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  • These are few objective type questions which i was not able to find the solution [closed]

    - by Tarun
    1. Which of the following advantages does System.Collections.IDictionaryEnumerator provide over System.Collections.IEnumerator? a. It adds properties for direct access to both the Key and the Value b. It is optimized to handle the structure of a Dictionary. c. It provides properties to determine if the Dictionary is enumerated in Key or Value order d. It provides reverse lookup methods to distinguish a Key from a specific Value 2. When Implementing System.EnterpriseServices.ServicedComponent derived classes, which of the following statements are true? a. Enabling object pooling requires an attribute on the class and the enabling of pooling in the COM+ catalog. b. Methods can be configured to automatically mark a transaction as complete by the use of attributes. c. You can configure authentication using the AuthenticationOption when the ActivationMode is set to Library. d. You can control the lifecycle policy of an individual instance using the SetLifetimeService method. 3. Which of the following are true regarding event declaration in the code below? class Sample { event MyEventHandlerType MyEvent; } a. MyEventHandlerType must be derived from System.EventHandler or System.EventHandler<TEventArgs> b. MyEventHandlerType must take two parameters, the first of the type Object, and the second of a class derived from System.EventArgs c. MyEventHandlerType may have a non-void return type d. If MyEventHandlerType is a generic type, event declaration must use a specialization of that type. e. MyEventHandlerType cannot be declared static 4. Which of the following statements apply to developing .NET code, using .NET utilities that are available with the SDK or Visual Studio? a. Developers can create assemblies directly from the MSIL Source Code. b. Developers can examine PE header information in an assembly. c. Developers can generate XML Schemas from class definitions contained within an assembly. d. Developers can strip all meta-data from managed assemblies. e. Developers can split an assembly into multiple assemblies. 5. Which of the following characteristics do classes in the System.Drawing namespace such as Brush,Font,Pen, and Icon share? a. They encapsulate native resource and must be properly Disposed to prevent potential exhausting of resources. b. They are all MarshalByRef derived classes, but functionality across AppDomains has specific limitations. c. You can inherit from these classes to provide enhanced or customized functionality 6. Which of the following are required to be true by objects which are going to be used as keys in a System.Collections.HashTable? a. They must handle case-sensitivity identically in both the GetHashCode() and Equals() methods. b. Key objects must be immutable for the duration they are used within a HashTable. c. Get HashCode() must be overridden to provide the same result, given the same parameters, regardless of reference equalityl unless the HashTable constructor is provided with an IEqualityComparer parameter. d. Each Element in a HashTable is stored as a Key/Value pair of the type System.Collections.DictionaryElement e. All of the above 7. Which of the following are true about Nullable types? a. A Nullable type is a reference type. b. A Nullable type is a structure. c. An implicit conversion exists from any non-nullable value type to a nullable form of that type. d. An implicit conversion exists from any nullable value type to a non-nullable form of that type. e. A predefined conversion from the nullable type S? to the nullable type T? exists if there is a predefined conversion from the non-nullable type S to the non-nullable type T 8. When using an automatic property, which of the following statements is true? a. The compiler generates a backing field that is completely inaccessible from the application code. b. The compiler generates a backing field that is a private instance member with a leading underscore that can be programmatically referenced. c. The compiler generates a backing field that is accessible via reflection d. The compiler generates a code that will store the information separately from the instance to ensure its security. 9. Which of the following does using Initializer Syntax with a collection as shown below require? CollectionClass numbers = new CollectionClass { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; a. The Collection Class must implement System.Collections.Generic.ICollection<T> b. The Collection Class must implement System.Collections.Generic.IList<T> c. Each of the Items in the Initializer List will be passed to the Add<T>(T item) method d. The items in the initializer will be treated as an IEnumerable<T> and passed to the collection constructor+K110 10. What impact will using implicitly typed local variables as in the following example have? var sample = "Hello World"; a. The actual type is determined at compilation time, and has no impact on the runtime b. The actual type is determined at runtime, and late binding takes effect c. The actual type is based on the native VARIANT concept, and no binding to a specific type takes place. d. "var" itself is a specific type defined by the framework, and no special binding takes place 11. Which of the following is not supported by remoting object types? a. well-known singleton b. well-known single call c. client activated d. context-agile 12. In which of the following ways do structs differ from classes? a. Structs can not implement interfaces b. Structs cannot inherit from a base struct c. Structs cannot have events interfaces d. Structs cannot have virtual methods 13. Which of the following is not an unboxing conversion? a. void Sample1(object o) { int i = (int)o; } b. void Sample1(ValueType vt) { int i = (int)vt; } c. enum E { Hello, World} void Sample1(System.Enum et) { E e = (E) et; } d. interface I { int Value { get; set; } } void Sample1(I vt) { int i = vt.Value; } e. class C { public int Value { get; set; } } void Sample1(C vt) { int i = vt.Value; } 14. Which of the following are characteristics of the System.Threading.Timer class? a. The method provided by the TimerCallback delegate will always be invoked on the thread which created the timer. b. The thread which creates the timer must have a message processing loop (i.e. be considered a UI thread) c. The class contains protection to prevent reentrancy to the method provided by the TimerCallback delegate d. You can receive notification of an instance being Disposed by calling an overload of the Dispose method. 15. What is the proper declaration of a method which will handle the following event? Class MyClass { public event EventHandler MyEvent; } a. public void A_MyEvent(object sender, MyArgs e) { } b. public void A_MyEvent(object sender, EventArgs e) { } c. public void A_MyEvent(MyArgs e) { } d. public void A_MyEvent(MyClass sender,EventArgs e) { } 16. Which of the following scenarios are applicable to Window Workflow Foundation? a. Document-centric workflows b. Human workflows c. User-interface page flows d. Builtin support for communications across multiple applications and/or platforms e. All of the above 17. When using an automatic property, which of the following statements is true? a. The compiler generates a backing field that is completely inaccessible from the application code. b. The compiler generates a backing field that is a private instance member with a leading underscore that can be programmatically referenced. c. The compiler generates a backing field that is accessible via reflection d. The compiler generates a code that will store the information separately from the instance to ensure its security. 18 While using the capabilities supplied by the System.Messaging classes, which of the following are true? a. Information must be explicitly converted to/from a byte stream before it uses the MessageQueue class b. Invoking the MessageQueue.Send member defaults to using the System.Messaging.XmlMessageFormatter to serialize the object. c. Objects must be XMLSerializable in order to be transferred over a MessageQueue instance. d. The first entry in a MessageQueue must be removed from the queue before the next entry can be accessed e. Entries removed from a MessageQueue within the scope of a transaction, will be pushed back into the front of the queue if the transaction fails. 19. Which of the following are true about declarative attributes? a. They must be inherited from the System.Attribute. b. Attributes are instantiated at the same time as instances of the class to which they are applied. c. Attribute classes may be restricted to be applied only to application element types. d. By default, a given attribute may be applied multiple times to the same application element. 20. When using version 3.5 of the framework in applications which emit a dynamic code, which of the following are true? a. A Partial trust code can not emit and execute a code b. A Partial trust application must have the SecurityCriticalAttribute attribute have called Assert ReflectionEmit permission c. The generated code no more permissions than the assembly which emitted it. d. It can be executed by calling System.Reflection.Emit.DynamicMethod( string name, Type returnType, Type[] parameterTypes ) without any special permissions Within Windows Workflow Foundation, Compensating Actions are used for: a. provide a means to rollback a failed transaction b. provide a means to undo a successfully committed transaction later c. provide a means to terminate an in process transaction d. achieve load balancing by adapting to the current activity 21. What is the proper declaration of a method which will handle the following event? Class MyClass { public event EventHandler MyEvent; } a. public void A_MyEvent(object sender, MyArgs e) { } b. public void A_MyEvent(object sender, EventArgs e) { } c. public void A_MyEvent(MyArgs e) { } d. public void A_MyEvent(MyClass sender,EventArgs e) { } 22. Which of the following controls allows the use of XSL to transform XML content into formatted content? a. System.Web.UI.WebControls.Xml b. System.Web.UI.WebControls.Xslt c. System.Web.UI.WebControls.Substitution d. System.Web.UI.WebControls.Transform 23. To which of the following do automatic properties refer? a. You declare (explicitly or implicitly) the accessibility of the property and get and set accessors, but do not provide any implementation or backing field b. You attribute a member field so that the compiler will generate get and set accessors c. The compiler creates properties for your class based on class level attributes d. They are properties which are automatically invoked as part of the object construction process 24. Which of the following are true about Nullable types? a. A Nullable type is a reference type. b. An implicit conversion exists from any non-nullable value type to a nullable form of that type. c. A predefined conversion from the nullable type S? to the nullable type T? exists if there is a predefined conversion from the non-nullable type S to the non-nullable type T 25. When using an automatic property, which of the following statements is true? a. The compiler generates a backing field that is completely inaccessible from the application code. b. The compiler generates a backing field that is accessible via reflection. c. The compiler generates a code that will store the information separately from the instance to ensure its security. 26. When using an implicitly typed array, which of the following is most appropriate? a. All elements in the initializer list must be of the same type. b. All elements in the initializer list must be implicitly convertible to a known type which is the actual type of at least one member in the initializer list c. All elements in the initializer list must be implicitly convertible to common type which is a base type of the items actually in the list 27. Which of the following is false about anonymous types? a. They can be derived from any reference type. b. Two anonymous types with the same named parameters in the same order declared in different classes have the same type. c. All properties of an anonymous type are read/write. 28. Which of the following are true about Extension methods. a. They can be declared either static or instance members b. They must be declared in the same assembly (but may be in different source files) c. Extension methods can be used to override existing instance methods d. Extension methods with the same signature for the same class may be declared in multiple namespaces without causing compilation errors

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  • Java JPanel not showing up....

    - by user69514
    I'm not sure what I am doing wrong, but the text for my JPanels is not showing up. I just get the question number text, but the question is not showing up. Any ideas what I am doing wrong? import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.event.*; class NewFrame extends JFrame { JPanel centerpanel; // For the questions. CardLayout card; // For the centerpanel. JTextField tf; // Used in question 1. boolean // Store selections for Q2. q2Option1, q2Option2, q2Option3, q2Option4; JList q4List; // For question 4. double // Score on each question. q1Score = 0, q2Score = 0, q3Score = 0, q4Score = 0; // Constructor. public NewFrame (int width, int height) { this.setTitle ("Snoot Club Membership Test"); this.setResizable (true); this.setSize (width, height); Container cPane = this.getContentPane(); // cPane.setLayout (new BorderLayout()); // First, a welcome message, as a Label. JLabel L = new JLabel ("<html><b>Are you elitist enough for our exclusive club?" + " <br>Fill out the form and find out</b></html>"); L.setForeground (Color.blue); cPane.add (L, BorderLayout.NORTH); // Now the center panel with the questions. card = new CardLayout (); centerpanel = new JPanel (); centerpanel.setLayout (card); centerpanel.setOpaque (false); // Each question will be created in a separate method. // The cardlayout requires a label as second parameter. centerpanel.add (firstQuestion (), "1"); centerpanel.add (secondQuestion(), "2"); centerpanel.add (thirdQuestion(), "3"); centerpanel.add (fourthQuestion(), "4"); cPane.add (centerpanel, BorderLayout.CENTER); // Next, a panel of four buttons at the bottom. // The four buttons: quit, submit, next-question, previous-question. JPanel bottomPanel = getBottomPanel (); cPane.add (bottomPanel, BorderLayout.SOUTH); // Finally, show the frame. this.setVisible (true); } // No-parameter constructor. public NewFrame () { this (500, 300); } // The first question uses labels for the question and // gets input via a textfield. A panel containing all // these things is returned. The question asks for // a vacation destination: the more exotic the location, // the higher the score. JPanel firstQuestion () { // We will package everything into a panel and return the panel. JPanel subpanel = new JPanel (); // We will place things in a single column, so // a GridLayout with one column is appropriate. subpanel.setLayout (new GridLayout (8,1)); JLabel L1 = new JLabel ("Question 1:"); L1.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L1); JLabel L2 = new JLabel (" Select a vacation destination"); L2.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L2); JLabel L3 = new JLabel (" 1. Baltimore"); L3.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L3); JLabel L4 = new JLabel (" 2. Disneyland"); L4.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L4); JLabel L5 = new JLabel (" 3. Grand Canyon"); L5.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L5); JLabel L6 = new JLabel (" 4. French Riviera"); L6.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L6); JLabel L7 = new JLabel ("Enter 1,2,3 or 4 below:"); L7.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L7); // Here's the textfield to get user-input. tf = new JTextField (); tf.addActionListener ( new ActionListener () { // This interface has only one method. public void actionPerformed (ActionEvent a) { String q1String = a.getActionCommand(); if (q1String.equals ("2")) q1Score = 2; else if (q1String.equals ("3")) q1Score = 3; else if (q1String.equals ("4")) q1Score = 4; else q1Score = 1; } } ); subpanel.add (tf); return subpanel; } // For the second question, a collection of checkboxes // will be used. More than one selection can be made. // A listener is required for each checkbox. The state // of each checkbox is recorded. JPanel secondQuestion () { JPanel subpanel = new JPanel (); subpanel.setLayout (new GridLayout (7,1)); JLabel L1 = new JLabel ("Question 2:"); L1.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L1); JLabel L2 = new JLabel (" Select ONE OR MORE things that "); L2.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L2); JLabel L3 = new JLabel (" you put into your lunch sandwich"); L3.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L3); // Initialize the selections to false. q2Option1 = q2Option2 = q2Option3 = q2Option4 = false; // First checkbox. JCheckBox c1 = new JCheckBox ("Ham, beef or turkey"); c1.addItemListener ( new ItemListener () { public void itemStateChanged (ItemEvent i) { JCheckBox c = (JCheckBox) i.getSource(); q2Option1 = c.isSelected(); } } ); subpanel.add (c1); // Second checkbox. JCheckBox c2 = new JCheckBox ("Cheese"); c2.addItemListener ( new ItemListener () { // This is where we will react to a change in checkbox. public void itemStateChanged (ItemEvent i) { JCheckBox c = (JCheckBox) i.getSource(); q2Option2 = c.isSelected(); } } ); subpanel.add (c2); // Third checkbox. JCheckBox c3 = new JCheckBox ("Sun-dried Arugula leaves"); c3.addItemListener ( new ItemListener () { public void itemStateChanged (ItemEvent i) { JCheckBox c = (JCheckBox) i.getSource(); q2Option3 = c.isSelected(); } } ); subpanel.add (c3); // Fourth checkbox. JCheckBox c4 = new JCheckBox ("Lemon-enhanced smoked Siberian caviar"); c4.addItemListener ( new ItemListener () { public void itemStateChanged (ItemEvent i) { JCheckBox c = (JCheckBox) i.getSource(); q2Option4 = c.isSelected(); } } ); subpanel.add (c4); return subpanel; } // The third question allows only one among four choices // to be selected. We will use radio buttons. JPanel thirdQuestion () { JPanel subpanel = new JPanel (); subpanel.setLayout (new GridLayout (6,1)); JLabel L1 = new JLabel ("Question 3:"); L1.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L1); JLabel L2 = new JLabel (" And which mustard do you use?"); L2.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L2); // First, create the ButtonGroup instance. // We will add radio buttons to this group. ButtonGroup bGroup = new ButtonGroup(); // First checkbox. JRadioButton r1 = new JRadioButton ("Who cares?"); r1.addItemListener ( new ItemListener () { public void itemStateChanged (ItemEvent i) { JRadioButton r = (JRadioButton) i.getSource(); if (r.isSelected()) q3Score = 1; } } ); bGroup.add (r1); subpanel.add (r1); // Second checkbox. JRadioButton r2 = new JRadioButton ("Safeway Brand"); r2.addItemListener ( new ItemListener () { public void itemStateChanged (ItemEvent i) { JRadioButton r = (JRadioButton) i.getSource(); if (r.isSelected()) q3Score = 2; } } ); bGroup.add (r2); subpanel.add (r2); // Third checkbox. JRadioButton r3 = new JRadioButton ("Fleishman's"); r3.addItemListener ( new ItemListener () { public void itemStateChanged (ItemEvent i) { JRadioButton r = (JRadioButton) i.getSource(); if (r.isSelected()) q3Score = 3; } } ); bGroup.add (r3); subpanel.add (r3); // Fourth checkbox. JRadioButton r4 = new JRadioButton ("Grey Poupon"); r4.addItemListener ( new ItemListener () { public void itemStateChanged (ItemEvent i) { JRadioButton r = (JRadioButton) i.getSource(); if (r.isSelected()) q3Score = 4; } } ); bGroup.add (r4); subpanel.add (r4); return subpanel; } // For the fourth question we will use a drop-down Choice. JPanel fourthQuestion () { JPanel subpanel = new JPanel (); subpanel.setLayout (new GridLayout (3,1)); JLabel L1 = new JLabel ("Question 4:"); L1.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L1); JLabel L2 = new JLabel (" Your movie preference, among these:"); L2.setFont (new Font ("SansSerif", Font.ITALIC, 15)); subpanel.add (L2); // Create a JList with options. String[] movies = { "Lethal Weapon IV", "Titanic", "Saving Private Ryan", "Le Art Movie avec subtitles"}; q4List = new JList (movies); q4Score = 1; q4List.addListSelectionListener ( new ListSelectionListener () { public void valueChanged (ListSelectionEvent e) { q4Score = 1 + q4List.getSelectedIndex(); } } ); subpanel.add (q4List); return subpanel; } void computeResult () { // Clear the center panel. centerpanel.removeAll(); // Create a new panel to display in the center. JPanel subpanel = new JPanel (new GridLayout (5,1)); // Score on question 1. JLabel L1 = new JLabel ("Score on question 1: " + q1Score); L1.setFont (new Font ("Serif", Font.ITALIC, 15)); subpanel.add (L1); // Score on question 2. if (q2Option1) q2Score += 1; if (q2Option2) q2Score += 2; if (q2Option3) q2Score += 3; if (q2Option4) q2Score += 4; q2Score = 0.6 * q2Score; JLabel L2 = new JLabel ("Score on question 2: " + q2Score); L2.setFont (new Font ("Serif", Font.ITALIC, 15)); subpanel.add (L2); // Score on question 3. JLabel L3 = new JLabel ("Score on question 3: " + q3Score); L3.setFont (new Font ("Serif", Font.ITALIC, 15)); subpanel.add (L3); // Score on question 4. JLabel L4 = new JLabel ("Score on question 4: " + q4Score); L4.setFont (new Font ("Serif", Font.ITALIC, 15)); subpanel.add (L4); // Weighted score. double avg = (q1Score + q2Score + q3Score + q4Score) / (double) 4; JLabel L5; if (avg <= 3.5) L5 = new JLabel ("Your average score: " + avg + " - REJECTED!"); else L5 = new JLabel ("Your average score: " + avg + " - WELCOME!"); L5.setFont (new Font ("Serif", Font.BOLD, 20)); //L5.setAlignment (JLabel.CENTER); subpanel.add (L5); // Now add the new subpanel. centerpanel.add (subpanel, "5"); // Need to mark the centerpanel as "altered" centerpanel.invalidate(); // Everything "invalid" (e.g., the centerpanel above) // is now re-computed. this.validate(); } JPanel getBottomPanel () { // Create a panel into which we will place buttons. JPanel bottomPanel = new JPanel (); // A "previous-question" button. JButton backward = new JButton ("Previous question"); backward.setFont (new Font ("Serif", Font.PLAIN | Font.BOLD, 15)); backward.addActionListener ( new ActionListener () { public void actionPerformed (ActionEvent a) { // Go back in the card layout. card.previous (centerpanel); } } ); bottomPanel.add (backward); // A forward button. JButton forward = new JButton ("Next question"); forward.setFont (new Font ("Serif", Font.PLAIN | Font.BOLD, 15)); forward.addActionListener ( new ActionListener () { public void actionPerformed (ActionEvent a) { // Go forward in the card layout. card.next (centerpanel); } } ); bottomPanel.add (forward); // A submit button. JButton submit = new JButton ("Submit"); submit.setFont (new Font ("Serif", Font.PLAIN | Font.BOLD, 15)); submit.addActionListener ( new ActionListener () { public void actionPerformed (ActionEvent a) { // Perform submit task. computeResult(); } } ); bottomPanel.add (submit); JButton quitb = new JButton ("Quit"); quitb.setFont (new Font ("Serif", Font.PLAIN | Font.BOLD, 15)); quitb.addActionListener ( new ActionListener () { public void actionPerformed (ActionEvent a) { System.exit (0); } } ); bottomPanel.add (quitb); return bottomPanel; } } public class Survey { public static void main (String[] argv) { NewFrame nf = new NewFrame (600, 300); } }

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  • Choosing a VS project type (C++)

    - by typoknig
    Hi all, I do not use C++ much (I try to stick to the easier stuff like Java and VB.NET), but the lately I have not had a choice. When I am picking a project type in VS for some C++ source I download, what project type should I pick? I had just been sticking with Win32 Console Applications, but I just downloaded some code (below) that will not work right even when it compiles with out errors. I have tried to use a CLR Console Application and an empty project too, and have changed many variables along the way, but I cannot get this code to work. I noticed that this code does not have "int main()" at its beginning, does that have something to do with it? Anyways, here is the code, got it from here: /* Demo of modified Lucas-Kanade optical flow algorithm. See the printf below */ #ifdef _CH_ #pragma package <opencv> #endif #ifndef _EiC #include "cv.h" #include "highgui.h" #include <stdio.h> #include <ctype.h> #endif #include <windows.h> #define FULL_IMAGE_AS_OUTPUT_FILE #define cvMirror cvFlip //IplImage *image = 0, *grey = 0, *prev_grey = 0, *pyramid = 0, *prev_pyramid = 0, *swap_temp; IplImage **buf = 0; IplImage *image1 = 0; IplImage *imageCopy=0; IplImage *image = 0; int win_size = 10; const int MAX_COUNT = 500; CvPoint2D32f* points[2] = {0,0}, *swap_points; char* status = 0; //int count = 0; //int need_to_init = 0; //int night_mode = 0; int flags = 0; //int add_remove_pt = 0; bool bLButtonDown = false; //bool bstopLoop = false; CvPoint pt, pt1,pt2; //IplImage* img1; FILE* FileDest; char* strImageDir = "E:\\Projects\\TSCreator\\Images"; char* strItemName = "b"; int imageCount=0; int bFirstFace = 1; // flag for first face int mode = 1; // Mode 1 - Haar Traing Sample Creation, 2 - HMM sample creation, Mode = 3 - Both Harr and HMM. //int startImgeNo = 1; bool isEqualRation = false; //Weidth to height ratio is equal //Selected Image data IplImage *selectedImage = 0; int selectedX = 0, selectedY = 0, currentImageNo = 0, selectedWidth = 0, selectedHeight= 0; CvRect selectedROI; void saveFroHarrTraining(IplImage *src, int x, int y, int width, int height, int imageCount); void saveForHMMTraining(IplImage *src, CvRect roi,int imageCount); // Code for draw ROI Cropping Image void on_mouse( int event, int x, int y, int flags, void* param ) { char f[200]; CvRect reg; if( !image ) return; if( event == CV_EVENT_LBUTTONDOWN ) { bLButtonDown = true; pt1.x = x; pt1.y = y; } else if ( event == CV_EVENT_MOUSEMOVE ) //Draw the selected area rectangle { pt2.x = x; pt2.y = y; if(bLButtonDown) { if( !image1 ) { /* allocate all the buffers */ image1 = cvCreateImage( cvGetSize(image), 8, 3 ); image1->origin = image->origin; points[0] = (CvPoint2D32f*)cvAlloc(MAX_COUNT*sizeof(points[0][0])); points[1] = (CvPoint2D32f*)cvAlloc(MAX_COUNT*sizeof(points[0][0])); status = (char*)cvAlloc(MAX_COUNT); flags = 0; } cvCopy( image, image1, 0 ); //Equal Weight-Height Ratio if(isEqualRation) { pt2.y = pt1.y + (pt2.x-pt1.x); } //Max Height and Width is the image width and height if(pt2.x>image->width) { pt2.x = image->width; } if(pt2.y>image->height) { pt2.y = image->height; } CvPoint InnerPt1 = pt1; CvPoint InnerPt2 = pt2; if ( InnerPt1.x > InnerPt2.x) { int tempX = InnerPt1.x; InnerPt1.x = InnerPt2.x; InnerPt2.x = tempX; } if ( pt2.y < InnerPt1.y ) { int tempY = InnerPt1.y; InnerPt1.y = InnerPt2.y; InnerPt2.y = tempY; } InnerPt1.y = image->height - InnerPt1.y; InnerPt2.y = image->height - InnerPt2.y; CvFont font; double hScale=1.0; double vScale=1.0; int lineWidth=1; cvInitFont(&font,CV_FONT_HERSHEY_SIMPLEX|CV_FONT_ITALIC, hScale,vScale,0,lineWidth); char size [200]; reg.x = pt1.x; reg.y = image->height - pt2.y; reg.height = abs (pt2.y - pt1.y); reg.width = InnerPt2.x -InnerPt1.x; //print width and heght of the selected reagion sprintf(size, "(%dx%d)",reg.width, reg.height); cvPutText (image1,size,cvPoint(10,10), &font, cvScalar(255,255,0)); cvRectangle(image1, InnerPt1, InnerPt2, CV_RGB(255,0,0), 1); //Mark Selected Reagion selectedImage = image; selectedX = pt1.x; selectedY = pt1.y; selectedWidth = reg.width; selectedHeight = reg.height; selectedROI = reg; //Show the modified image cvShowImage("HMM-Harr Positive Image Creator",image1); } } else if ( event == CV_EVENT_LBUTTONUP ) { bLButtonDown = false; // pt2.x = x; // pt2.y = y; // // if ( pt1.x > pt2.x) // { // int tempX = pt1.x; // pt1.x = pt2.x; // pt2.x = tempX; // } // // if ( pt2.y < pt1.y ) // { // int tempY = pt1.y; // pt1.y = pt2.y; // pt2.y = tempY; // // } // //reg.x = pt1.x; //reg.y = image->height - pt2.y; // //reg.height = abs (pt2.y - pt1.y); ////reg.width = reg.height/3; //reg.width = pt2.x -pt1.x; ////reg.height = (2 * reg.width)/3; #ifdef FULL_IMAGE_AS_OUTPUT_FILE CvRect FullImageRect; FullImageRect.x = 0; FullImageRect.y = 0; FullImageRect.width = image->width; FullImageRect.height = image->height; IplImage *regionFullImage =0; regionFullImage = cvCreateImage(cvSize (FullImageRect.width, FullImageRect.height), image->depth, image->nChannels); image->roi = NULL; //cvSetImageROI (image, FullImageRect); //cvCopy (image, regionFullImage, 0); #else IplImage *region =0; region = cvCreateImage(cvSize (reg.width, reg.height), image1->depth, image1->nChannels); image->roi = NULL; cvSetImageROI (image1, reg); cvCopy (image1, region, 0); #endif //cvNamedWindow("Result", CV_WINDOW_AUTOSIZE); //selectedImage = image; //selectedX = pt1.x; //selectedY = pt1.y; //selectedWidth = reg.width; //selectedHeight = reg.height; ////currentImageNo = startImgeNo; //selectedROI = reg; /*if(mode == 1) { saveFroHarrTraining(image,pt1.x,pt1.y,reg.width,reg.height,startImgeNo); } else if(mode == 2) { saveForHMMTraining(image,reg,startImgeNo); } else if(mode ==3) { saveFroHarrTraining(image,pt1.x,pt1.y,reg.width,reg.height,startImgeNo); saveForHMMTraining(image,reg,startImgeNo); } else { printf("Invalid mode."); } startImgeNo++;*/ } } /* Save popsitive samples for Harr Training. Also add an entry to the PositiveSample.txt with the location of the item of interest. */ void saveFroHarrTraining(IplImage *src, int x, int y, int width, int height, int imageCount) { char f[255] ; sprintf(f,"%s\\%s\\harr_%s%d%d.jpg",strImageDir,strItemName,strItemName,imageCount/10, imageCount%10); cvNamedWindow("Harr", CV_WINDOW_AUTOSIZE); cvShowImage("Harr", src); cvSaveImage(f, src); printf("output%d%d \t ", imageCount/10, imageCount%10); printf("width %d \t", width); printf("height %d \t", height); printf("x1 %d \t", x); printf("y1 %d \t\n", y); char f1[255]; sprintf(f1,"%s\\PositiveSample.txt",strImageDir); FileDest = fopen(f1, "a"); fprintf(FileDest, "%s\\harr_%s%d.jpg 1 %d %d %d %d \n",strItemName,strItemName, imageCount, x, y, width, height); fclose(FileDest); } /* Create Sample Images for HMM recognition algorythm trai ning. */ void saveForHMMTraining(IplImage *src, CvRect roi,int imageCount) { char f[255] ; printf("x=%d, y=%d, w= %d, h= %d\n",roi.x,roi.y,roi.width,roi.height); //Create the file name sprintf(f,"%s\\%s\\hmm_%s%d.pgm",strImageDir,strItemName,strItemName, imageCount); //Create storage for grayscale image IplImage* gray = cvCreateImage(cvSize(roi.width,roi.height), 8, 1); //Create storage for croped reagon IplImage* regionFullImage = cvCreateImage(cvSize(roi.width,roi.height),8,3); //Croped marked region cvSetImageROI(src,roi); cvCopy(src,regionFullImage); cvResetImageROI(src); //Flip croped image - otherwise it will saved upside down cvConvertImage(regionFullImage, regionFullImage, CV_CVTIMG_FLIP); //Convert croped image to gray scale cvCvtColor(regionFullImage,gray, CV_BGR2GRAY); //Show final grayscale image cvNamedWindow("HMM", CV_WINDOW_AUTOSIZE); cvShowImage("HMM", gray); //Save final grayscale image cvSaveImage(f, gray); } int maina( int argc, char** argv ) { CvCapture* capture = 0; //if( argc == 1 || (argc == 2 && strlen(argv[1]) == 1 && isdigit(argv[1][0]))) // capture = cvCaptureFromCAM( argc == 2 ? argv[1][0] - '0' : 0 ); //else if( argc == 2 ) // capture = cvCaptureFromAVI( argv[1] ); char* video; if(argc ==7) { mode = atoi(argv[1]); strImageDir = argv[2]; strItemName = argv[3]; video = argv[4]; currentImageNo = atoi(argv[5]); int a = atoi(argv[6]); if(a==1) { isEqualRation = true; } else { isEqualRation = false; } } else { printf("\nUsage: TSCreator.exe <Mode> <Sample Image Save Path> <Sample Image Save Directory> <Video File Location> <Start Image No> <Is Equal Ratio>\n"); printf("Mode = 1 - Haar Traing Sample Creation. \nMode = 2 - HMM sample creation.\nMode = 3 - Both Harr and HMM\n"); printf("Is Equal Ratio = 0 or 1. 1 - Equal weidth and height, 0 - custom."); printf("Note: You have to create the image save directory in correct path first.\n"); printf("Eg: TSCreator.exe 1 E:\Projects\TSCreator\Images A 11.avi 1 1\n\n"); return 0; } capture = cvCaptureFromAVI(video); if( !capture ) { fprintf(stderr,"Could not initialize capturing...\n"); return -1; } cvNamedWindow("HMM-Harr Positive Image Creator", CV_WINDOW_AUTOSIZE); cvSetMouseCallback("HMM-Harr Positive Image Creator", on_mouse, 0); //cvShowImage("Test", image1); for(;;) { IplImage* frame = 0; int i, k, c; frame = cvQueryFrame( capture ); if( !frame ) break; if( !image ) { /* allocate all the buffers */ image = cvCreateImage( cvGetSize(frame), 8, 3 ); image->origin = frame->origin; //grey = cvCreateImage( cvGetSize(frame), 8, 1 ); //prev_grey = cvCreateImage( cvGetSize(frame), 8, 1 ); //pyramid = cvCreateImage( cvGetSize(frame), 8, 1 ); // prev_pyramid = cvCreateImage( cvGetSize(frame), 8, 1 ); points[0] = (CvPoint2D32f*)cvAlloc(MAX_COUNT*sizeof(points[0][0])); points[1] = (CvPoint2D32f*)cvAlloc(MAX_COUNT*sizeof(points[0][0])); status = (char*)cvAlloc(MAX_COUNT); flags = 0; } cvCopy( frame, image, 0 ); // cvCvtColor( image, grey, CV_BGR2GRAY ); cvShowImage("HMM-Harr Positive Image Creator", image); cvSetMouseCallback("HMM-Harr Positive Image Creator", on_mouse, 0); c = cvWaitKey(0); if((char)c == 's') { //Save selected reagion as training data if(selectedImage) { printf("Selected Reagion Saved\n"); if(mode == 1) { saveFroHarrTraining(selectedImage,selectedX,selectedY,selectedWidth,selectedHeight,currentImageNo); } else if(mode == 2) { saveForHMMTraining(selectedImage,selectedROI,currentImageNo); } else if(mode ==3) { saveFroHarrTraining(selectedImage,selectedX,selectedY,selectedWidth,selectedHeight,currentImageNo); saveForHMMTraining(selectedImage,selectedROI,currentImageNo); } else { printf("Invalid mode."); } currentImageNo++; } } } cvReleaseCapture( &capture ); //cvDestroyWindow("HMM-Harr Positive Image Creator"); cvDestroyAllWindows(); return 0; } #ifdef _EiC main(1,"lkdemo.c"); #endif If I put... #include "stdafx.h" int _tmain(int argc, _TCHAR* argv[]) { return 0; } ... before the previous code (and link it to the correct OpenCV .lib files) it compiles without errors, but does nothing at the command line. How do I make it work?

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  • Full Screen Video Tumblr

    - by Kodi Lane
    I have a tumblr theme seen on http://www.kodilane.com and i am trying to make my Video Posts full screen. I have tried editing the code but i can only get the pictures to stretch. I have attached the template i have so far, if you can spot the changes that need to be done to make the video posts stretch full screen like the pictures do i would really appreciate it. Thank You - Kodi <!DOCTYPE html> <html lang="en"> <head> <title>{Title} {block:PostSummary}- {PostSummary}{/block:PostSummary}</title> <link rel="shortcut icon" href="{Favicon}"> <link rel="alternate" type="application/rss+xml" href="{RSS}"> {block:Description} <meta name="description" content="{MetaDescription}" /> {/block:Description} <meta http-equiv="content-type" content="text/html; charset=utf-8" /> {block:Posts} <meta name="if:Reverse Description" content="0"/> <meta name="if:Include Attribution" content="1"/> <meta name="image:Background" content="http://static.tumblr.com/ffvtarv/QxLlmnswt/kims4.jpeg"/> <meta name="font:Body" content="Arial, Helvetica, sans"/> <meta name="color:Body Text" content="#fff"/> <meta name="color:Link" content="#d5d5d5"/> <meta name="color:Hover" content="#fff"/> <style type="text/css"> html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, b, u, i, center, dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td, article, aside, canvas, details, embed, figure, figcaption, footer, header, hgroup, menu, nav, output, ruby, section, summary, time, mark, audio, video { margin: 0; padding: 0; border: 0; font-size: 100%; font: inherit; vertical-align: baseline; } /* HTML5 display-role reset for older browsers */ article, aside, details, figcaption, figure, footer, header, hgroup, menu, nav, section { display: block; } body { line-height: 1; font-family: {font:Body}; } ol, ul, .bigcats li { list-style: none; } .main ol{ list-style:decimal; margin-left:25px; margin-bottom:10px; } .main ul{ list-style: disc; margin-left:25px; margin-bottom:10px; } blockquote, q { quotes: none; font-style: italic; padding:7px 7px; display:block; } ol.notes blockquote a{ line-height:22px; } blockquote:before, blockquote:after, q:before, q:after { content: ''; content: none; } table { border-collapse: collapse; border-spacing: 0; } strong{ color:#9d9d9d; font-weight: bold; } em{ font-style: italic; } {block:IfNotReverseDescription} .article{ max-width:420px; position:fixed; bottom:43px; right:0; } {/block:IfNotReverseDescription} {block:IfReverseDescription} .article{ max-width:420px; position:fixed; bottom:43px; left:0; } {/block:IfReverseDescription} h1, h2{ position:absolute; top:-9999px; left:-9999px; } .nav{ width:100%; padding: 10px 0px 10px 0px; text-align:left; z-index: 10; color:{color:Link}; margin-left:5px; } .navwrap{ background-color:#000; position:fixed; width:100%; bottom:0px; clear:both; /* Firefox 3.6+ */ background: -moz-linear-gradient(left, rgba(0, 0, 0, .5), rgba(0, 0, 0, 0.8)); /* Safari 4-5, Chrome 1-9 */ background: -webkit-gradient(linear, left top, right top, from(rgba(0, 0, 0, .5)), to(rgba(0, 0, 0, 0.8))); /* Safari 5.1+, Chrome 10+ */ background: -webkit-linear-gradient(left, rgba(0, 0, 0, .5), rgba(0, 0, 0, 0.8)); /* Opera 11.10+ */ background: -o-linear-gradient(left, rgba(0, 0, 0, .5), rgba(0, 0, 0, 0.8)); padding-bottom:2px; box-shadow:0px 0px 3px #000000; } .nav ul li{ display:inline; font-size:13px; text-transform:uppercase; color:{color:Link}; list-style:none; text-align:center; } .nav li{ list-style: none; } .nav ul li a, .nav ul li a:visited { color:{color:Link}; padding: 10px 10px 3px 10px; } .nav ul li a:hover{ color:{color:Hover}; } a{ text-decoration:none; } .main a{ border-bottom: 1px {color:Link} dotted; color: {color:Link}; padding: 0 1px; } .main a:hover, .main a:focus{ color:{color:Hover}; border-bottom: transparent 1px solid; } a:visited, .main a:visited, { color: {color:Link}; } a:active {outline: none;} ol.notes, ol.notes li{ margin-bottom:2px; line-height:16px; } .audiometa{ padding-bottom:10px; } h3.push{ margin-bottom:10px; } h3{ margin-bottom:10px; } h3 a{ margin-bottom:10px; font-size:16px; color:{color:Hover}; } .main, .tags{ color:{color:Body Text}; display:block; padding: 15px; font-size: 12px; line-height: 16px; text-align: left; /* fallback */ background-color: #000; /* Firefox 3.6+ */ background: -moz-linear-gradient(left, rgba(0, 0, 0, .8), rgba(0, 0, 0, 0.6)); /* Safari 4-5, Chrome 1-9 */ background: -webkit-gradient(linear, left top, right top, from(rgba(0, 0, 0, .8)), to(rgba(0, 0, 0, 0.6))); /* Safari 5.1+, Chrome 10+ */ background: -webkit-linear-gradient(left, rgba(0, 0, 0, .8), rgba(0, 0, 0, 0.6)); /* Opera 11.10+ */ background: -o-linear-gradient(left, rgba(0, 0, 0, .8), rgba(0, 0, 0, 0.6)); margin-top:5px; box-shadow:0px 0px 3px #000000 } .tags{ padding: 5px 15px; padding-bottom:7px; } .main iframe, .main embed{ margin-left:-5px; margin-top:-5px; } a.more-link, .tags a, .meta a{ line-height:18px; font-size:10px; border-bottom: 1px #888 dotted; color: {color:Link}; padding: 0 1px; margin: 0 2px; } p.meta{ margin-bottom:5px; } .tags a:hover, a.more-link:hover{ color:{color:Hover}; border-bottom: 1px #FFF dotted; } .pagination{ color: {color:Body Text}; padding: 10px 15px; font-size: 10px; line-height: 16px; text-align: left; /* fallback */ background-color: #000; /* Firefox 3.6+ */ background: -moz-linear-gradient(left, rgba(0, 0, 0, .8), rgba(0, 0, 0, 0.6)); /* Safari 4-5, Chrome 1-9 */ background: -webkit-gradient(linear, left top, right top, from(rgba(0, 0, 0, .8)), to(rgba(0, 0, 0, 0.6))); /* Safari 5.1+, Chrome 10+ */ background: -webkit-linear-gradient(left, rgba(0, 0, 0, .8), rgba(0, 0, 0, 0.6)); /* Opera 11.10+ */ background: -o-linear-gradient(left, rgba(0, 0, 0, .8), rgba(0, 0, 0, 0.6)); margin-top:5px; box-shadow:0px 0px 3px #000000 } .pagination:hover{ /* Firefox 3.6+ */ background: -moz-linear-gradient(left, rgba(0, 0, 0, .6), rgba(0, 0, 0, 0.8)); /* Safari 4-5, Chrome 1-9 */ background: -webkit-gradient(linear, left top, right top, from(rgba(0, 0, 0, .6)), to(rgba(0, 0, 0, 0.8))); /* Safari 5.1+, Chrome 10+ */ background: -webkit-linear-gradient(left, rgba(0, 0, 0, .6), rgba(0, 0, 0, 0.8)); /* Opera 11.10+ */ background: -o-linear-gradient(left, rgba(0, 0, 0, .6), rgba(0, 0, 0, 0.8)); } #nextslide { width:48%; height:100%; background: url(http://static.tumblr.com/szanjxb/vI6lmo15u/forward.png) no-repeat right center, url(http://static.tumblr.com/ffvtarv/gemlmnsks/next-shadow.png) repeat-y right; position:fixed; top:0; right:0; float:left; opacity:0; filter:alpha(opacity=0); -webkit-transition: opacity .5s ease-out; -moz-transition: opacity .5s ease-out; -o-transition: opacity .5s ease-out; overflow:none; } p{ margin-bottom: 10px; } p:last-child{ margin-bottom: 0px; } #prevslide{ width:48%; float:left; height:100%; background: url(http://static.tumblr.com/szanjxb/MSClmo15g/back.png) no-repeat left center, url(http://static.tumblr.com/ffvtarv/bKulmnsl6/prev-shadow.png) repeat-y left; position:fixed; top: 0; left: 0; opacity:0; filter:alpha(opacity=0); -webkit-transition: opacity .5s ease-out; -moz-transition: opacity .5s ease-out; -o-transition: opacity .5s ease-out; } #nextslide:hover, #prevslide:hover{ filter:alpha(opacity=100); opacity:1.0; -webkit-transition: opacity .2s ease-out; -moz-transition: opacity .2s ease-out; -o-transition: opacity .2s ease-out; } p.time{ padding-bottom:10px; margin-bottom:10px; text-align: right; } .left{ float:left; } .right{ float:right; } .button{ position:fixed; bottom: 9px; right: 15px; line-height:12px; font-size:13px; color:{color:Link}; cursor: pointer; float:left; padding-bottom:1px; border-bottom: 2px solid transparent; } .button:hover{ color:{color:Link}; } .notes{ line-height: 11px; } ol.notes li{ list-style: none; } .clear { clear: both; display: block; overflow: hidden; visibility: hidden; width: 0; height: 0; } .hidden{ display:none; } {block:Photo} body {background: url({PhotoURL-HighRes}) no-repeat center center fixed black; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover;} {/block:Photo} {block:Text} body {background: url({image:Background}) no-repeat center center fixed black; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover;} {/block:Text} {block:Video} body {background: url({image:Background}) no-repeat center center fixed black; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover;} {/block:Video} {block:Quote} body {background: url({image:Background}) no-repeat center center fixed black; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover;} {/block:Quote} {block:Link} body {background: url({image:Background}) no-repeat center center fixed black; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover;} {/block:Link} {block:Audio} body {background: url({image:Background}) no-repeat center center fixed black; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover;} {block:AlbumArt} body{ background: url({AlbumArtURL}) no-repeat center center fixed black; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover; } {/block:AlbumArt} {/block:Audio} {block:Answer} body {background: url({image:Background}) no-repeat center center fixed black; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover;} {/block:Answer} {block:Chat} body {background: url({image:Background}) no-repeat center center fixed black; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover;} {/block:Chat} {CustomCSS} </style> <script src="http://static.tumblr.com/ffvtarv/W6Llmnske/jquery-git.js"></script> <script src="http://static.tumblr.com/ffvtarv/QpUlmnsje/jquery.cookie.js"></script> <script> var uiStatus = $.cookie("uiStatus") $(document).ready(function(){ if(uiStatus == 'hidden') { $(".article,.navwrap").hide() }; $(".button").click(function () { $(".article,.navwrap").fadeToggle("slow", "swing"); if(uiStatus == 'hidden') { $.cookie("uiStatus", "visible"); } else { $.cookie("uiStatus", "hidden"); }; }); }); </script> </head> <h1><a href="/">{Title}</a></h1> <h2>{Description}</h2> <!-- Main Side Navigation --> {block:Pagination} {block:PreviousPage} <a href="{PreviousPage}" title="Next Post"><div id="nextslide"></div></a> {/block:PreviousPage} {block:NextPage} <a href="{NextPage}" title="Previous Post"><div id="prevslide"></div></a> {/block:NextPage} {/block:Pagination} {block:PermalinkPagination} {block:PreviousPost} <a href="{PreviousPost}" title="Previous Post"><div id="prevslide"></div></a> {/block:PreviousPost} {block:NextPost} <a href="{NextPost}" title="Next Post"><div id="nextslide"></div></a> {/block:NextPost} {/block:PermalinkPagination} <div class="article"> {block:Pagination} {block:PreviousPage} <a href="{PreviousPage}" title="Newer Post"><div class="pagination">Newer Post</div></a> {/block:PreviousPage} {block:NextPage} <a href="{NextPage}" title="Older Post"><div class="pagination">Older Post</div></a> {/block:NextPage} {/block:Pagination} {block:PermalinkPagination} {block:NextPost} <a href="{NextPost}" title="Newer Post"><div class="pagination">Newer Post</div></a> {/block:NextPost} {block:PreviousPost} <a href="{PreviousPost}" title="Older Post"><div class="pagination">Older Post</div></a> {/block:PreviousPost} {/block:PermalinkPagination} {block:HasTags} <div class="tags"> {block:Tags} <a href="{TagURL}">{Tag}</a> {/block:Tags} </div> {/block:HasTags} <div class="main"> {block:Photo} {block:Caption} {Caption} {/block:Caption} {/block:Photo} {block:Video} {Video-400} {block:Caption} {Caption} {/block:Caption} {/block:Video} {block:Link} <h3><a href="{URL}" target="{Target}">{Name}</a></h3> {block:Description} {Description} {/block:Description} {/block:Link} {block:Quote} <h3>{Quote}</h3> {block:Source} <strong><p>{Source}</p></strong> {/block:Source} {/block:Quote} {block:Audio} {AudioPlayerBlack} <div class="audiometa"> {block:Artist} {Artist} {/block:Artist} {block:Album} {Album} {/block:Album} {block:TrackName} {TrackName} {/block:TrackName} </div> {block:Caption} {Caption} {/block:Caption} {/block:Audio} {block:Chat} <h3 class="push">{Title}</h3> {block:Lines} <p class="chat {Alt}"><strong>{block:Label}{Label}{/block:Label}</strong> {Line}</p> {/block:Lines} {/block:Chat} {block:Text} {Body} {block:Text} <p class="meta"> <a href="http://tmv.proto.jp/reblog.php?post_url={Permalink};" title="Reblog this" class="more-link left">Reblog</a> <span class="hidden">{block:Photo}{LinkOpenTag}Source{LinkCloseTag}{/block:Photo}</span> <a href="{Permalink}" title="Permalink{PhotoAlt}" class="more-link right notes">{NoteCountWithLabel}</a> </p> <div class="clear"></div> </div> </div> <script type="text/javascript"> document.onkeyup = KeyCheck; function KeyCheck(e) { var KeyID = (window.event) ? event.keyCode : e.keyCode; switch(KeyID) { {block:Pagination} {block:PreviousPage} case 39: window.location = "{PreviousPage}"; break; {/block:PreviousPage} {block:NextPage} case 37: window.location = "{NextPage}"; break; {/block:NextPage} {/block:Pagination} {block:PermalinkPagination} {block:PreviousPost} case 39: window.location = "{NextPost}"; break; {/block:PreviousPost} {block:NextPost} case 37: window.location = "{PreviousPost}"; break; {/block:NextPost} {/block:PermalinkPagination} } } </script> <div class="navwrap"> <div class="nav"> <ul> <li><a href="/" title="{Title}">KODI LANE</a></li> <li><a href="/archive" title="Archive of posts">Archive</a></li> {block:AskEnabled}<li><a href="/ask" title="Ask">{AskLabel}</a></li>{/block:AskEnabled} {block:SubmissionsEnabled}<li><a href="/submit" title="Submit">{SubmitLabel}</a></li>{/block:SubmissionsEnabled} {block:HasPages}{block:Pages}<li><a href="{URL}">{Label}</a></li>{/block:Pages}{/block:HasPages} {block:IfIncludeAttribution}<li><a href="http://jonathanhaggard.com/">Theme by Jon</a></li>{/block:IfIncludeAttribution} </ul> </div> </div> <div class="button">HIDE/SHOW UI</div> {/block:Posts}

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  • Thread not behaving correctly

    - by ivor
    Hello, I wonder if anyone can help me to understand where I could be going wrong with this code; Basically I'm working on a turorial and calling the class below from another class - and it is getting the following error; Exception in thread "Thread-1" java.lang.NullPointerException at org.newdawn.spaceinvaders.TCPChat.run(TCPChat.java:322) at java.lang.Thread.run(Unknown Source) I realise the error is beibg flagged in another class- but I have tested the other class with a small class which sets up a separate thread - and it works fine, but as soon as I try and implement a new thread in this class - it causes all sorts of problems. Am I setting up the thread correctly in this class? Basically I can set up a thread in this class, with a test loop and it's fine, but when I bring in the functionality of the rest of the game it sometimes hangs, or does not display at all. Any suggestions on where I could be going wrong would be greatly appreciated. Thanks for looking. package org.newdawn.spaceinvaders; import java.awt.BorderLayout; import java.awt.Canvas; import java.awt.Color; import java.awt.Dimension; import java.awt.FlowLayout; import java.awt.Graphics2D; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyAdapter; import java.awt.event.KeyEvent; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.awt.image.BufferStrategy; import java.util.ArrayList; import java.util.Scanner; import java.awt.*;//maybe not needed import javax.swing.*;//maybenot needed import java.util.Random; //import java.io.*; /** * The main hook of our game. This class with both act as a manager * for the display and central mediator for the game logic. * * Display management will consist of a loop that cycles round all * entities in the game asking them to move and then drawing them * in the appropriate place. With the help of an inner class it * will also allow the player to control the main ship. * * As a mediator it will be informed when entities within our game * detect events (e.g. alient killed, played died) and will take * appropriate game actions. * * @author Kevin Glass */ public class Game extends Canvas implements Runnable{ /** The stragey that allows us to use accelerate page flipping */ private BufferStrategy strategy; /** True if the game is currently "running", i.e. the game loop is looping */ private boolean gameRunning = true; /** The list of all the entities that exist in our game */ private ArrayList entities = new ArrayList(); /** The list of entities that need to be removed from the game this loop */ private ArrayList removeList = new ArrayList(); /** The entity representing the player */ private Entity ship; /** The speed at which the player's ship should move (pixels/sec) */ private double moveSpeed = 300; /** The time at which last fired a shot */ private long lastFire = 0; /** The interval between our players shot (ms) */ private long firingInterval = 500; /** The number of aliens left on the screen */ private int alienCount; /** The number of levels progressed */ private double levelCount; /** high score for the user */ private int highScore; /** high score for the user */ private String player = "bob"; //private GetUserInput getPlayer; /** The list of entities that need to be removed from the game this loop */ /** The message to display which waiting for a key press */ private String message = ""; /** True if we're holding up game play until a key has been pressed */ private boolean waitingForKeyPress = true; /** True if the left cursor key is currently pressed */ private boolean leftPressed = false; /** True if the right cursor key is currently pressed */ private boolean rightPressed = false; /** True if we are firing */ private boolean firePressed = false; /** True if game logic needs to be applied this loop, normally as a result of a game event */ private boolean logicRequiredThisLoop = false; //private Thread cThread = new Thread(this); //public Thread t = new Thread(this); //private Thread g = new Thread(this); void setHighscore(int setHS) { highScore = setHS; } public int getHighscore() { return highScore; } public void setPlayer(String setPlayer) { player = setPlayer; } public String getPlayer() { return player; } public void run() { //setup(); System.out.println("hello im running bob"); /*int count = 1; do { System.out.println("Count is: " + count); count++; try{Thread.sleep(1);} catch(InterruptedException e){} } while (count <= 2000000);*/ //Game g =new Game(); //Game g = this; // Start the main game loop, note: this method will not // return until the game has finished running. Hence we are // using the actual main thread to run the game. //setup(); //this.gameLoop(); //try{thread.sleep(1);} //catch{InterruptedException e} } /** * Construct our game and set it running. */ public Game () { //Thread t = new Thread(this);//set up new thread for invaders game //t.run();//run the run method of the game //Game g =new Game(); //setup(); //Thread t = new Thread(this); //thread.start(); //SwingUtilities.invokeLater(this); Thread er = new Thread(this); er.start(); } public void setup(){ //initialise highscore setHighscore(0); // create a frame to contain our game JFrame container = new JFrame("Space Invaders 101"); // get hold the content of the frame and set up the resolution of the game JPanel panel = (JPanel) container.getContentPane(); panel.setPreferredSize(new Dimension(800,600)); //panel.setLayout(null); // setup our canvas size and put it into the content of the frame setBounds(0,0,800,600); panel.add(this); // Tell AWT not to bother repainting our canvas since we're // going to do that our self in accelerated mode setIgnoreRepaint(true); // finally make the window visible container.pack(); container.setResizable(false); container.setVisible(true); // add a listener to respond to the user closing the window. If they // do we'd like to exit the game container.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { //cThread.interrupt(); System.exit(0); } }); // add a key input system (defined below) to our canvas // so we can respond to key pressed addKeyListener(new KeyInputHandler()); // request the focus so key events come to us requestFocus(); // create the buffering strategy which will allow AWT // to manage our accelerated graphics createBufferStrategy(2); strategy = getBufferStrategy(); // initialise the entities in our game so there's something // to see at startup initEntities(); } /** * Start a fresh game, this should clear out any old data and * create a new set. */ private void startGame() { // clear out any existing entities and intialise a new set entities.clear(); initEntities(); //initialise highscore setHighscore(0); // blank out any keyboard settings we might currently have leftPressed = false; rightPressed = false; firePressed = false; } /** * Initialise the starting state of the entities (ship and aliens). Each * entitiy will be added to the overall list of entities in the game. */ //private void initEntities() { public void initEntities() { Random randomAlien = new Random(); // create the player ship and place it roughly in the center of the screen //ship = new ShipEntity(this,"sprites/ship.gif",370,550);//orignal ship = new ShipEntity(this,"sprites/ship.gif",700,300);//changed postioning to right hand side entities.add(ship); // create a block of aliens (5 rows, by 12 aliens, spaced evenly) alienCount = 0; levelCount = 1.02; for (int row=0;row<7;row++) {//altered number of rows for (int x=0;x<5;x++) { int r = randomAlien.nextInt(100);//loop added to produce random aliens if (r < 50){ //Entity alien = new AlienEntity(this,"sprites/alien.gif",/*100+*/(x*50),(50)+row*30); Entity alien = new AlienEntity(this,"sprites/alien.gif",100+(x*90),(12)+row*85); entities.add(alien); alienCount++; } } } } //private void initEntities() { public void initAlienEntities() { Random randomAlien = new Random(); // create the player ship and place it roughly in the center of the screen //ship = new ShipEntity(this,"sprites/ship.gif",370,550);//orignal //ship = new ShipEntity(this,"sprites/ship.gif",700,300);//changed postioning to right hand side //entities.add(ship); // create a block of aliens (5 rows, by 12 aliens, spaced evenly) alienCount = 0; levelCount = levelCount + 0.10;//this increases the speed on every level for (int row=0;row<7;row++) {//altered number of rows for (int x=0;x<5;x++) { int r = randomAlien.nextInt(100);//loop added to produce random aliens if (r < 50){//randome check to show alien //Entity alien = new AlienEntity(this,"sprites/alien.gif",/*100+*/(x*50),(50)+row*30); Entity alien = new AlienEntity(this,"sprites/alien.gif",-250+(x*90),(12)+row*85); entities.add(alien); alienCount++; } } } advanceAlienSpeed(levelCount); } /** * Notification from a game entity that the logic of the game * should be run at the next opportunity (normally as a result of some * game event) */ public void updateLogic() { logicRequiredThisLoop = true; } /** * Remove an entity from the game. The entity removed will * no longer move or be drawn. * * @param entity The entity that should be removed */ public void removeEntity(Entity entity) { removeList.add(entity); } /** * Notification that the player has died. */ public void notifyDeath() { message = "Oh no! They got you, try again?"; waitingForKeyPress = true; } /** * Notification that the player has won since all the aliens * are dead. */ public void notifyWin() { message = "Well done! You Win!"; waitingForKeyPress = true; } /** * Notification that an alien has been killed */ public void notifyAlienKilled() { // reduce the alient count, if there are none left, the player has won! alienCount--; if (alienCount == 0) { //notifyWin();win not relevant here... this.initAlienEntities();//call fresh batch of aliens } // if there are still some aliens left then they all need to get faster, so // speed up all the existing aliens advanceAlienSpeed(1.30); } public void advanceAlienSpeed(double speed) { // if there are still some aliens left then they all need to get faster, so // speed up all the existing aliens for (int i=0;i<entities.size();i++) { Entity entity = (Entity) entities.get(i); if (entity instanceof AlienEntity) { // speed up by 2% entity.setHorizontalMovement(entity.getHorizontalMovement() * speed); //entity.setVerticalMovement(entity.getVerticalMovement() * 1.02); } } } /** * Attempt to fire a shot from the player. Its called "try" * since we must first check that the player can fire at this * point, i.e. has he/she waited long enough between shots */ public void tryToFire() { // check that we have waiting long enough to fire if (System.currentTimeMillis() - lastFire < firingInterval) { return; } // if we waited long enough, create the shot entity, and record the time. lastFire = System.currentTimeMillis(); ShotEntity shot = new ShotEntity(this,"sprites/shot.gif",ship.getX()+10,ship.getY()-30); entities.add(shot); } /** * The main game loop. This loop is running during all game * play as is responsible for the following activities: * <p> * - Working out the speed of the game loop to update moves * - Moving the game entities * - Drawing the screen contents (entities, text) * - Updating game events * - Checking Input * <p> */ public void gameLoop() { long lastLoopTime = System.currentTimeMillis(); // keep looping round til the game ends while (gameRunning) { // work out how long its been since the last update, this // will be used to calculate how far the entities should // move this loop long delta = System.currentTimeMillis() - lastLoopTime; lastLoopTime = System.currentTimeMillis(); // Get hold of a graphics context for the accelerated // surface and blank it out Graphics2D g = (Graphics2D) strategy.getDrawGraphics(); g.setColor(Color.black); g.fillRect(0,0,800,600); // cycle round asking each entity to move itself if (!waitingForKeyPress) { for (int i=0;i<entities.size();i++) { Entity entity = (Entity) entities.get(i); entity.move(delta); } } // cycle round drawing all the entities we have in the game for (int i=0;i<entities.size();i++) { Entity entity = (Entity) entities.get(i); entity.draw(g); } // brute force collisions, compare every entity against // every other entity. If any of them collide notify // both entities that the collision has occured for (int p=0;p<entities.size();p++) { for (int s=p+1;s<entities.size();s++) { Entity me = (Entity) entities.get(p); Entity him = (Entity) entities.get(s); if (me.collidesWith(him)) { me.collidedWith(him); him.collidedWith(me); } } } // remove any entity that has been marked for clear up entities.removeAll(removeList); removeList.clear(); // if a game event has indicated that game logic should // be resolved, cycle round every entity requesting that // their personal logic should be considered. if (logicRequiredThisLoop) { //g.drawString("Press any key",(800-g.getFontMetrics().stringWidth("Press any key"))/2,300); for (int i=0;i<entities.size();i++) { Entity entity = (Entity) entities.get(i); entity.doLogic(); } logicRequiredThisLoop = false; } // if we're waiting for an "any key" press then draw the // current message //show highscore at top of screen //show name at top of screen g.setColor(Color.white); g.drawString("Player : "+getPlayer()+" : Score : "+getHighscore(),20,20); if (waitingForKeyPress) { g.setColor(Color.white); g.drawString(message,(800-g.getFontMetrics().stringWidth(message))/2,250); g.drawString("Press any key",(800-g.getFontMetrics().stringWidth("Press any key"))/2,300); } // finally, we've completed drawing so clear up the graphics // and flip the buffer over g.dispose(); strategy.show(); // resolve the movement of the ship. First assume the ship // isn't moving. If either cursor key is pressed then // update the movement appropraitely ship.setVerticalMovement(0);//set to vertical movement if ((leftPressed) && (!rightPressed)) { ship.setVerticalMovement(-moveSpeed);//**took out setHorizaontalMOvement } else if ((rightPressed) && (!leftPressed)) { ship.setVerticalMovement(moveSpeed);//**took out setHorizaontalMOvement } // if we're pressing fire, attempt to fire if (firePressed) { tryToFire(); } // finally pause for a bit. Note: this should run us at about // 100 fps but on windows this might vary each loop due to // a bad implementation of timer try { Thread.sleep(10); } catch (Exception e) {} } } /** * A class to handle keyboard input from the user. The class * handles both dynamic input during game play, i.e. left/right * and shoot, and more static type input (i.e. press any key to * continue) * * This has been implemented as an inner class more through * habbit then anything else. Its perfectly normal to implement * this as seperate class if slight less convienient. * * @author Kevin Glass */ private class KeyInputHandler extends KeyAdapter { /** The number of key presses we've had while waiting for an "any key" press */ private int pressCount = 1; /** * Notification from AWT that a key has been pressed. Note that * a key being pressed is equal to being pushed down but *NOT* * released. Thats where keyTyped() comes in. * * @param e The details of the key that was pressed */ public void keyPressed(KeyEvent e) { // if we're waiting for an "any key" typed then we don't // want to do anything with just a "press" if (waitingForKeyPress) { return; } // if (e.getKeyCode() == KeyEvent.VK_LEFT) { ////leftPressed = true; ///} //// if (e.getKeyCode() == KeyEvent.VK_RIGHT) { //rightPressed = true; if (e.getKeyCode() == KeyEvent.VK_UP) { leftPressed = true; } if (e.getKeyCode() == KeyEvent.VK_DOWN) { rightPressed = true; } if (e.getKeyCode() == KeyEvent.VK_SPACE) { firePressed = true; } } /** * Notification from AWT that a key has been released. * * @param e The details of the key that was released */ public void keyReleased(KeyEvent e) { // if we're waiting for an "any key" typed then we don't // want to do anything with just a "released" if (waitingForKeyPress) { return; } if (e.getKeyCode() == KeyEvent.VK_UP) {//changed from VK_LEFT leftPressed = false; } if (e.getKeyCode() == KeyEvent.VK_DOWN) {//changed from VK_RIGHT rightPressed = false; } if (e.getKeyCode() == KeyEvent.VK_SPACE) { firePressed = false; } } /** * Notification from AWT that a key has been typed. Note that * typing a key means to both press and then release it. * * @param e The details of the key that was typed. */ public void keyTyped(KeyEvent e) { // if we're waiting for a "any key" type then // check if we've recieved any recently. We may // have had a keyType() event from the user releasing // the shoot or move keys, hence the use of the "pressCount" // counter. if (waitingForKeyPress) { if (pressCount == 1) { // since we've now recieved our key typed // event we can mark it as such and start // our new game waitingForKeyPress = false; startGame(); pressCount = 0; } else { pressCount++; } } // if we hit escape, then quit the game if (e.getKeyChar() == 27) { //cThread.interrupt(); System.exit(0); } } } /** * The entry point into the game. We'll simply create an * instance of class which will start the display and game * loop. * * @param argv The arguments that are passed into our game */ //public static void main(String argv[]) { //Game g =new Game(); // Start the main game loop, note: this method will not // return until the game has finished running. Hence we are // using the actual main thread to run the game. //g.gameLoop(); //} }

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  • What are good design practices when working with Entity Framework

    - by AD
    This will apply mostly for an asp.net application where the data is not accessed via soa. Meaning that you get access to the objects loaded from the framework, not Transfer Objects, although some recommendation still apply. This is a community post, so please add to it as you see fit. Applies to: Entity Framework 1.0 shipped with Visual Studio 2008 sp1. Why pick EF in the first place? Considering it is a young technology with plenty of problems (see below), it may be a hard sell to get on the EF bandwagon for your project. However, it is the technology Microsoft is pushing (at the expense of Linq2Sql, which is a subset of EF). In addition, you may not be satisfied with NHibernate or other solutions out there. Whatever the reasons, there are people out there (including me) working with EF and life is not bad.make you think. EF and inheritance The first big subject is inheritance. EF does support mapping for inherited classes that are persisted in 2 ways: table per class and table the hierarchy. The modeling is easy and there are no programming issues with that part. (The following applies to table per class model as I don't have experience with table per hierarchy, which is, anyway, limited.) The real problem comes when you are trying to run queries that include one or many objects that are part of an inheritance tree: the generated sql is incredibly awful, takes a long time to get parsed by the EF and takes a long time to execute as well. This is a real show stopper. Enough that EF should probably not be used with inheritance or as little as possible. Here is an example of how bad it was. My EF model had ~30 classes, ~10 of which were part of an inheritance tree. On running a query to get one item from the Base class, something as simple as Base.Get(id), the generated SQL was over 50,000 characters. Then when you are trying to return some Associations, it degenerates even more, going as far as throwing SQL exceptions about not being able to query more than 256 tables at once. Ok, this is bad, EF concept is to allow you to create your object structure without (or with as little as possible) consideration on the actual database implementation of your table. It completely fails at this. So, recommendations? Avoid inheritance if you can, the performance will be so much better. Use it sparingly where you have to. In my opinion, this makes EF a glorified sql-generation tool for querying, but there are still advantages to using it. And ways to implement mechanism that are similar to inheritance. Bypassing inheritance with Interfaces First thing to know with trying to get some kind of inheritance going with EF is that you cannot assign a non-EF-modeled class a base class. Don't even try it, it will get overwritten by the modeler. So what to do? You can use interfaces to enforce that classes implement some functionality. For example here is a IEntity interface that allow you to define Associations between EF entities where you don't know at design time what the type of the entity would be. public enum EntityTypes{ Unknown = -1, Dog = 0, Cat } public interface IEntity { int EntityID { get; } string Name { get; } Type EntityType { get; } } public partial class Dog : IEntity { // implement EntityID and Name which could actually be fields // from your EF model Type EntityType{ get{ return EntityTypes.Dog; } } } Using this IEntity, you can then work with undefined associations in other classes // lets take a class that you defined in your model. // that class has a mapping to the columns: PetID, PetType public partial class Person { public IEntity GetPet() { return IEntityController.Get(PetID,PetType); } } which makes use of some extension functions: public class IEntityController { static public IEntity Get(int id, EntityTypes type) { switch (type) { case EntityTypes.Dog: return Dog.Get(id); case EntityTypes.Cat: return Cat.Get(id); default: throw new Exception("Invalid EntityType"); } } } Not as neat as having plain inheritance, particularly considering you have to store the PetType in an extra database field, but considering the performance gains, I would not look back. It also cannot model one-to-many, many-to-many relationship, but with creative uses of 'Union' it could be made to work. Finally, it creates the side effet of loading data in a property/function of the object, which you need to be careful about. Using a clear naming convention like GetXYZ() helps in that regards. Compiled Queries Entity Framework performance is not as good as direct database access with ADO (obviously) or Linq2SQL. There are ways to improve it however, one of which is compiling your queries. The performance of a compiled query is similar to Linq2Sql. What is a compiled query? It is simply a query for which you tell the framework to keep the parsed tree in memory so it doesn't need to be regenerated the next time you run it. So the next run, you will save the time it takes to parse the tree. Do not discount that as it is a very costly operation that gets even worse with more complex queries. There are 2 ways to compile a query: creating an ObjectQuery with EntitySQL and using CompiledQuery.Compile() function. (Note that by using an EntityDataSource in your page, you will in fact be using ObjectQuery with EntitySQL, so that gets compiled and cached). An aside here in case you don't know what EntitySQL is. It is a string-based way of writing queries against the EF. Here is an example: "select value dog from Entities.DogSet as dog where dog.ID = @ID". The syntax is pretty similar to SQL syntax. You can also do pretty complex object manipulation, which is well explained [here][1]. Ok, so here is how to do it using ObjectQuery< string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); The first time you run this query, the framework will generate the expression tree and keep it in memory. So the next time it gets executed, you will save on that costly step. In that example EnablePlanCaching = true, which is unnecessary since that is the default option. The other way to compile a query for later use is the CompiledQuery.Compile method. This uses a delegate: static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => ctx.DogSet.FirstOrDefault(it => it.ID == id)); or using linq static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet where dog.ID == id select dog).FirstOrDefault()); to call the query: query_GetDog.Invoke( YourContext, id ); The advantage of CompiledQuery is that the syntax of your query is checked at compile time, where as EntitySQL is not. However, there are other consideration... Includes Lets say you want to have the data for the dog owner to be returned by the query to avoid making 2 calls to the database. Easy to do, right? EntitySQL string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)).Include("Owner"); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); CompiledQuery static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet.Include("Owner") where dog.ID == id select dog).FirstOrDefault()); Now, what if you want to have the Include parametrized? What I mean is that you want to have a single Get() function that is called from different pages that care about different relationships for the dog. One cares about the Owner, another about his FavoriteFood, another about his FavotireToy and so on. Basicly, you want to tell the query which associations to load. It is easy to do with EntitySQL public Dog Get(int id, string include) { string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)) .IncludeMany(include); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); } The include simply uses the passed string. Easy enough. Note that it is possible to improve on the Include(string) function (that accepts only a single path) with an IncludeMany(string) that will let you pass a string of comma-separated associations to load. Look further in the extension section for this function. If we try to do it with CompiledQuery however, we run into numerous problems: The obvious static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.Include(include) where dog.ID == id select dog).FirstOrDefault()); will choke when called with: query_GetDog.Invoke( YourContext, id, "Owner,FavoriteFood" ); Because, as mentionned above, Include() only wants to see a single path in the string and here we are giving it 2: "Owner" and "FavoriteFood" (which is not to be confused with "Owner.FavoriteFood"!). Then, let's use IncludeMany(), which is an extension function static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.IncludeMany(include) where dog.ID == id select dog).FirstOrDefault()); Wrong again, this time it is because the EF cannot parse IncludeMany because it is not part of the functions that is recognizes: it is an extension. Ok, so you want to pass an arbitrary number of paths to your function and Includes() only takes a single one. What to do? You could decide that you will never ever need more than, say 20 Includes, and pass each separated strings in a struct to CompiledQuery. But now the query looks like this: from dog in ctx.DogSet.Include(include1).Include(include2).Include(include3) .Include(include4).Include(include5).Include(include6) .[...].Include(include19).Include(include20) where dog.ID == id select dog which is awful as well. Ok, then, but wait a minute. Can't we return an ObjectQuery< with CompiledQuery? Then set the includes on that? Well, that what I would have thought so as well: static readonly Func<Entities, int, ObjectQuery<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, ObjectQuery<Dog>>((ctx, id) => (ObjectQuery<Dog>)(from dog in ctx.DogSet where dog.ID == id select dog)); public Dog GetDog( int id, string include ) { ObjectQuery<Dog> oQuery = query_GetDog(id); oQuery = oQuery.IncludeMany(include); return oQuery.FirstOrDefault; } That should have worked, except that when you call IncludeMany (or Include, Where, OrderBy...) you invalidate the cached compiled query because it is an entirely new one now! So, the expression tree needs to be reparsed and you get that performance hit again. So what is the solution? You simply cannot use CompiledQueries with parametrized Includes. Use EntitySQL instead. This doesn't mean that there aren't uses for CompiledQueries. It is great for localized queries that will always be called in the same context. Ideally CompiledQuery should always be used because the syntax is checked at compile time, but due to limitation, that's not possible. An example of use would be: you may want to have a page that queries which two dogs have the same favorite food, which is a bit narrow for a BusinessLayer function, so you put it in your page and know exactly what type of includes are required. Passing more than 3 parameters to a CompiledQuery Func is limited to 5 parameters, of which the last one is the return type and the first one is your Entities object from the model. So that leaves you with 3 parameters. A pitance, but it can be improved on very easily. public struct MyParams { public string param1; public int param2; public DateTime param3; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where dog.Age == myParams.param2 && dog.Name == myParams.param1 and dog.BirthDate > myParams.param3 select dog); public List<Dog> GetSomeDogs( int age, string Name, DateTime birthDate ) { MyParams myParams = new MyParams(); myParams.param1 = name; myParams.param2 = age; myParams.param3 = birthDate; return query_GetDog(YourContext,myParams).ToList(); } Return Types (this does not apply to EntitySQL queries as they aren't compiled at the same time during execution as the CompiledQuery method) Working with Linq, you usually don't force the execution of the query until the very last moment, in case some other functions downstream wants to change the query in some way: static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public IEnumerable<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name); } public void DataBindStuff() { IEnumerable<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } What is going to happen here? By still playing with the original ObjectQuery (that is the actual return type of the Linq statement, which implements IEnumerable), it will invalidate the compiled query and be force to re-parse. So, the rule of thumb is to return a List< of objects instead. static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public List<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name).ToList(); //<== change here } public void DataBindStuff() { List<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } When you call ToList(), the query gets executed as per the compiled query and then, later, the OrderBy is executed against the objects in memory. It may be a little bit slower, but I'm not even sure. One sure thing is that you have no worries about mis-handling the ObjectQuery and invalidating the compiled query plan. Once again, that is not a blanket statement. ToList() is a defensive programming trick, but if you have a valid reason not to use ToList(), go ahead. There are many cases in which you would want to refine the query before executing it. Performance What is the performance impact of compiling a query? It can actually be fairly large. A rule of thumb is that compiling and caching the query for reuse takes at least double the time of simply executing it without caching. For complex queries (read inherirante), I have seen upwards to 10 seconds. So, the first time a pre-compiled query gets called, you get a performance hit. After that first hit, performance is noticeably better than the same non-pre-compiled query. Practically the same as Linq2Sql When you load a page with pre-compiled queries the first time you will get a hit. It will load in maybe 5-15 seconds (obviously more than one pre-compiled queries will end up being called), while subsequent loads will take less than 300ms. Dramatic difference, and it is up to you to decide if it is ok for your first user to take a hit or you want a script to call your pages to force a compilation of the queries. Can this query be cached? { Dog dog = from dog in YourContext.DogSet where dog.ID == id select dog; } No, ad-hoc Linq queries are not cached and you will incur the cost of generating the tree every single time you call it. Parametrized Queries Most search capabilities involve heavily parametrized queries. There are even libraries available that will let you build a parametrized query out of lamba expressions. The problem is that you cannot use pre-compiled queries with those. One way around that is to map out all the possible criteria in the query and flag which one you want to use: public struct MyParams { public string name; public bool checkName; public int age; public bool checkAge; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where (myParams.checkAge == true && dog.Age == myParams.age) && (myParams.checkName == true && dog.Name == myParams.name ) select dog); protected List<Dog> GetSomeDogs() { MyParams myParams = new MyParams(); myParams.name = "Bud"; myParams.checkName = true; myParams.age = 0; myParams.checkAge = false; return query_GetDog(YourContext,myParams).ToList(); } The advantage here is that you get all the benifits of a pre-compiled quert. The disadvantages are that you most likely will end up with a where clause that is pretty difficult to maintain, that you will incur a bigger penalty for pre-compiling the query and that each query you run is not as efficient as it could be (particularly with joins thrown in). Another way is to build an EntitySQL query piece by piece, like we all did with SQL. protected List<Dod> GetSomeDogs( string name, int age) { string query = "select value dog from Entities.DogSet where 1 = 1 "; if( !String.IsNullOrEmpty(name) ) query = query + " and dog.Name == @Name "; if( age > 0 ) query = query + " and dog.Age == @Age "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); if( !String.IsNullOrEmpty(name) ) oQuery.Parameters.Add( new ObjectParameter( "Name", name ) ); if( age > 0 ) oQuery.Parameters.Add( new ObjectParameter( "Age", age ) ); return oQuery.ToList(); } Here the problems are: - there is no syntax checking during compilation - each different combination of parameters generate a different query which will need to be pre-compiled when it is first run. In this case, there are only 4 different possible queries (no params, age-only, name-only and both params), but you can see that there can be way more with a normal world search. - Noone likes to concatenate strings! Another option is to query a large subset of the data and then narrow it down in memory. This is particularly useful if you are working with a definite subset of the data, like all the dogs in a city. You know there are a lot but you also know there aren't that many... so your CityDog search page can load all the dogs for the city in memory, which is a single pre-compiled query and then refine the results protected List<Dod> GetSomeDogs( string name, int age, string city) { string query = "select value dog from Entities.DogSet where dog.Owner.Address.City == @City "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); oQuery.Parameters.Add( new ObjectParameter( "City", city ) ); List<Dog> dogs = oQuery.ToList(); if( !String.IsNullOrEmpty(name) ) dogs = dogs.Where( it => it.Name == name ); if( age > 0 ) dogs = dogs.Where( it => it.Age == age ); return dogs; } It is particularly useful when you start displaying all the data then allow for filtering. Problems: - Could lead to serious data transfer if you are not careful about your subset. - You can only filter on the data that you returned. It means that if you don't return the Dog.Owner association, you will not be able to filter on the Dog.Owner.Name So what is the best solution? There isn't any. You need to pick the solution that works best for you and your problem: - Use lambda-based query building when you don't care about pre-compiling your queries. - Use fully-defined pre-compiled Linq query when your object structure is not too complex. - Use EntitySQL/string concatenation when the structure could be complex and when the possible number of different resulting queries are small (which means fewer pre-compilation hits). - Use in-memory filtering when you are working with a smallish subset of the data or when you had to fetch all of the data on the data at first anyway (if the performance is fine with all the data, then filtering in memory will not cause any time to be spent in the db). Singleton access The best way to deal with your context and entities accross all your pages is to use the singleton pattern: public sealed class YourContext { private const string instanceKey = "On3GoModelKey"; YourContext(){} public static YourEntities Instance { get { HttpContext context = HttpContext.Current; if( context == null ) return Nested.instance; if (context.Items[instanceKey] == null) { On3GoEntities entity = new On3GoEntities(); context.Items[instanceKey] = entity; } return (YourEntities)context.Items[instanceKey]; } } class Nested { // Explicit static constructor to tell C# compiler // not to mark type as beforefieldinit static Nested() { } internal static readonly YourEntities instance = new YourEntities(); } } NoTracking, is it worth it? When executing a query, you can tell the framework to track the objects it will return or not. What does it mean? With tracking enabled (the default option), the framework will track what is going on with the object (has it been modified? Created? Deleted?) and will also link objects together, when further queries are made from the database, which is what is of interest here. For example, lets assume that Dog with ID == 2 has an owner which ID == 10. Dog dog = (from dog in YourContext.DogSet where dog.ID == 2 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Person owner = (from o in YourContext.PersonSet where o.ID == 10 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == true; If we were to do the same with no tracking, the result would be different. ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog = oDogQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>) (from o in YourContext.PersonSet where o.ID == 10 select o); oPersonQuery.MergeOption = MergeOption.NoTracking; Owner owner = oPersonQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Tracking is very useful and in a perfect world without performance issue, it would always be on. But in this world, there is a price for it, in terms of performance. So, should you use NoTracking to speed things up? It depends on what you are planning to use the data for. Is there any chance that the data your query with NoTracking can be used to make update/insert/delete in the database? If so, don't use NoTracking because associations are not tracked and will causes exceptions to be thrown. In a page where there are absolutly no updates to the database, you can use NoTracking. Mixing tracking and NoTracking is possible, but it requires you to be extra careful with updates/inserts/deletes. The problem is that if you mix then you risk having the framework trying to Attach() a NoTracking object to the context where another copy of the same object exist with tracking on. Basicly, what I am saying is that Dog dog1 = (from dog in YourContext.DogSet where dog.ID == 2).FirstOrDefault(); ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog2 = oDogQuery.FirstOrDefault(); dog1 and dog2 are 2 different objects, one tracked and one not. Using the detached object in an update/insert will force an Attach() that will say "Wait a minute, I do already have an object here with the same database key. Fail". And when you Attach() one object, all of its hierarchy gets attached as well, causing problems everywhere. Be extra careful. How much faster is it with NoTracking It depends on the queries. Some are much more succeptible to tracking than other. I don't have a fast an easy rule for it, but it helps. So I should use NoTracking everywhere then? Not exactly. There are some advantages to tracking object. The first one is that the object is cached, so subsequent call for that object will not hit the database. That cache is only valid for the lifetime of the YourEntities object, which, if you use the singleton code above, is the same as the page lifetime. One page request == one YourEntity object. So for multiple calls for the same object, it will load only once per page request. (Other caching mechanism could extend that). What happens when you are using NoTracking and try to load the same object multiple times? The database will be queried each time, so there is an impact there. How often do/should you call for the same object during a single page request? As little as possible of course, but it does happens. Also remember the piece above about having the associations connected automatically for your? You don't have that with NoTracking, so if you load your data in multiple batches, you will not have a link to between them: ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>)(from dog in YourContext.DogSet select dog); oDogQuery.MergeOption = MergeOption.NoTracking; List<Dog> dogs = oDogQuery.ToList(); ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>)(from o in YourContext.PersonSet select o); oPersonQuery.MergeOption = MergeOption.NoTracking; List<Person> owners = oPersonQuery.ToList(); In this case, no dog will have its .Owner property set. Some things to keep in mind when you are trying to optimize the performance. No lazy loading, what am I to do? This can be seen as a blessing in disguise. Of course it is annoying to load everything manually. However, it decreases the number of calls to the db and forces you to think about when you should load data. The more you can load in one database call the better. That was always true, but it is enforced now with this 'feature' of EF. Of course, you can call if( !ObjectReference.IsLoaded ) ObjectReference.Load(); if you want to, but a better practice is to force the framework to load the objects you know you will need in one shot. This is where the discussion about parametrized Includes begins to make sense. Lets say you have you Dog object public class Dog { public Dog Get(int id) { return YourContext.DogSet.FirstOrDefault(it => it.ID == id ); } } This is the type of function you work with all the time. It gets called from all over the place and once you have that Dog object, you will do very different things to it in different functions. First, it should be pre-compiled, because you will call that very often. Second, each different pages will want to have access to a different subset of the Dog data. Some will want the Owner, some the FavoriteToy, etc. Of course, you could call Load() for each reference you need anytime you need one. But that will generate a call to the database each time. Bad idea. So instead, each page will ask for the data it wants to see when it first request for the Dog object: static public Dog Get(int id) { return GetDog(entity,"");} static public Dog Get(int id, string includePath) { string query = "select value o " + " from YourEntities.DogSet as o " +

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