Tutorial by Examples: g

By default, the navigation pattern works like a stack of pages, calling the newest pages over the previous pages. You will need to use the NavigationPage object for this. Pushing new pages ... public class App : Application { public App() { MainPage = new NavigationPage(new ...

Modal pages can created in three ways: From NavigationPage object for full screen pages For Alerts and Notifications For ActionSheets that are pop-ups menus Full screen modals ... // to open await Navigation.PushModalAsync(new ModalPage()); // to close await Navigation.PopModalAsync(); ...

In CSS3, we can stack multiple background in the same element. #mydiv { background-image: url(img_1.png), /* top image */ url(img_2.png), /* middle image */ url(img_3.png); /* bottom image */ background-position: right bottom, ...

SELECT Name FROM Customers WHERE PhoneNumber IS NULL Selection with nulls take a different syntax. Don't use =, use IS NULL or IS NOT NULL instead.

The below code will turn the table with an id of tableid into a DataTable, as well as return a DataTables API instance: $(document).ready(function() { $('#tableid').DataTable(); }); Compare this to the below code, which will turn the table into a DataTable but will not return a DataTables ...

' Sometimes we don't need to evaluate all the conditions in an if statement's boolean check. ' Let's suppose we have a list of strings: Dim MyCollection as List(Of String) = New List(of String)() ' We want to evaluate the first value inside our list: If MyCollection.Count > 0 And MyCo...

' The OrElse operator is the homologous of AndAlso. It lets us perform a boolean ' comparison evaluating the second condition only if the first one is False If testFunction(5) = True OrElse otherFunction(4) = True Then ' If testFunction(5) is True, otherFunction(4) is not called. ' In...

Yes, you need to SETKEY pre 1.9.6 In the past (pre 1.9.6), your data.table was sped up by setting columns as keys to the table, particularly for large tables. [See intro vignette page 5 of September 2015 version, where speed of search was 544 times better.] You may find older code making use of t...

Creating an alert dialog AlertDialog.Builder builder = new AlertDialog.Builder(Context); builder.SetIcon(Resource.Drawable.Icon); builder.SetTitle(title); builder.SetMessage(message); builder.SetNeutralButton("Neutral", (evt, args) => { // code here for handling the Neutral...

Given this data User_IDCompletion_Date12016-07-2012016-07-2122016-07-2022016-07-2122016-07-22 ;with CTE as (SELECT *, ROW_NUMBER() OVER (PARTITION BY User_ID ORDER BY Completion_Date DESC) Row_Num FROM Data) SELECT * FORM CTE WHERE Row_Num <= n Us...

Some functions only work on a certain type of argument: function foo(tab) return tab.bar end --> returns nil if tab has no field bar, which is acceptable --> returns 'attempt to index a number value' if tab is, for example, 3 --> which is unacceptable function kungfoo(tab) ...

A non-blocking assignment (<=) is used for assignment inside edge-sensitive always blocks. Within a block, the new values are not visible until the entire block has been processed. For example: module flip( input clk, input reset ) reg f1; reg f2; always @ (posedge clk) begin ...

A 2-tuple or a 3-tuple represent a group of related items. (Points in 2D space, RGB values of a color, etc.) A 1-tuple is not very useful since it could easily be replaced with a single int. A 0-tuple seems even more useless since it contains absolutely nothing. Yet it has properties that make it v...

An Enum instance can be created by parsing a string representation of the Enum. Module Module1 Enum Size Small Medium Large End Enum Sub Main() Dim shirtSize As Size = DirectCast([Enum].Parse(GetType(Size), "Medium"), Size) ...

Sitecore ships with a set of standard indexes pre-configured which you can extend, or you can define your own. Of the pre-configured, sitecore_master_index & sitecore_web_index are of most interest for your site search. These are the predefined indexes for all of your Sitecore items in the tree ...

Demo HTML <script type="x-template" id="form-template"> <label>{{inputLabel}} :</label> <input type="text" v-model="name" /> </script> <div id="app"> <h2>{{appName}}</h2> <form-co...

//Swift imageView.tintColor = UIColor.redColor() imageView.image = imageView.image?.imageWithRenderingMode(.AlwaysTemplate) //Swift 3 imageView.tintColor = UIColor.red imageView.image = imageView.image?.withRenderingMode(.alwaysTemplate) //Objective-C imageView.tintColor = [UIColor redCol...

We start off with $db, an instance of the PDO class. After executing a query we often want to determine the number of rows that have been affected by it. The rowCount() method of the PDOStatement will work nicely: $query = $db->query("DELETE FROM table WHERE name = 'John'"); $count = ...

All you need is a variable of type IHostingEnvironment: get environment name: env.EnvironmentName for predefined Development, Staging, Production environments the best way is to use extension methods from HostingEnvironmentExtensions class env.IsDevelopment() env.IsStaging() ...

A true relational database must go beyond throwing data into a few tables and writing some SQL statements to pull that data out. At best a badly designed table structure will slow the execution of queries and could make it impossible for the database to function as intended. A database table shoul...