selected - Page 57 - Developer IT

Item of one combobox should not come into the other

- by syedsaleemss

Im using c# .net windows form application. I have a database with some tables.I have two comboboxes (A & B). I have populated a combo box A with column names of a table using sys.columns. Now when i select an item in combo box A ,combo box B should be populated with the same items except the selected item which was selected in combobox A .

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how to add javascript to html page

- by user1888584

I was given this chunk of code to place in my html page but I know nothing about javascript so I have no idea where to place it and what kind of tag to place it in. Can someone please help me. Thanks Code: $('input[type=radio]').change(function() { $('input[type=radio]').each(function(index) { $(this).closest('tr').removeClass('selected'); }); $(this).closest('tr').addClass('selected'); });

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What's wrong with this "if"?

- by Gurzo

Hello, I'm currently trying to make an AppleScript which should recognize the selected file in Finder and do the relative command in Terminal. Everything was going fine since I reached the part where it should define the language of the selected file: it just doesn't check the ifs. I checked if it writes fileExtension correctly (via return) and it does. Here is the Gist with the code, any help would be appreciated. Thanks

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jquery select list remove

- by mazhar

there are 2 multiple select list on my page , one is there with a seperate remove button . selecting an item there in the selected list is removing the item from the first select list also.how will i specify which list to remove item from in this code $().ready(function() { $('#remove').click(function() { return !$('#FeatureList option:selected').remove(); }); });

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How to check results of LINQ to SQL query?

- by rem

In a WPF app I'd like to check if a return of a LINQ to SQL query contains some records, but my approach doesn't work: TdbDataContext context = new TdbDataContext(); var sh = from p in context.Items where p.Selected == true select p; if (sh == null) { MessageBox.Show("There are no Selected Items"); } Where am I wrong?

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how to get category value from xml params?

- by C-link Nepal

I have the following field in xml: <field name="cat1" type="category" extension="COM_CONTENT" label="MOD_ITEM_CAT1" description="MOD_ITEM_CAT_DESC" /> Now, I wanted to get selected value: echo $params->get('cat1'); Which shows me 8 (the value of selected option) not it's title. I've category title people and it should show people instead of 8. So, how to extract the title of the category?

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jquery elementby class and set name

- by tom

Hello can some one help me with code to get element by classname and also change the name currently ive tried $('selected').attr("name", 'blah blah'); and also $('.selected').attr("name", 'blah blah'); noneof these work thanks

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What groupbox method (if any) monitors radio button selections?

- by JohnK813

I'm creating a VB.NET application that includes two radio buttons inside of a groupbox. If the first radio button is selected, a certain tab on a tab form should be enabled. If the second radio button is selected, that tab should be disabled. Is there a groupbox method that monitors both radio buttons and fires when the selection changes? Or do I need to set up individual methods for each radio button?

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image processing

- by sam

hi folks, i have some images..if these images are selected then it should generate another image which is the combination of all the selected images.. can anyone suggest as how to start with? thanks

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When to call selectRow: on a UIPickerView that has just loaded?

- by ragnarius

I am trying to learn iPhone/iOS programming. I have an UIPickerView that should dispay its selected row as soon as it becomes visible (it is contained on a flippSideView). Unfortunately, the flipSideViewController's awakeFromNib is not called. It is too early to call [pickView selectRow ..] from viewWillLoad (the pickView does not exist at that time), and somewhat too late to do it in viewDidAppear. So, how can I make the pickerView display the selected row as soon it becomes visible?

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C# setting case constant expressions, do they have to follow a specific order?

- by Umeed

Say I'm making a simple program, and the user is in the menu. And the menu options are 1 3 5 7 (i wouldn't actually do that but lets just go with it). and I want to make my switch statement using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace DecisionMaking2 { class Program { static void Main(string[] args) { Console.WriteLine("Please choose an option: "); string SelectedOpt = Console.ReadLine(); double Selection = Convert.ToDouble(SelectedOpt); double MenuOption = (Selection); switch (MenuOption) { case 1: Console.WriteLine("Selected option #1"); break; case 2: Console.WriteLine("Selected option #3"); break; case 3: Console.WriteLine("Selected option #5"); break; case 4: Console.WriteLine("Selected option #7"); break; default: Console.WriteLine("Please choose from the options List!"); break; } } } } would that work? or would I have to name each case constant expression the option number I am using? I went to the microsoft website and I didn't quite pick up on anything i was looking for. . Also while I have your attention, how would I make it so the user chooses from either option and because I don't know which option the user will select " double MenuOption = " could be anything, whatever the user inputs right? so would what I have even work? I am doing this all by hand, and don't get much lab time to work on this as I have tons of other courses to work on and then a boring job to go to, and my PC at home has a restarting issue lol. soo any and all help is greatly appreciated. p.s the computer I'm on right now posting this, doesn't have any compilers, coding programs, and it's not mine just to get that out of the way. Thanks again!

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asp.net dropdownlist databind on init causes data loss

- by user2191496

On which event or how should I bind data to the dropdownlist to avoid selected value overridden? For some reasons, I can't use "IsPostBack" to bind data only on postback I've tried binding data on page init, it works ok but when postback, the selected value will be overridden (Loss) protected void Page_Init(object sender, EventArgs e) { this.BindData(); } protected void BindData() { //grab the source of dropdownlist }

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date in future for Rails

- by Adnan

Hello, I am trying to make a validation that will validate that the entered date is in future and that the selected date is in the next 7 days. In order to validate if the date is in future I use; valid_until.future? and this one works fine, but to make a validation to check if the date selected is withing 7 days from now?

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FLEX: Datagrid, how to select an item given my data attribute values

- by Patrick

hi, I'm using a custom component CheckBoxList DataGrid (http://blogs.adobe.com/aharui/2008/02/checkbox_selection_in_datagrid.html) and as dataProvider I have an ArrayCollection with items such this one: name="item name" selected="true" I would like the CheckBox list updated when the selected attribute is set to false or true in the data model. thanks

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asp.net selecting a checkbox from the grid view

- by baburam

i am trying to get checkbox value ,using c# In grid view the datasource is from oracle i have added the checkbox but the value is not coming please help me in checking the value of check box this is for selecting the candidate if the checkbox is selected the particular candidate name is selected and the candidate names are appended in a string

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A free standing ASP.NET Pager Web Control

- by Rick Strahl

Paging in ASP.NET has been relatively easy with stock controls supporting basic paging functionality. However, recently I built an MVC application and one of the things I ran into was that I HAD TO build manual paging support into a few of my pages. Dealing with list controls and rendering markup is easy enough, but doing paging is a little more involved. I ended up with a small but flexible component that can be dropped anywhere. As it turns out the task of creating a semi-generic Pager control for MVC was fairly easily. Now I’m back to working in Web Forms and thought to myself that the way I created the pager in MVC actually would also work in ASP.NET – in fact quite a bit easier since the whole thing can be conveniently wrapped up into an easily reusable control. A standalone pager would provider easier reuse in various pages and a more consistent pager display regardless of what kind of 'control’ the pager is associated with. Why a Pager Control? At first blush it might sound silly to create a new pager control – after all Web Forms has pretty decent paging support, doesn’t it? Well, sort of. Yes the GridView control has automatic paging built in and the ListView control has the related DataPager control. The built in ASP.NET paging has several issues though: Postback and JavaScript requirements If you look at paging links in ASP.NET they are always postback links with javascript:__doPostback() calls that go back to the server. While that works fine and actually has some benefit like the fact that paging saves changes to the page and post them back, it’s not very SEO friendly. Basically if you use javascript based navigation nosearch engine will follow the paging links which effectively cuts off list content on the first page. The DataPager control does support GET based links via the QueryStringParameter property, but the control is effectively tied to the ListView control (which is the only control that implements IPageableItemContainer). DataSource Controls required for Efficient Data Paging Retrieval The only way you can get paging to work efficiently where only the few records you display on the page are queried for and retrieved from the database you have to use a DataSource control - only the Linq and Entity DataSource controls support this natively. While you can retrieve this data yourself manually, there’s no way to just assign the page number and render the pager based on this custom subset. Other than that default paging requires a full resultset for ASP.NET to filter the data and display only a subset which can be very resource intensive and wasteful if you’re dealing with largish resultsets (although I’m a firm believer in returning actually usable sets :-}). If you use your own business layer that doesn’t fit an ObjectDataSource you’re SOL. That’s a real shame too because with LINQ based querying it’s real easy to retrieve a subset of data that is just the data you want to display but the native Pager functionality doesn’t support just setting properties to display just the subset AFAIK. DataPager is not Free Standing The DataPager control is the closest thing to a decent Pager implementation that ASP.NET has, but alas it’s not a free standing component – it works off a related control and the only one that it effectively supports from the stock ASP.NET controls is the ListView control. This means you can’t use the same data pager formatting for a grid and a list view or vice versa and you’re always tied to the control. Paging Events In order to handle paging you have to deal with paging events. The events fire at specific time instances in the page pipeline and because of this you often have to handle data binding in a way to work around the paging events or else end up double binding your data sources based on paging. Yuk. Styling The GridView pager is a royal pain to beat into submission for styled rendering. The DataPager control has many more options and template layout and it renders somewhat cleaner, but it too is not exactly easy to get a decent display for. Not a Generic Solution The problem with the ASP.NET controls too is that it’s not generic. GridView, DataGrid use their own internal paging, ListView can use a DataPager and if you want to manually create data layout – well you’re on your own. IOW, depending on what you use you likely have very different looking Paging experiences. So, I figured I’ve struggled with this once too many and finally sat down and built a Pager control. The Pager Control My goal was to create a totally free standing control that has no dependencies on other controls and certainly no requirements for using DataSource controls. The idea is that you should be able to use this pager control without any sort of data requirements at all – you should just be able to set properties and be able to display a pager. The Pager control I ended up with has the following features: Completely free standing Pager control – no control or data dependencies Complete manual control – Pager can render without any data dependency Easy to use: Only need to set PageSize, ActivePage and TotalItems Supports optional filtering of IQueryable for efficient queries and Pager rendering Supports optional full set filtering of IEnumerable<T> and DataTable Page links are plain HTTP GET href Links Control automatically picks up Page links on the URL and assigns them (automatic page detection no page index changing events to hookup) Full CSS Styling support On the downside there’s no templating support for the control so the layout of the pager is relatively fixed. All elements however are stylable and there are options to control the text, and layout options such as whether to display first and last pages and the previous/next buttons and so on. To give you an idea what the pager looks like, here are two differently styled examples (all via CSS): The markup for these two pagers looks like this: <ww:Pager runat="server" id="ItemPager" PageSize="5" PageLinkCssClass="gridpagerbutton" SelectedPageCssClass="gridpagerbutton-selected" PagesTextCssClass="gridpagertext" CssClass="gridpager" RenderContainerDiv="true" ContainerDivCssClass="gridpagercontainer" MaxPagesToDisplay="6" PagesText="Item Pages:" NextText="next" PreviousText="previous" /> <ww:Pager runat="server" id="ItemPager2" PageSize="5" RenderContainerDiv="true" MaxPagesToDisplay="6" /> The latter example uses default style settings so it there’s not much to set. The first example on the other hand explicitly assigns custom styles and overrides a few of the formatting options. Styling The styling is based on a number of CSS classes of which the the main pager, pagerbutton and pagerbutton-selected classes are the important ones. Other styles like pagerbutton-next/prev/first/last are based on the pagerbutton style. The default styling shown for the red outlined pager looks like this: .pagercontainer { margin: 20px 0; background: whitesmoke; padding: 5px; } .pager { float: right; font-size: 10pt; text-align: left; } .pagerbutton,.pagerbutton-selected,.pagertext { display: block; float: left; text-align: center; border: solid 2px maroon; min-width: 18px; margin-left: 3px; text-decoration: none; padding: 4px; } .pagerbutton-selected { font-size: 130%; font-weight: bold; color: maroon; border-width: 0px; background: khaki; } .pagerbutton-first { margin-right: 12px; } .pagerbutton-last,.pagerbutton-prev { margin-left: 12px; } .pagertext { border: none; margin-left: 30px; font-weight: bold; } .pagerbutton a { text-decoration: none; } .pagerbutton:hover { background-color: maroon; color: cornsilk; } .pagerbutton-prev { background-image: url(images/prev.png); background-position: 2px center; background-repeat: no-repeat; width: 35px; padding-left: 20px; } .pagerbutton-next { background-image: url(images/next.png); background-position: 40px center; background-repeat: no-repeat; width: 35px; padding-right: 20px; margin-right: 0px; } Yup that’s a lot of styling settings although not all of them are required. The key ones are pagerbutton, pager and pager selection. The others (which are implicitly created by the control based on the pagerbutton style) are for custom markup of the ‘special’ buttons. In my apps I tend to have two kinds of pages: Those that are associated with typical ‘grid’ displays that display purely tabular data and those that have a more looser list like layout. The two pagers shown above represent these two views and the pager and gridpager styles in my standard style sheet reflect these two styles. Configuring the Pager with Code Finally lets look at what it takes to hook up the pager. As mentioned in the highlights the Pager control is completely independent of other controls so if you just want to display a pager on its own it’s as simple as dropping the control and assigning the PageSize, ActivePage and either TotalPages or TotalItems. So for this markup: <ww:Pager runat="server" id="ItemPagerManual" PageSize="5" MaxPagesToDisplay="6" /> I can use code as simple as: ItemPagerManual.PageSize = 3; ItemPagerManual.ActivePage = 4;ItemPagerManual.TotalItems = 20; Note that ActivePage is not required - it will automatically use any Page=x query string value and assign it, although you can override it as I did above. TotalItems can be any value that you retrieve from a result set or manually assign as I did above. A more realistic scenario based on a LINQ to SQL IQueryable result is even easier. In this example, I have a UserControl that contains a ListView control that renders IQueryable data. I use a User Control here because there are different views the user can choose from with each view being a different user control. This incidentally also highlights one of the nice features of the pager: Because the pager is independent of the control I can put the pager on the host page instead of into each of the user controls. IOW, there’s only one Pager control, but there are potentially many user controls/listviews that hold the actual display data. The following code demonstrates how to use the Pager with an IQueryable that loads only the records it displays: protected voidPage_Load(objectsender, EventArgs e) { Category = Request.Params["Category"] ?? string.Empty; IQueryable<wws_Item> ItemList = ItemRepository.GetItemsByCategory(Category); // Update the page and filter the list down ItemList = ItemPager.FilterIQueryable<wws_Item>(ItemList); // Render user control with a list view Control ulItemList = LoadControl("~/usercontrols/" + App.Configuration.ItemListType + ".ascx"); ((IInventoryItemListControl)ulItemList).InventoryItemList = ItemList; phItemList.Controls.Add(ulItemList); // placeholder } The code uses a business object to retrieve Items by category as an IQueryable which means that the result is only an expression tree that hasn’t execute SQL yet and can be further filtered. I then pass this IQueryable to the FilterIQueryable() helper method of the control which does two main things: Filters the IQueryable to retrieve only the data displayed on the active page Sets the Totaltems property and calculates TotalPages on the Pager and that’s it! When the Pager renders it uses those values, plus the PageSize and ActivePage properties to render the Pager. In addition to IQueryable there are also filter methods for IEnumerable<T> and DataTable, but these versions just filter the data by removing rows/items from the entire already retrieved data. Output Generated and Paging Links The output generated creates pager links as plain href links. Here’s what the output looks like: <div id="ItemPager" class="pagercontainer"> <div class="pager"> <span class="pagertext">Pages: </span><a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=1" class="pagerbutton" />1</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=2" class="pagerbutton" />2</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=3" class="pagerbutton" />3</a> <span class="pagerbutton-selected">4</span> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=5" class="pagerbutton" />5</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=6" class="pagerbutton" />6</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=20" class="pagerbutton pagerbutton-last" />20</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=3" class="pagerbutton pagerbutton-prev" />Prev</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=5" class="pagerbutton pagerbutton-next" />Next</a></div> <br clear="all" /> </div> </div> The links point back to the current page and simply append a Page= page link into the page. When the page gets reloaded with the new page number the pager automatically detects the page number and automatically assigns the ActivePage property which results in the appropriate page to be displayed. The code shown in the previous section is all that’s needed to handle paging. Note that HTTP GET based paging is different than the Postback paging ASP.NET uses by default. Postback paging preserves modified page content when clicking on pager buttons, but this control will simply load a new page – no page preservation at this time. The advantage of not using Postback paging is that the URLs generated are plain HTML links that a search engine can follow where __doPostback() links are not. Pager with a Grid The pager also works in combination with grid controls so it’s easy to bypass the grid control’s paging features if desired. In the following example I use a gridView control and binds it to a DataTable result which is also filterable by the Pager control. The very basic plain vanilla ASP.NET grid markup looks like this: <div style="width: 600px; margin: 0 auto;padding: 20px; "> <asp:DataGrid runat="server" AutoGenerateColumns="True" ID="gdItems" CssClass="blackborder" style="width: 600px;"> <AlternatingItemStyle CssClass="gridalternate" /> <HeaderStyle CssClass="gridheader" /> </asp:DataGrid> <ww:Pager runat="server" ID="Pager" CssClass="gridpager" ContainerDivCssClass="gridpagercontainer" PageLinkCssClass="gridpagerbutton" SelectedPageCssClass="gridpagerbutton-selected" PageSize="8" RenderContainerDiv="true" MaxPagesToDisplay="6" /> </div> and looks like this when rendered: using custom set of CSS styles. The code behind for this code is also very simple: protected void Page_Load(object sender, EventArgs e) { string category = Request.Params["category"] ?? ""; busItem itemRep = WebStoreFactory.GetItem(); var items = itemRep.GetItemsByCategory(category) .Select(itm => new {Sku = itm.Sku, Description = itm.Description}); // run query into a DataTable for demonstration DataTable dt = itemRep.Converter.ToDataTable(items,"TItems"); // Remove all items not on the current page dt = Pager.FilterDataTable(dt,0); // bind and display gdItems.DataSource = dt; gdItems.DataBind(); } A little contrived I suppose since the list could already be bound from the list of elements, but this is to demonstrate that you can also bind against a DataTable if your business layer returns those. Unfortunately there’s no way to filter a DataReader as it’s a one way forward only reader and the reader is required by the DataSource to perform the bindings. However, you can still use a DataReader as long as your business logic filters the data prior to rendering and provides a total item count (most likely as a second query). Control Creation The control itself is a pretty brute force ASP.NET control. Nothing clever about this other than some basic rendering logic and some simple calculations and update routines to determine which buttons need to be shown. You can take a look at the full code from the West Wind Web Toolkit’s Repository (note there are a few dependencies). To give you an idea how the control works here is the Render() method: /// <summary> /// overridden to handle custom pager rendering for runtime and design time /// </summary> /// <param name="writer"></param> protected override void Render(HtmlTextWriter writer) { base.Render(writer); if (TotalPages == 0 && TotalItems > 0) TotalPages = CalculateTotalPagesFromTotalItems(); if (DesignMode) TotalPages = 10; // don't render pager if there's only one page if (TotalPages < 2) return; if (RenderContainerDiv) { if (!string.IsNullOrEmpty(ContainerDivCssClass)) writer.AddAttribute("class", ContainerDivCssClass); writer.RenderBeginTag("div"); } // main pager wrapper writer.WriteBeginTag("div"); writer.AddAttribute("id", this.ClientID); if (!string.IsNullOrEmpty(CssClass)) writer.WriteAttribute("class", this.CssClass); writer.Write(HtmlTextWriter.TagRightChar + "\r\n"); // Pages Text writer.WriteBeginTag("span"); if (!string.IsNullOrEmpty(PagesTextCssClass)) writer.WriteAttribute("class", PagesTextCssClass); writer.Write(HtmlTextWriter.TagRightChar); writer.Write(this.PagesText); writer.WriteEndTag("span"); // if the base url is empty use the current URL FixupBaseUrl(); // set _startPage and _endPage ConfigurePagesToRender(); // write out first page link if (ShowFirstAndLastPageLinks && _startPage != 1) { writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, (1).ToString()); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass + " " + PageLinkCssClass + "-first"); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write("1"); writer.WriteEndTag("a"); writer.Write(" "); } // write out all the page links for (int i = _startPage; i < _endPage + 1; i++) { if (i == ActivePage) { writer.WriteBeginTag("span"); if (!string.IsNullOrEmpty(SelectedPageCssClass)) writer.WriteAttribute("class", SelectedPageCssClass); writer.Write(HtmlTextWriter.TagRightChar); writer.Write(i.ToString()); writer.WriteEndTag("span"); } else { writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, i.ToString()).TrimEnd('&'); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write(i.ToString()); writer.WriteEndTag("a"); } writer.Write("\r\n"); } // write out last page link if (ShowFirstAndLastPageLinks && _endPage < TotalPages) { writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, TotalPages.ToString()); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass + " " + PageLinkCssClass + "-last"); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write(TotalPages.ToString()); writer.WriteEndTag("a"); } // Previous link if (ShowPreviousNextLinks && !string.IsNullOrEmpty(PreviousText) && ActivePage > 1) { writer.Write(" "); writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, (ActivePage - 1).ToString()); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass + " " + PageLinkCssClass + "-prev"); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write(PreviousText); writer.WriteEndTag("a"); } // Next link if (ShowPreviousNextLinks && !string.IsNullOrEmpty(NextText) && ActivePage < TotalPages) { writer.Write(" "); writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, (ActivePage + 1).ToString()); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass + " " + PageLinkCssClass + "-next"); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write(NextText); writer.WriteEndTag("a"); } writer.WriteEndTag("div"); if (RenderContainerDiv) { if (RenderContainerDivBreak) writer.Write("<br clear=\"all\" />\r\n"); writer.WriteEndTag("div"); } } As I said pretty much brute force rendering based on the control’s property settings of which there are quite a few: You can also see the pager in the designer above. unfortunately the VS designer (both 2010 and 2008) fails to render the float: left CSS styles properly and starts wrapping after margins are applied in the special buttons. Not a big deal since VS does at least respect the spacing (the floated elements overlay). Then again I’m not using the designer anyway :-}. Filtering Data What makes the Pager easy to use is the filter methods built into the control. While this functionality is clearly not the most politically correct design choice as it violates separation of concerns, it’s very useful for typical pager operation. While I actually have filter methods that do something similar in my business layer, having it exposed on the control makes the control a lot more useful for typical databinding scenarios. Of course these methods are optional – if you have a business layer that can provide filtered page queries for you can use that instead and assign the TotalItems property manually. There are three filter method types available for IQueryable, IEnumerable and for DataTable which tend to be the most common use cases in my apps old and new. The IQueryable version is pretty simple as it can simply rely on on .Skip() and .Take() with LINQ: /// <summary> /// <summary> /// Queries the database for the ActivePage applied manually /// or from the Request["page"] variable. This routine /// figures out and sets TotalPages, ActivePage and /// returns a filtered subset IQueryable that contains /// only the items from the ActivePage. /// </summary> /// <param name="query"></param> /// <param name="activePage"> /// The page you want to display. Sets the ActivePage property when passed. /// Pass 0 or smaller to use ActivePage setting. /// </param> /// <returns></returns> public IQueryable<T> FilterIQueryable<T>(IQueryable<T> query, int activePage) where T : class, new() { ActivePage = activePage < 1 ? ActivePage : activePage; if (ActivePage < 1) ActivePage = 1; TotalItems = query.Count(); if (TotalItems <= PageSize) { ActivePage = 1; TotalPages = 1; return query; } int skip = ActivePage - 1; if (skip > 0) query = query.Skip(skip * PageSize); _TotalPages = CalculateTotalPagesFromTotalItems(); return query.Take(PageSize); } The IEnumerable<T> version simply converts the IEnumerable to an IQuerable and calls back into this method for filtering. The DataTable version requires a little more work to manually parse and filter records (I didn’t want to add the Linq DataSetExtensions assembly just for this): /// <summary> /// Filters a data table for an ActivePage. /// /// Note: Modifies the data set permanently by remove DataRows /// </summary> /// <param name="dt">Full result DataTable</param> /// <param name="activePage">Page to display. 0 to use ActivePage property </param> /// <returns></returns> public DataTable FilterDataTable(DataTable dt, int activePage) { ActivePage = activePage < 1 ? ActivePage : activePage; if (ActivePage < 1) ActivePage = 1; TotalItems = dt.Rows.Count; if (TotalItems <= PageSize) { ActivePage = 1; TotalPages = 1; return dt; } int skip = ActivePage - 1; if (skip > 0) { for (int i = 0; i < skip * PageSize; i++ ) dt.Rows.RemoveAt(0); } while(dt.Rows.Count > PageSize) dt.Rows.RemoveAt(PageSize); return dt; } Using the Pager Control The pager as it is is a first cut I built a couple of weeks ago and since then have been tweaking a little as part of an internal project I’m working on. I’ve replaced a bunch of pagers on various older pages with this pager without any issues and have what now feels like a more consistent user interface where paging looks and feels the same across different controls. As a bonus I’m only loading the data from the database that I need to display a single page. With the preset class tags applied too adding a pager is now as easy as dropping the control and adding the style sheet for styling to be consistent – no fuss, no muss. Schweet. Hopefully some of you may find this as useful as I have or at least as a baseline to build ontop of… Resources The Pager is part of the West Wind Web & Ajax Toolkit Pager.cs Source Code (some toolkit dependencies) Westwind.css base stylesheet with .pager and .gridpager styles Pager Example Page © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET

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Setting up a new Silverlight 4 Project with WCF RIA Services

- by Kevin Grossnicklaus

Many of my clients are actively using Silverlight 4 and RIA Services to build powerful line of business applications. Getting things set up correctly is critical to being to being able to take full advantage of the RIA services plumbing and when developers struggle with the setup they tend to shy away from the solution as a whole. I’m a big proponent of RIA services and wanted to take the opportunity to share some of my experiences in setting up these types of projects. In late 2010 I presented a RIA Services Master Class here in St. Louis, MO through my firm (ArchitectNow) and the information shared in this post was promised during that presentation. One other thing I want to mention before diving in is the existence of a number of other great posts on this subject. I’ve learned a lot from many of them and wanted to call out a few of them. The purpose of my post is to point out some of the gotchas that people get caught up on in the process but I would still encourage you to do as much additional research as you can to find the perfect setup for your needs. Here are a few additional blog posts and articles you should check out on the subject: http://msdn.microsoft.com/en-us/library/ee707351(VS.91).aspx http://adam-thompson.com/post/2010/07/03/Getting-Started-with-WCF-RIA-Services-for-Silverlight-4.aspx Technologies I don’t intend for this post to turn into a full WCF RIA Services tutorial but I did want to point out what technologies we will be using: Visual Studio.NET 2010 Silverlight 4.0 WCF RIA Services for Visual Studio 2010 Entity Framework 4.0 I also wanted to point out that the screenshots came from my personal development box which has a number of additional plug-ins and frameworks loaded so a few of the screenshots might not match 100% with what you see on your own machines. If you do not have Visual Studio 2010 you can download the express version from http://www.microsoft.com/express. The Silverlight 4.0 tools and the WCF RIA Services components are installed via the Web Platform Installer (http://www.microsoft.com/web/download). Also, the examples given in this post are done in C#…sorry to you VB folks but the concepts are 100% identical. Setting up anew RIA Services Project This section will provide a step-by-step walkthrough of setting up a new RIA services project using a shared DLL for server side code and a simple Entity Framework model for data access. All projects are created with the consistent ArchitectNow.RIAServices filename prefix and default namespace. This would be modified to match your companies standards. First, open Visual Studio and open the new project window via File->New->Project. In the New Project window, select the Silverlight folder in the Installed Templates section on the left and select “Silverlight Application” as your project type. Verify your solution name and location are set appropriately. Note that the project name we specified in the example below ends with .Client. This indicates the name which will be given to our Silverlight project. I consider Silverlight a client-side technology and thus use this name to reflect that. Click Ok to continue. During the creation on a new Silverlight 4 project you will be prompted with the following dialog to create a new web ASP.NET web project to host your Silverlight content. As we are demonstrating the setup of a WCF RIA Services infrastructure, make sure the “Enable WCF RIA Services” option is checked and click OK. Obviously, there are some other options here which have an effect on your solution and you are welcome to look around. For our example we are going to leave the ASP.NET Web Application Project selected. If you are interested in having your Silverlight project hosted in an MVC 2 application or a Web Site project these options are available as well. Also, whichever web project type you select, the name can be modified here as well. Note that it defaults to the same name as your Silverlight project with the addition of a .Web suffix. At this point, your full Silverlight 4 project and host ASP.NET Web Application should be created and will now display in your Visual Studio solution explorer as part of a single Visual Studio solution as follows: Now we want to add our WCF RIA Services projects to this same solution. To do so, right-click on the Solution node in the solution explorer and select Add->New Project. In the New Project dialog again select the Silverlight folder under the Visual C# node on the left and, in the main area of the screen, select the WCF RIA Services Class Library project template as shown below. Make sure your project name is set appropriately as well. For the sample below, we will name the project “ArchitectNow.RIAServices.Server.Entities”. The .Server.Entities suffix we use is meant to simply indicate that this particular project will contain our WCF RIA Services entity classes (as you will see below). Click OK to continue. Once you have created the WCF RIA Services Class Library specified above, Visual Studio will automatically add TWO projects to your solution. The first will be an project called .Server.Entities (using our naming conventions) and the other will have the same name with a .Web extension. The full solution (with all 4 projects) is shown in the image below. The .Entities project will essentially remain empty and is actually a Silverlight 4 class library that will contain generated RIA Services domain objects. It will be referenced by our front-end Silverlight project and thus allow for simplified sharing of code between the client and the server. The .Entities.Web project is a .NET 4.0 class library into which we will put our data access code (via Entity Framework). This is our server side code and business logic and the RIA Services plumbing will maintain a link between this project and the front end. Specific entities such as our domain objects and other code we set to be shared will be copied automatically into the .Entities project to be used in both the front end and the back end. At this point, we want to do a little cleanup of the projects in our solution and we will do so by deleting the “Class1.cs” class from both the .Entities project and the .Entities.Web project. (Has anyone ever intentionally named a class “Class1”?) Next, we need to configure a few references to make RIA Services work. THIS IS A KEY STEP THAT CAUSES MANY HEADACHES FOR DEVELOPERS NEW TO THIS INFRASTRUCTURE! Using the Add References dialog in Visual Studio, add a project reference from the *.Client project (our Silverlight 4 client) to the *.Entities project (our RIA Services class library). Next, again using the Add References dialog in Visual Studio, add a project reference from the *.Client.Web project (our ASP.NET host project) to the *.Entities.Web project (our back-end data services DLL). To get to the Add References dialog, simply right-click on the project you with to add a reference to in the Visual Studio solution explorer and select “Add Reference” from the resulting context menu. You will want to make sure these references are added as “Project” references to simplify your future debugging. To reiterate the reference direction using the project names we have utilized in this example thus far: .Client references .Entities and .Client.Web reference .Entities.Web. If you have opted for a different naming convention, then the Silverlight project must reference the RIA Services Silverlight class library and the ASP.NET host project must reference the server-side class library. Next, we are going to add a new Entity Framework data model to our data services project (.Entities.Web). We will do this by right clicking on this project (ArchitectNow.Server.Entities.Web in the above diagram) and selecting Add->New Project. In the New Project dialog we will select ADO.NET Entity Data Model as in the following diagram. For now we will call this simply SampleDataModel.edmx and click OK. It is worth pointing out that WCF RIA Services is in no way tied to the Entity Framework as a means of accessing data and any data access technology is supported (as long as the server side implementation maps to the RIA Services pattern which is a topic beyond the scope of this post). We are using EF to quickly demonstrate the RIA Services concepts and setup infrastructure, as such, I am not providing a database schema with this post but am instead connecting to a small sample database on my local machine. The following diagram shows a simple EF Data Model with two tables that I reverse engineered from a local data store. If you are putting together your own solution, feel free to reverse engineer a few tables from any local database to which you have access. At this point, once you have an EF data model generated as an EDMX into your .Entites.Web project YOU MUST BUILD YOUR SOLUTION. I know it seems strange to call that out but it important that the solution be built at this point for the next step to be successful. Obviously, if you have any build errors, these must be addressed at this point. At this point we will add a RIA Services Domain Service to our .Entities.Web project (our server side code). We will need to right-click on the .Entities.Web project and select Add->New Item. In the Add New Item dialog, select Domain Service Class and verify the name of your new Domain Service is correct (ours is called SampleService.cs in the image below). Next, click "Add”. After clicking “Add” to include the Domain Service Class in the selected project, you will be presented with the following dialog. In it, you can choose which entities from the selected EDMX to include in your services and if they should be allowed to be edited (i.e. inserted, updated, or deleted) via this service. If the “Available DataContext/ObjectContext classes” dropdown is empty, this indicates you have not yes successfully built your project after adding your EDMX. I would also recommend verifying that the “Generate associated classes for metadata” option is selected. Once you have selected the appropriate options, click “OK”. Once you have added the domain service class to the .Entities.Web project, the resulting solution should look similar to the following: Note that in the solution you now have a SampleDataModel.edmx which represents your EF data mapping to your database and a SampleService.cs which will contain a large amount of generated RIA Services code which RIA Services utilizes to access this data from the Silverlight front-end. You will put all your server side data access code and logic into the SampleService.cs class. The SampleService.metadata.cs class is for decorating the generated domain objects with attributes from the System.ComponentModel.DataAnnotations namespace for validation purposes. FINAL AND KEY CONFIGURATION STEP! One key step that causes significant headache to developers configuring RIA Services for the first time is the fact that, when we added the EDMX to the .Entities.Web project for our EF data access, a connection string was generated and placed within a newly generated App.Context file within that project. While we didn’t point it out at the time you can see it in the image above. This connection string will be required for the EF data model to successfully locate it’s data. Also, when we added the Domain Service class to the .Entities.Web project, a number of RIA Services configuration options were added to the same App.Config file. Unfortunately, when we ultimately begin to utilize the RIA Services infrastructure, our Silverlight UI will be making RIA services calls through the ASP.NET host project (i.e. .Client.Web). This host project has a reference to the .Entities.Web project which actually contains the code so all will pass through correctly EXCEPT the fact that the host project will utilize it’s own Web.Config for any configuration settings. For this reason we must now merge all the sections of the App.Config file in the .Entities.Web project into the Web.Config file in the .Client.Web project. I know this is a bit tedious and I wish there were a simpler solution but it is required for our RIA Services Domain Service to be made available to the front end Silverlight project. Much of this manual merge can be achieved by simply cutting and pasting from App.Config into Web.Config. Unfortunately, the <system.webServer> section will exist in both and the contents of this section will need to be manually merged. Fortunately, this is a step that needs to be taken only once per solution. As you add additional data structures and Domain Services methods to the server no additional changes will be necessary to the Web.Config. Next Steps At this point, we have walked through the basic setup of a simple RIA services solution. Unfortunately, there is still a lot to know about RIA services and we have not even begun to take advantage of the plumbing which we just configured (meaning we haven’t even made a single RIA services call). I plan on posting a few more introductory posts over the next few weeks to take us to this step. If you have any questions on the content in this post feel free to reach out to me via this Blog and I’ll gladly point you in (hopefully) the right direction. Resources Prior to closing out this post, I wanted to share a number or resources to help you get started with RIA services. While I plan on posting more on the subject, I didn’t invent any of this stuff and wanted to give credit to the following areas for helping me put a lot of these pieces into place. The books and online resources below will go a long way to making you extremely productive with RIA services in the shortest time possible. The only thing required of you is the dedication to take advantage of the resources available. Books Pro Business Applications with Silverlight 4 http://www.amazon.com/Pro-Business-Applications-Silverlight-4/dp/1430272074/ref=sr_1_2?ie=UTF8&qid=1291048751&sr=8-2 Silverlight 4 in Action http://www.amazon.com/Silverlight-4-Action-Pete-Brown/dp/1935182374/ref=sr_1_1?ie=UTF8&qid=1291048751&sr=8-1 Pro Silverlight for the Enterprise (Books for Professionals by Professionals) http://www.amazon.com/Pro-Silverlight-Enterprise-Books-Professionals/dp/1430218673/ref=sr_1_3?ie=UTF8&qid=1291048751&sr=8-3 Web Content RIA Services http://channel9.msdn.com/Blogs/RobBagby/NET-RIA-Services-in-5-Minutes http://silverlight.net/riaservices/ http://www.silverlight.net/learn/videos/all/net-ria-services-intro/ http://www.silverlight.net/learn/videos/all/ria-services-support-visual-studio-2010/ http://channel9.msdn.com/learn/courses/Silverlight4/SL4BusinessModule2/SL4LOB_02_01_RIAServices http://www.myvbprof.com/MainSite/index.aspx#/zSL4_RIA_01 http://channel9.msdn.com/blogs/egibson/silverlight-firestarter-ria-services http://msdn.microsoft.com/en-us/library/ee707336%28v=VS.91%29.aspx Silverlight www.silverlight.net http://msdn.microsoft.com/en-us/silverlight4trainingcourse.aspx http://channel9.msdn.com/shows/silverlighttv

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Metro Walkthrough: Creating a Task List with a ListView and IndexedDB

- by Stephen.Walther

The goal of this blog entry is to describe how you can work with data in a Metro style application written with JavaScript. In particular, we create a super simple Task List application which enables you to create and delete tasks. Here’s a video which demonstrates how the Task List application works: In order to build this application, I had to take advantage of several features of the WinJS library and technologies including: IndexedDB – The Task List application stores data in an IndexedDB database. HTML5 Form Validation – The Task List application uses HTML5 validation to ensure that a required field has a value. ListView Control – The Task List application displays the tasks retrieved from the IndexedDB database in a WinJS ListView control. Creating the IndexedDB Database The Task List application stores all of its data in an IndexedDB database named TasksDB. This database is opened/created with the following code: var db; var req = window.msIndexedDB.open("TasksDB", 1); req.onerror = function () { console.log("Could not open database"); }; req.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement:true }); }; The msIndexedDB.open() method accepts two parameters: the name of the database to open and the version of the database to open. If a database with a matching version already exists, then calling the msIndexedDB.open() method opens a connection to the existing database. If the database does not exist then the upgradeneeded event is raised. You handle the upgradeneeded event to create a new database. In the code above, the upgradeneeded event handler creates an object store named “tasks” (An object store roughly corresponds to a database table). When you add items to the tasks object store then each item gets an id property with an auto-incremented value automatically. The code above also includes an error event handler. If the IndexedDB database cannot be opened or created, for whatever reason, then an error message is written to the Visual Studio JavaScript Console window. Displaying a List of Tasks The TaskList application retrieves its list of tasks from the tasks object store, which we created above, and displays the list of tasks in a ListView control. Here is how the ListView control is declared: <div id="tasksListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: TaskList.tasks.dataSource, itemTemplate: select('#taskTemplate'), tapBehavior: 'toggleSelect', selectionMode: 'multi', layout: { type: WinJS.UI.ListLayout } }"> </div> The ListView control is bound to the TaskList.tasks.dataSource data source. The TaskList.tasks.dataSource is created with the following code: // Create the data source var tasks = new WinJS.Binding.List(); // Open the database var db; var req = window.msIndexedDB.open("TasksDB", 1); req.onerror = function () { console.log("Could not open database"); }; req.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement:true }); }; // Load the data source with data from the database req.onsuccess = function () { db = req.result; var tran = db.transaction("tasks"); tran.objectStore("tasks").openCursor().onsuccess = function(event) { var cursor = event.target.result; if (cursor) { tasks.dataSource.insertAtEnd(null, cursor.value); cursor.continue(); }; }; }; // Expose the data source and functions WinJS.Namespace.define("TaskList", { tasks: tasks }); Notice the success event handler. This handler is called when a database is successfully opened/created. In the code above, all of the items from the tasks object store are retrieved into a cursor and added to a WinJS.Binding.List object named tasks. Because the ListView control is bound to the WinJS.Binding.List object, copying the tasks from the object store into the WinJS.Binding.List object causes the tasks to appear in the ListView: Adding a New Task You add a new task in the Task List application by entering the title of a new task into an HTML form and clicking the Add button. Here’s the markup for creating the form: <form id="addTaskForm"> <input id="newTaskTitle" title="New Task" required /> <button>Add</button> </form> Notice that the INPUT element includes a required attribute. In a Metro application, you can take advantage of HTML5 Validation to validate form fields. If you don’t enter a value for the newTaskTitle field then the following validation error message is displayed: For a brief introduction to HTML5 validation, see my previous blog entry: http://stephenwalther.com/blog/archive/2012/03/13/html5-form-validation.aspx When you click the Add button, the form is submitted and the form submit event is raised. The following code is executed in the default.js file: // Handle Add Task document.getElementById("addTaskForm").addEventListener("submit", function (evt) { evt.preventDefault(); var newTaskTitle = document.getElementById("newTaskTitle"); TaskList.addTask({ title: newTaskTitle.value }); newTaskTitle.value = ""; }); The code above retrieves the title of the new task and calls the addTask() method in the tasks.js file. Here’s the code for the addTask() method which is responsible for actually adding the new task to the IndexedDB database: // Add a new task function addTask(taskToAdd) { var transaction = db.transaction("tasks", "readwrite"); var addRequest = transaction.objectStore("tasks").add(taskToAdd); addRequest.onsuccess = function (evt) { taskToAdd.id = evt.target.result; tasks.dataSource.insertAtEnd(null, taskToAdd); } } The code above does two things. First, it adds the new task to the tasks object store in the IndexedDB database. Second, it adds the new task to the data source bound to the ListView. The dataSource.insertAtEnd() method is called to add the new task to the data source so the new task will appear in the ListView (with a nice little animation). Deleting Existing Tasks The Task List application enables you to select one or more tasks by clicking or tapping on one or more tasks in the ListView. When you click the Delete button, the selected tasks are removed from both the IndexedDB database and the ListView. For example, in the following screenshot, two tasks are selected. The selected tasks appear with a teal background and a checkmark: When you click the Delete button, the following code in the default.js file is executed: // Handle Delete Tasks document.getElementById("btnDeleteTasks").addEventListener("click", function (evt) { tasksListView.winControl.selection.getItems().then(function(items) { items.forEach(function (item) { TaskList.deleteTask(item); }); }); }); The selected tasks are retrieved with the TaskList selection.getItem() method. In the code above, the deleteTask() method is called for each of the selected tasks. Here’s the code for the deleteTask() method: // Delete an existing task function deleteTask(listViewItem) { // Database key != ListView key var dbKey = listViewItem.data.id; var listViewKey = listViewItem.key; // Remove item from db and, if success, remove item from ListView var transaction = db.transaction("tasks", “readwrite”); var deleteRequest = transaction.objectStore("tasks").delete(dbKey); deleteRequest.onsuccess = function () { tasks.dataSource.remove(listViewKey); } } This code does two things: it deletes the existing task from the database and removes the existing task from the ListView. In both cases, the right task is removed by using the key associated with the task. However, the task key is different in the case of the database and in the case of the ListView. In the case of the database, the task key is the value of the task id property. In the case of the ListView, on the other hand, the task key is auto-generated by the ListView. When the task is removed from the ListView, an animation is used to collapse the tasks which appear above and below the task which was removed. The Complete Code Above, I did a lot of jumping around between different files in the application and I left out sections of code. For the sake of completeness, I want to include the entire code here: the default.html, default.js, and tasks.js files. Here are the contents of the default.html file. This file contains the UI for the Task List application: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Task List</title>  <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script>  <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script type="text/javascript" src="js/tasks.js"></script> <style type="text/css"> body { font-size: x-large; } form { display: inline; } #appContainer { margin: 20px; width: 600px; } .win-container { padding: 10px; } </style> </head> <body> <div>  <div id="taskTemplate" data-win-control="WinJS.Binding.Template"> <div> <span data-win-bind="innerText:title"></span> </div> </div> <h1>Super Task List</h1> <div id="appContainer"> <form id="addTaskForm"> <input id="newTaskTitle" title="New Task" required /> <button>Add</button> </form> <button id="btnDeleteTasks">Delete</button> <div id="tasksListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: TaskList.tasks.dataSource, itemTemplate: select('#taskTemplate'), tapBehavior: 'toggleSelect', selectionMode: 'multi', layout: { type: WinJS.UI.ListLayout } }"> </div> </div> </div> </body> </html> Here is the code for the default.js file. This code wires up the Add Task form and Delete button: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll().then(function () { // Get reference to Tasks ListView var tasksListView = document.getElementById("tasksListView"); // Handle Add Task document.getElementById("addTaskForm").addEventListener("submit", function (evt) { evt.preventDefault(); var newTaskTitle = document.getElementById("newTaskTitle"); TaskList.addTask({ title: newTaskTitle.value }); newTaskTitle.value = ""; }); // Handle Delete Tasks document.getElementById("btnDeleteTasks").addEventListener("click", function (evt) { tasksListView.winControl.selection.getItems().then(function(items) { items.forEach(function (item) { TaskList.deleteTask(item); }); }); }); }); } }; app.start(); })(); Finally, here is the tasks.js file. This file contains all of the code for opening, creating, and interacting with IndexedDB: (function () { "use strict"; // Create the data source var tasks = new WinJS.Binding.List(); // Open the database var db; var req = window.msIndexedDB.open("TasksDB", 1); req.onerror = function () { console.log("Could not open database"); }; req.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement:true }); }; // Load the data source with data from the database req.onsuccess = function () { db = req.result; var tran = db.transaction("tasks"); tran.objectStore("tasks").openCursor().onsuccess = function(event) { var cursor = event.target.result; if (cursor) { tasks.dataSource.insertAtEnd(null, cursor.value); cursor.continue(); }; }; }; // Add a new task function addTask(taskToAdd) { var transaction = db.transaction("tasks", "readwrite"); var addRequest = transaction.objectStore("tasks").add(taskToAdd); addRequest.onsuccess = function (evt) { taskToAdd.id = evt.target.result; tasks.dataSource.insertAtEnd(null, taskToAdd); } } // Delete an existing task function deleteTask(listViewItem) { // Database key != ListView key var dbKey = listViewItem.data.id; var listViewKey = listViewItem.key; // Remove item from db and, if success, remove item from ListView var transaction = db.transaction("tasks", "readwrite"); var deleteRequest = transaction.objectStore("tasks").delete(dbKey); deleteRequest.onsuccess = function () { tasks.dataSource.remove(listViewKey); } } // Expose the data source and functions WinJS.Namespace.define("TaskList", { tasks: tasks, addTask: addTask, deleteTask: deleteTask }); })(); Summary I wrote this blog entry because I wanted to create a walkthrough of building a simple database-driven application. In particular, I wanted to demonstrate how you can use a ListView control with an IndexedDB database to store and retrieve database data.

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Metro Walkthrough: Creating a Task List with a ListView and IndexedDB

- by Stephen.Walther

The goal of this blog entry is to describe how you can work with data in a Metro style application written with JavaScript. In particular, we create a super simple Task List application which enables you to create and delete tasks. Here’s a video which demonstrates how the Task List application works: In order to build this application, I had to take advantage of several features of the WinJS library and technologies including: IndexedDB – The Task List application stores data in an IndexedDB database. HTML5 Form Validation – The Task List application uses HTML5 validation to ensure that a required field has a value. ListView Control – The Task List application displays the tasks retrieved from the IndexedDB database in a WinJS ListView control. Creating the IndexedDB Database The Task List application stores all of its data in an IndexedDB database named TasksDB. This database is opened/created with the following code: var db; var req = window.msIndexedDB.open("TasksDB", 1); req.onerror = function () { console.log("Could not open database"); }; req.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement:true }); }; The msIndexedDB.open() method accepts two parameters: the name of the database to open and the version of the database to open. If a database with a matching version already exists, then calling the msIndexedDB.open() method opens a connection to the existing database. If the database does not exist then the upgradeneeded event is raised. You handle the upgradeneeded event to create a new database. In the code above, the upgradeneeded event handler creates an object store named “tasks” (An object store roughly corresponds to a database table). When you add items to the tasks object store then each item gets an id property with an auto-incremented value automatically. The code above also includes an error event handler. If the IndexedDB database cannot be opened or created, for whatever reason, then an error message is written to the Visual Studio JavaScript Console window. Displaying a List of Tasks The TaskList application retrieves its list of tasks from the tasks object store, which we created above, and displays the list of tasks in a ListView control. Here is how the ListView control is declared: <div id="tasksListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: TaskList.tasks.dataSource, itemTemplate: select('#taskTemplate'), tapBehavior: 'toggleSelect', selectionMode: 'multi', layout: { type: WinJS.UI.ListLayout } }"> </div> The ListView control is bound to the TaskList.tasks.dataSource data source. The TaskList.tasks.dataSource is created with the following code: // Create the data source var tasks = new WinJS.Binding.List(); // Open the database var db; var req = window.msIndexedDB.open("TasksDB", 1); req.onerror = function () { console.log("Could not open database"); }; req.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement:true }); }; // Load the data source with data from the database req.onsuccess = function () { db = req.result; var tran = db.transaction("tasks"); tran.objectStore("tasks").openCursor().onsuccess = function(event) { var cursor = event.target.result; tasks.dataSource.beginEdits(); if (cursor) { tasks.dataSource.insertAtEnd(null, cursor.value); cursor.continue(); } else { tasks.dataSource.endEdits(); }; }; }; // Expose the data source and functions WinJS.Namespace.define("TaskList", { tasks: tasks }); Notice the success event handler. This handler is called when a database is successfully opened/created. In the code above, all of the items from the tasks object store are retrieved into a cursor and added to a WinJS.Binding.List object named tasks. Because the ListView control is bound to the WinJS.Binding.List object, copying the tasks from the object store into the WinJS.Binding.List object causes the tasks to appear in the ListView: Adding a New Task You add a new task in the Task List application by entering the title of a new task into an HTML form and clicking the Add button. Here’s the markup for creating the form: <form id="addTaskForm"> <input id="newTaskTitle" title="New Task" required /> <button>Add</button> </form> Notice that the INPUT element includes a required attribute. In a Metro application, you can take advantage of HTML5 Validation to validate form fields. If you don’t enter a value for the newTaskTitle field then the following validation error message is displayed: For a brief introduction to HTML5 validation, see my previous blog entry: http://stephenwalther.com/blog/archive/2012/03/13/html5-form-validation.aspx When you click the Add button, the form is submitted and the form submit event is raised. The following code is executed in the default.js file: // Handle Add Task document.getElementById("addTaskForm").addEventListener("submit", function (evt) { evt.preventDefault(); var newTaskTitle = document.getElementById("newTaskTitle"); TaskList.addTask({ title: newTaskTitle.value }); newTaskTitle.value = ""; }); The code above retrieves the title of the new task and calls the addTask() method in the tasks.js file. Here’s the code for the addTask() method which is responsible for actually adding the new task to the IndexedDB database: // Add a new task function addTask(taskToAdd) { var transaction = db.transaction("tasks", IDBTransaction.READ_WRITE); var addRequest = transaction.objectStore("tasks").add(taskToAdd); addRequest.onsuccess = function (evt) { taskToAdd.id = evt.target.result; tasks.dataSource.insertAtEnd(null, taskToAdd); } } The code above does two things. First, it adds the new task to the tasks object store in the IndexedDB database. Second, it adds the new task to the data source bound to the ListView. The dataSource.insertAtEnd() method is called to add the new task to the data source so the new task will appear in the ListView (with a nice little animation). Deleting Existing Tasks The Task List application enables you to select one or more tasks by clicking or tapping on one or more tasks in the ListView. When you click the Delete button, the selected tasks are removed from both the IndexedDB database and the ListView. For example, in the following screenshot, two tasks are selected. The selected tasks appear with a teal background and a checkmark: When you click the Delete button, the following code in the default.js file is executed: // Handle Delete Tasks document.getElementById("btnDeleteTasks").addEventListener("click", function (evt) { tasksListView.winControl.selection.getItems().then(function(items) { items.forEach(function (item) { TaskList.deleteTask(item); }); }); }); The selected tasks are retrieved with the TaskList selection.getItem() method. In the code above, the deleteTask() method is called for each of the selected tasks. Here’s the code for the deleteTask() method: // Delete an existing task function deleteTask(listViewItem) { // Database key != ListView key var dbKey = listViewItem.data.id; var listViewKey = listViewItem.key; // Remove item from db and, if success, remove item from ListView var transaction = db.transaction("tasks", IDBTransaction.READ_WRITE); var deleteRequest = transaction.objectStore("tasks").delete(dbKey); deleteRequest.onsuccess = function () { tasks.dataSource.remove(listViewKey); } } This code does two things: it deletes the existing task from the database and removes the existing task from the ListView. In both cases, the right task is removed by using the key associated with the task. However, the task key is different in the case of the database and in the case of the ListView. In the case of the database, the task key is the value of the task id property. In the case of the ListView, on the other hand, the task key is auto-generated by the ListView. When the task is removed from the ListView, an animation is used to collapse the tasks which appear above and below the task which was removed. The Complete Code Above, I did a lot of jumping around between different files in the application and I left out sections of code. For the sake of completeness, I want to include the entire code here: the default.html, default.js, and tasks.js files. Here are the contents of the default.html file. This file contains the UI for the Task List application: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Task List</title>  <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script>  <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script type="text/javascript" src="js/tasks.js"></script> <style type="text/css"> body { font-size: x-large; } form { display: inline; } #appContainer { margin: 20px; width: 600px; } .win-container { padding: 10px; } </style> </head> <body> <div>  <div id="taskTemplate" data-win-control="WinJS.Binding.Template"> <div> <span data-win-bind="innerText:title"></span> </div> </div> <h1>Super Task List</h1> <div id="appContainer"> <form id="addTaskForm"> <input id="newTaskTitle" title="New Task" required /> <button>Add</button> </form> <button id="btnDeleteTasks">Delete</button> <div id="tasksListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: TaskList.tasks.dataSource, itemTemplate: select('#taskTemplate'), tapBehavior: 'toggleSelect', selectionMode: 'multi', layout: { type: WinJS.UI.ListLayout } }"> </div> </div> </div> </body> </html> Here is the code for the default.js file. This code wires up the Add Task form and Delete button: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll().then(function () { // Get reference to Tasks ListView var tasksListView = document.getElementById("tasksListView"); // Handle Add Task document.getElementById("addTaskForm").addEventListener("submit", function (evt) { evt.preventDefault(); var newTaskTitle = document.getElementById("newTaskTitle"); TaskList.addTask({ title: newTaskTitle.value }); newTaskTitle.value = ""; }); // Handle Delete Tasks document.getElementById("btnDeleteTasks").addEventListener("click", function (evt) { tasksListView.winControl.selection.getItems().then(function(items) { items.forEach(function (item) { TaskList.deleteTask(item); }); }); }); }); } }; app.start(); })(); Finally, here is the tasks.js file. This file contains all of the code for opening, creating, and interacting with IndexedDB: (function () { "use strict"; // Create the data source var tasks = new WinJS.Binding.List(); // Open the database var db; var req = window.msIndexedDB.open("TasksDB", 1); req.onerror = function () { console.log("Could not open database"); }; req.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement:true }); }; // Load the data source with data from the database req.onsuccess = function () { db = req.result; var tran = db.transaction("tasks"); tran.objectStore("tasks").openCursor().onsuccess = function(event) { var cursor = event.target.result; tasks.dataSource.beginEdits(); if (cursor) { tasks.dataSource.insertAtEnd(null, cursor.value); cursor.continue(); } else { tasks.dataSource.endEdits(); }; }; }; // Add a new task function addTask(taskToAdd) { var transaction = db.transaction("tasks", IDBTransaction.READ_WRITE); var addRequest = transaction.objectStore("tasks").add(taskToAdd); addRequest.onsuccess = function (evt) { taskToAdd.id = evt.target.result; tasks.dataSource.insertAtEnd(null, taskToAdd); } } // Delete an existing task function deleteTask(listViewItem) { // Database key != ListView key var dbKey = listViewItem.data.id; var listViewKey = listViewItem.key; // Remove item from db and, if success, remove item from ListView var transaction = db.transaction("tasks", IDBTransaction.READ_WRITE); var deleteRequest = transaction.objectStore("tasks").delete(dbKey); deleteRequest.onsuccess = function () { tasks.dataSource.remove(listViewKey); } } // Expose the data source and functions WinJS.Namespace.define("TaskList", { tasks: tasks, addTask: addTask, deleteTask: deleteTask }); })(); Summary I wrote this blog entry because I wanted to create a walkthrough of building a simple database-driven application. In particular, I wanted to demonstrate how you can use a ListView control with an IndexedDB database to store and retrieve database data.

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Building a “real” extension for Expression Blend

- by Timmy Kokke

.Last time I showed you how to get started building extensions for Expression Blend. Lets build a useful extension this time and go a bit deeper into Blend. Source of project => here Compiled dll => here (extract into /extensions folder of Expression Blend) The Extension When working on large Xaml files in Blend it’s often hard to find a specific control in the "Objects and Timeline Pane”. An extension that searches the active document and presents all elements that satisfy the query would be helpful. When the user starts typing a search query a search will be performed and the results are shown in the list. After the user selects an item in the results list, the control in the "Objects and Timeline Pane” will be selected. Below is a sketch of what it is going to look like. The Solution Create a new WPF User Control project as shown in the earlier tutorial in the Configuring the extension project section, but name it AdvancedSearch this time. Delete the default UserControl1.Xaml to clear the solution (a new user control will be added later thought, but adding a user control is easier then renaming one). Create the main entry point of the addin by adding a new class to the solution and naming this AdvancedSearchPackage. Add a reference to Microsoft.Expression.Extensibility and to System.ComponentModel.Composition . Implement the IPackage interface and add the Export attribute from the MEF to the definition. While you’re at it. Add references to Microsoft.Expression.DesignSurface, Microsoft.Expression.FrameWork and Microsoft.Expression.Markup. These will be used later. The Load method from the IPackage interface is going to create a ViewModel to bind to from the UI. Add another class to the solution and name this AdvancedSearchViewModel. This class needs to implement the INotifyPropertyChanged interface to enable notifications to the view. Add a constructor to the class that takes an IServices interface as a parameter. Create a new instance of the AdvancedSearchViewModel in the load method in the AdvanceSearchPackage class. The AdvancedSearchPackage class should looks like this now: using System.ComponentModel.Composition; using Microsoft.Expression.Extensibility; namespace AdvancedSearch { [Export(typeof(IPackage))] public class AdvancedSearchPackage:IPackage { public void Load(IServices services) { new AdvancedSearchViewModel(services); } public void Unload() { } } } Add a new UserControl to the project and name this AdvancedSearchView. The View will be created by the ViewModel, which will pass itself to the constructor of the view. Change the constructor of the View to take a AdvancedSearchViewModel object as a parameter. Add a private field to store the ViewModel and set this field in the constructor. Point the DataContext of the view to the ViewModel. The View will look something like this now: namespace AdvancedSearch { public partial class AdvancedSearchView:UserControl { private readonly AdvancedSearchViewModel _advancedSearchViewModel; public AdvancedSearchView(AdvancedSearchViewModel advancedSearchViewModel) { _advancedSearchViewModel = advancedSearchViewModel; InitializeComponent(); this.DataContext = _advancedSearchViewModel; } } } The View is going to be created in the constructor of the ViewModel and stored in a read only property. public FrameworkElement View { get; private set; } public AdvancedSearchViewModel(IServices services) { _services = services; View = new AdvancedSearchView(this); } The last thing the solution needs before we’ll wire things up is a new class, PossibleNode. This class will be used later to store the search results. The solution should look like this now: Adding UI to the UI The extension should build and run now, although nothing is showing up in Blend yet. To enable the user to perform a search query add a TextBox and a ListBox to the AdvancedSearchView.xaml file. I’ve set the rows of the grid too to make them look a little better. Add the TextChanged event to the TextBox and the SelectionChanged event to the ListBox, we’ll need those later on. <Grid> <Grid.RowDefinitions> <RowDefinition Height="32" /> <RowDefinition Height="*" /> </Grid.RowDefinitions> <TextBox TextChanged="SearchQueryTextChanged" HorizontalAlignment="Stretch" Margin="4" Name="SearchQuery" VerticalAlignment="Stretch" /> <ListBox SelectionChanged="SearchResultSelectionChanged" HorizontalAlignment="Stretch" Margin="4" Name="SearchResult" VerticalAlignment="Stretch" Grid.Row="1" /> </Grid> This will create a user interface like: To make the View show up in Blend it has to be registered with the WindowService. The GetService<T> method is used to get services from Blend, which are your entry points into Blend.When writing extensions you will encounter this method very often. In this case we’re asking for an IWindowService interface. The IWindowService interface serves events for changing windows and themes, is used for adding or removing resources and is used for registering and unregistering Palettes. All panes in Blend are palettes and are registered thru the RegisterPalette method. The first parameter passed to this method is a string containing a unique ID for the palette. This ID can be used to get access to the palette later. The second parameter is the View. The third parameter is a title for the pane. This title is shown when the pane is visible. It is also shown in the window menu of Blend. The last parameter is a KeyBinding. I have chosen Ctrl+Shift+F to call the Advanced Search pane. This value is also shown in the window menu of Blend. services.GetService<IWindowService>().RegisterPalette( "AdvancedSearch", viewModel.View, "Advanced Search", new KeyBinding { Key = Key.F, Modifiers = ModifierKeys.Control | ModifierKeys.Shift } ); You can compiler and run now. After Blend starts you can hit Ctrl+Shift+F or go the windows menu to call the advanced search extension. Searching for controls The search has to be cleared on every change of the active document. The DocumentServices fires an event every time a new document is opened, a document is closed or another document view is selected. Add the following line to the constructor of the ViewModel to handle the ActiveDocumentChanged event: _services.GetService<IDocumentService>().ActiveDocumentChanged += ActiveDocumentChanged; And implement the ActiveDocumentChanged method: private void ActiveDocumentChanged(object sender, DocumentChangedEventArgs e) { } To get to the contents of the document we first need to get access to the “Objects and Timeline” pane. This pane is registered in the PaletteRegistry in the same way as this extension has registered itself. The palettes are accessible thru an associative array. All you need to provide is the Identifier of the palette you want. The Id of the “Objects and Timeline” pane is “Designer_TimelinePane”. I’ve included a list of the other default panes at the bottom of this article. Each palette has a Content property which can be cast to the type of the pane. var timelinePane = (TimelinePane)_services.GetService<IWindowService>() .PaletteRegistry["Designer_TimelinePane"] .Content; Add a private field to the top of the AdvancedSearchViewModel class to store the active SceneViewModel. The SceneViewModel is needed to set the current selection and to get the little icons for the type of control. private SceneViewModel _activeSceneViewModel; When the active SceneViewModel changes, the ActiveSceneViewModel is stored in this field. The list of possible nodes is cleared and an PropertyChanged event is fired for this list to notify the UI to clear the list. This will make the eventhandler look like this: private void ActiveDocumentChanged(object sender, DocumentChangedEventArgs e) { var timelinePane = (TimelinePane)_services.GetService<IWindowService>() .PaletteRegistry["Designer_TimelinePane"].Content; _activeSceneViewModel = timelinePane.ActiveSceneViewModel; PossibleNodes = new List<PossibleNode>(); InvokePropertyChanged("PossibleNodes"); } The PossibleNode class used to store information about the controls found by the search. It’s a dumb data class with only 3 properties, the name of the control, the SceneNode and a brush used for the little icon. The SceneNode is the base class for every possible object you can create in Blend, like Brushes, Controls, Annotations, ResourceDictionaries and VisualStates. The entire PossibleNode class looks like this: using System.Windows.Media; using Microsoft.Expression.DesignSurface.ViewModel; namespace AdvancedSearch { public class PossibleNode { public string Name { get; set; } public SceneNode SceneNode { get; set; } public DrawingBrush IconBrush { get; set; } } } Add these two methods to the AdvancedSearchViewModel class: public void Search(string searchText) { } public void SelectElement(PossibleNode node){ } Both these methods are going to be called from the view. The Search method performs the search and updates the PossibleNodes list. The controls in the active document can be accessed thru TimeLineItemsManager class. This class contains a read only collection of TimeLineItems. By using a Linq query the possible nodes are selected and placed in the PossibleNodes list. var timelineItemManager = new TimelineItemManager(_activeSceneViewModel); PossibleNodes = new List<PossibleNode>( (from d in timelineItemManager.ItemList where d.DisplayName.ToLowerInvariant().StartsWith( searchText.ToLowerInvariant()) select new PossibleNode() { IconBrush = d.IconBrush, SceneNode = d.SceneNode, Name = d.DisplayName }).ToList() ); InvokePropertyChanged(InternalConst.PossibleNodes); The Select method is pretty straight forward. It contains two lines.The first to clear the selection. Otherwise the selected element would be added to the current selection. The second line selects the nodes. It is given a new array with the node to be selected. _activeSceneViewModel.ClearSelections(); _activeSceneViewModel.SelectNodes(new[] { node.SceneNode }); The last thing that needs to be done is to wire the whole thing to the View. The two event handlers just call the Search and SelectElement methods on the ViewModel. private void SearchQueryTextChanged(object sender, TextChangedEventArgs e) { _advancedSearchViewModel.Search(SearchQuery.Text); } private void SearchResultSelectionChanged(object sender, SelectionChangedEventArgs e) { if(e.AddedItems.Count>0) { _advancedSearchViewModel.SelectElement(e.AddedItems[0] as PossibleNode); } } The Listbox has to be bound to the PossibleNodes list and a simple DataTemplate is added to show the selection. The IconWithOverlay control can be found in the Microsoft.Expression.DesignSurface.UserInterface.Timeline.UI namespace in the Microsoft.Expression.DesignSurface assembly. The ListBox should look something like: <ListBox SelectionChanged="SearchResultSelectionChanged" HorizontalAlignment="Stretch" Margin="4" Name="SearchResult" VerticalAlignment="Stretch" Grid.Row="1" ItemsSource="{Binding PossibleNodes}"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <tlui:IconWithOverlay Margin="2,0,10,0" Width="12" Height="12" SourceBrush="{Binding Path=IconBrush, Mode=OneWay}" /> <TextBlock Text="{Binding Name}"/> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> Compile and run. Inside Blend the extension could look something like below. What’s Next When you’ve got the extension running. Try placing breakpoints in the code and see what else is in there. There’s a lot to explore and build extension on. I personally would love an extension to search for resources. Last but not least, you can download the source of project here. If you have any questions let me know. If you just want to use this extension, you can download the compiled dll here. Just extract the . zip into the /extensions folder of Expression Blend. Notes Target framework I ran into some issues when using the .NET Framework 4 Client Profile as a target framework. I got some strange error saying certain obvious namespaces could not be found, Microsoft.Expression in my case. If you run into something like this, try setting the target framework to .NET Framework 4 instead of the client version. Identifiers of default panes Identifier Type Title Designer_TimelinePane TimelinePane Objects and Timeline Designer_ToolPane ToolPane Tools Designer_ProjectPane ProjectPane Projects Designer_DataPane DataPane Data Designer_ResourcePane ResourcePane Resources Designer_PropertyInspector PropertyInspector Properties Designer_TriggersPane TriggersPane Triggers Interaction_Skin SkinView States Designer_AssetPane AssetPane Assets Interaction_Parts PartsPane Parts Designer_ResultsPane ResultsPane Results

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jQuery - Why editable-select list plugin doesn't work with latest jQuery?

- by Binyamin

Why editable-select list plugin<select><option>value</option>doesn't work with latest jQuery? editable-select code: /** * Copyright (c) 2009 Anders Ekdahl (http://coffeescripter.com/) * Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php) * and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses. * * Version: 1.3.1 * * Demo and documentation: http://coffeescripter.com/code/editable-select/ */ (function($) { var instances = []; $.fn.editableSelect = function(options) { var defaults = { bg_iframe: false, onSelect: false, items_then_scroll: 10, case_sensitive: false }; var settings = $.extend(defaults, options); // Only do bg_iframe for browsers that need it if(settings.bg_iframe && !$.browser.msie) { settings.bg_iframe = false; }; var instance = false; $(this).each(function() { var i = instances.length; if(typeof $(this).data('editable-selecter') == 'undefined') { instances[i] = new EditableSelect(this, settings); $(this).data('editable-selecter', i); }; }); return $(this); }; $.fn.editableSelectInstances = function() { var ret = []; $(this).each(function() { if(typeof $(this).data('editable-selecter') != 'undefined') { ret[ret.length] = instances[$(this).data('editable-selecter')]; }; }); return ret; }; var EditableSelect = function(select, settings) { this.init(select, settings); }; EditableSelect.prototype = { settings: false, text: false, select: false, wrapper: false, list_item_height: 20, list_height: 0, list_is_visible: false, hide_on_blur_timeout: false, bg_iframe: false, current_value: '', init: function(select, settings) { this.settings = settings; this.select = $(select); this.text = $('<input type="text">'); this.text.attr('name', this.select.attr('name')); this.text.data('editable-selecter', this.select.data('editable-selecter')); // Because we don't want the value of the select when the form // is submitted this.select.attr('disabled', 'disabled'); var id = this.select.attr('id'); if(!id) { id = 'editable-select'+ instances.length; }; this.text.attr('id', id); this.text.attr('autocomplete', 'off'); this.text.addClass('editable-select'); this.select.attr('id', id +'_hidden_select'); this.initInputEvents(this.text); this.duplicateOptions(); this.positionElements(); this.setWidths(); if(this.settings.bg_iframe) { this.createBackgroundIframe(); }; }, duplicateOptions: function() { var context = this; var wrapper = $(document.createElement('div')); wrapper.addClass('editable-select-options'); var option_list = $(document.createElement('ul')); wrapper.append(option_list); var options = this.select.find('option'); options.each(function() { if($(this).attr('selected')) { context.text.val($(this).val()); context.current_value = $(this).val(); }; var li = $('<li>'+ $(this).val() +'</li>'); context.initListItemEvents(li); option_list.append(li); }); this.wrapper = wrapper; this.checkScroll(); }, checkScroll: function() { var options = this.wrapper.find('li'); if(options.length > this.settings.items_then_scroll) { this.list_height = this.list_item_height * this.settings.items_then_scroll; this.wrapper.css('height', this.list_height +'px'); this.wrapper.css('overflow', 'auto'); } else { this.wrapper.css('height', 'auto'); this.wrapper.css('overflow', 'visible'); }; }, addOption: function(value) { var li = $('<li>'+ value +'</li>'); var option = $('<option>'+ value +'</option>'); this.select.append(option); this.initListItemEvents(li); this.wrapper.find('ul').append(li); this.setWidths(); this.checkScroll(); }, initInputEvents: function(text) { var context = this; var timer = false; $(document.body).click( function() { context.clearSelectedListItem(); context.hideList(); } ); text.focus( function() { // Can't use the blur event to hide the list, because the blur event // is fired in some browsers when you scroll the list context.showList(); context.highlightSelected(); } ).click( function(e) { e.stopPropagation(); context.showList(); context.highlightSelected(); } ).keydown( // Capture key events so the user can navigate through the list function(e) { switch(e.keyCode) { // Down case 40: if(!context.listIsVisible()) { context.showList(); context.highlightSelected(); } else { e.preventDefault(); context.selectNewListItem('down'); }; break; // Up case 38: e.preventDefault(); context.selectNewListItem('up'); break; // Tab case 9: context.pickListItem(context.selectedListItem()); break; // Esc case 27: e.preventDefault(); context.hideList(); return false; break; // Enter, prevent form submission case 13: e.preventDefault(); context.pickListItem(context.selectedListItem()); return false; }; } ).keyup( function(e) { // Prevent lots of calls if it's a fast typer if(timer !== false) { clearTimeout(timer); timer = false; }; timer = setTimeout( function() { // If the user types in a value, select it if it's in the list if(context.text.val() != context.current_value) { context.current_value = context.text.val(); context.highlightSelected(); }; }, 200 ); } ).keypress( function(e) { if(e.keyCode == 13) { // Enter, prevent form submission e.preventDefault(); return false; }; } ); }, initListItemEvents: function(list_item) { var context = this; list_item.mouseover( function() { context.clearSelectedListItem(); context.selectListItem(list_item); } ).mousedown( // Needs to be mousedown and not click, since the inputs blur events // fires before the list items click event function(e) { e.stopPropagation(); context.pickListItem(context.selectedListItem()); } ); }, selectNewListItem: function(direction) { var li = this.selectedListItem(); if(!li.length) { li = this.selectFirstListItem(); }; if(direction == 'down') { var sib = li.next(); } else { var sib = li.prev(); }; if(sib.length) { this.selectListItem(sib); this.scrollToListItem(sib); this.unselectListItem(li); }; }, selectListItem: function(list_item) { this.clearSelectedListItem(); list_item.addClass('selected'); }, selectFirstListItem: function() { this.clearSelectedListItem(); var first = this.wrapper.find('li:first'); first.addClass('selected'); return first; }, unselectListItem: function(list_item) { list_item.removeClass('selected'); }, selectedListItem: function() { return this.wrapper.find('li.selected'); }, clearSelectedListItem: function() { this.wrapper.find('li.selected').removeClass('selected'); }, pickListItem: function(list_item) { if(list_item.length) { this.text.val(list_item.text()); this.current_value = this.text.val(); }; if(typeof this.settings.onSelect == 'function') { this.settings.onSelect.call(this, list_item); }; this.hideList(); }, listIsVisible: function() { return this.list_is_visible; }, showList: function() { this.wrapper.show(); this.hideOtherLists(); this.list_is_visible = true; if(this.settings.bg_iframe) { this.bg_iframe.show(); }; }, highlightSelected: function() { var context = this; var current_value = this.text.val(); if(current_value.length < 0) { if(highlight_first) { this.selectFirstListItem(); }; return; }; if(!context.settings.case_sensitive) { current_value = current_value.toLowerCase(); }; var best_candiate = false; var value_found = false; var list_items = this.wrapper.find('li'); list_items.each( function() { if(!value_found) { var text = $(this).text(); if(!context.settings.case_sensitive) { text = text.toLowerCase(); }; if(text == current_value) { value_found = true; context.clearSelectedListItem(); context.selectListItem($(this)); context.scrollToListItem($(this)); return false; } else if(text.indexOf(current_value) === 0 && !best_candiate) { // Can't do return false here, since we still need to iterate over // all list items to see if there is an exact match best_candiate = $(this); }; }; } ); if(best_candiate && !value_found) { context.clearSelectedListItem(); context.selectListItem(best_candiate); context.scrollToListItem(best_candiate); } else if(!best_candiate && !value_found) { this.selectFirstListItem(); }; }, scrollToListItem: function(list_item) { if(this.list_height) { this.wrapper.scrollTop(list_item[0].offsetTop - (this.list_height / 2)); }; }, hideList: function() { this.wrapper.hide(); this.list_is_visible = false; if(this.settings.bg_iframe) { this.bg_iframe.hide(); }; }, hideOtherLists: function() { for(var i = 0; i < instances.length; i++) { if(i != this.select.data('editable-selecter')) { instances[i].hideList(); }; }; }, positionElements: function() { var offset = this.select.offset(); offset.top += this.select[0].offsetHeight; this.select.after(this.text); this.select.hide(); this.wrapper.css({top: offset.top +'px', left: offset.left +'px'}); $(document.body).append(this.wrapper); // Need to do this in order to get the list item height this.wrapper.css('visibility', 'hidden'); this.wrapper.show(); this.list_item_height = this.wrapper.find('li')[0].offsetHeight; this.wrapper.css('visibility', 'visible'); this.wrapper.hide(); }, setWidths: function() { // The text input has a right margin because of the background arrow image // so we need to remove that from the width var width = this.select.width() + 2; var padding_right = parseInt(this.text.css('padding-right').replace(/px/, ''), 10); this.text.width(width - padding_right); this.wrapper.width(width + 2); if(this.bg_iframe) { this.bg_iframe.width(width + 4); }; }, createBackgroundIframe: function() { var bg_iframe = $('<iframe frameborder="0" class="editable-select-iframe" src="about:blank;"></iframe>'); $(document.body).append(bg_iframe); bg_iframe.width(this.select.width() + 2); bg_iframe.height(this.wrapper.height()); bg_iframe.css({top: this.wrapper.css('top'), left: this.wrapper.css('left')}); this.bg_iframe = bg_iframe; } }; })(jQuery); $(function() { $('.editable-select').editableSelect( { bg_iframe: true, onSelect: function(list_item) { alert('List item text: '+ list_item.text()); // 'this' is a reference to the instance of EditableSelect // object, so you have full access to everything there // alert('Input value: '+ this.text.val()); }, case_sensitive: false, // If set to true, the user has to type in an exact // match for the item to get highlighted items_then_scroll: 10 // If there are more than 10 items, display a scrollbar } ); var select = $('.editable-select:first'); var instances = select.editableSelectInstances(); // instances[0].addOption('Germany, value added programmatically'); });

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Forensic Analysis of the OOM-Killer

- by Oddthinking

Ubuntu's Out-Of-Memory Killer wreaked havoc on my server, quietly assassinating my applications, sendmail, apache and others. I've managed to learn what the OOM Killer is, and about its "badness" rules. While my machine is small, my applications are even smaller, and typically only half of my physical memory is in use, let alone swap-space, so I was surprised. I am trying to work out the culprit, but I don't know how to read the OOM-Killer logs. Can anyone please point me to a tutorial on how to read the data in the logs (what are ve, free and gen?), or help me parse these logs? Apr 20 20:03:27 EL135 kernel: kill_signal(13516.0): selecting to kill, queued 0, seq 1, exc 2326 0 goal 2326 0... Apr 20 20:03:27 EL135 kernel: kill_signal(13516.0): task ebb0c6f0, thg d33a1b00, sig 1 Apr 20 20:03:27 EL135 kernel: kill_signal(13516.0): selected 1, signalled 1, queued 1, seq 1, exc 2326 0 red 61795 745 Apr 20 20:03:27 EL135 kernel: kill_signal(13516.0): selecting to kill, queued 0, seq 2, exc 122 0 goal 383 0... Apr 20 20:03:27 EL135 kernel: kill_signal(13516.0): task ebb0c6f0, thg d33a1b00, sig 1 Apr 20 20:03:27 EL135 kernel: kill_signal(13516.0): selected 1, signalled 1, queued 1, seq 2, exc 383 0 red 61795 745 Apr 20 20:03:27 EL135 kernel: kill_signal(13516.0): task ebb0c6f0, thg d33a1b00, sig 2 Apr 20 20:03:27 EL135 kernel: OOM killed process watchdog (pid=14490, ve=13516) exited, free=43104 gen=24501. Apr 20 20:03:27 EL135 kernel: OOM killed process tail (pid=4457, ve=13516) exited, free=43104 gen=24502. Apr 20 20:03:27 EL135 kernel: OOM killed process ntpd (pid=10816, ve=13516) exited, free=43104 gen=24503. Apr 20 20:03:27 EL135 kernel: OOM killed process tail (pid=27401, ve=13516) exited, free=43104 gen=24504. Apr 20 20:03:27 EL135 kernel: OOM killed process tail (pid=29009, ve=13516) exited, free=43104 gen=24505. Apr 20 20:03:27 EL135 kernel: OOM killed process apache2 (pid=10557, ve=13516) exited, free=49552 gen=24506. Apr 20 20:03:27 EL135 kernel: OOM killed process apache2 (pid=24983, ve=13516) exited, free=53117 gen=24507. Apr 20 20:03:27 EL135 kernel: OOM killed process apache2 (pid=29129, ve=13516) exited, free=68493 gen=24508. Apr 20 20:03:27 EL135 kernel: OOM killed process sendmail-mta (pid=941, ve=13516) exited, free=68803 gen=24509. Apr 20 20:03:27 EL135 kernel: OOM killed process tail (pid=12418, ve=13516) exited, free=69330 gen=24510. Apr 20 20:03:27 EL135 kernel: OOM killed process python (pid=22953, ve=13516) exited, free=72275 gen=24511. Apr 20 20:03:27 EL135 kernel: OOM killed process apache2 (pid=6624, ve=13516) exited, free=76398 gen=24512. Apr 20 20:03:27 EL135 kernel: OOM killed process python (pid=23317, ve=13516) exited, free=94285 gen=24513. Apr 20 20:03:27 EL135 kernel: OOM killed process tail (pid=29030, ve=13516) exited, free=95339 gen=24514. Apr 20 20:03:28 EL135 kernel: OOM killed process apache2 (pid=20583, ve=13516) exited, free=101663 gen=24515. Apr 20 20:03:28 EL135 kernel: OOM killed process logger (pid=12894, ve=13516) exited, free=101694 gen=24516. Apr 20 20:03:28 EL135 kernel: OOM killed process bash (pid=21119, ve=13516) exited, free=101849 gen=24517. Apr 20 20:03:28 EL135 kernel: OOM killed process atd (pid=991, ve=13516) exited, free=101880 gen=24518. Apr 20 20:03:28 EL135 kernel: OOM killed process apache2 (pid=14649, ve=13516) exited, free=102748 gen=24519. Apr 20 20:03:28 EL135 kernel: OOM killed process grep (pid=21375, ve=13516) exited, free=132167 gen=24520. Apr 20 20:03:57 EL135 kernel: kill_signal(13516.0): selecting to kill, queued 0, seq 4, exc 4215 0 goal 4826 0... Apr 20 20:03:57 EL135 kernel: kill_signal(13516.0): task ede29370, thg df98b880, sig 1 Apr 20 20:03:57 EL135 kernel: kill_signal(13516.0): selected 1, signalled 1, queued 1, seq 4, exc 4826 0 red 189481 331 Apr 20 20:03:57 EL135 kernel: kill_signal(13516.0): task ede29370, thg df98b880, sig 2 Apr 20 20:04:53 EL135 kernel: kill_signal(13516.0): selecting to kill, queued 0, seq 5, exc 3564 0 goal 3564 0... Apr 20 20:04:53 EL135 kernel: kill_signal(13516.0): task c6c90110, thg cdb1a100, sig 1 Apr 20 20:04:53 EL135 kernel: kill_signal(13516.0): selected 1, signalled 1, queued 1, seq 5, exc 3564 0 red 189481 331 Apr 20 20:04:53 EL135 kernel: kill_signal(13516.0): task c6c90110, thg cdb1a100, sig 2 Apr 20 20:07:14 EL135 kernel: kill_signal(13516.0): selecting to kill, queued 0, seq 6, exc 8071 0 goal 8071 0... Apr 20 20:07:14 EL135 kernel: kill_signal(13516.0): task d7294050, thg c03f42c0, sig 1 Apr 20 20:07:14 EL135 kernel: kill_signal(13516.0): selected 1, signalled 1, queued 1, seq 6, exc 8071 0 red 189481 331 Apr 20 20:07:14 EL135 kernel: kill_signal(13516.0): task d7294050, thg c03f42c0, sig 2 Watchdog is a watchdog task, that was idle; nothing in the logs to suggest it had done anything for days. Its job is to restart one of the applications if it dies, so a bit ironic that it is the first to get killed. Tail was monitoring a few logs files. Unlikely to be consuming memory madly. The apache web-server only serves pages to a little old lady who only uses it to get to church on Sundays a couple of developers who were in bed asleep, and hadn't visited a page on the site for a few weeks. The only traffic it might have had is from the port-scanners; all the content is password-protected and not linked from anywhere, so no spiders are interested. Python is running two separate custom applications. Nothing in the logs to suggest they weren't humming along as normal. One of them was a relatively recent implementation, which makes suspect #1. It doesn't have any data-structures of any significance, and normally uses only about 8% of the total physical RAW. It hasn't misbehaved since. The grep is suspect #2, and the one I want to be guilty, because it was a once-off command. The command (which piped the output of a grep -r to another grep) had been started at least 30 minutes earlier, and the fact it was still running is suspicious. However, I wouldn't have thought grep would ever use a significant amount of memory. It took a while for the OOM killer to get to it, which suggests it wasn't going mad, but the OOM killer stopped once it was killed, suggesting it may have been a memory-hog that finally satisfied the OOM killer's blood-lust.

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Add keyboard languages to XP, Vista, and Windows 7

- by Matthew Guay

Do you regularly need to type in multiple languages in Windows? Here we’ll show you the easy way to add and change input languages to your keyboard in XP, Vista, and Windows 7. Windows Vista and 7 come preinstalled with support for viewing a wide variety of languages, so adding an input language is fairly simply. Adding an input language is slightly more difficult in XP, and requires installing additional files if you need an Asian or Complex script language. First we show how to add an input language in Windows Vista and 7; it’s basically the same in both versions. Then, we show how to add a language to XP, and also how to add Complex Script support. Please note that this is only for adding an input language, which will allow you to type in the language you select. This does not change your user interface language. Change keyboard language in Windows 7 and Vista It is fairly simple to add or change a keyboard language in Windows 7 or Vista. In Windows 7, enter “keyboard language” in the Start menu search box, and select “Change keyboards or other input methods”. In Windows Vista, open Control Panel and enter “input language” in the search box and select “Change keyboards or other input methods”. This also works in Windows 7. Now, click Change Keyboards to add another keyboard language or change your default one. Our default input language is US English, and our default keyboard is the US keyboard layout. Click Add to insert another input language while still leaving your default input language installed. Here we selected the standard Thai keyboard language (Thai Kedmanee), but you can select any language you want. Windows offers almost any language you can imagine, so just look for the language you want, select it, and click Ok. Alternately, if you want, you can click Preview to see your layout choice before accepting it. This is only the default characters, not ones that will be activated with Shift or other keys (many Asian languages use many more characters than English, and require the use of Shift and other keys to access them all). Once your finished previewing, click close and then press Ok on the previous dialog. Now you will see both of your keyboard languages in the Installed services box. You can click Add to go back and get more, or move your selected language up or down (to change its priority), or simply click Apply to add the new language. Also, you can now change the default input language from the top menu. This is the language that your keyboard will start with when you boot your computer. So, if you mainly use English but also use another language, usually it is best to leave English as your default input language. Once you’ve pressed Apply or Ok, you will see a new icon beside your system tray with the initials of your default input language. If you click it, you can switch between input languages. Alternately you can switch input languages by pressing Alt+Shift on your keyboard. Some complex languages, such as Chinese, may have extra buttons to change input modes to accommodate their large alphabet. If you would like to change the keyboard shortcut for changing languages, go back to the Input Languages dialog, and select the “Advanced Key Settings” tab. Here you can change settings for Caps Lock and change or add key sequences to change between languages. Also, the On-Screen keyboard will display the correct keyboard language (here the keyboard is displaying Thai), which can be a helpful reference if your physical keyboard doesn’t have your preferred input language printed on it. To open this, simply enter “On-Screen keyboard” in the start menu search, or click All Programs>Accessories>On-Screen keyboard. Change keyboard language in Windows XP The process for changing the keyboard language in Windows XP is slightly different. Open Control Panel, and select “Date, Time, Language, and Regional Options”. Select “Add other languages”. Now, click Details to add another language. XP does not include support for Asian and complex languages by default, so if you need to add one of those languages we have details for that below. Click Add to add an input language. Select your desired language from the list, and choose your desired keyboard layout if your language offers multiple layouts. Here we selected Canadian French with the default layout. Now you will see both of your keyboard languages in the Installed services box. You can click Add to go back and add more, or move your selected language up or down (to change its priority), or simply click Apply to add the new language. Once you’ve pressed Apply or Ok, you will see a new icon beside your system tray with the initials of your default input language. If you click it, you can switch between input languages. Alternately you can switch input languages by pressing Alt+Shift on your keyboard. If you would like to change the keyboard shortcut for changing languages, go back to the Input Languages dialog, and click the “Key Settings” button on the bottom of the dialog. Here you can change settings for Caps Lock and change or add key sequences to change between languages. Add support to XP for Asian and Complex script languages Windows XP does not include support for Asian and Complex script languages by default, but you can easily add them to your computer. This is useful if you wish to type in one of these languages, or simply want to read text written in these languages, since XP will not display these languages correctly if they are not installed. If you wish to install Chinese, Japanese, and/or Korean, check the “Install files for East Asian languages” box. Or, if you need to install a complex script language (including Arabic, Armenian, Georgian, Hebrew, the Indic languages, Thai, and Vietnamese), check the “Install files for complex script and right-to-left languages” box. Choosing either of these options will open a prompt reminding you that this option will take up more disk space. Support for complex languages will require around 10Mb of hard drive space, but East Asian language support may require 230 Mb or more free disk space. Click Ok, and click apply to install your language files. You may have to insert your XP CD into your CD drive to install these files. Insert the disk, and then click Ok. Windows will automatically copy the files, including fonts for these languages… …and then will ask you to reboot your computer to finalize the settings. Click Yes, and then reopen the “Add other languages” dialog when your computer is rebooted, and add a language as before. Now you can add Complex and/or Asian languages to XP, just as above. Here is the XP taskbar language selector with Thai installed. Conclusion Unfortunately we haven’t found a way to add Asian and complex languages in XP without having an XP disc. If you know of a way, let us know in the comments. (No downloading the XP disc from torrent site answers please) Adding an input language is very important for bilingual individuals, and can also be useful if you simply need to occasionally view Asian or Complex languages in XP. And by following the correct instructions for your version of Windows, it should be very easy to add, change, and remove input languages. Similar Articles Productive Geek Tips Show Keyboard Shortcut Access Keys in Windows VistaKeyboard Ninja: 21 Keyboard Shortcut ArticlesAnother Desktop Cube for Windows XP/VistaThe "Up" Keyboard Shortcut for Windows 7 or Vista ExplorerWhat is ctfmon.exe And Why Is It Running? TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 PCmover Professional Make your Joomla & Drupal Sites Mobile with OSMOBI Integrate Twitter and Delicious and Make Life Easier Design Your Web Pages Using the Golden Ratio Worldwide Growth of the Internet How to Find Your Mac Address Use My TextTools to Edit and Organize Text

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How can a code editor effectively hint at code nesting level - without using indentation?

- by pgfearo

I've written an XML text editor that provides 2 view options for the same XML text, one indented (virtually), the other left-justified. The motivation for the left-justified view is to help users 'see' the whitespace characters they're using for indentation of plain-text or XPath code without interference from indentation that is an automated side-effect of the XML context. I want to provide visual clues (in the non-editable part of the editor) for the left-justified mode that will help the user, but without getting too elaborate. I tried just using connecting lines, but that seemed too busy. The best I've come up with so far is shown in a mocked up screenshot of the editor below, but I'm seeking better/simpler alternatives (that don't require too much code). [Edit] Taking the heatmap idea (from: @jimp) I get this and 3 alternatives - labelled a, b and c: The following section describes the accepted answer as a proposal, bringing together ideas from a number of other answers and comments. As this question is now community wiki, please feel free to update this. NestView The name for this idea which provides a visual method to improve the readability of nested code without using indentation. Contour Lines The name for the differently shaded lines within the NestView The image above shows the NestView used to help visualise an XML snippet. Though XML is used for this illustration, any other code syntax that uses nesting could have been used for this illustration. An Overview: The contour lines are shaded (as in a heatmap) to convey nesting level The contour lines are angled to show when a nesting level is being either opened or closed. A contour line links the start of a nesting level to the corresponding end. The combined width of contour lines give a visual impression of nesting level, in addition to the heatmap. The width of the NestView may be manually resizable, but should not change as the code changes. Contour lines can either be compressed or truncated to keep acheive this. Blank lines are sometimes used code to break up text into more digestable chunks. Such lines could trigger special behaviour in the NestView. For example the heatmap could be reset or a background color contour line used, or both. One or more contour lines associated with the currently selected code can be highlighted. The contour line associated with the selected code level would be emphasized the most, but other contour lines could also 'light up' in addition to help highlight the containing nested group Different behaviors (such as code folding or code selection) can be associated with clicking/double-clicking on a Contour Line. Different parts of a contour line (leading, middle or trailing edge) may have different dynamic behaviors associated. Tooltips can be shown on a mouse hover event over a contour line The NestView is updated continously as the code is edited. Where nesting is not well-balanced assumptions can be made where the nesting level should end, but the associated temporary contour lines must be highlighted in some way as a warning. Drag and drop behaviors of Contour Lines can be supported. Behaviour may vary according to the part of the contour line being dragged. Features commonly found in the left margin such as line numbering and colour highlighting for errors and change state could overlay the NestView. Additional Functionality The proposal addresses a range of additional issues - many are outside the scope of the original question, but a useful side-effect. Visually linking the start and end of a nested region The contour lines connect the start and end of each nested level Highlighting the context of the currently selected line As code is selected, the associated nest-level in the NestView can be highlighted Differentiating between code regions at the same nesting level In the case of XML different hues could be used for different namespaces. Programming languages (such as c#) support named regions that could be used in a similar way. Dividing areas within a nesting area into different visual blocks Extra lines are often inserted into code to aid readability. Such empty lines could be used to reset the saturation level of the NestView's contour lines. Multi-Column Code View Code without indentation makes the use of a multi-column view more effective because word-wrap or horizontal scrolling is less likely to be required. In this view, once code has reach the bottom of one column, it flows into the next one: Usage beyond merely providing a visual aid As proposed in the overview, the NestView could provide a range of editing and selection features which would be broadly in line with what is expected from a TreeView control. The key difference is that a typical TreeView node has 2 parts: an expander and the node icon. A NestView contour line can have as many as 3 parts: an opener (sloping), a connector (vertical) and a close (sloping). On Indentation The NestView presented alongside non-indented code complements, but is unlikely to replace, the conventional indented code view. It's likely that any solutions adopting a NestView, will provide a method to switch seamlessly between indented and non-indented code views without affecting any of the code text itself - including whitespace characters. One technique for the indented view would be 'Virtual Formatting' - where a dynamic left-margin is used in lieu of tab or space characters. The same nesting-level data used to dynamically render the NestView could also used for the more conventional-looking indented view. Printing Indentation will be important for the readability of printed code. Here, the absence of tab/space characters and a dynamic left-margin means that the text can wrap at the right-margin and still maintain the integrity of the indented view. Line numbers can be used as visual markers that indicate where code is word-wrapped and also the exact position of indentation: Screen Real-Estate: Flat Vs Indented Addressing the question of whether the NestView uses up valuable screen real-estate: Contour lines work well with a width the same as the code editor's character width. A NestView width of 12 character widths can therefore accommodate 12 levels of nesting before contour lines are truncated/compressed. If an indented view uses 3 character-widths for each nesting level then space is saved until nesting reaches 4 levels of nesting, after this nesting level the flat view has a space-saving advantage that increases with each nesting level. Note: A minimum indentation of 4 character widths is often recommended for code, however XML often manages with less. Also, Virtual Formatting permits less indentation to be used because there's no risk of alignment issues A comparison of the 2 views is shown below: Based on the above, its probably fair to conclude that view style choice will be based on factors other than screen real-estate. The one exception is where screen space is at a premium, for example on a Netbook/Tablet or when multiple code windows are open. In these cases, the resizable NestView would seem to be a clear winner. Use Cases Examples of real-world examples where NestView may be a useful option: Where screen real-estate is at a premium a. On devices such as tablets, notepads and smartphones b. When showing code on websites c. When multiple code windows need to be visible on the desktop simultaneously Where consistent whitespace indentation of text within code is a priority For reviewing deeply nested code. For example where sub-languages (e.g. Linq in C# or XPath in XSLT) might cause high levels of nesting. Accessibility Resizing and color options must be provided to aid those with visual impairments, and also to suit environmental conditions and personal preferences: Compatability of edited code with other systems A solution incorporating a NestView option should ideally be capable of stripping leading tab and space characters (identified as only having a formatting role) from imported code. Then, once stripped, the code could be rendered neatly in both the left-justified and indented views without change. For many users relying on systems such as merging and diff tools that are not whitespace-aware this will be a major concern (if not a complete show-stopper). Other Works: Visualisation of Overlapping Markup Published research by Wendell Piez, dated from 2004, addresses the issue of the visualisation of overlapping markup, specifically LMNL. This includes SVG graphics with significant similarities to the NestView proposal, as such, they are acknowledged here. The visual differences are clear in the images (below), the key functional distinction is that NestView is intended only for well-nested XML or code, whereas Wendell Piez's graphics are designed to represent overlapped nesting. The graphics above were reproduced - with kind permission - from http://www.piez.org Sources: Towards Hermenutic Markup Half-steps toward LMNL

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Using Radio Button in GridView with Validation

- by Vincent Maverick Durano

A developer is asking how to select one radio button at a time if the radio button is inside the GridView. As you may know setting the group name attribute of radio button will not work if the radio button is located within a Data Representation control like GridView. This because the radio button inside the gridview bahaves differentely. Since a gridview is rendered as table element , at run time it will assign different "name" to each radio button. Hence you are able to select multiple rows. In this post I'm going to demonstrate how select one radio button at a time in gridview and add a simple validation on it. To get started let's go ahead and fire up visual studio and the create a new web application / website project. Add a WebForm and then add gridview. The mark up would look something like this: <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" > <Columns> <asp:TemplateField> <ItemTemplate> <asp:RadioButton ID="rb" runat="server" /> </ItemTemplate> </asp:TemplateField> <asp:BoundField DataField="RowNumber" HeaderText="Row Number" /> <asp:BoundField DataField="Col1" HeaderText="First Column" /> <asp:BoundField DataField="Col2" HeaderText="Second Column" /> </Columns> </asp:GridView> Noticed that I've added a templatefield column so that we can add the radio button there. Also I have set up some BoundField columns and set the DataFields as RowNumber, Col1 and Col2. These columns are just dummy columns and i used it for the simplicity of this example. Now where these columns came from? These columns are created by hand at the code behind file of the ASPX. Here's the code below: private DataTable FillData() { DataTable dt = new DataTable(); DataRow dr = null; //Create DataTable columns dt.Columns.Add(new DataColumn("RowNumber", typeof(string))); dt.Columns.Add(new DataColumn("Col1", typeof(string))); dt.Columns.Add(new DataColumn("Col2", typeof(string))); //Create Row for each columns dr = dt.NewRow(); dr["RowNumber"] = 1; dr["Col1"] = "A"; dr["Col2"] = "B"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 2; dr["Col1"] = "AA"; dr["Col2"] = "BB"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 3; dr["Col1"] = "A"; dr["Col2"] = "B"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 4; dr["Col1"] = "A"; dr["Col2"] = "B"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["RowNumber"] = 5; dr["Col1"] = "A"; dr["Col2"] = "B"; dt.Rows.Add(dr); return dt; } And here's the code for binding the GridView with the dummy data above. protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { GridView1.DataSource = FillData(); GridView1.DataBind(); } } Okay we have now a GridView data with a radio button on each row. Now lets go ahead and switch back to ASPX mark up. In this example I'm going to use a JavaScript for validating the radio button to select one radio button at a time. Here's the javascript code below: function CheckOtherIsCheckedByGVID(rb) { var isChecked = rb.checked; var row = rb.parentNode.parentNode; if (isChecked) { row.style.backgroundColor = '#B6C4DE'; row.style.color = 'black'; } var currentRdbID = rb.id; parent = document.getElementById("<%= GridView1.ClientID %>"); var items = parent.getElementsByTagName('input'); for (i = 0; i < items.length; i++) { if (items[i].id != currentRdbID && items[i].type == "radio") { if (items[i].checked) { items[i].checked = false; items[i].parentNode.parentNode.style.backgroundColor = 'white'; items[i].parentNode.parentNode.style.color = '#696969'; } } } } The function above sets the row of the current selected radio button's style to determine that the row is selected and then loops through the radio buttons in the gridview and then de-select the previous selected radio button and set the row style back to its default. You can then call the javascript function above at onlick event of radio button like below: <asp:RadioButton ID="rb" runat="server" onclick="javascript:CheckOtherIsCheckedByGVID(this);" /> Here's the output below: On Load: After Selecting a Radio Button: As you have noticed, on initial load there's no default selected radio in the GridView. Now let's add a simple validation for that. We will basically display an error message if a user clicks a button that triggers a postback without selecting a radio button in the GridView. Here's the javascript for the validation: function ValidateRadioButton(sender, args) { var gv = document.getElementById("<%= GridView1.ClientID %>"); var items = gv.getElementsByTagName('input'); for (var i = 0; i < items.length ; i++) { if (items[i].type == "radio") { if (items[i].checked) { args.IsValid = true; return; } else { args.IsValid = false; } } } } The function above loops through the rows in gridview and find all the radio buttons within it. It will then check each radio button checked property. If a radio is checked then set IsValid to true else set it to false. The reason why I'm using IsValid is because I'm using the ASP validator control for validation. Now add the following mark up below under the GridView declaration: <br /> <asp:Label ID="lblMessage" runat="server" /> <br /> <asp:Button ID="btn" runat="server" Text="POST" onclick="btn_Click" ValidationGroup="GroupA" /> <asp:CustomValidator ID="CustomValidator1" runat="server" ErrorMessage="Please select row in the grid." ClientValidationFunction="ValidateRadioButton" ValidationGroup="GroupA" style="display:none"></asp:CustomValidator> <asp:ValidationSummary ID="ValidationSummary1" runat="server" ValidationGroup="GroupA" HeaderText="Error List:" DisplayMode="BulletList" ForeColor="Red" /> And then at Button Click event add this simple code below just to test if the validation works: protected void btn_Click(object sender, EventArgs e) { lblMessage.Text = "Postback at: " + DateTime.Now.ToString("hh:mm:ss tt"); } Here's the output below that you can see in the browser: That's it! I hope someone find this post useful! Technorati Tags: ASP.NET,JavaScript,GridView

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