string name = evo.propertyName.ToLower();
object o = element.getAttribute(evo.propertyName, 0);
switch (name)
{
case "x1":
if (o is System.Int32)
point1.X = (int) o;
break;
case "y1":
if (o is System.Int32)
point1.Y = (int) o;
break;
case "x2":
if (o is System.Int32)
point2.X = (int) o;
break;
case "y2":
if (o is System.Int32)
point2.Y = (int) o;
break;
case "coords": // NOT CALLED, because of our coords property (above)
UpdateCoords((string) o); // Object is a string (BSTR).
break;
case "width":
if (o is System.Int32)
penwidth = (int) o;
break;
case "argb":
// ARGB will come as double if too big to fit as Int32.
if (o is System.Double)
pencolor = Color.FromArgb((int) Convert.ToUInt32((double) o));
else if (o is System.Int32)
pencolor = Color.FromArgb((int) o);
break;
default:
break;
}
DoLineDraw();
}
/// <summary>
/// Update the coordinates members (x1, y1, x2, y2)
/// given a string representation.
/// </summary>
/// <param name="coords">String representation of x1, y1, x2, y2.</param>
private void UpdateCoords(string coords)
{
// May have: coords=" x1 ;y1 , x2 y2 ", etc.
string s = coords.Trim();
Regex re = new Regex("\\s*[,;]\\s*|\\s+"); // Separate at: space | punct.
// Order of alts is important.
string[] segs = re.Split(s, 5);
if (segs.Length >= 4)
{
point1.X = Convert.ToInt32(segs[0]);
point1.Y = Convert.ToInt32(segs[1]);
point2.X = Convert.ToInt32(segs[2]);
point2.Y = Convert.ToInt32(segs[3]);
UpdateAttributes();
}
}
/// <summary>
/// Update the HTML attributes to reflect actual property values.
/// </summary>
private void UpdateAttributes()
{
this.element.setAttribute("x1", point1.X.ToString(), 0);
this.element.setAttribute("y1", point1.Y.ToString(), 0);
this.element.setAttribute("x2", point2.X.ToString(), 0);
this.element.setAttribute("y2", point2.Y.ToString(), 0);
}
// .
}
}
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