Search Results

Search found 29498 results on 1180 pages for 'object destruction'.

Page 193/1180 | < Previous Page | 189 190 191 192 193 194 195 196 197 198 199 200  | Next Page >

• SSAS: Using fake dimension and scopes for dynamic ranges

  - by DigiMortal

  In one of my BI projects I needed to find count of objects in income range. Usual solution with range dimension was useless because range where object belongs changes in time. These ranges depend on calculation that is done over incomes measure so I had really no option to use some classic solution. Thanks to SSAS forums I got my problem solved and here is the solution. The problem – how to create dynamic ranges? I have two dimensions in SSAS cube: one for invoices related to objects rent and the other for objects. There is measure that sums invoice totals and two calculations. One of these calculations performs some computations based on object income and some other object attributes. Second calculation uses first one to define income ranges where object belongs. What I need is query that returns me how much objects there are in each group. I cannot use dimension for range because on one date object may belong to one range and two days later to another income range. By example, if object is not rented out for two days it makes no money and it’s income stays the same as before. If object is rented out after two days it makes some income and this income may move it to another income range. Solution – fake dimension and scopes Thanks to Gerhard Brueckl from pmOne I got everything work fine after some struggling with BI Studio. The original discussion he pointed out can be found from SSAS official forums thread Create a banding dimension that groups by a calculated measure. Solution was pretty simple by nature – we have to define fake dimension for our range and use scopes to assign values for object count measure. Object count measure is primitive – it just counts objects and that’s it. We will use it to find out how many objects belong to one or another range. We also need table for fake ranges and we have to fill it with ranges used in ranges calculation. After creating the table and filling it with ranges we can add fake range dimension to our cube. Let’s see now how to solve the problem step-by-step. Solving the problem Suppose you have ranges calculation defined like this: CASE WHEN [Measures].[ComplexCalc] < 0 THEN 'Below 0'WHEN [Measures].[ComplexCalc] >=0 AND  [Measures].[ComplexCalc] <=50 THEN '0 - 50'...END Let’s create now new table to our analysis database and name it as FakeIncomeRange. Here is the definition for table: CREATE TABLE [FakeIncomeRange] (     [range_id] [int] IDENTITY(1,1) NOT NULL,     [range_name] [nvarchar](50) NOT NULL,     CONSTRAINT [pk_fake_income_range] PRIMARY KEY CLUSTERED      (         [range_id] ASC     ) ) Don’t forget to fill this table with range labels you are using in ranges calculation. To use ranges from table we have to add this table to our data source view and create new dimension. We cannot bind this table to other tables but we have to leave it like it is. Our dimension has two attributes: ID and Name. The next thing to create is calculation that returns objects count. This calculation is also fake because we override it’s values for all ranges later. Objects count measure can be defined as calculation like this: COUNT([Object].[Object].[Object].members) Now comes the most crucial part of our solution – defining the scopes. Based on data used in this posting we have to define scope for each of our ranges. Here is the example for first range. SCOPE([FakeIncomeRange].[Name].&[Below 0], [Measures].[ObjectCount])     This=COUNT(            FILTER(                [Object].[Object].[Object].members,                 [Measures].[ComplexCalc] < 0          )     ) END SCOPE To get these scopes defined in cube we need MDX script blocks for each line given here. Take a look at the screenshot to get better idea what I mean. This example is given from SQL Server books online to avoid conflicts with NDA. :) From previous example the lines (MDX scripts) are: Line starting with SCOPE Block for This = Line with END SCOPE And now it is time to deploy and process our cube. Although you may see examples where there are semicolons in the end of statements you don’t need them. Visual Studio BI tools generate separate command from each script block so you don’t need to worry about it.

  Read the article

• C#/.NET Little Pitfalls: The Dangers of Casting Boxed Values

  - by James Michael Hare

  Starting a new series to parallel the Little Wonders series.  In this series, I will examine some of the small pitfalls that can occasionally trip up developers. Introduction: Of Casts and Conversions What happens when we try to assign from an int and a double and vice-versa? 1: double pi = 3.14; 2: int theAnswer = 42; 3:  4: // implicit widening conversion, compiles! 5: double doubleAnswer = theAnswer; 6:  7: // implicit narrowing conversion, compiler error! 8: int intPi = pi; As you can see from the comments above, a conversion from a value type where there is no potential data loss is can be done with an implicit conversion.  However, when converting from one value type to another may result in a loss of data, you must make the conversion explicit so the compiler knows you accept this risk.  That is why the conversion from double to int will not compile with an implicit conversion, we can make the conversion explicit by adding a cast: 1: // explicit narrowing conversion using a cast, compiler 2: // succeeds, but results may have data loss: 3: int intPi = (int)pi; So for value types, the conversions (implicit and explicit) both convert the original value to a new value of the given type.  With widening and narrowing references, however, this is not the case.  Converting reference types is a bit different from converting value types.  First of all when you perform a widening or narrowing you don’t really convert the instance of the object, you just convert the reference itself to the wider or narrower reference type, but both the original and new reference type both refer back to the same object. Secondly, widening and narrowing for reference types refers the going down and up the class hierarchy instead of referring to precision as in value types.  That is, a narrowing conversion for a reference type means you are going down the class hierarchy (for example from Shape to Square) whereas a widening conversion means you are going up the class hierarchy (from Square to Shape).  1: var square = new Square(); 2:  3: // implicitly convers because all squares are shapes 4: // (that is, all subclasses can be referenced by a superclass reference) 5: Shape myShape = square; 6:  7: // implicit conversion not possible, not all shapes are squares! 8: // (that is, not all superclasses can be referenced by a subclass reference) 9: Square mySquare = (Square) myShape; So we had to cast the Shape back to Square because at that point the compiler has no way of knowing until runtime whether the Shape in question is truly a Square.  But, because the compiler knows that it’s possible for a Shape to be a Square, it will compile.  However, if the object referenced by myShape is not truly a Square at runtime, you will get an invalid cast exception. Of course, there are other forms of conversions as well such as user-specified conversions and helper class conversions which are beyond the scope of this post.  The main thing we want to focus on is this seemingly innocuous casting method of widening and narrowing conversions that we come to depend on every day and, in some cases, can bite us if we don’t fully understand what is going on!  The Pitfall: Conversions on Boxed Value Types Can Fail What if you saw the following code and – knowing nothing else – you were asked if it was legal or not, what would you think: 1: // assuming x is defined above this and this 2: // assignment is syntactically legal. 3: x = 3.14; 4:  5: // convert 3.14 to int. 6: int truncated = (int)x; You may think that since x is obviously a double (can’t be a float) because 3.14 is a double literal, but this is inaccurate.  Our x could also be dynamic and this would work as well, or there could be user-defined conversions in play.  But there is another, even simpler option that can often bite us: what if x is object? 1: object x; 2:  3: x = 3.14; 4:  5: int truncated = (int) x; On the surface, this seems fine.  We have a double and we place it into an object which can be done implicitly through boxing (no cast) because all types inherit from object.  Then we cast it to int.  This theoretically should be possible because we know we can explicitly convert a double to an int through a conversion process which involves truncation. But here’s the pitfall: when casting an object to another type, we are casting a reference type, not a value type!  This means that it will attempt to see at runtime if the value boxed and referred to by x is of type int or derived from type int.  Since it obviously isn’t (it’s a double after all) we get an invalid cast exception! Now, you may say this looks awfully contrived, but in truth we can run into this a lot if we’re not careful.  Consider using an IDataReader to read from a database, and then attempting to select a result row of a particular column type: 1: using (var connection = new SqlConnection("some connection string")) 2: using (var command = new SqlCommand("select * from employee", connection)) 3: using (var reader = command.ExecuteReader()) 4: { 5: while (reader.Read()) 6: { 7: // if the salary is not an int32 in the SQL database, this is an error! 8: // doesn't matter if short, long, double, float, reader [] returns object! 9: total += (int) reader["annual_salary"]; 10: } 11: } Notice that since the reader indexer returns object, if we attempt to convert using a cast to a type, we have to make darn sure we use the true, actual type or this will fail!  If the SQL database column is a double, float, short, etc this will fail at runtime with an invalid cast exception because it attempts to convert the object reference! So, how do you get around this?  There are two ways, you could first cast the object to its actual type (double), and then do a narrowing cast to on the value to int.  Or you could use a helper class like Convert which analyzes the actual run-time type and will perform a conversion as long as the type implements IConvertible. 1: object x; 2:  3: x = 3.14; 4:  5: // if you want to cast, must cast out of object to double, then 6: // cast convert. 7: int truncated = (int)(double) x; 8:  9: // or you can call a helper class like Convert which examines runtime 10: // type of the value being converted 11: int anotherTruncated = Convert.ToInt32(x); Summary You should always be careful when performing a conversion cast from values boxed in object that you are actually casting to the true type (or a sub-type). Since casting from object is a widening of the reference, be careful that you either know the exact, explicit type you expect to be held in the object, or instead avoid the cast and use a helper class to perform a safe conversion to the type you desire. Technorati Tags: C#,.NET,Pitfalls,Little Pitfalls,BlackRabbitCoder

  Read the article

• Yet another blog about IValueConverter

  - by codingbloke

  After my previous blog on a Generic Boolean Value Converter I thought I might as well blog up another IValueConverter implementation that I use. The Generic Boolean Value Converter effectively converters an input which only has two possible values to one of two corresponding objects.  The next logical step would be to create a similar converter that can take an input which has multiple (but finite and discrete) values to one of multiple corresponding objects.  To put it more simply a Generic Enum Value Converter. Now we already have a tool that can help us in this area, the ResourceDictionary.  A simple IValueConverter implementation around it would create a StringToObjectConverter like so:- StringToObjectConverter using System; using System.Windows; using System.Windows.Data; using System.Linq; using System.Windows.Markup; namespace SilverlightApplication1 {     [ContentProperty("Items")]     public class StringToObjectConverter : IValueConverter     {         public ResourceDictionary Items { get; set; }         public string DefaultKey { get; set; }                  public StringToObjectConverter()         {             DefaultKey = "__default__";         }         public virtual object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)         {             if (value != null && Items.Contains(value.ToString()))                 return Items[value.ToString()];             else                 return Items[DefaultKey];         }         public virtual object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)         {             return Items.FirstOrDefault(kvp => value.Equals(kvp.Value)).Key;         }     } } There are some things to note here.  The bulk of managing the relationship between an object instance and the related string key is handled by the Items property being an ResourceDictionary.  Also there is a catch all “__default__” key value which allows for only a subset of the possible input values to mapped to an object with the rest falling through to the default. We can then set one of these up in Xaml:-             <local:StringToObjectConverter x:Key="StatusToBrush">                 <ResourceDictionary>                     <SolidColorBrush Color="Red" x:Key="Overdue" />                     <SolidColorBrush Color="Orange" x:Key="Urgent" />                     <SolidColorBrush Color="Silver" x:Key="__default__" />                 </ResourceDictionary>             </local:StringToObjectConverter> You could well imagine that in the model being bound these key names would actually be members of an enum.  This still works due to the use of ToString in the Convert method.  Hence the only requirement for the incoming object is that it has a ToString implementation which generates a sensible string instead of simply the type name. I can’t imagine right now a scenario where this converter would be used in a TwoWay binding but there is no reason why it can’t.  I prefer to avoid leaving the ConvertBack throwing an exception if that can be be avoided.  Hence it just enumerates the KeyValuePair entries to find a value that matches and returns the key its mapped to. Ah but now my sense of balance is assaulted again.  Whilst StringToObjectConverter is quite happy to accept an enum type via the Convert method it returns a string from the ConvertBack method not the original input enum type that arrived in the Convert.  Now I could address this by complicating the ConvertBack method and examining the targetType parameter etc.  However I prefer to a different approach, deriving a new EnumToObjectConverter class instead. EnumToObjectConverter using System; namespace SilverlightApplication1 {     public class EnumToObjectConverter : StringToObjectConverter     {         public override object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)         {             string key = Enum.GetName(value.GetType(), value);             return base.Convert(key, targetType, parameter, culture);         }         public override object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)         {             string key = (string)base.ConvertBack(value, typeof(String), parameter, culture);             return Enum.Parse(targetType, key, false);         }     } }   This is a more belts and braces solution with specific use of Enum.GetName and Enum.Parse.  Whilst its more explicit in that the a developer has to  choose to use it, it is only really necessary when using TwoWay binding, in OneWay binding the base StringToObjectConverter would serve just as well. The observant might note that there is actually no “Generic” aspect to this solution in the end.  The use of a ResourceDictionary eliminates the need for that.

  Read the article

• The design of a generic data synchronizer, or, an [object] that does [actions] with the aid of [helpers]

  - by acheong87

  I'd like to create a generic data-source "synchronizer," where data-source "types" may include MySQL databases, Google Spreadsheets documents, CSV files, among others. I've been trying to figure out how to structure this in terms of classes and interfaces, keeping in mind (what I've read about) composition vs. inheritance and is-a vs. has-a, but each route I go down seems to violate some principle. For simplicity, assume that all data-sources have a header-row-plus-data-rows format. For example, assume that the first rows of Google Spreadsheets documents and CSV files will have column headers, a.k.a. "fields" (to parallel database fields). Also, eventually, I would like to implement this in PHP, but avoiding language-specific discussion would probably be more productive. Here's an overview of what I've tried. Part 1/4: ISyncable class CMySQL implements ISyncable GetFields() // sql query, pdo statement, whatever AddFields() RemFields() ... _dbh class CGoogleSpreadsheets implements ISyncable GetFields() // zend gdata api AddFields() RemFields() ... _spreadsheetKey _worksheetId class CCsvFile implements ISyncable GetFields() // read from buffer AddFields() RemFields() ... _buffer interface ISyncable GetFields() AddFields($field1, $field2, ...) RemFields($field1, $field2, ...) ... CanAddFields() // maybe the spreadsheet is locked for write, or CanRemFields() // maybe no permission to alter a database table ... AddRow() ModRow() RemRow() ... Open() Close() ... First Question: Does it make sense to use an interface, as above? Part 2/4: CSyncer Next, the thing that does the syncing. class CSyncer __construct(ISyncable $A, ISyncable $B) Push() // sync A to B Pull() // sync B to A Sync() // Push() and Pull() only differ in direction; factor. // Sync()'s job is to make sure that the fields on each side // match, to add fields where appropriate and possible, to // account for different column-orderings, etc., and of // course, to add and remove rows as necessary to sync. ... _A _B Second Question: Does it make sense to define such a class, or am I treading dangerously close to the "Kingdom of Nouns"? Part 3/4: CTranslator? ITranslator? Now, here's where I actually get lost, assuming the above is passable. Sometimes, two ISyncables speak different "dialects." For example, believe it or not, Google Spreadsheets (accessed through the Google Data API "list feed") returns column headers lower-cased and stripped of all spaces and symbols! That is, sys_TIMESTAMP is systimestamp, as far as my code can tell. (Yes, I am aware that the "cell feed" does not strip the name so; however cell-by-cell manipulation is too slow for what I'm doing.) One can imagine other hypothetical examples. Perhaps even the data itself can be in different "dialects." But let's take it as given for now, and not argue this if possible. Third Question: How would you implement "translation"? Note: Taking all this as an exercise, I'm more interested in the "idealized" design, rather than the practical one. (God knows that shipped sailed when I began this project.) Part 4/4: Further Thought Here's my train of thought to demonstrate I've thunk, albeit unfruitfully: First, I thought, primitively, "I'll just modify CMySQL::GetFields() to lower-case and strip field names so they're compatible with Google Spreadsheets." But of course, then my class should really be called, CMySQLForGoogleSpreadsheets, and that can't be right. So, the thing which translates must exist outside of an ISyncable implementor. And surely it can't be right to make each translation a method in CSyncer. If it exists outside of both ISyncable and CSyncer, then what is it? (Is it even an "it"?) Is it an abstract class, i.e. abstract CTranslator? Is it an interface, since a translator only does, not has, i.e. interface ITranslator? Does it even require instantiation? e.g. If it's an ITranslator, then should its translation methods be static? (I learned what "late static binding" meant, today.) And, dear God, whatever it is, how should a CSyncer use it? Does it "have" it? Is it, "it"? Who am I? ...am I, "I"? I've attempted to break up the question into sub-questions, but essentially my question is singular: How does one implement an object A that conceptually "links" (has) two objects b1 and b2 that share a common interface B, where certain pairs of b1 and b2 require a helper, e.g. a translator, to be handled by A? Something tells me that I've overcomplicated this design, or violated a principle much higher up. Thank you all very much for your time and any advice you can provide.

  Read the article

• Do I need to store a generic rotation point/radius for rotating around a point other than the origin for object transforms?

  - by Casey

  I'm having trouble implementing a non-origin point rotation. I have a class Transform that stores each component separately in three 3D vectors for position, scale, and rotation. This is fine for local rotations based on the center of the object. The issue is how do I determine/concatenate non-origin rotations in addition to origin rotations. Normally this would be achieved as a Transform-Rotate-Transform for the center rotation followed by a Transform-Rotate-Transform for the non-origin point. The problem is because I am storing the individual components, the final Transform matrix is not calculated until needed by using the individual components to fill an appropriate Matrix. (See GetLocalTransform()) Do I need to store an additional rotation (and radius) for world rotations as well or is there a method of implementation that works while only using the single rotation value? Transform.h #ifndef A2DE_CTRANSFORM_H #define A2DE_CTRANSFORM_H #include "../a2de_vals.h" #include "CMatrix4x4.h" #include "CVector3D.h" #include <vector> A2DE_BEGIN class Transform { public: Transform(); Transform(Transform* parent); Transform(const Transform& other); Transform& operator=(const Transform& rhs); virtual ~Transform(); void SetParent(Transform* parent); void AddChild(Transform* child); void RemoveChild(Transform* child); Transform* FirstChild(); Transform* LastChild(); Transform* NextChild(); Transform* PreviousChild(); Transform* GetChild(std::size_t index); std::size_t GetChildCount() const; std::size_t GetChildCount(); void SetPosition(const a2de::Vector3D& position); const a2de::Vector3D& GetPosition() const; a2de::Vector3D& GetPosition(); void SetRotation(const a2de::Vector3D& rotation); const a2de::Vector3D& GetRotation() const; a2de::Vector3D& GetRotation(); void SetScale(const a2de::Vector3D& scale); const a2de::Vector3D& GetScale() const; a2de::Vector3D& GetScale(); a2de::Matrix4x4 GetLocalTransform() const; a2de::Matrix4x4 GetLocalTransform(); protected: private: a2de::Vector3D _position; a2de::Vector3D _scale; a2de::Vector3D _rotation; std::size_t _curChildIndex; Transform* _parent; std::vector<Transform*> _children; }; A2DE_END #endif Transform.cpp #include "CTransform.h" #include "CVector2D.h" #include "CVector4D.h" A2DE_BEGIN Transform::Transform() : _position(), _scale(1.0, 1.0), _rotation(), _curChildIndex(0), _parent(nullptr), _children() { /* DO NOTHING */ } Transform::Transform(Transform* parent) : _position(), _scale(1.0, 1.0), _rotation(), _curChildIndex(0), _parent(parent), _children() { /* DO NOTHING */ } Transform::Transform(const Transform& other) : _position(other._position), _scale(other._scale), _rotation(other._rotation), _curChildIndex(0), _parent(other._parent), _children(other._children) { /* DO NOTHING */ } Transform& Transform::operator=(const Transform& rhs) { if(this == &rhs) return *this; this->_position = rhs._position; this->_scale = rhs._scale; this->_rotation = rhs._rotation; this->_curChildIndex = 0; this->_parent = rhs._parent; this->_children = rhs._children; return *this; } Transform::~Transform() { _children.clear(); _parent = nullptr; } void Transform::SetParent(Transform* parent) { _parent = parent; } void Transform::AddChild(Transform* child) { if(child == nullptr) return; _children.push_back(child); } void Transform::RemoveChild(Transform* child) { if(_children.empty()) return; _children.erase(std::remove(_children.begin(), _children.end(), child), _children.end()); } Transform* Transform::FirstChild() { if(_children.empty()) return nullptr; return *(_children.begin()); } Transform* Transform::LastChild() { if(_children.empty()) return nullptr; return *(_children.end()); } Transform* Transform::NextChild() { if(_children.empty()) return nullptr; std::size_t s(_children.size()); if(_curChildIndex >= s) { _curChildIndex = s; return nullptr; } return _children[_curChildIndex++]; } Transform* Transform::PreviousChild() { if(_children.empty()) return nullptr; if(_curChildIndex == 0) { return nullptr; } return _children[_curChildIndex--]; } Transform* Transform::GetChild(std::size_t index) { if(_children.empty()) return nullptr; if(index > _children.size()) return nullptr; return _children[index]; } std::size_t Transform::GetChildCount() const { if(_children.empty()) return 0; return _children.size(); } std::size_t Transform::GetChildCount() { return static_cast<const Transform&>(*this).GetChildCount(); } void Transform::SetPosition(const a2de::Vector3D& position) { _position = position; } const a2de::Vector3D& Transform::GetPosition() const { return _position; } a2de::Vector3D& Transform::GetPosition() { return const_cast<a2de::Vector3D&>(static_cast<const Transform&>(*this).GetPosition()); } void Transform::SetRotation(const a2de::Vector3D& rotation) { _rotation = rotation; } const a2de::Vector3D& Transform::GetRotation() const { return _rotation; } a2de::Vector3D& Transform::GetRotation() { return const_cast<a2de::Vector3D&>(static_cast<const Transform&>(*this).GetRotation()); } void Transform::SetScale(const a2de::Vector3D& scale) { _scale = scale; } const a2de::Vector3D& Transform::GetScale() const { return _scale; } a2de::Vector3D& Transform::GetScale() { return const_cast<a2de::Vector3D&>(static_cast<const Transform&>(*this).GetScale()); } a2de::Matrix4x4 Transform::GetLocalTransform() const { Matrix4x4 p((_parent ? _parent->GetLocalTransform() : a2de::Matrix4x4::GetIdentity())); Matrix4x4 t(a2de::Matrix4x4::GetTranslationMatrix(_position)); Matrix4x4 r(a2de::Matrix4x4::GetRotationMatrix(_rotation)); Matrix4x4 s(a2de::Matrix4x4::GetScaleMatrix(_scale)); return (p * t * r * s); } a2de::Matrix4x4 Transform::GetLocalTransform() { return static_cast<const Transform&>(*this).GetLocalTransform(); } A2DE_END

  Read the article

• How to follow object on CatmullRomSplines at constant speed (e.g. train and train carriage)?

  - by Simon

  I have a CatmullRomSpline, and using the very good example at https://github.com/libgdx/libgdx/wiki/Path-interface-%26-Splines I have my object moving at an even pace over the spline. Using a simple train and carriage example, I now want to have the carriage follow the train at the same speed as the train (not jolting along as it does with my code below). This leads into my main questions: How can I make the carriage have the same constant speed as the train and make it non jerky (it has something to do with the derivative I think, I don't understand how that part works)? Why do I need to divide by the line length to convert to metres per second, and is that correct? It wasn't done in the linked examples? I have used the example I linked to above, and modified for my specific example: private void process(CatmullRomSpline catmullRomSpline) { // Render path with precision of 1000 points renderPath(catmullRomSpline, 1000); float length = catmullRomSpline.approxLength(catmullRomSpline.spanCount * 1000); // Render the "train" Vector2 trainDerivative = new Vector2(); Vector2 trainLocation = new Vector2(); catmullRomSpline.derivativeAt(trainDerivative, current); // For some reason need to divide by length to convert from pixel speed to metres per second but I do not // really understand why I need it, it wasn't done in the examples??????? current += (Gdx.graphics.getDeltaTime() * speed / length) / trainDerivative.len(); catmullRomSpline.valueAt(trainLocation, current); renderCircleAtLocation(trainLocation); if (current >= 1) { current -= 1; } // Render the "carriage" Vector2 carriageLocation = new Vector2(); float carriagePercentageCovered = (((current * length) - 1f) / length); // I would like it to follow at 1 metre behind carriagePercentageCovered = Math.max(carriagePercentageCovered, 0); catmullRomSpline.valueAt(carriageLocation, carriagePercentageCovered); renderCircleAtLocation(carriageLocation); } private void renderPath(CatmullRomSpline catmullRomSpline, int k) { // catMulPoints would normally be cached when initialising, but for sake of example... Vector2[] catMulPoints = new Vector2[k]; for (int i = 0; i < k; ++i) { catMulPoints[i] = new Vector2(); catmullRomSpline.valueAt(catMulPoints[i], ((float) i) / ((float) k - 1)); } SHAPE_RENDERER.begin(ShapeRenderer.ShapeType.Line); SHAPE_RENDERER.setColor(Color.NAVY); for (int i = 0; i < k - 1; ++i) { SHAPE_RENDERER.line((Vector2) catMulPoints[i], (Vector2) catMulPoints[i + 1]); } SHAPE_RENDERER.end(); } private void renderCircleAtLocation(Vector2 location) { SHAPE_RENDERER.begin(ShapeRenderer.ShapeType.Filled); SHAPE_RENDERER.setColor(Color.YELLOW); SHAPE_RENDERER.circle(location.x, location.y, .5f); SHAPE_RENDERER.end(); } To create a decent sized CatmullRomSpline for testing this out: Vector2[] controlPoints = makeControlPointsArray(); CatmullRomSpline myCatmull = new CatmullRomSpline(controlPoints, false); .... private Vector2[] makeControlPointsArray() { Vector2[] pointsArray = new Vector2[78]; pointsArray[0] = new Vector2(1.681817f, 10.379999f); pointsArray[1] = new Vector2(2.045455f, 10.379999f); pointsArray[2] = new Vector2(2.663636f, 10.479999f); pointsArray[3] = new Vector2(3.027272f, 10.700000f); pointsArray[4] = new Vector2(3.663636f, 10.939999f); pointsArray[5] = new Vector2(4.245455f, 10.899999f); pointsArray[6] = new Vector2(4.736363f, 10.720000f); pointsArray[7] = new Vector2(4.754545f, 10.339999f); pointsArray[8] = new Vector2(4.518181f, 9.860000f); pointsArray[9] = new Vector2(3.790908f, 9.340000f); pointsArray[10] = new Vector2(3.172727f, 8.739999f); pointsArray[11] = new Vector2(3.300000f, 8.340000f); pointsArray[12] = new Vector2(3.700000f, 8.159999f); pointsArray[13] = new Vector2(4.227272f, 8.520000f); pointsArray[14] = new Vector2(4.681818f, 8.819999f); pointsArray[15] = new Vector2(5.081817f, 9.200000f); pointsArray[16] = new Vector2(5.463636f, 9.460000f); pointsArray[17] = new Vector2(5.972727f, 9.300000f); pointsArray[18] = new Vector2(6.063636f, 8.780000f); pointsArray[19] = new Vector2(6.027272f, 8.259999f); pointsArray[20] = new Vector2(5.700000f, 7.739999f); pointsArray[21] = new Vector2(5.300000f, 7.440000f); pointsArray[22] = new Vector2(4.645454f, 7.179999f); pointsArray[23] = new Vector2(4.136363f, 6.940000f); pointsArray[24] = new Vector2(3.427272f, 6.720000f); pointsArray[25] = new Vector2(2.572727f, 6.559999f); pointsArray[26] = new Vector2(1.900000f, 7.100000f); pointsArray[27] = new Vector2(2.336362f, 7.440000f); pointsArray[28] = new Vector2(2.590908f, 7.940000f); pointsArray[29] = new Vector2(2.318181f, 8.500000f); pointsArray[30] = new Vector2(1.663636f, 8.599999f); pointsArray[31] = new Vector2(1.209090f, 8.299999f); pointsArray[32] = new Vector2(1.118181f, 7.700000f); pointsArray[33] = new Vector2(1.045455f, 6.880000f); pointsArray[34] = new Vector2(1.154545f, 6.100000f); pointsArray[35] = new Vector2(1.281817f, 5.580000f); pointsArray[36] = new Vector2(1.700000f, 5.320000f); pointsArray[37] = new Vector2(2.190908f, 5.199999f); pointsArray[38] = new Vector2(2.900000f, 5.100000f); pointsArray[39] = new Vector2(3.700000f, 5.100000f); pointsArray[40] = new Vector2(4.372727f, 5.220000f); pointsArray[41] = new Vector2(4.827272f, 5.220000f); pointsArray[42] = new Vector2(5.463636f, 5.160000f); pointsArray[43] = new Vector2(5.554545f, 4.700000f); pointsArray[44] = new Vector2(5.245453f, 4.340000f); pointsArray[45] = new Vector2(4.445455f, 4.280000f); pointsArray[46] = new Vector2(3.609091f, 4.260000f); pointsArray[47] = new Vector2(2.718181f, 4.160000f); pointsArray[48] = new Vector2(1.990908f, 4.140000f); pointsArray[49] = new Vector2(1.427272f, 3.980000f); pointsArray[50] = new Vector2(1.609090f, 3.580000f); pointsArray[51] = new Vector2(2.136363f, 3.440000f); pointsArray[52] = new Vector2(3.227272f, 3.280000f); pointsArray[53] = new Vector2(3.972727f, 3.340000f); pointsArray[54] = new Vector2(5.027272f, 3.360000f); pointsArray[55] = new Vector2(5.718181f, 3.460000f); pointsArray[56] = new Vector2(6.100000f, 4.240000f); pointsArray[57] = new Vector2(6.209091f, 4.500000f); pointsArray[58] = new Vector2(6.118181f, 5.320000f); pointsArray[59] = new Vector2(5.772727f, 5.920000f); pointsArray[60] = new Vector2(4.881817f, 6.140000f); pointsArray[61] = new Vector2(5.318181f, 6.580000f); pointsArray[62] = new Vector2(6.263636f, 7.020000f); pointsArray[63] = new Vector2(6.645453f, 7.420000f); pointsArray[64] = new Vector2(6.681817f, 8.179999f); pointsArray[65] = new Vector2(6.627272f, 9.080000f); pointsArray[66] = new Vector2(6.572727f, 9.699999f); pointsArray[67] = new Vector2(6.263636f, 10.820000f); pointsArray[68] = new Vector2(5.754546f, 11.479999f); pointsArray[69] = new Vector2(4.536363f, 11.599998f); pointsArray[70] = new Vector2(3.572727f, 11.700000f); pointsArray[71] = new Vector2(2.809090f, 11.660000f); pointsArray[72] = new Vector2(1.445455f, 11.559999f); pointsArray[73] = new Vector2(0.936363f, 11.280000f); pointsArray[74] = new Vector2(0.754545f, 10.879999f); pointsArray[75] = new Vector2(0.700000f, 9.939999f); pointsArray[76] = new Vector2(0.918181f, 9.620000f); pointsArray[77] = new Vector2(1.463636f, 9.600000f); return pointsArray; } Disclaimer: My math is very rusty, so please explain in lay mans terms....

  Read the article

• Using IOperationBehavior to supply a WCF parameter

  - by Chris Kemp

  This is my first step into the world of stackoverflow, so apologies if I cock anything up. I'm trying to create a WCF Operation which has a parameter that is not exposed to the outside world, but is instead automatically passed into the function. So the world sees this: int Add(int a, int b) But it is implemented as: int Add(object context, int a, int b) Then, the context gets supplied by the system at run-time. The example I'm working with is completely artificial, but mimics something that I'm looking into in a real-world scenario. I'm able to get close, but not quite the whole way there. First off, I created a simple method and wrote an application to confirm it works. It does. It returns a + b and writes the context as a string to my debug. Yay. [OperationContract] int Add(object context, int a, int b); I then wrote the following code: public class SupplyContextAttribute : Attribute, IOperationBehavior { public void Validate(OperationDescription operationDescription) { if (!operationDescription.Messages.Any(m => m.Body.Parts.First().Name == "context")) throw new FaultException("Parameter 'context' is missing."); } public void ApplyDispatchBehavior(OperationDescription operationDescription, DispatchOperation dispatchOperation) { dispatchOperation.Invoker = new SupplyContextInvoker(dispatchOperation.Invoker); } public void ApplyClientBehavior(OperationDescription operationDescription, ClientOperation clientOperation) { } public void AddBindingParameters(OperationDescription operationDescription, BindingParameterCollection bindingParameters) { // Remove the 'context' parameter from the inbound message operationDescription.Messages[0].Body.Parts.RemoveAt(0); } } public class SupplyContextInvoker : IOperationInvoker { readonly IOperationInvoker _invoker; public SupplyContextInvoker(IOperationInvoker invoker) { _invoker = invoker; } public object[] AllocateInputs() { return _invoker.AllocateInputs().Skip(1).ToArray(); } private object[] IntroduceContext(object[] inputs) { return new[] { "MyContext" }.Concat(inputs).ToArray(); } public object Invoke(object instance, object[] inputs, out object[] outputs) { return _invoker.Invoke(instance, IntroduceContext(inputs), out outputs); } public IAsyncResult InvokeBegin(object instance, object[] inputs, AsyncCallback callback, object state) { return _invoker.InvokeBegin(instance, IntroduceContext(inputs), callback, state); } public object InvokeEnd(object instance, out object[] outputs, IAsyncResult result) { return _invoker.InvokeEnd(instance, out outputs, result); } public bool IsSynchronous { get { return _invoker.IsSynchronous; } } } And my WCF operation now looks like this: [OperationContract, SupplyContext] int Amend(object context, int a, int b); My updated references no longer show the 'context' parameter, which is exactly what I want. The trouble is that whenver I run the code, it gets past the AllocateInputs and then throws an Index was outside the bounds of the Array. error somewhere in the WCF guts. I've tried other things, and I find that I can successfully change the type of the parameter and rename it and have my code work. But the moment I remove the parameter it falls over. Can anyone give me some idea of how to get this to work (or if it can be done at all).

  Read the article

• ODI 11g – Insight to the SDK

  - by David Allan

  This post is a useful index into the ODI SDK that cross references the type names from the user interface with the SDK class and also the finder for how to get a handle on the object or objects. The volume of content in the SDK might seem a little ominous, there is a lot there, but there is a general pattern to the SDK that I will describe here. Also I will illustrate some basic CRUD operations so you can see how the SDK usage pattern works. The examples are written in groovy, you can simply run from the groovy console in ODI 11.1.1.6. Entry to the Platform   Object Finder SDK odiInstance odiInstance (groovy variable for console) OdiInstance Topology Objects Object Finder SDK Technology IOdiTechnologyFinder OdiTechnology Context IOdiContextFinder OdiContext Logical Schema IOdiLogicalSchemaFinder OdiLogicalSchema Data Server IOdiDataServerFinder OdiDataServer Physical Schema IOdiPhysicalSchemaFinder OdiPhysicalSchema Logical Schema to Physical Mapping IOdiContextualSchemaMappingFinder OdiContextualSchemaMapping Logical Agent IOdiLogicalAgentFinder OdiLogicalAgent Physical Agent IOdiPhysicalAgentFinder OdiPhysicalAgent Logical Agent to Physical Mapping IOdiContextualAgentMappingFinder OdiContextualAgentMapping Master Repository IOdiMasterRepositoryInfoFinder OdiMasterRepositoryInfo Work Repository IOdiWorkRepositoryInfoFinder OdiWorkRepositoryInfo Project Objects Object Finder SDK Project IOdiProjectFinder OdiProject Folder IOdiFolderFinder OdiFolder Interface IOdiInterfaceFinder OdiInterface Package IOdiPackageFinder OdiPackage Procedure IOdiUserProcedureFinder OdiUserProcedure User Function IOdiUserFunctionFinder OdiUserFunction Variable IOdiVariableFinder OdiVariable Sequence IOdiSequenceFinder OdiSequence KM IOdiKMFinder OdiKM Load Plans and Scenarios   Object Finder SDK Load Plan IOdiLoadPlanFinder OdiLoadPlan Load Plan and Scenario Folder IOdiScenarioFolderFinder OdiScenarioFolder Model Objects Object Finder SDK Model IOdiModelFinder OdiModel Sub Model IOdiSubModel OdiSubModel DataStore IOdiDataStoreFinder OdiDataStore Column IOdiColumnFinder OdiColumn Key IOdiKeyFinder OdiKey Condition IOdiConditionFinder OdiCondition Operator Objects   Object Finder SDK Session Folder IOdiSessionFolderFinder OdiSessionFolder Session IOdiSessionFinder OdiSession Schedule OdiSchedule How to Create an Object? Here is a simple example to create a project, it uses IOdiEntityManager.persist to persist the object. import oracle.odi.domain.project.OdiProject; import oracle.odi.core.persistence.transaction.support.DefaultTransactionDefinition; txnDef = new DefaultTransactionDefinition(); tm = odiInstance.getTransactionManager() txnStatus = tm.getTransaction(txnDef) project = new OdiProject("Project For Demo", "PROJECT_DEMO") odiInstance.getTransactionalEntityManager().persist(project) tm.commit(txnStatus) How to Update an Object? This update example uses the methods on the OdiProject object to change the project’s name that was created above, it is then persisted. import oracle.odi.domain.project.OdiProject; import oracle.odi.domain.project.finder.IOdiProjectFinder; import oracle.odi.core.persistence.transaction.support.DefaultTransactionDefinition; txnDef = new DefaultTransactionDefinition(); tm = odiInstance.getTransactionManager() txnStatus = tm.getTransaction(txnDef) prjFinder = (IOdiProjectFinder)odiInstance.getTransactionalEntityManager().getFinder(OdiProject.class); project = prjFinder.findByCode("PROJECT_DEMO"); project.setName("A Demo Project"); odiInstance.getTransactionalEntityManager().persist(project) tm.commit(txnStatus) How to Delete an Object? Here is a simple example to delete all of the sessions, it uses IOdiEntityManager.remove to delete the object. import oracle.odi.domain.runtime.session.finder.IOdiSessionFinder; import oracle.odi.domain.runtime.session.OdiSession; import oracle.odi.core.persistence.transaction.support.DefaultTransactionDefinition; txnDef = new DefaultTransactionDefinition(); tm = odiInstance.getTransactionManager() txnStatus = tm.getTransaction(txnDef) sessFinder = (IOdiSessionFinder)odiInstance.getTransactionalEntityManager().getFinder(OdiSession.class); sessc = sessFinder.findAll(); sessItr = sessc.iterator() while (sessItr.hasNext()) {   sess = (OdiSession) sessItr.next()   odiInstance.getTransactionalEntityManager().remove(sess) } tm.commit(txnStatus) This isn't an all encompassing summary of the SDK, but covers a lot of the content to give you a good handle on the objects and how they work. For details of how specific complex objects are created via the SDK, its best to look at postings such as the interface builder posting here. Have fun, happy coding!

  Read the article

• using ‘using’ and scope. Not try finally!

  - by Edward Boyle

  An object that implements IDisposable has, you guessed it, a Dispose() method. In the code you write you should both declare and instantiate any object that implements IDisposable with the using statement. The using statement allows you to set the scope of an object and when your code exits that scope, the object will be disposed of. Note that when an exception occurs, this will pull your code out of scope, so it still forces a Dispose() using (mObject o = new mObject()) { // do stuff } //<- out of Scope, object is disposed. // Note that you can also use multiple objects using // the using statement if of the same type: using (mObject o = new mObject(), o2 = new mObject(), o3 = new mObject()) { // do stuff } //<- out of Scope, objects are disposed. What about try{ }finally{}? It is not needed when you use the using statement. Additionally, using is preferred, Microsoft’s own documents put it this way: As a rule, when you use an IDisposable object, you should declare and instantiate it in a using statement. When I started out in .NET I had a very bad habit of not using the using statement. As a result I ran into what many developers do: #region BAD CODE - DO NOT DO try { mObject o = new mObject(); //do stuff } finally { o.Dispose(); // error - o is out of scope, no such object. } // and here is what I find on blogs all over the place as a solution // pox upon them for creating bad habits. mObject o = new mObject(); try { //do stuff } finally { o.Dispose(); } #endregion So when should I use the using statement? Very simple rule, if an object implements IDisposable, use it. This of course does not apply if the object is going to be used as a global object outside of a method. If that is the case, don’t forget to dispose of the object in code somewhere. It should be made clear that using the try{}finally{} code block is not going to break your code, nor cause memory leaks. It is perfectly acceptable coding practice, just not best coding practice in C#. This is how VB.NET developers must code, as there is no using equivalent for them to use.

  Read the article

• Database design and performance impact

  - by Craige

  I have a database design issue that I'm not quite sure how to approach, nor if the benefits out weigh the costs. I'm hoping some P.SE members can give some feedback on my suggested design, as well as any similar experiences they may have came across. As it goes, I am building an application that has large reporting demands. Speed is an important issue, as there will be peak usages throughout the year. This application/database has a multiple-level, many-to-many relationship. eg object a object b object c object d object b has relationship to object a object c has relationship to object b, a object d has relationship to object c, b, a Theoretically, this could go on for unlimited levels, though logic dictates it could only go so far. My idea here, to speed up reporting, would be to create a syndicate table that acts as a global many-to-many join table. In this table (with the given example), one might see: +----------+-----------+---------+ | child_id | parent_id | type_id | +----------+-----------+---------+ | b | a | 1 | | c | b | 2 | | c | a | 3 | | d | c | 4 | | d | b | 5 | | d | a | 6 | +----------+-----------+---------+ Where a, b, c and d would translate to their respective ID's in their respective tables. So, for ease of reporting all of a which exist on object d, one could query SELECT * FROM `syndicates` ... JOINS TO child and parent tables ... WHERE parent_id=a and type_id=6; rather than having a query with a join to each level up the chain. The Problem This table grows exponentially, and in a given year, could easily grow past 20,000 records for one client. Given multiple clients over multiple years, this table will VERY quickly explode to millions of records and beyond. Now, the database will, in time, be partitioned across multiple servers, but I would like (as most would) to keep the number of servers as low as possible while still offering flexibility. Also writes and updates would be exponentially longer (though possibly not noticeable to the end user) as there would be multiple inserts/updates/scans on this table to keep it in sync. Am I going in the right direction here, or am I way off track. What would you do in a similar situation? This solution seems overly complex, but allows the greatest flexibility and fastest read-operations. Sidenote 1 - This structure allows me to add new levels to the tree easily. Sidenote 2 - The database querying for this database is done through an ORM framework.

  Read the article

• SharePoint 2010 Data Retrival Techinques

  - by Jayant Sharma

  In SharePoint, we have two options to perform CRUD operation.1. using server side code2. using client side codeusing server side code, we have 1. CAML2. LINQusing client side code, we have 1. Client Object Model    1.1.      Managed Client Object Model     1.2.     Silverlight Client Object Model    1.3.     ECMA Client Object Model2. SharePoint Web Services3. ADO Data Service (based on REST Web Services)4. Using RPC Call (owssvr.dll)Which and when these options are used depend upon requirements. Every options are certain advantages and disadvantages. So, before start development of any new sharepoint project, it is important to understand the limitations of different methods.Server Object Model is used when our application is host on the same server on which sharepoint is installed. while Client Side code is used to access sharepoint from client system. In SharePoint 2010 specially Client Object Model (COM) are introduced to perform the sharepoint operations from client system. Advantage of CAML:    -  It is fast.    -  Can be use it from all kind of technology like Silverlight, or Jquery    -  You can use U2U CAML Query builder to generate CAML Query.Disadvantage Of CAML:    - Error Prone, as we can detect the error only at runtimeAdvantage of LINQ:    -  Object Oriented technique (Object Relation Model)    -  LINQ  to SharePoint provider are working with Strongly Type List Item Objects, So intellisence are present at runtime    -  No need of knowledge of CAML    -  Less Error Prone as it as it uses C# syntex.    -  You can compare two Fields of SharePoint ListDisadvantage Of LINQ:    -  List Attachment is not supported in SPMetal Tool    -  Created By, Created, Modified and Modified By Fields are not created by SPMetal Tool.    -  Custom fields are not created by SPMetal Tools    -  External Lists are not supported    -  Though at backend LINQ genenates CAML Query so it is slower than directly using CAML in Code.  Advantage of Client Object Model    -  Used to access sharepoint from client system    -  No WebServer is required at Client End    - Can use Silverlight and JavaScripts to make better and fast User experienceDisadvantage of Client Object Model    -  You cannot use RunwithEleveatedPrivilege    - Cross Site Collection query are not possible    - Lesser API's are availableADO.Net Data Services:    -  Only List based operations are possible, other type of operations are not possible.SharePoint Web Services and RPC Call:    - Previously it was used in SharePoint 2007 but after the introduction  of Client Object Model,  Microsoft recommends not to use Web Services to fetch data from SharePoint. In SharePoint 2010 it is avaliable only for backward compatibility.Ref: http://msdn.microsoft.com/en-us/library/ee539764Jayant Sharma

  Read the article

• Creating a Yes/No MessageBox in a NuGet install/uninstall script

  - by ParadigmShift

  Sometimes getting a little feedback during the install/uninstall process of a NuGet package could be really useful. Instead of accounting for all possible ways to install your NuGet package for every user, you can simplify the installation by clarifying with the user what they want. This example shows how to generate a windows yes/no message box to get input from the user in the PowerShell install or uninstall script. We’ll use the prompt on the uninstall to confirm if the user wants to delete a custom setting that the initial install placed in their configuration.  Obviously you could use the prompt in any way you want. The objects of the message box are generated similar to the controls in the code behind of a WinForm. At the beginning of your script enter this: param($installPath, $toolsPath, $package, $project)   # Set up path variables $solutionDir = Get-SolutionDir $projectName = (Get-Project).ProjectName $projectPath = Join-Path $solutionDir $projectName   ################################################################################################ # WinForm generation for prompt ################################################################################################ function Ask-Delete-Custom-Settings { [void][reflection.assembly]::loadwithpartialname("System.Windows.Forms") [Void][reflection.assembly]::loadwithpartialname("System.Drawing")   $title = "Package Uninstall" $message = "Delete the customized settings?" #Create form and controls $form1 = New-Object System.Windows.Forms.Form $label1 = New-Object System.Windows.Forms.Label $btnYes = New-Object System.Windows.Forms.Button $btnNo = New-Object System.Windows.Forms.Button   #Set properties of controls and form ############ # label1 # ############ $label1.Location = New-Object System.Drawing.Point(12,9) $label1.Name = "label1" $label1.Size = New-Object System.Drawing.Size(254,17) $label1.TabIndex = 0 $label1.Text = $message   ############# # btnYes # ############# $btnYes.Location = New-Object System.Drawing.Point(156,45) $btnYes.Name = "btnYes" $btnYes.Size = New-Object System.Drawing.Size(48,25) $btnYes.TabIndex = 1 $btnYes.Text = "Yes"   ########### # btnNo # ########### $btnNo.Location = New-Object System.Drawing.Point(210,45) $btnNo.Name = "btnNo" $btnNo.Size = New-Object System.Drawing.Size(48,25) $btnNo.TabIndex = 2 $btnNo.Text = "No"   ########### # form1 # ########### $form1.ClientSize = New-Object System.Drawing.Size(281,86) $form1.Controls.Add($label1) $form1.Controls.Add($btnYes) $form1.Controls.Add($btnNo) $form1.Name = "Form1" $form1.Text = $title #Event Handler $btnYes.add_Click({btnYes_Click}) $btnNo.add_Click({btnNo_Click}) return $form1.ShowDialog() } function btnYes_Click { #6 = Yes $form1.DialogResult = 6 } function btnNo_Click { #7 = No $form1.DialogResult = 7 } ################################################################################################ This has also wired up the click events to the form.  This is all it takes to create the message box. Now we have to actually use the message box and get the user’s response or this is all pointless.  We’ll then delete the section of the application/web configuration called <Custom.Settings> [xml] $configXmlContent = Get-Content $configFile   Write-Host "Please respond to the question in the Dialog Box." $dialogResult = Ask-Delete-Custom-Settings #6 = Yes #7 = No Write-Host "dialogResult = $dialogResult" if ($dialogResult.ToString() -eq "Yes") { Write-Host "Deleting customized settings" $customSettingsNode = $configXmlContent.configuration.Item("Custom.Settings") $configXmlContent.configuration.RemoveChild($customSettingsNode) $configXmlContent.Save($configFile) } if ($dialogResult.ToString() -eq "No") { Write-Host "Do not delete customized settings" } The part where I check if ($dialog.Result.ToString() –eq “Yes”) could just as easily check the value for either 6 or 7 (Yes or No).  I just personally decided I liked this way better.   Shahzad Qureshi is a Software Engineer and Consultant in Salt Lake City, Utah, USA His certifications include: Microsoft Certified System Engineer 3CX Certified Partner Global Information Assurance Certification – Secure Software Programmer – .NET He is the owner of Utah VoIP Store at http://www.utahvoipstore.com/ and SWS Development at http://www.swsdev.com/ and publishes windows apps under the name Blue Voice.

  Read the article

• WPF Designer has bug with parsing generic control with overrided property

  - by Ivan Laktyunkin

  I've created a generic lookless control with virtual property: public abstract class TestControlBase<TValue> : Control { public static readonly DependencyProperty ValueProperty; static TestControlBase() { ValueProperty = DependencyProperty.Register("Value", typeof(TValue), typeof(TestControlBase<TValue>)); } protected TestControlBase() { Focusable = false; Value = default(TValue); } public virtual TValue Value { get { return (TValue)GetValue(ValueProperty); } set { SetValue(ValueProperty, value); } } } Then I've made a control derived from it and overrided Value property: public class TestControl : TestControlBase<int> { public override int Value { get { return base.Value; } set { base.Value = value; } } } So I use it in a Window XAML: <TestControls:TestControl /> When I open window in designer all is OK, but when I put mouse cursor to this line, or to this control in designer I receive exception: Exception has been thrown by the target of an invocation. at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) at System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks) at System.Delegate.DynamicInvokeImpl(Object[] args) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) Ambiguous match found. at System.RuntimeType.GetPropertyImpl(String name, BindingFlags bindingAttr, Binder binder, Type returnType, Type[] types, ParameterModifier[] modifiers) at System.Type.GetProperty(String name) at MS.Internal.ComponentModel.DependencyPropertyKind.get_IsDirect() at MS.Internal.ComponentModel.DependencyPropertyKind.get_IsAttached() at MS.Internal.ComponentModel.APCustomTypeDescriptor.GetProperties(Attribute[] attributes) at MS.Internal.ComponentModel.APCustomTypeDescriptor.GetProperties() at System.ComponentModel.TypeDescriptor.TypeDescriptionNode.DefaultExtendedTypeDescriptor.System.ComponentModel.ICustomTypeDescriptor.GetProperties() at System.ComponentModel.TypeDescriptor.GetPropertiesImpl(Object component, Attribute[] attributes, Boolean noCustomTypeDesc, Boolean noAttributes) at System.ComponentModel.TypeDescriptor.GetProperties(Object component) at MS.Internal.Model.ModelPropertyCollectionImpl.GetProperties(String propertyNameHint) at MS.Internal.Model.ModelPropertyCollectionImpl.<GetEnumerator>d__0.MoveNext() at MS.Internal.Designer.PropertyEditing.Model.ModelPropertyMerger.<GetFirstProperties>d__0.MoveNext() at MS.Internal.Designer.PropertyEditing.PropertyInspector.UpdateCategories(Selection selection) at MS.Internal.Designer.PropertyEditing.PropertyInspector.OnSelectionChangedIdle() Who know this problem? Please explain :) I have no ideas except that WPF Designer doesn't like generics. If I replace generics by Object all is OK.

  Read the article

• Why is my code returning a Null Object Refrence error when using WatIn?

  - by Fuzz Evans

  I keep getting a Null Object Refrence Error, but can't tell why. I have a CSV file that contains 100 urls. The file is read into an array called "lines". public partial class Form1 : System.Windows.Forms.Form { string[] lines; public Form1() ... private void ReadLinksIntoMemory() { //this reads the chosen csv file into our "lines" array //and splits on comma's and new lines to create new objects within the array using (StreamReader sr = new StreamReader(@"C:\temp.csv")) { //reads everything in our csv into 1 long line string fileContents = sr.ReadToEnd(); //splits the 1 long line read in into multiple objects of the lines array lines = fileContents.Split(new string[] { ",", Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries); sr.Dispose(); } } The next part is where I get the null object error. When I try to use WatIn to go to the first item in the lines array it says I'm referencing a null object. private void GoToEditLinks() { for (int i = 0; i < lines.Length; i++) { //go to each link sequentially myIE.GoTo(lines[i].ToString()); //sleep so we can make sure the page loads System.Threading.Thread.Sleep(5000); } } When I debug the code it says that the GoTo request calls lines which is null. It seems like I need to declare the array, but don't I need to tell it an exact size to do that? Example: lines = new string[10] I thought I could use the lines.Length to tell it how big to make the array but that didn't work. What is weird to me is I can use the following code without problem: //returns the accurate number of urls that were in the CSV we read in earlier txtbx1.text = lines.Length; //or //this returns the last entry in the csv, as well as the last entry in the array TextBox2.Text = lines[lines.Length - 1]; I am confused why the array clearly has items in it, they can be called to fill a text box, but when I try to call them in my for loop it says its a null reference? UPDATE: By placing my cursor on both calls to lines and pressing f12 I find they both go to the same instance. The thought next is that I am not calling ReadLinksIntoMemory in time, below is my code: private void button1_Click(object sender, EventArgs e) { button1.Enabled = false; ReadLinksIntoMemory(); GoToEditLinks(); button1.Enabled = true; } Unless I'm mistaken the code says that the ReadLinksIntoMemory method must complete before GoToEditLinks can be called? If ReadLinksIntoMemory didn't finish in time I shouldn't be able to fill my text boxes with the lines array length and/or last entry. UPDATE: Stepping into the method GoToEditLinks() I see that lines is null before it calls: myIE.GoTo(lines[i]); but when it hits the goto command the value changes from null to the url it is suppose to go to, but at that same time it gives me the null object error? UPDATE: I added a IsNullOrEmpty check method and lines array passes it without any issue. I'm beginning to think it is an issue with WatIn and the myIE.GoTo command. I think this is the stack trace/call stack? Program.exe!Program.Form1.GoToEditLinks() Line 284 C# Program.exe!Program.Form1.button1_Click(object sender, System.EventArgs e) Line 191 + 0x8 bytes C# [External Code] Program.exe!Program.Program.Main() Line 18 + 0x1d bytes C# [External Code]

  Read the article

• Need some help to determine the amount of recursive calls in PHP

  - by Ben Fransen

  Hi all, I've got a, I think fairly easy question, but this is bugging me for a while now. So I figured, maybe I can get some help here. Since recursive functions are always a bit tricky, and sometimes a bit unclear to me, I keep struggling to create a nice working solution to get my menudata. In one of my classes I have this function, which gives me all menu-items recursivly. The thing I want is to determine at which recursionlevel a certain object was retrieved so I can create a nicely looking HTML output with indents for the levels of nesting. public function GetObjectList($parentID = 0, $objectlist = null) { if(is_null($objectlist)) { $objectlist = new ObjectList("Model_Navigation"); } $query = MySQL::Query("SELECT * FROM `Navigation` WHERE `WebsiteID` = ".SITE_ID. " AND `LanguageID` = ".LANG_ID." AND `ParentID` = ".$parentID); while($result = MySQL::FetchAssoc($query)) { $object = new Model_Navigation(); $object->ID = $result["ID"]; $object->WebsiteID = $result["WebsiteID"]; $object->LanguageID = $result["LanguageID"]; $object->ParentID = $result["ParentID"]; $object->Name = $result["Name"]; $object->Page = Model_Page::GetObjectByID($result["PageID"]); $object->ExternalURL = $result["ExternalURL"]; $object->Index = $result["Index"]; $object->Level = [here lies my problem]; $objectlist->Add($object); self::GetObjectList($object->ID, $objectlist); } return $objectlist; } Hope to hear from you! Greetings from Holland, Ben Fransen

  Read the article

• Why does my Doctrine DBAL query return no results when quoted?

  - by braveterry

  I'm using the Doctrine DataBase Abstraction Layer (DBAL) to perform some queries. For some reason, when I quote a parameter before passing it to the query, I get back no rows. When I pass it unquoted, it works fine. Here's the relevant snippet of code I'm using: public function get($game) { load::helper('doctrinehelper'); $conn = doctrinehelper::getconnection(); $statement = $conn->prepare('SELECT games.id as id, games.name as name, games.link_url, games.link_text, services.name as service_name, image_url FROM games, services WHERE games.name = ? AND services.key = games.service_key'); $quotedGame = $conn->quote($game); load::helper('loghelper'); $logger = loghelper::getLogger(); $logger->debug("Quoted Game: $quotedGame"); $logger->debug("Unquoted Game: $game"); $statement->execute(array($quotedGame)); $resultsArray = $statement->fetchAll(); $logger->debug("Number of rows returned: " . count($resultsArray)); return $resultsArray; } Here's what the log shows: 01/01/11 17:00:13,269 [2112] DEBUG root - Quoted Game: 'Diablo II Lord of Destruction' 01/01/11 17:00:13,269 [2112] DEBUG root - Unquoted Game: Diablo II Lord of Destruction 01/01/11 17:00:13,270 [2112] DEBUG root - Number of rows returned: 0 If I change this line: $statement->execute(array($quotedGame)); to this: $statement->execute(array($game)); I get this in the log: 01/01/11 16:51:42,934 [2112] DEBUG root - Quoted Game: 'Diablo II Lord of Destruction' 01/01/11 16:51:42,935 [2112] DEBUG root - Unquoted Game: Diablo II Lord of Destruction 01/01/11 16:51:42,936 [2112] DEBUG root - Number of rows returned: 1 Have I fat-fingered something?

  Read the article

• C# ref Confusion

  - by Rahat

  I have a confusion that when i pass a variable by refrence in the constructor of another class and after passing that object by refrence i recreate the refrence object with the new keyword. Now the class in which i have passed the refrenced object dosen't reflect the updated data. An exabple of the above problem is shown below: Object to be passed by Refrence: public class DummyObject { public string Name = "My Name"; public DummyObject() { } } Class which is passing the Refrence: public partial class Form1 : Form { // Object to be passed as refrence DummyObject dummyObject = new DummyObject(); public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { // assigning value dummyObject.Name = "I am Dummy"; // Passing object Form2 frm = new Form2(ref dummyObject); frm.Show(); } private void button2_Click(object sender, EventArgs e) { // Displaying Name MessageBox.Show(this.dummyObject.Name); } private void button3_Click(object sender, EventArgs e) { // Assigning new object this.dummyObject = new DummyObject(); // Changing Name Variable this.dummyObject.Name = "I am Rechanged"; // Displaying Name MessageBox.Show(this.dummyObject.Name); } } Class to which Object is passed by Reference: public partial class Form2 : Form { private DummyObject dummyObject = null; public Form2(ref DummyObject DummyObject) { InitializeComponent(); this.dummyObject = DummyObject; this.dummyObject.Name = "I am Changed"; } private void button2_Click(object sender, EventArgs e) { MessageBox.Show(this.dummyObject.Name); } } whn i reaasign the object in Form 1 and cdisplay its value in form 2 it still displays "I am Changed" instead of "I am Rechanged". How to keep the data synchronized?

  Read the article

• how can i handle calculator buutons in c# window form program

  - by sama

  using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; namespace lab8ass1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button11_Click(object sender, EventArgs e) { textBox1.Text += "."; } private void btnone_Click(object sender, EventArgs e) { textBox1.Text += "1"; } private void btnrwo_Click(object sender, EventArgs e) { textBox1.Text += "2"; } private void btnthree_Click(object sender, EventArgs e) { textBox1.Text += "3"; } private void btnfour_Click(object sender, EventArgs e) { textBox1.Text += "4"; } private void btnfive_Click(object sender, EventArgs e) { textBox1.Text += "5"; } private void btnsix_Click(object sender, EventArgs e) { textBox1.Text += "6"; } private void btnseven_Click(object sender, EventArgs e) { textBox1.Text += "7"; } private void btneight_Click(object sender, EventArgs e) { textBox1.Text += "8"; } private void btnnine_Click(object sender, EventArgs e) { textBox1.Text += "9"; } private void btnzero_Click(object sender, EventArgs e) { textBox1.Text += "0"; } string s1,s; private void btnplus_Click(object sender, EventArgs e) { s1 = textBox1.Text; textBox1.Text = ""; s = textBox1.Text; //textBox1.Text } private void btnequal_Click(object sender, EventArgs e) { } } } here my code how can i handle calculator buutons

  Read the article

• how are association, aggregation and composition written?

  - by ajsie

  i have read some posts about the differences between these 3 relationships and i think i get the point. i just wonder, are all these written the same when coding? question 1: all 3 are just a value of the object type in a instance variable? class A { public $b = '' public function __construct($object) { $this->b = $object // <-- could be a association, aggregation or a composition relation? } } question 2: does it have to be an instance variable or can it be a static one? class A { public static $b = '' // <-- nothing changed? public function __construct($object) { $this->b = $object } } question 3: is there a difference in where the object is created? i tend to think that composition object is created inside the object: class A { public $b = '' public function __construct() { $this->b = new Object // is created inside the object } } and aggregation/association is passed through a constructor or another method: class A { public $b = '' public function __construct($object) { // passed through a method $this->b = $object } } question 4: why/when is this important to know. do i have to comment an object inside another what relation its about or do you do it in an UML diagram? could someone shed a light on these questions. thanks!

  Read the article

• Using JSON.NET for dynamic JSON parsing

  - by Rick Strahl

  With the release of ASP.NET Web API as part of .NET 4.5 and MVC 4.0, JSON.NET has effectively pushed out the .NET native serializers to become the default serializer for Web API. JSON.NET is vastly more flexible than the built in DataContractJsonSerializer or the older JavaScript serializer. The DataContractSerializer in particular has been very problematic in the past because it can't deal with untyped objects for serialization - like values of type object, or anonymous types which are quite common these days. The JavaScript Serializer that came before it actually does support non-typed objects for serialization but it can't do anything with untyped data coming in from JavaScript and it's overall model of extensibility was pretty limited (JavaScript Serializer is what MVC uses for JSON responses). JSON.NET provides a robust JSON serializer that has both high level and low level components, supports binary JSON, JSON contracts, Xml to JSON conversion, LINQ to JSON and many, many more features than either of the built in serializers. ASP.NET Web API now uses JSON.NET as its default serializer and is now pulled in as a NuGet dependency into Web API projects, which is great. Dynamic JSON Parsing One of the features that I think is getting ever more important is the ability to serialize and deserialize arbitrary JSON content dynamically - that is without mapping the JSON captured directly into a .NET type as DataContractSerializer or the JavaScript Serializers do. Sometimes it isn't possible to map types due to the differences in languages (think collections, dictionaries etc), and other times you simply don't have the structures in place or don't want to create them to actually import the data. If this topic sounds familiar - you're right! I wrote about dynamic JSON parsing a few months back before JSON.NET was added to Web API and when Web API and the System.Net HttpClient libraries included the System.Json classes like JsonObject and JsonArray. With the inclusion of JSON.NET in Web API these classes are now obsolete and didn't ship with Web API or the client libraries. I re-linked my original post to this one. In this post I'll discus JToken, JObject and JArray which are the dynamic JSON objects that make it very easy to create and retrieve JSON content on the fly without underlying types. Why Dynamic JSON? So, why Dynamic JSON parsing rather than strongly typed parsing? Since applications are interacting more and more with third party services it becomes ever more important to have easy access to those services with easy JSON parsing. Sometimes it just makes lot of sense to pull just a small amount of data out of large JSON document received from a service, because the third party service isn't directly related to your application's logic most of the time - and it makes little sense to map the entire service structure in your application. For example, recently I worked with the Google Maps Places API to return information about businesses close to me (or rather the app's) location. The Google API returns a ton of information that my application had no interest in - all I needed was few values out of the data. Dynamic JSON parsing makes it possible to map this data, without having to map the entire API to a C# data structure. Instead I could pull out the three or four values I needed from the API and directly store it on my business entities that needed to receive the data - no need to map the entire Maps API structure. Getting JSON.NET The easiest way to use JSON.NET is to grab it via NuGet and add it as a reference to your project. You can add it to your project with: PM> Install-Package Newtonsoft.Json From the Package Manager Console or by using Manage NuGet Packages in your project References. As mentioned if you're using ASP.NET Web API or MVC 4 JSON.NET will be automatically added to your project. Alternately you can also go to the CodePlex site and download the latest version including source code: http://json.codeplex.com/ Creating JSON on the fly with JObject and JArray Let's start with creating some JSON on the fly. It's super easy to create a dynamic object structure with any of the JToken derived JSON.NET objects. The most common JToken derived classes you are likely to use are JObject and JArray. JToken implements IDynamicMetaProvider and so uses the dynamic  keyword extensively to make it intuitive to create object structures and turn them into JSON via dynamic object syntax. Here's an example of creating a music album structure with child songs using JObject for the base object and songs and JArray for the actual collection of songs:[TestMethod] public void JObjectOutputTest() { // strong typed instance var jsonObject = new JObject(); // you can explicitly add values here using class interface jsonObject.Add("Entered", DateTime.Now); // or cast to dynamic to dynamically add/read properties dynamic album = jsonObject; album.AlbumName = "Dirty Deeds Done Dirt Cheap"; album.Artist = "AC/DC"; album.YearReleased = 1976; album.Songs = new JArray() as dynamic; dynamic song = new JObject(); song.SongName = "Dirty Deeds Done Dirt Cheap"; song.SongLength = "4:11"; album.Songs.Add(song); song = new JObject(); song.SongName = "Love at First Feel"; song.SongLength = "3:10"; album.Songs.Add(song); Console.WriteLine(album.ToString()); } This produces a complete JSON structure: { "Entered": "2012-08-18T13:26:37.7137482-10:00", "AlbumName": "Dirty Deeds Done Dirt Cheap", "Artist": "AC/DC", "YearReleased": 1976, "Songs": [ { "SongName": "Dirty Deeds Done Dirt Cheap", "SongLength": "4:11" }, { "SongName": "Love at First Feel", "SongLength": "3:10" } ] } Notice that JSON.NET does a nice job formatting the JSON, so it's easy to read and paste into blog posts :-). JSON.NET includes a bunch of configuration options that control how JSON is generated. Typically the defaults are just fine, but you can override with the JsonSettings object for most operations. The important thing about this code is that there's no explicit type used for holding the values to serialize to JSON. Rather the JSON.NET objects are the containers that receive the data as I build up my JSON structure dynamically, simply by adding properties. This means this code can be entirely driven at runtime without compile time restraints of structure for the JSON output. Here I use JObject to create a album 'object' and immediately cast it to dynamic. JObject() is kind of similar in behavior to ExpandoObject in that it allows you to add properties by simply assigning to them. Internally, JObject values are stored in pseudo collections of key value pairs that are exposed as properties through the IDynamicMetaObject interface exposed in JSON.NET's JToken base class. For objects the syntax is very clean - you add simple typed values as properties. For objects and arrays you have to explicitly create new JObject or JArray, cast them to dynamic and then add properties and items to them. Always remember though these values are dynamic - which means no Intellisense and no compiler type checking. It's up to you to ensure that the names and values you create are accessed consistently and without typos in your code. Note that you can also access the JObject instance directly (not as dynamic) and get access to the underlying JObject type. This means you can assign properties by string, which can be useful for fully data driven JSON generation from other structures. Below you can see both styles of access next to each other:// strong type instance var jsonObject = new JObject(); // you can explicitly add values here jsonObject.Add("Entered", DateTime.Now); // expando style instance you can just 'use' properties dynamic album = jsonObject; album.AlbumName = "Dirty Deeds Done Dirt Cheap"; JContainer (the base class for JObject and JArray) is a collection so you can also iterate over the properties at runtime easily:foreach (var item in jsonObject) { Console.WriteLine(item.Key + " " + item.Value.ToString()); } The functionality of the JSON objects are very similar to .NET's ExpandObject and if you used it before, you're already familiar with how the dynamic interfaces to the JSON objects works. Importing JSON with JObject.Parse() and JArray.Parse() The JValue structure supports importing JSON via the Parse() and Load() methods which can read JSON data from a string or various streams respectively. Essentially JValue includes the core JSON parsing to turn a JSON string into a collection of JsonValue objects that can be then referenced using familiar dynamic object syntax. Here's a simple example:public void JValueParsingTest() { var jsonString = @"{""Name"":""Rick"",""Company"":""West Wind"", ""Entered"":""2012-03-16T00:03:33.245-10:00""}"; dynamic json = JValue.Parse(jsonString); // values require casting string name = json.Name; string company = json.Company; DateTime entered = json.Entered; Assert.AreEqual(name, "Rick"); Assert.AreEqual(company, "West Wind"); } The JSON string represents an object with three properties which is parsed into a JObject class and cast to dynamic. Once cast to dynamic I can then go ahead and access the object using familiar object syntax. Note that the actual values - json.Name, json.Company, json.Entered - are actually of type JToken and I have to cast them to their appropriate types first before I can do type comparisons as in the Asserts at the end of the test method. This is required because of the way that dynamic types work which can't determine the type based on the method signature of the Assert.AreEqual(object,object) method. I have to either assign the dynamic value to a variable as I did above, or explicitly cast ( (string) json.Name) in the actual method call. The JSON structure can be much more complex than this simple example. Here's another example of an array of albums serialized to JSON and then parsed through with JsonValue():[TestMethod] public void JsonArrayParsingTest() { var jsonString = @"[ { ""Id"": ""b3ec4e5c"", ""AlbumName"": ""Dirty Deeds Done Dirt Cheap"", ""Artist"": ""AC/DC"", ""YearReleased"": 1976, ""Entered"": ""2012-03-16T00:13:12.2810521-10:00"", ""AlbumImageUrl"": ""http://ecx.images-amazon.com/images/I/61kTaH-uZBL._AA115_.jpg"", ""AmazonUrl"": ""http://www.amazon.com/gp/product/…ASIN=B00008BXJ4"", ""Songs"": [ { ""AlbumId"": ""b3ec4e5c"", ""SongName"": ""Dirty Deeds Done Dirt Cheap"", ""SongLength"": ""4:11"" }, { ""AlbumId"": ""b3ec4e5c"", ""SongName"": ""Love at First Feel"", ""SongLength"": ""3:10"" }, { ""AlbumId"": ""b3ec4e5c"", ""SongName"": ""Big Balls"", ""SongLength"": ""2:38"" } ] }, { ""Id"": ""7b919432"", ""AlbumName"": ""End of the Silence"", ""Artist"": ""Henry Rollins Band"", ""YearReleased"": 1992, ""Entered"": ""2012-03-16T00:13:12.2800521-10:00"", ""AlbumImageUrl"": ""http://ecx.images-amazon.com/images/I/51FO3rb1tuL._SL160_AA160_.jpg"", ""AmazonUrl"": ""http://www.amazon.com/End-Silence-Rollins-Band/dp/B0000040OX/ref=sr_1_5?ie=UTF8&qid=1302232195&sr=8-5"", ""Songs"": [ { ""AlbumId"": ""7b919432"", ""SongName"": ""Low Self Opinion"", ""SongLength"": ""5:24"" }, { ""AlbumId"": ""7b919432"", ""SongName"": ""Grip"", ""SongLength"": ""4:51"" } ] } ]"; JArray jsonVal = JArray.Parse(jsonString) as JArray; dynamic albums = jsonVal; foreach (dynamic album in albums) { Console.WriteLine(album.AlbumName + " (" + album.YearReleased.ToString() + ")"); foreach (dynamic song in album.Songs) { Console.WriteLine("\t" + song.SongName); } } Console.WriteLine(albums[0].AlbumName); Console.WriteLine(albums[0].Songs[1].SongName); } JObject and JArray in ASP.NET Web API Of course these types also work in ASP.NET Web API controller methods. If you want you can accept parameters using these object or return them back to the server. The following contrived example receives dynamic JSON input, and then creates a new dynamic JSON object and returns it based on data from the first:[HttpPost] public JObject PostAlbumJObject(JObject jAlbum) { // dynamic input from inbound JSON dynamic album = jAlbum; // create a new JSON object to write out dynamic newAlbum = new JObject(); // Create properties on the new instance // with values from the first newAlbum.AlbumName = album.AlbumName + " New"; newAlbum.NewProperty = "something new"; newAlbum.Songs = new JArray(); foreach (dynamic song in album.Songs) { song.SongName = song.SongName + " New"; newAlbum.Songs.Add(song); } return newAlbum; } The raw POST request to the server looks something like this: POST http://localhost/aspnetwebapi/samples/PostAlbumJObject HTTP/1.1User-Agent: FiddlerContent-type: application/jsonHost: localhostContent-Length: 88 {AlbumName: "Dirty Deeds",Songs:[ { SongName: "Problem Child"},{ SongName: "Squealer"}]} and the output that comes back looks like this: {  "AlbumName": "Dirty Deeds New",  "NewProperty": "something new",  "Songs": [    {      "SongName": "Problem Child New"    },    {      "SongName": "Squealer New"    }  ]} The original values are echoed back with something extra appended to demonstrate that we're working with a new object. When you receive or return a JObject, JValue, JToken or JArray instance in a Web API method, Web API ignores normal content negotiation and assumes your content is going to be received and returned as JSON, so effectively the parameter and result type explicitly determines the input and output format which is nice. Dynamic to Strong Type Mapping You can also map JObject and JArray instances to a strongly typed object, so you can mix dynamic and static typing in the same piece of code. Using the 2 Album jsonString shown earlier, the code below takes an array of albums and picks out only a single album and casts that album to a static Album instance.[TestMethod] public void JsonParseToStrongTypeTest() { JArray albums = JArray.Parse(jsonString) as JArray; // pick out one album JObject jalbum = albums[0] as JObject; // Copy to a static Album instance Album album = jalbum.ToObject<Album>(); Assert.IsNotNull(album); Assert.AreEqual(album.AlbumName,jalbum.Value<string>("AlbumName")); Assert.IsTrue(album.Songs.Count > 0); } This is pretty damn useful for the scenario I mentioned earlier - you can read a large chunk of JSON and dynamically walk the property hierarchy down to the item you want to access, and then either access the specific item dynamically (as shown earlier) or map a part of the JSON to a strongly typed object. That's very powerful if you think about it - it leaves you in total control to decide what's dynamic and what's static. Strongly typed JSON Parsing With all this talk of dynamic let's not forget that JSON.NET of course also does strongly typed serialization which is drop dead easy. Here's a simple example on how to serialize and deserialize an object with JSON.NET:[TestMethod] public void StronglyTypedSerializationTest() { // Demonstrate deserialization from a raw string var album = new Album() { AlbumName = "Dirty Deeds Done Dirt Cheap", Artist = "AC/DC", Entered = DateTime.Now, YearReleased = 1976, Songs = new List<Song>() { new Song() { SongName = "Dirty Deeds Done Dirt Cheap", SongLength = "4:11" }, new Song() { SongName = "Love at First Feel", SongLength = "3:10" } } }; // serialize to string string json2 = JsonConvert.SerializeObject(album,Formatting.Indented); Console.WriteLine(json2); // make sure we can serialize back var album2 = JsonConvert.DeserializeObject<Album>(json2); Assert.IsNotNull(album2); Assert.IsTrue(album2.AlbumName == "Dirty Deeds Done Dirt Cheap"); Assert.IsTrue(album2.Songs.Count == 2); } JsonConvert is a high level static class that wraps lower level functionality, but you can also use the JsonSerializer class, which allows you to serialize/parse to and from streams. It's a little more work, but gives you a bit more control. The functionality available is easy to discover with Intellisense, and that's good because there's not a lot in the way of documentation that's actually useful. Summary JSON.NET is a pretty complete JSON implementation with lots of different choices for JSON parsing from dynamic parsing to static serialization, to complex querying of JSON objects using LINQ. It's good to see this open source library getting integrated into .NET, and pushing out the old and tired stock .NET parsers so that we finally have a bit more flexibility - and extensibility - in our JSON parsing. Good to go! Resources Sample Test Project http://json.codeplex.com/© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET  Web Api  AJAX   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

  Read the article

• ASP.NET Podcast Show #148 - ASP.NET WebForms to build a Mobile Web Application

  - by Wallym

  Check the podcast site for the original url. This is the video and source code for an ASP.NET WebForms app that I wrote that is optimized for the iPhone and mobile environments.  Subscribe to everything. Subscribe to WMV. Subscribe to M4V for iPhone/iPad. Subscribe to MP3. Download WMV. Download M4V for iPhone/iPad. Download MP3. Link to iWebKit. Source Code: <%@ Page Title="MapSplore" Language="C#" MasterPageFile="iPhoneMaster.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="AT_iPhone_Default" %> <asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server"></asp:Content><asp:Content ID="Content2" ContentPlaceHolderID="Content" Runat="Server" ClientIDMode="Static">    <asp:ScriptManager ID="sm" runat="server"         EnablePartialRendering="true" EnableHistory="false" EnableCdn="true" />    <script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=true"></script>    <script  language="javascript"  type="text/javascript">    <!--    Sys.WebForms.PageRequestManager.getInstance().add_endRequest(endRequestHandle);    function endRequestHandle(sender, Args) {        setupMapDiv();        setupPlaceIveBeen();    }    function setupPlaceIveBeen() {        var mapPlaceIveBeen = document.getElementById('divPlaceIveBeen');        if (mapPlaceIveBeen != null) {            var PlaceLat = document.getElementById('<%=hdPlaceIveBeenLatitude.ClientID %>').value;            var PlaceLon = document.getElementById('<%=hdPlaceIveBeenLongitude.ClientID %>').value;            var PlaceTitle = document.getElementById('<%=lblPlaceIveBeenName.ClientID %>').innerHTML;            var latlng = new google.maps.LatLng(PlaceLat, PlaceLon);            var myOptions = {                zoom: 14,                center: latlng,                mapTypeId: google.maps.MapTypeId.ROADMAP            };            var map = new google.maps.Map(mapPlaceIveBeen, myOptions);            var marker = new google.maps.Marker({                position: new google.maps.LatLng(PlaceLat, PlaceLon),                map: map,                title: PlaceTitle,                clickable: false            });        }    }    function setupMapDiv() {        var mapdiv = document.getElementById('divImHere');        if (mapdiv != null) {            var PlaceLat = document.getElementById('<%=hdPlaceLat.ClientID %>').value;            var PlaceLon = document.getElementById('<%=hdPlaceLon.ClientID %>').value;            var PlaceTitle = document.getElementById('<%=hdPlaceTitle.ClientID %>').value;            var latlng = new google.maps.LatLng(PlaceLat, PlaceLon);            var myOptions = {                zoom: 14,                center: latlng,                mapTypeId: google.maps.MapTypeId.ROADMAP            };            var map = new google.maps.Map(mapdiv, myOptions);            var marker = new google.maps.Marker({                position: new google.maps.LatLng(PlaceLat, PlaceLon),                map: map,                title: PlaceTitle,                clickable: false            });        }     }    -->    </script>    <asp:HiddenField ID="Latitude" runat="server" />    <asp:HiddenField ID="Longitude" runat="server" />    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js%22%3E%3C/script>    <script language="javascript" type="text/javascript">        $(document).ready(function () {            GetLocation();            setupMapDiv();            setupPlaceIveBeen();        });        function GetLocation() {            if (navigator.geolocation != null) {                navigator.geolocation.getCurrentPosition(getData);            }            else {                var mess = document.getElementById('<%=Message.ClientID %>');                mess.innerHTML = "Sorry, your browser does not support geolocation. " +                    "Try the latest version of Safari on the iPhone, Android browser, or the latest version of FireFox.";            }        }        function UpdateLocation_Click() {            GetLocation();        }        function getData(position) {            var latitude = position.coords.latitude;            var longitude = position.coords.longitude;            var hdLat = document.getElementById('<%=Latitude.ClientID %>');            var hdLon = document.getElementById('<%=Longitude.ClientID %>');            hdLat.value = latitude;            hdLon.value = longitude;        }    </script>    <asp:Label ID="Message" runat="server" />    <asp:UpdatePanel ID="upl" runat="server">        <ContentTemplate>    <asp:Panel ID="pnlStart" runat="server" Visible="true">    <div id="topbar">        <div id="title">MapSplore</div>    </div>    <div id="content">        <ul class="pageitem">            <li class="menu">                <asp:LinkButton ID="lbLocalDeals" runat="server" onclick="lbLocalDeals_Click">                <asp:Image ID="imLocalDeals" runat="server" ImageUrl="~/Images/ArtFavor_Money_Bag_Icon.png" Height="30" />                <span class="name">Local Deals.</span>                <span class="arrow"></span>                </asp:LinkButton>                </li>            <li class="menu">                <asp:LinkButton ID="lbLocalPlaces" runat="server" onclick="lbLocalPlaces_Click">                <asp:Image ID="imLocalPlaces" runat="server" ImageUrl="~/Images/Andy_Houses_on_the_horizon_-_Starburst_remix.png" Height="30" />                <span class="name">Local Places.</span>                <span class="arrow"></span>                </asp:LinkButton>                </li>            <li class="menu">                <asp:LinkButton ID="lbWhereIveBeen" runat="server" onclick="lbWhereIveBeen_Click">                <asp:Image ID="imImHere" runat="server" ImageUrl="~/Images/ryanlerch_flagpole.png" Height="30" />                <span class="name">I've been here.</span>                <span class="arrow"></span>                </asp:LinkButton>                </li>            <li class="menu">                <asp:LinkButton ID="lbMyStats" runat="server">                <asp:Image ID="imMyStats" runat="server" ImageUrl="~/Images/Anonymous_Spreadsheet.png" Height="30" />                <span class="name">My Stats.</span>                <span class="arrow"></span>                </asp:LinkButton>                </li>            <li class="menu">                <asp:LinkButton ID="lbAddAPlace" runat="server" onclick="lbAddAPlace_Click">                <asp:Image ID="imAddAPlace" runat="server" ImageUrl="~/Images/jean_victor_balin_add.png" Height="30" />                <span class="name">Add a Place.</span>                <span class="arrow"></span>                </asp:LinkButton>                </li>            <li class="button">                <input type="button" value="Update Your Current Location" onclick="UpdateLocation_Click()">                </li>        </ul>    </div>    </asp:Panel>    <div>    <asp:Panel ID="pnlCoupons" runat="server" Visible="false">        <div id="topbar">        <div id="title">MapSplore</div>        <div id="leftbutton">            <asp:LinkButton runat="server" Text="Return"                 ID="ReturnFromDeals" OnClick="ReturnFromDeals_Click" /></div></div>    <div class="content">    <asp:ListView ID="lvCoupons" runat="server">        <LayoutTemplate>            <ul class="pageitem" runat="server">                <asp:PlaceHolder ID="itemPlaceholder" runat="server" />            </ul>        </LayoutTemplate>        <ItemTemplate>            <li class="menu">                <asp:LinkButton ID="lbBusiness" runat="server" Text='<%#Eval("Place.Name") %>' OnClick="lbBusiness_Click">                    <span class="comment">                    <asp:Label ID="lblAddress" runat="server" Text='<%#Eval("Place.Address1") %>' />                    <asp:Label ID="lblDis" runat="server" Text='<%# Convert.ToString(Convert.ToInt32(Eval("Place.Distance"))) + " meters" %>' CssClass="smallText" />                    <asp:HiddenField ID="hdPlaceId" runat="server" Value='<%#Eval("PlaceId") %>' />                    <asp:HiddenField ID="hdGeoPromotionId" runat="server" Value='<%#Eval("GeoPromotionId") %>' />                    </span>                    <span class="arrow"></span>                </asp:LinkButton></li></ItemTemplate></asp:ListView><asp:GridView ID="gvCoupons" runat="server" AutoGenerateColumns="false">            <HeaderStyle BackColor="Silver" />            <AlternatingRowStyle BackColor="Wheat" />            <Columns>                <asp:TemplateField AccessibleHeaderText="Business" HeaderText="Business">                    <ItemTemplate>                        <asp:Image ID="imPlaceType" runat="server" Text='<%#Eval("Type") %>' ImageUrl='<%#Eval("Image") %>' />                        <asp:LinkButton ID="lbBusiness" runat="server" Text='<%#Eval("Name") %>' OnClick="lbBusiness_Click" />                        <asp:LinkButton ID="lblAddress" runat="server" Text='<%#Eval("Address1") %>' CssClass="smallText" />                        <asp:Label ID="lblDis" runat="server" Text='<%# Convert.ToString(Convert.ToInt32(Eval("Distance"))) + " meters" %>' CssClass="smallText" />                        <asp:HiddenField ID="hdPlaceId" runat="server" Value='<%#Eval("PlaceId") %>' />                        <asp:HiddenField ID="hdGeoPromotionId" runat="server" Value='<%#Eval("GeoPromotionId") %>' />                        <asp:Label ID="lblInfo" runat="server" Visible="false" />                    </ItemTemplate>                </asp:TemplateField>            </Columns>        </asp:GridView>    </div>    </asp:Panel>    <asp:Panel ID="pnlPlaces" runat="server" Visible="false">    <div id="topbar">        <div id="title">            MapSplore</div><div id="leftbutton">            <asp:LinkButton runat="server" Text="Return"                 ID="ReturnFromPlaces" OnClick="ReturnFromPlaces_Click" /></div></div>        <div id="content">        <asp:ListView ID="lvPlaces" runat="server">            <LayoutTemplate>                <ul id="ulPlaces" class="pageitem" runat="server">                    <asp:PlaceHolder ID="itemPlaceholder" runat="server" />                    <li class="menu">                        <asp:LinkButton ID="lbNotListed" runat="server" CssClass="name"                            OnClick="lbNotListed_Click">                            Place not listed                            <span class="arrow"></span>                            </asp:LinkButton>                    </li>                </ul>            </LayoutTemplate>            <ItemTemplate>            <li class="menu">                <asp:LinkButton ID="lbImHere" runat="server" CssClass="name"                     OnClick="lbImHere_Click">                <%#DisplayName(Eval("Name")) %>&nbsp;                <%# Convert.ToString(Convert.ToInt32(Eval("Distance"))) + " meters" %>                <asp:HiddenField ID="hdPlaceId" runat="server" Value='<%#Eval("PlaceId") %>' />                <span class="arrow"></span>                </asp:LinkButton></li></ItemTemplate></asp:ListView>    </div>    </asp:Panel>    <asp:Panel ID="pnlImHereNow" runat="server" Visible="false">        <div id="topbar">        <div id="title">            MapSplore</div><div id="leftbutton">            <asp:LinkButton runat="server" Text="Places"                 ID="lbImHereNowReturn" OnClick="lbImHereNowReturn_Click" /></div></div>            <div id="rightbutton">            <asp:LinkButton runat="server" Text="Beginning"                ID="lbBackToBeginning" OnClick="lbBackToBeginning_Click" />            </div>        <div id="content">        <ul class="pageitem">        <asp:HiddenField ID="hdPlaceId" runat="server" />        <asp:HiddenField ID="hdPlaceLat" runat="server" />        <asp:HiddenField ID="hdPlaceLon" runat="server" />        <asp:HiddenField ID="hdPlaceTitle" runat="server" />        <asp:Button ID="btnImHereNow" runat="server"             Text="I'm here" OnClick="btnImHereNow_Click" />             <asp:Label ID="lblPlaceTitle" runat="server" /><br />        <asp:TextBox ID="txtWhatsHappening" runat="server" TextMode="MultiLine" Rows="2" style="width:300px" /><br />        <div id="divImHere" style="width:300px; height:300px"></div>        </div>        </ul>    </asp:Panel>    <asp:Panel runat="server" ID="pnlIveBeenHere" Visible="false">        <div id="topbar">        <div id="title">            Where I've been</div><div id="leftbutton">            <asp:LinkButton ID="lbIveBeenHereBack" runat="server" Text="Back" OnClick="lbIveBeenHereBack_Click" /></div></div>        <div id="content">        <asp:ListView ID="lvWhereIveBeen" runat="server">            <LayoutTemplate>                <ul id="ulWhereIveBeen" class="pageitem" runat="server">                    <asp:PlaceHolder ID="itemPlaceholder" runat="server" />                </ul>            </LayoutTemplate>            <ItemTemplate>            <li class="menu" runat="server">                <asp:LinkButton ID="lbPlaceIveBeen" runat="server" OnClick="lbPlaceIveBeen_Click" CssClass="name">                    <asp:Label ID="lblPlace" runat="server" Text='<%#Eval("PlaceName") %>' /> at                    <asp:Label ID="lblTime" runat="server" Text='<%#Eval("ATTime") %>' CssClass="content" />                    <asp:HiddenField ID="hdATID" runat="server" Value='<%#Eval("ATID") %>' />                    <span class="arrow"></span>                </asp:LinkButton>            </li>            </ItemTemplate>        </asp:ListView>        </div>        </asp:Panel>    <asp:Panel runat="server" ID="pnlPlaceIveBeen" Visible="false">        <div id="topbar">        <div id="title">            I've been here        </div>        <div id="leftbutton">            <asp:LinkButton ID="lbPlaceIveBeenBack" runat="server" Text="Back" OnClick="lbPlaceIveBeenBack_Click" />        </div>        <div id="rightbutton">            <asp:LinkButton ID="lbPlaceIveBeenBeginning" runat="server" Text="Beginning" OnClick="lbPlaceIveBeenBeginning_Click" />        </div>        </div>        <div id="content">            <ul class="pageitem">            <li>            <asp:HiddenField ID="hdPlaceIveBeenPlaceId" runat="server" />            <asp:HiddenField ID="hdPlaceIveBeenLatitude" runat="server" />            <asp:HiddenField ID="hdPlaceIveBeenLongitude" runat="server" />            <asp:Label ID="lblPlaceIveBeenName" runat="server" /><br />            <asp:Label ID="lblPlaceIveBeenAddress" runat="server" /><br />            <asp:Label ID="lblPlaceIveBeenCity" runat="server" />,             <asp:Label ID="lblPlaceIveBeenState" runat="server" />            <asp:Label ID="lblPlaceIveBeenZipCode" runat="server" /><br />            <asp:Label ID="lblPlaceIveBeenCountry" runat="server" /><br />            <div id="divPlaceIveBeen" style="width:300px; height:300px"></div>            </li>            </ul>        </div>                </asp:Panel>         <asp:Panel ID="pnlAddPlace" runat="server" Visible="false">                <div id="topbar"><div id="title">MapSplore</div><div id="leftbutton"><asp:LinkButton ID="lbAddPlaceReturn" runat="server" Text="Back" OnClick="lbAddPlaceReturn_Click" /></div><div id="rightnav"></div></div><div id="content">    <ul class="pageitem">        <li id="liPlaceAddMessage" runat="server" visible="false">        <asp:Label ID="PlaceAddMessage" runat="server" />        </li>        <li class="bigfield">        <asp:TextBox ID="txtPlaceName" runat="server" placeholder="Name of Establishment" />        </li>        <li class="bigfield">        <asp:TextBox ID="txtAddress1" runat="server" placeholder="Address 1" />        </li>        <li class="bigfield">        <asp:TextBox ID="txtCity" runat="server" placeholder="City" />        </li>        <li class="select">        <asp:DropDownList ID="ddlProvince" runat="server" placeholder="Select State" />          <span class="arrow"></span>              </li>        <li class="bigfield">        <asp:TextBox ID="txtZipCode" runat="server" placeholder="Zip Code" />        </li>        <li class="select">        <asp:DropDownList ID="ddlCountry" runat="server"             onselectedindexchanged="ddlCountry_SelectedIndexChanged" />        <span class="arrow"></span>        </li>        <li class="bigfield">        <asp:TextBox ID="txtPhoneNumber" runat="server" placeholder="Phone Number" />        </li>        <li class="checkbox">            <span class="name">You Here Now:</span> <asp:CheckBox ID="cbYouHereNow" runat="server" Checked="true" />        </li>        <li class="button">        <asp:Button ID="btnAdd" runat="server" Text="Add Place"             onclick="btnAdd_Click" />        </li>    </ul></div>        </asp:Panel>        <asp:Panel ID="pnlImHere" runat="server" Visible="false">            <asp:TextBox ID="txtImHere" runat="server"                 TextMode="MultiLine" Rows="3" Columns="40" /><br />            <asp:DropDownList ID="ddlPlace" runat="server" /><br />            <asp:Button ID="btnHere" runat="server" Text="Tell Everyone I'm Here"                 onclick="btnHere_Click" /><br />        </asp:Panel>     </div>    </ContentTemplate>    </asp:UpdatePanel> </asp:Content> Code Behind .cs file: using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.HtmlControls;using System.Web.UI.WebControls;using LocationDataModel; public partial class AT_iPhone_Default : ViewStatePage{    private iPhoneDevice ipd;     protected void Page_Load(object sender, EventArgs e)    {        LocationDataEntities lde = new LocationDataEntities();        if (!Page.IsPostBack)        {            var Countries = from c in lde.Countries select c;            foreach (Country co in Countries)            {                ddlCountry.Items.Add(new ListItem(co.Name, co.CountryId.ToString()));            }            ddlCountry_SelectedIndexChanged(ddlCountry, null);            if (AppleIPhone.IsIPad())                ipd = iPhoneDevice.iPad;            if (AppleIPhone.IsIPhone())                ipd = iPhoneDevice.iPhone;            if (AppleIPhone.IsIPodTouch())                ipd = iPhoneDevice.iPodTouch;        }    }    protected void btnPlaces_Click(object sender, EventArgs e)    {    }    protected void btnAdd_Click(object sender, EventArgs e)    {        bool blImHere = cbYouHereNow.Checked;        string Place = txtPlaceName.Text,            Address1 = txtAddress1.Text,            City = txtCity.Text,            ZipCode = txtZipCode.Text,            PhoneNumber = txtPhoneNumber.Text,            ProvinceId = ddlProvince.SelectedItem.Value,            CountryId = ddlCountry.SelectedItem.Value;        int iProvinceId, iCountryId;        double dLatitude, dLongitude;        DataAccess da = new DataAccess();        if ((!String.IsNullOrEmpty(ProvinceId)) &&            (!String.IsNullOrEmpty(CountryId)))        {            iProvinceId = Convert.ToInt32(ProvinceId);            iCountryId = Convert.ToInt32(CountryId);            if (blImHere)            {                dLatitude = Convert.ToDouble(Latitude.Value);                dLongitude = Convert.ToDouble(Longitude.Value);                da.StorePlace(Place, Address1, String.Empty, City,                    iProvinceId, ZipCode, iCountryId, PhoneNumber,                    dLatitude, dLongitude);            }            else            {                da.StorePlace(Place, Address1, String.Empty, City,                    iProvinceId, ZipCode, iCountryId, PhoneNumber);            }            liPlaceAddMessage.Visible = true;            PlaceAddMessage.Text = "Awesome, your place has been added. Add Another!";            txtPlaceName.Text = String.Empty;            txtAddress1.Text = String.Empty;            txtCity.Text = String.Empty;            ddlProvince.SelectedIndex = -1;            txtZipCode.Text = String.Empty;            txtPhoneNumber.Text = String.Empty;        }        else        {            liPlaceAddMessage.Visible = true;            PlaceAddMessage.Text = "Please select a State and a Country.";        }    }    protected void ddlCountry_SelectedIndexChanged(object sender, EventArgs e)    {        string CountryId = ddlCountry.SelectedItem.Value;        if (!String.IsNullOrEmpty(CountryId))        {            int iCountryId = Convert.ToInt32(CountryId);            LocationDataModel.LocationDataEntities lde = new LocationDataModel.LocationDataEntities();            var prov = from p in lde.Provinces where p.CountryId == iCountryId                        orderby p.ProvinceName select p;                        ddlProvince.Items.Add(String.Empty);            foreach (Province pr in prov)            {                ddlProvince.Items.Add(new ListItem(pr.ProvinceName, pr.ProvinceId.ToString()));            }        }        else        {            ddlProvince.Items.Clear();        }    }    protected void btnImHere_Click(object sender, EventArgs e)    {        int i = 0;        DataAccess da = new DataAccess();        double Lat = Convert.ToDouble(Latitude.Value),            Lon = Convert.ToDouble(Longitude.Value);        List<Place> lp = da.NearByLocations(Lat, Lon);        foreach (Place p in lp)        {            ListItem li = new ListItem(p.Name, p.PlaceId.ToString());            if (i == 0)            {                li.Selected = true;            }            ddlPlace.Items.Add(li);            i++;        }        pnlAddPlace.Visible = false;        pnlImHere.Visible = true;    }    protected void lbImHere_Click(object sender, EventArgs e)    {        string UserName = Membership.GetUser().UserName;        ListViewItem lvi = (ListViewItem)(((LinkButton)sender).Parent);        HiddenField hd = (HiddenField)lvi.FindControl("hdPlaceId");        long PlaceId = Convert.ToInt64(hd.Value);        double dLatitude = Convert.ToDouble(Latitude.Value);        double dLongitude = Convert.ToDouble(Longitude.Value);        DataAccess da = new DataAccess();        Place pl = da.GetPlace(PlaceId);        pnlImHereNow.Visible = true;        pnlPlaces.Visible = false;        hdPlaceId.Value = PlaceId.ToString();        hdPlaceLat.Value = pl.Latitude.ToString();        hdPlaceLon.Value = pl.Longitude.ToString();        hdPlaceTitle.Value = pl.Name;        lblPlaceTitle.Text = pl.Name;    }    protected void btnHere_Click(object sender, EventArgs e)    {        string UserName = Membership.GetUser().UserName;        string WhatsH = txtImHere.Text;        long PlaceId = Convert.ToInt64(ddlPlace.SelectedValue);        double dLatitude = Convert.ToDouble(Latitude.Value);        double dLongitude = Convert.ToDouble(Longitude.Value);        DataAccess da = new DataAccess();        da.StoreUserAT(UserName, PlaceId, WhatsH,            dLatitude, dLongitude);    }    protected void btnLocalCoupons_Click(object sender, EventArgs e)    {        double dLatitude = Convert.ToDouble(Latitude.Value);        double dLongitude = Convert.ToDouble(Longitude.Value);        DataAccess da = new DataAccess();     }    protected void lbBusiness_Click(object sender, EventArgs e)    {        string UserName = Membership.GetUser().UserName;        GridViewRow gvr = (GridViewRow)(((LinkButton)sender).Parent.Parent);        HiddenField hd = (HiddenField)gvr.FindControl("hdPlaceId");        string sPlaceId = hd.Value;        Int64 PlaceId;        if (!String.IsNullOrEmpty(sPlaceId))        {            PlaceId = Convert.ToInt64(sPlaceId);        }    }    protected void lbLocalDeals_Click(object sender, EventArgs e)    {        double dLatitude = Convert.ToDouble(Latitude.Value);        double dLongitude = Convert.ToDouble(Longitude.Value);        DataAccess da = new DataAccess();        pnlCoupons.Visible = true;        pnlStart.Visible = false;        List<GeoPromotion> lgp = da.NearByDeals(dLatitude, dLongitude);        lvCoupons.DataSource = lgp;        lvCoupons.DataBind();    }    protected void lbLocalPlaces_Click(object sender, EventArgs e)    {        DataAccess da = new DataAccess();        double Lat = Convert.ToDouble(Latitude.Value);        double Lon = Convert.ToDouble(Longitude.Value);        List<LocationDataModel.Place> places = da.NearByLocations(Lat, Lon);        lvPlaces.DataSource = places;        lvPlaces.SelectedIndex = -1;        lvPlaces.DataBind();        pnlPlaces.Visible = true;        pnlStart.Visible = false;    }    protected void ReturnFromPlaces_Click(object sender, EventArgs e)    {        pnlPlaces.Visible = false;        pnlStart.Visible = true;    }    protected void ReturnFromDeals_Click(object sender, EventArgs e)    {        pnlCoupons.Visible = false;        pnlStart.Visible = true;    }    protected void btnImHereNow_Click(object sender, EventArgs e)    {        long PlaceId = Convert.ToInt32(hdPlaceId.Value);        string UserName = Membership.GetUser().UserName;        string WhatsHappening = txtWhatsHappening.Text;        double UserLat = Convert.ToDouble(Latitude.Value);        double UserLon = Convert.ToDouble(Longitude.Value);        DataAccess da = new DataAccess();        da.StoreUserAT(UserName, PlaceId, WhatsHappening,             UserLat, UserLon);    }    protected void lbImHereNowReturn_Click(object sender, EventArgs e)    {        pnlImHereNow.Visible = false;        pnlPlaces.Visible = true;    }    protected void lbBackToBeginning_Click(object sender, EventArgs e)    {        pnlStart.Visible = true;        pnlImHereNow.Visible = false;    }    protected void lbWhereIveBeen_Click(object sender, EventArgs e)    {        string UserName = Membership.GetUser().UserName;        pnlStart.Visible = false;        pnlIveBeenHere.Visible = true;        DataAccess da = new DataAccess();        lvWhereIveBeen.DataSource = da.UserATs(UserName, 0, 15);        lvWhereIveBeen.DataBind();    }    protected void lbIveBeenHereBack_Click(object sender, EventArgs e)    {        pnlIveBeenHere.Visible = false;        pnlStart.Visible = true;    }     protected void lbPlaceIveBeen_Click(object sender, EventArgs e)    {        LinkButton lb = (LinkButton)sender;        ListViewItem lvi = (ListViewItem)lb.Parent.Parent;        HiddenField hdATID = (HiddenField)lvi.FindControl("hdATID");        Int64 ATID = Convert.ToInt64(hdATID.Value);        DataAccess da = new DataAccess();        pnlIveBeenHere.Visible = false;        pnlPlaceIveBeen.Visible = true;        var plac = da.GetPlaceViaATID(ATID);        hdPlaceIveBeenPlaceId.Value = plac.PlaceId.ToString();        hdPlaceIveBeenLatitude.Value = plac.Latitude.ToString();        hdPlaceIveBeenLongitude.Value = plac.Longitude.ToString();        lblPlaceIveBeenName.Text = plac.Name;        lblPlaceIveBeenAddress.Text = plac.Address1;        lblPlaceIveBeenCity.Text = plac.City;        lblPlaceIveBeenState.Text = plac.Province.ProvinceName;        lblPlaceIveBeenZipCode.Text = plac.ZipCode;        lblPlaceIveBeenCountry.Text = plac.Country.Name;    }     protected void lbNotListed_Click(object sender, EventArgs e)    {        SetupAddPoint();        pnlPlaces.Visible = false;    }     protected void lbAddAPlace_Click(object sender, EventArgs e)    {        SetupAddPoint();    }     private void SetupAddPoint()    {        double lat = Convert.ToDouble(Latitude.Value);        double lon = Convert.ToDouble(Longitude.Value);        DataAccess da = new DataAccess();        var zip = da.WhereAmIAt(lat, lon);        if (zip.Count > 0)        {            var z0 = zip[0];            txtCity.Text = z0.City;            txtZipCode.Text = z0.ZipCode;            ddlProvince.ClearSelection();            if (z0.ProvinceId.HasValue == true)            {                foreach (ListItem li in ddlProvince.Items)                {                    if (li.Value == z0.ProvinceId.Value.ToString())                    {                        li.Selected = true;                        break;                    }                }            }        }        pnlAddPlace.Visible = true;        pnlStart.Visible = false;    }    protected void lbAddPlaceReturn_Click(object sender, EventArgs e)    {        pnlAddPlace.Visible = false;        pnlStart.Visible = true;        liPlaceAddMessage.Visible = false;        PlaceAddMessage.Text = String.Empty;    }    protected void lbPlaceIveBeenBack_Click(object sender, EventArgs e)    {        pnlIveBeenHere.Visible = true;        pnlPlaceIveBeen.Visible = false;            }    protected void lbPlaceIveBeenBeginning_Click(object sender, EventArgs e)    {        pnlPlaceIveBeen.Visible = false;        pnlStart.Visible = true;    }    protected string DisplayName(object val)    {        string strVal = Convert.ToString(val);         if (AppleIPhone.IsIPad())        {            ipd = iPhoneDevice.iPad;        }        if (AppleIPhone.IsIPhone())        {            ipd = iPhoneDevice.iPhone;        }        if (AppleIPhone.IsIPodTouch())        {            ipd = iPhoneDevice.iPodTouch;        }        return (iPhoneHelper.DisplayContentOnMenu(strVal, ipd));    }} iPhoneHelper.cs file: using System;using System.Collections.Generic;using System.Linq;using System.Web; public enum iPhoneDevice{    iPhone, iPodTouch, iPad}/// <summary>/// Summary description for iPhoneHelper/// </summary>/// public class iPhoneHelper{ public iPhoneHelper() {  //  // TODO: Add constructor logic here  // } // This code is stupid in retrospect. Use css to solve this problem      public static string DisplayContentOnMenu(string val, iPhoneDevice ipd)    {        string Return = val;        string Elipsis = "...";        int iPadMaxLength = 30;        int iPhoneMaxLength = 15;        if (ipd == iPhoneDevice.iPad)        {            if (Return.Length > iPadMaxLength)            {                Return = Return.Substring(0, iPadMaxLength - Elipsis.Length) + Elipsis;            }        }        else        {            if (Return.Length > iPhoneMaxLength)            {                Return = Return.Substring(0, iPhoneMaxLength - Elipsis.Length) + Elipsis;            }        }        return (Return);    }}  Source code for the ViewStatePage: using System;using System.Data;using System.Data.SqlClient;using System.Configuration;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls; /// <summary>/// Summary description for BasePage/// </summary>#region Base class for a page.public class ViewStatePage : System.Web.UI.Page{     PageStatePersisterToDatabase myPageStatePersister;        public ViewStatePage()        : base()    {        myPageStatePersister = new PageStatePersisterToDatabase(this);    }     protected override PageStatePersister PageStatePersister    {        get        {            return myPageStatePersister;        }    } }#endregion #region This class will override the page persistence to store page state in a database.public class PageStatePersisterToDatabase : PageStatePersister{    private string ViewStateKeyField = "__VIEWSTATE_KEY";    private string _exNoConnectionStringFound = "No Database Configuration information is in the web.config.";     public PageStatePersisterToDatabase(Page page)        : base(page)    {    }     public override void Load()    {         // Get the cache key from the web form data        System.Int64 key = Convert.ToInt64(Page.Request.Params[ViewStateKeyField]);         Pair state = this.LoadState(key);         // Abort if cache object is not of type Pair        if (state == null)            throw new ApplicationException("Missing valid " + ViewStateKeyField);         // Set view state and control state        ViewState = state.First;        ControlState = state.Second;    }     public override void Save()    {         // No processing needed if no states available        if (ViewState == null && ControlState != null)            return;         System.Int64 key;        IStateFormatter formatter = this.StateFormatter;        Pair statePair = new Pair(ViewState, ControlState);         // Serialize the statePair object to a string.        string serializedState = formatter.Serialize(statePair);         // Save the ViewState and get a unique identifier back.        key = SaveState(serializedState);         // Register hidden field to store cache key in        // Page.ClientScript does not work properly with Atlas.        //Page.ClientScript.RegisterHiddenField(ViewStateKeyField, key.ToString());        ScriptManager.RegisterHiddenField(this.Page, ViewStateKeyField, key.ToString());    }     private System.Int64 SaveState(string PageState)    {        System.Int64 i64Key = 0;        string strConn = String.Empty,            strProvider = String.Empty;         string strSql = "insert into tblPageState ( SerializedState ) values ( '" + SqlEscape(PageState) + "');select scope_identity();";        SqlConnection sqlCn;        SqlCommand sqlCm;        try        {            GetDBConnectionString(ref strConn, ref strProvider);            sqlCn = new SqlConnection(strConn);            sqlCm = new SqlCommand(strSql, sqlCn);            sqlCn.Open();            i64Key = Convert.ToInt64(sqlCm.ExecuteScalar());            if (sqlCn.State != ConnectionState.Closed)            {                sqlCn.Close();            }            sqlCn.Dispose();            sqlCm.Dispose();        }        finally        {            sqlCn = null;            sqlCm = null;        }        return i64Key;    }     private Pair LoadState(System.Int64 iKey)    {        string strConn = String.Empty,            strProvider = String.Empty,            SerializedState = String.Empty,            strMinutesInPast = GetMinutesInPastToDelete();        Pair PageState;        string strSql = "select SerializedState from tblPageState where tblPageStateID=" + iKey.ToString() + ";" +            "delete from tblPageState where DateUpdated<DateAdd(mi, " + strMinutesInPast + ", getdate());";        SqlConnection sqlCn;        SqlCommand sqlCm;        try        {            GetDBConnectionString(ref strConn, ref strProvider);            sqlCn = new SqlConnection(strConn);            sqlCm = new SqlCommand(strSql, sqlCn);             sqlCn.Open();            SerializedState = Convert.ToString(sqlCm.ExecuteScalar());            IStateFormatter formatter = this.StateFormatter;             if ((null == SerializedState) ||                (String.Empty == SerializedState))            {                throw (new ApplicationException("No ViewState records were returned."));            }             // Deserilize returns the Pair object that is serialized in            // the Save method.            PageState = (Pair)formatter.Deserialize(SerializedState);             if (sqlCn.State != ConnectionState.Closed)            {                sqlCn.Close();            }            sqlCn.Dispose();            sqlCm.Dispose();        }        finally        {            sqlCn = null;            sqlCm = null;        }        return PageState;    }     private string SqlEscape(string Val)    {        string ReturnVal = String.Empty;        if (null != Val)        {            ReturnVal = Val.Replace("'", "''");        }        return (ReturnVal);    }    private void GetDBConnectionString(ref string ConnectionStringValue, ref string ProviderNameValue)    {        if (System.Configuration.ConfigurationManager.ConnectionStrings.Count > 0)        {            ConnectionStringValue = System.Configuration.ConfigurationManager.ConnectionStrings["ApplicationServices"].ConnectionString;            ProviderNameValue = System.Configuration.ConfigurationManager.ConnectionStrings["ApplicationServices"].ProviderName;        }        else        {            throw new ConfigurationErrorsException(_exNoConnectionStringFound);        }    }    private string GetMinutesInPastToDelete()    {        string strReturn = "-60";        if (null != System.Configuration.ConfigurationManager.AppSettings["MinutesInPastToDeletePageState"])        {            strReturn = System.Configuration.ConfigurationManager.AppSettings["MinutesInPastToDeletePageState"].ToString();        }        return (strReturn);    }}#endregion AppleiPhone.cs file: using System;using System.Collections.Generic;using System.Linq;using System.Web; /// <summary>/// Summary description for AppleIPhone/// </summary>public class AppleIPhone{ public AppleIPhone() {  //  // TODO: Add constructor logic here  // }     static public bool IsIPhoneOS()    {        return (IsIPad() || IsIPhone() || IsIPodTouch());    }     static public bool IsIPhone()    {        return IsTest("iPhone");    }     static public bool IsIPodTouch()    {        return IsTest("iPod");    }     static public bool IsIPad()    {        return IsTest("iPad");    }     static private bool IsTest(string Agent)    {        bool bl = false;        string ua = HttpContext.Current.Request.UserAgent.ToLower();        try        {            bl = ua.Contains(Agent.ToLower());        }        catch { }        return (bl);        }} Master page .cs: using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.HtmlControls;using System.Web.UI.WebControls; public partial class MasterPages_iPhoneMaster : System.Web.UI.MasterPage{    protected void Page_Load(object sender, EventArgs e)    {            HtmlHead head = Page.Header;            HtmlMeta meta = new HtmlMeta();            if (AppleIPhone.IsIPad() == true)            {                meta.Content = "width=400,user-scalable=no";                head.Controls.Add(meta);             }            else            {                meta.Content = "width=device-width, user-scalable=no";                meta.Attributes.Add("name", "viewport");            }            meta.Attributes.Add("name", "viewport");            head.Controls.Add(meta);            HtmlLink cssLink = new HtmlLink();            HtmlGenericControl script = new HtmlGenericControl("script");            script.Attributes.Add("type", "text/javascript");            script.Attributes.Add("src", ResolveUrl("~/Scripts/iWebKit/javascript/functions.js"));            head.Controls.Add(script);            cssLink.Attributes.Add("rel", "stylesheet");            cssLink.Attributes.Add("href", ResolveUrl("~/Scripts/iWebKit/css/style.css") );            cssLink.Attributes.Add("type", "text/css");            head.Controls.Add(cssLink);            HtmlGenericControl jsLink = new HtmlGenericControl("script");            //jsLink.Attributes.Add("type", "text/javascript");            //jsLink.Attributes.Add("src", ResolveUrl("~/Scripts/jquery-1.4.1.min.js") );            //head.Controls.Add(jsLink);            HtmlLink appleIcon = new HtmlLink();            appleIcon.Attributes.Add("rel", "apple-touch-icon");            appleIcon.Attributes.Add("href", ResolveUrl("~/apple-touch-icon.png"));            HtmlMeta appleMobileWebAppStatusBarStyle = new HtmlMeta();            appleMobileWebAppStatusBarStyle.Attributes.Add("name", "apple-mobile-web-app-status-bar-style");            appleMobileWebAppStatusBarStyle.Attributes.Add("content", "black");            head.Controls.Add(appleMobileWebAppStatusBarStyle);    }     internal string FindPath(string Location)    {        string Url = Server.MapPath(Location);        return (Url);    }}

  Read the article

• How can I use functools.partial on multiple methods on an object, and freeze parameters out of order

  - by Joseph Garvin

  I find functools.partial to be extremely useful, but I would like to be able to freeze arguments out of order (the argument you want to freeze is not always the first one) and I'd like to be able to apply it to several methods on a class at once, to make a proxy object that has the same methods as the underlying object except with some of its methods parameter being frozen (think of it as generalizing partial to apply to classes). I've managed to scrap together a version of functools.partial called 'bind' that lets me specify parameters out of order by passing them by keyword argument. That part works: >>> def foo(x, y): ... print x, y ... >>> bar = bind(foo, y=3) >>> bar(2) 2 3 But my proxy class does not work, and I'm not sure why: >>> class Foo(object): ... def bar(self, x, y): ... print x, y ... >>> a = Foo() >>> b = PureProxy(a, bar=bind(Foo.bar, y=3)) >>> b.bar(2) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: bar() takes exactly 3 arguments (2 given) I'm probably doing this all sorts of wrong because I'm just going by what I've pieced together from random documentation, blogs, and running dir() on all the pieces. Suggestions both on how to make this work and better ways to implement it would be appreciated ;) One detail I'm unsure about is how this should all interact with descriptors. Code follows. from types import MethodType class PureProxy(object): def __init__(self, underlying, **substitutions): self.underlying = underlying for name in substitutions: subst_attr = substitutions[name] if hasattr(subst_attr, "underlying"): setattr(self, name, MethodType(subst_attr, self, PureProxy)) def __getattribute__(self, name): return getattr(object.__getattribute__(self, "underlying"), name) def bind(f, *args, **kwargs): """ Lets you freeze arguments of a function be certain values. Unlike functools.partial, you can freeze arguments by name, which has the bonus of letting you freeze them out of order. args will be treated just like partial, but kwargs will properly take into account if you are specifying a regular argument by name. """ argspec = inspect.getargspec(f) argdict = copy(kwargs) if hasattr(f, "im_func"): f = f.im_func args_idx = 0 for arg in argspec.args: if args_idx >= len(args): break argdict[arg] = args[args_idx] args_idx += 1 num_plugged = args_idx def new_func(*inner_args, **inner_kwargs): args_idx = 0 for arg in argspec.args[num_plugged:]: if arg in argdict: continue if args_idx >= len(inner_args): # We can't raise an error here because some remaining arguments # may have been passed in by keyword. break argdict[arg] = inner_args[args_idx] args_idx += 1 f(**dict(argdict, **inner_kwargs)) new_func.underlying = f return new_func

  Read the article

• Repeating a object that only occurs couple of times and has different values with htmlagilitypack c#.

  - by dtd

  I have a problem I cant seem to solve here. Lets say I have some html like beneth here that I want to parse. All this html is within one list on the page. And the names repeat themself like in the example I wrote. <li class = "seperator"> a date </li> <li class = "lol"> some text </li> <li class = "lol"> some text </li> <li class = "lol"> some text </li> <li class = "seperator"> a new date </li> <li class = "lol"> some text </li> <li class = "seperator"> a nother new date </li> <li class = "lol"> some text </li> <li class = "lol"> some text </li> I did manage to use htmlagility pack to parse every li object seperate, and almost formating it how I want. My print atm looks something like this: "a date" "some text" "some text" "some text" "some text" "a new date" "some text" "a nother new date " "some text" "some text" "some text" What I want to achive: "a date" "some text" "a date" "some text" "a date" "some text" "a date" "some text" "a new date" "some text" "a nother new date " "some text" "a nother new date " "some text" "a nother new date " "some text" But the problem is that beneath every seperator, the count of every lol object may vary. So one day, the webpage may have one lol object beneth date 1, and the next day it may have 10 lol objects. So I am woundering if there is an smart/easy way to somehow count the number of lol objects in between the seperators. Or if there is another way to figure this out? Within for example htmlagilitypack. And yes, I need the correct date in front of every lol object, not just infront the first one. This would have been a pice of cake if the seperator class would have ended beneath the last lol object, but sadly that is not the case... I dont think that I need to paste my code here, but basicly what I do is to parse the page, extract the seperators and lol objects and add them to a list, where I split them up to seperator and lol objects. Then I print it out to a file and since the seperator only occure 3 times(in the example) I will only get out 3 seperate dates.

  Read the article

• Better way to write an object generator for an RAII template class?

  - by Dan

  I would like to write an object generator for a templated RAII class -- basically a function template to construct an object using type deduction of parameters so the types don't have to be specified explicitly. The problem I foresee is that the helper function that takes care of type deduction for me is going to return the object by value, which will result in a premature call to the RAII destructor when the copy is made. Perhaps C++0x move semantics could help but that's not an option for me. Anyone seen this problem before and have a good solution? This is what I have: template<typename T, typename U, typename V> class FooAdder { private: typedef OtherThing<T, U, V> Thing; Thing &thing_; int a_; // many other members public: FooAdder(Thing &thing, int a); ~FooAdder(); void foo(T t, U u); void bar(V v); }; The gist is that OtherThing has a horrible interface, and FooAdder is supposed to make it easier to use. The intended use is roughly like this: FooAdder(myThing, 2) .foo(3, 4) .foo(5, 6) .bar(7) .foo(8, 9); The FooAdder constructor initializes some internal data structures. The foo and bar methods populate those data structures. The ~FooAdder dtor wraps things up and calls a method on thing_, taking care of all the nastiness. That would work fine if FooAdder wasn't a template. But since it is, I would need to put the types in, more like this: FooAdder<Abc, Def, Ghi>(myThing, 2) ... That's annoying, because the types can be inferred based on myThing. So I would prefer to create a templated object generator, similar to std::make_pair, that will do the type deduction for me. Something like this: template<typename T, typename U, typename V> FooAdder<T, U, V> AddFoo(Thing &thing, int a) { return FooAdder<T, U, V>(thing, a); } That seems problematic: because it returns by value, the stack temporary object will be destructed, which will cause the RAII dtor to run prematurely. One thought I had was to give FooAdder a copy ctor with move semantics, kinda like std::auto_ptr. But I would like to do this without dynamic memory allocation, so I thought the copy ctor could set a flag within FooAdder indicating the dtor shouldn't do the wrap-up. Like this: FooAdder(FooAdder &rhs) // Note: rhs is not const : thing_(rhs.thing_) , a_(rhs.a_) , // etc... lots of other members, annoying. , moved(false) { rhs.moved = true; } ~FooAdder() { if (!moved) { // do whatever it would have done } } Seems clunky. Anyone got a better way?

  Read the article

• Entity Association Mapping with Code First Part 1 : Mapping Complex Types

  - by mortezam

  Last week the CTP5 build of the new Entity Framework Code First has been released by data team at Microsoft. Entity Framework Code-First provides a pretty powerful code-centric way to work with the databases. When it comes to associations, it brings ultimate flexibility. I’m a big fan of the EF Code First approach and am planning to explain association mapping with code first in a series of blog posts and this one is dedicated to Complex Types. If you are new to Code First approach, you can find a great walkthrough here. In order to build a solid foundation for our discussion, we will start by learning about some of the core concepts around the relationship mapping.   What is Mapping?Mapping is the act of determining how objects and their relationships are persisted in permanent data storage, in our case, relational databases. What is Relationship mapping?A mapping that describes how to persist a relationship (association, aggregation, or composition) between two or more objects. Types of RelationshipsThere are two categories of object relationships that we need to be concerned with when mapping associations. The first category is based on multiplicity and it includes three types: One-to-one relationships: This is a relationship where the maximums of each of its multiplicities is one. One-to-many relationships: Also known as a many-to-one relationship, this occurs when the maximum of one multiplicity is one and the other is greater than one. Many-to-many relationships: This is a relationship where the maximum of both multiplicities is greater than one. The second category is based on directionality and it contains two types: Uni-directional relationships: when an object knows about the object(s) it is related to but the other object(s) do not know of the original object. To put this in EF terminology, when a navigation property exists only on one of the association ends and not on the both. Bi-directional relationships: When the objects on both end of the relationship know of each other (i.e. a navigation property defined on both ends). How Object Relationships Are Implemented in POCO domain models?When the multiplicity is one (e.g. 0..1 or 1) the relationship is implemented by defining a navigation property that reference the other object (e.g. an Address property on User class). When the multiplicity is many (e.g. 0..*, 1..*) the relationship is implemented via an ICollection of the type of other object. How Relational Database Relationships Are Implemented? Relationships in relational databases are maintained through the use of Foreign Keys. A foreign key is a data attribute(s) that appears in one table and must be the primary key or other candidate key in another table. With a one-to-one relationship the foreign key needs to be implemented by one of the tables. To implement a one-to-many relationship we implement a foreign key from the “one table” to the “many table”. We could also choose to implement a one-to-many relationship via an associative table (aka Join table), effectively making it a many-to-many relationship. Introducing the ModelNow, let's review the model that we are going to use in order to implement Complex Type with Code First. It's a simple object model which consist of two classes: User and Address. Each user could have one billing address. The Address information of a User is modeled as a separate class as you can see in the UML model below: In object-modeling terms, this association is a kind of aggregation—a part-of relationship. Aggregation is a strong form of association; it has some additional semantics with regard to the lifecycle of objects. In this case, we have an even stronger form, composition, where the lifecycle of the part is fully dependent upon the lifecycle of the whole. Fine-grained domain models The motivation behind this design was to achieve Fine-grained domain models. In crude terms, fine-grained means “more classes than tables”. For example, a user may have both a billing address and a home address. In the database, you may have a single User table with the columns BillingStreet, BillingCity, and BillingPostalCode along with HomeStreet, HomeCity, and HomePostalCode. There are good reasons to use this somewhat denormalized relational model (performance, for one). In our object model, we can use the same approach, representing the two addresses as six string-valued properties of the User class. But it’s much better to model this using an Address class, where User has the BillingAddress and HomeAddress properties. This object model achieves improved cohesion and greater code reuse and is more understandable. Complex Types: Splitting a Table Across Multiple Types Back to our model, there is no difference between this composition and other weaker styles of association when it comes to the actual C# implementation. But in the context of ORM, there is a big difference: A composed class is often a candidate Complex Type. But C# has no concept of composition—a class or property can’t be marked as a composition. The only difference is the object identifier: a complex type has no individual identity (i.e. no AddressId defined on Address class) which make sense because when it comes to the database everything is going to be saved into one single table. How to implement a Complex Types with Code First Code First has a concept of Complex Type Discovery that works based on a set of Conventions. The convention is that if Code First discovers a class where a primary key cannot be inferred, and no primary key is registered through Data Annotations or the fluent API, then the type will be automatically registered as a complex type. Complex type detection also requires that the type does not have properties that reference entity types (i.e. all the properties must be scalar types) and is not referenced from a collection property on another type. Here is the implementation: public class User{    public int UserId { get; set; }    public string FirstName { get; set; }    public string LastName { get; set; }    public string Username { get; set; }    public Address Address { get; set; }} public class Address {     public string Street { get; set; }     public string City { get; set; }            public string PostalCode { get; set; }        }public class EntityMappingContext : DbContext {     public DbSet<User> Users { get; set; }        } With code first, this is all of the code we need to write to create a complex type, we do not need to configure any additional database schema mapping information through Data Annotations or the fluent API. Database SchemaThe mapping result for this object model is as follows: Limitations of this mappingThere are two important limitations to classes mapped as Complex Types: Shared references is not possible: The Address Complex Type doesn’t have its own database identity (primary key) and so can’t be referred to by any object other than the containing instance of User (e.g. a Shipping class that also needs to reference the same User Address). No elegant way to represent a null reference There is no elegant way to represent a null reference to an Address. When reading from database, EF Code First always initialize Address object even if values in all mapped columns of the complex type are null. This means that if you store a complex type object with all null property values, EF Code First returns a initialized complex type when the owning entity object is retrieved from the database. SummaryIn this post we learned about fine-grained domain models which complex type is just one example of it. Fine-grained is fully supported by EF Code First and is known as the most important requirement for a rich domain model. Complex type is usually the simplest way to represent one-to-one relationships and because the lifecycle is almost always dependent in such a case, it’s either an aggregation or a composition in UML. In the next posts we will revisit the same domain model and will learn about other ways to map a one-to-one association that does not have the limitations of the complex types. References ADO.NET team blog Mapping Objects to Relational Databases Java Persistence with Hibernate

  Read the article

< Previous Page | 189 190 191 192 193 194 195 196 197 198 199 200  | Next Page >