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this is the advanced presentation from Codemash 2008
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Advanced Silverlight
Jeff BlankenburgDeveloper Evangelist
[email protected]://www.jeffblankenburg.com
Who's Even Using Silverlight 1.0?
What are we going to see today?
Why HTML elements?
• Silverlight user controls are coming with the 2.0 release.
• 3rd party vendors are creating control suites as we speak.
• No effective way to generate a Silverlight 1.0 user control currently
We are actually laying HTML <div> tags over the Silverlight content, and communicating via Javascript.
Overlaying HTML Elements<div style=“position:awesome;”></div>
What about using actual data?
• It’s as easy as using AJAX was, because that’s exactly what you’re doing.
• Silverlight is not meant to replace AJAX, it’s a presentation layer. They’re meant to be complimentary.
We’re actually using AJAX to call our web service, and then rewriting the XAML on the server. This updates our Silverlight presentation.
Using Web ServicesgetMeSomeData();
Where's the cool user interactions?
• Have you ever tried to do Drag & Drop using <div> elements and Javascript?
• Let’s compare straight Javascript to Silverlight.
// iMouseDown represents the current mouse button state: up or down /* lMouseState represents the previous mouse button state so that we can check for button clicks and button releases: if(iMouseDown && !lMouseState) // button just clicked! if(!iMouseDown && lMouseState) // button just released! */ var mouseOffset = null; var iMouseDown = false; var lMouseState = false; var dragObject = null; // Demo 0 variables var DragDrops = []; var curTarget = null; var lastTarget = null; var dragHelper = null; var tempDiv = null; var rootParent = null; var rootSibling = null; Number.prototype.NaN0=function(){return isNaN(this)?0:this;} function CreateDragContainer(){ /* Create a new "Container Instance" so that items from one "Set" can not be dragged into items from another "Set" */ var cDrag = DragDrops.length; DragDrops[cDrag] = []; /* Each item passed to this function should be a "container". Store each of these items in our current container */ for(var i=0; i<arguments.length; i++){ var cObj = arguments[i]; DragDrops[cDrag].push(cObj); cObj.setAttribute('DropObj', cDrag); /* Every top level item in these containers should be draggable. Do this by setting the DragObj attribute on each item and then later checking this attribute in the mouseMove function */ for(var j=0; j<cObj.childNodes.length; j++){ // Firefox puts in lots of #text nodes...skip these if(cObj.childNodes[j].nodeName=='#text') continue; cObj.childNodes[j].setAttribute('DragObj', cDrag); } } } function mouseMove(ev){ ev = ev || window.event; /* We are setting target to whatever item the mouse is currently on Firefox uses event.target here, MSIE uses event.srcElement */ var target = ev.target || ev.srcElement; var mousePos = mouseCoords(ev); // mouseOut event - fires if the item the mouse is on has changed if(lastTarget && (target!==lastTarget)){ // reset the classname for the target element var origClass = lastTarget.getAttribute('origClass'); if(origClass) lastTarget.className = origClass; } /* dragObj is the grouping our item is in (set from the createDragContainer function). if the item is not in a grouping we ignore it since it can't be dragged with this script. */ var dragObj = target.getAttribute('DragObj'); // if the mouse was moved over an element that is draggable if(dragObj!=null){ // mouseOver event - Change the item's class if necessary if(target!=lastTarget){ var oClass = target.getAttribute('overClass'); if(oClass){ target.setAttribute('origClass', target.className); target.className = oClass; } } // if the user is just starting to drag the element if(iMouseDown && !lMouseState){ // mouseDown target curTarget = target; // Record the mouse x and y offset for the element rootParent = curTarget.parentNode; rootSibling = curTarget.nextSibling; mouseOffset = getMouseOffset(target, ev); // We remove anything that is in our dragHelper DIV so we can put a new item in it. for(var i=0; i<dragHelper.childNodes.length; i++) dragHelper.removeChild(dragHelper.childNodes[i]); // Make a copy of the current item and put it in our drag helper. dragHelper.appendChild(curTarget.cloneNode(true)); dragHelper.style.display = 'block'; // set the class on our helper DIV if necessary var dragClass = curTarget.getAttribute('dragClass'); if(dragClass){ dragHelper.firstChild.className = dragClass; } // disable dragging from our helper DIV (it's already being dragged) dragHelper.firstChild.removeAttribute('DragObj'); /* Record the current position of all drag/drop targets related to the element. We do this here so that we do not have to do it on the general mouse move event which fires when the mouse moves even 1 pixel. If we don't do this here the script would run much slower. */ var dragConts = DragDrops[dragObj]; /* first record the width/height of our drag item. Then hide it since it is going to (potentially) be moved out of its parent. */ curTarget.setAttribute('startWidth', parseInt(curTarget.offsetWidth)); curTarget.setAttribute('startHeight', parseInt(curTarget.offsetHeight)); curTarget.style.display = 'none'; // loop through each possible drop container for(var i=0; i<dragConts.length; i++){ with(dragConts[i]){ var pos = getPosition(dragConts[i]); /* save the width, height and position of each container. Even though we are saving the width and height of each container back to the container this is much faster because we are saving the number and do not have to run through any calculations again. Also, offsetHeight and offsetWidth are both fairly slow. You would never normally notice any performance hit from these two functions but our code is going to be running hundreds of times each second so every little bit helps! Note that the biggest performance gain here, by far, comes from not having to run through the getPosition function hundreds of times. */ setAttribute('startWidth', parseInt(offsetWidth)); setAttribute('startHeight', parseInt(offsetHeight)); setAttribute('startLeft', pos.x); setAttribute('startTop', pos.y); } // loop through each child element of each container for(var j=0; j<dragConts[i].childNodes.length; j++){ with(dragConts[i].childNodes[j]){ if((nodeName=='#text') || (dragConts[i].childNodes[j]==curTarget)) continue; var pos = getPosition(dragConts[i].childNodes[j]); // save the width, height and position of each element setAttribute('startWidth', parseInt(offsetWidth)); setAttribute('startHeight', parseInt(offsetHeight)); setAttribute('startLeft', pos.x); setAttribute('startTop', pos.y); } } } } } // If we get in here we are dragging something if(curTarget){ // move our helper div to wherever the mouse is (adjusted by mouseOffset) dragHelper.style.top = mousePos.y - mouseOffset.y; dragHelper.style.left = mousePos.x - mouseOffset.x; var dragConts = DragDrops[curTarget.getAttribute('DragObj')]; var activeCont = null; var xPos = mousePos.x - mouseOffset.x + (parseInt(curTarget.getAttribute('startWidth')) /2); var yPos = mousePos.y - mouseOffset.y + (parseInt(curTarget.getAttribute('startHeight'))/2); // check each drop container to see if our target object is "inside" the container for(var i=0; i<dragConts.length; i++){ with(dragConts[i]){ if(((getAttribute('startLeft')) < xPos) && ((getAttribute('startTop')) < yPos) && ((getAttribute('startLeft') + getAttribute('startWidth')) > xPos) && ((getAttribute('startTop') + getAttribute('startHeight')) > yPos)){ /* our target is inside of our container so save the container into the activeCont variable and then exit the loop since we no longer need to check the rest of the containers */ activeCont = dragConts[i]; // exit the for loop break; } } } // Our target object is in one of our containers. Check to see where our div belongs if(activeCont){ // beforeNode will hold the first node AFTER where our div belongs var beforeNode = null; // loop through each child node (skipping text nodes). for(var i=activeCont.childNodes.length-1; i>=0; i--){ with(activeCont.childNodes[i]){ if(nodeName=='#text') continue; // if the current item is "After" the item being dragged if( curTarget != activeCont.childNodes[i] && ((getAttribute('startLeft') + getAttribute('startWidth')) > xPos) && ((getAttribute('startTop') + getAttribute('startHeight')) > yPos)){ beforeNode = activeCont.childNodes[i]; } } } // the item being dragged belongs before another item if(beforeNode){ if(beforeNode!=curTarget.nextSibling){ activeCont.insertBefore(curTarget, beforeNode); } // the item being dragged belongs at the end of the current container } else { if((curTarget.nextSibling) || (curTarget.parentNode!=activeCont)){ activeCont.appendChild(curTarget); } } // make our drag item visible if(curTarget.style.display!=''){ curTarget.style.display = ''; } } else { // our drag item is not in a container, so hide it. if(curTarget.style.display!='none'){ curTarget.style.display = 'none'; } } } // track the current mouse state so we can compare against it next time lMouseState = iMouseDown; // mouseMove target lastTarget = target; // track the current mouse state so we can compare against it next time lMouseState = iMouseDown; // this helps prevent items on the page from being highlighted while dragging return false; } function mouseUp(ev){ if(curTarget){ // hide our helper object - it is no longer needed dragHelper.style.display = 'none'; // if the drag item is invisible put it back where it was before moving it if(curTarget.style.display == 'none'){ if(rootSibling){ rootParent.insertBefore(curTarget, rootSibling); } else { rootParent.appendChild(curTarget); } } // make sure the drag item is visible curTarget.style.display = ''; } curTarget = null; iMouseDown = false; } function mouseDown(){ iMouseDown = true; if(lastTarget){ return false; } } document.onmousemove = mouseMove; document.onmousedown = mouseDown; document.onmouseup = mouseUp; window.onload = function(){ // Create our helper object that will show the item while dragging dragHelper = document.createElement('DIV'); dragHelper.style.cssText = 'position:absolute;display:none;'; CreateDragContainer( document.getElementById('DragContainer1'), document.getElementById('DragContainer2'), document.getElementById('DragContainer3') ); document.body.appendChild(dragHelper); } <!--the mouse over and dragging class are defined on each item--> <div class="DragContainer" id="DragContainer1"> <div class="DragBox" id="Item1" overClass="OverDragBox" dragClass="DragDragBox">Item #1</div> <div class="DragBox" id="Item2" overClass="OverDragBox" dragClass="DragDragBox">Item #2</div> <div class="DragBox" id="Item3" overClass="OverDragBox" dragClass="DragDragBox">Item #3</div> <div class="DragBox" id="Item4" overClass="OverDragBox" dragClass="DragDragBox">Item #4</div> </div> <div class="DragContainer" id="DragContainer2"> <div class="DragBox" id="Item5" overClass="OverDragBox" dragClass="DragDragBox">Item #5</div> <div class="DragBox" id="Item6" overClass="OverDragBox" dragClass="DragDragBox">Item #6</div> <div class="DragBox" id="Item7" overClass="OverDragBox" dragClass="DragDragBox">Item #7</div> <div class="DragBox" id="Item8" overClass="OverDragBox" dragClass="DragDragBox">Item #8</div> </div> <div class="DragContainer" id="DragContainer3"> <div class="DragBox" id="Item9" overClass="OverDragBox" dragClass="DragDragBox">Item #9</div> <div class="DragBox" id="Item10" overClass="OverDragBox" dragClass="DragDragBox">Item #10</div> <div class="DragBox" id="Item11" overClass="OverDragBox" dragClass="DragDragBox">Item #11</div> <div class="DragBox" id="Item12" overClass="OverDragBox" dragClass="DragDragBox">Item #12</div> </div>
Taken from http://www.webreference.com/programming/javascript/mk/column2/3.html
Here's the code needed for Silverlightvar beginX;var beginY;var trackingMouseMove = false;var zIndex = 0;function onMouseDown(sender, mouseEventArgs){ beginX = mouseEventArgs.getPosition(null).x; beginY = mouseEventArgs.getPosition(null).y; trackingMouseMove = true; sender.captureMouse(); //zIndex += 1; //sender["Canvas.ZIndex"] = zIndex;}function onMouseUp(sender, mouseEventArgs){sender.releaseMouseCapture(); trackingMouseMove = false;}function onMouseMove(sender, mouseEventArgs){ if (trackingMouseMove == true) { var currentX = mouseEventArgs.getPosition(null).x; var currentY = mouseEventArgs.getPosition(null).y; sender["Canvas.Left"] += currentX - beginX; sender["Canvas.Top"] += currentY - beginY; beginX = currentX; beginY = currentY; }}
Drag and Drop (using Event Handlers)
mouseEnter = “EatCheese”
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presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.
How To Contact Me
Email: [email protected]
Blog: http://www.jeffblankenburg.com
Twitter: http://www.twitter.com/jeffblankenburg
