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  • Data Access example using Entity Framework

    - by Dan
    Does anyone know of or having any good examples of how to use Entity Framework version 2 in the Data Access layer and put an interface on it so the business layer uses the interface rather than knowing about EF? I have found some examples but they are all from 2009 and I'm not sure how they relate to Entity Framework version 2.

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  • Entity Component System for HUD and GUI

    - by Jason L.
    This is a very rough sketch of how I currently have things designed. It should, at least, give an idea of how my ECS is currently designed. If you notice in that diagram, I have basically split the HUD out of the ECS. They have their own set of things (HudLayer, HudComponent, etc) and are handled differently. This is where I'm struggling, though. There are many different instances in which the HUD will need to know about entities. Not just data changing (I have an event dispatcher for that), but the actual entity and all it encompasses. There are also situations where entities will need to be able to query the HUD for data. Let's take a couple examples: First, my equipment screen. On here I can change the equipment on a character (Entity). In order for this to happen, I need to know about the entity. At least I think I do? How can I handle this? The second scenario involves my Systems needing to query a HudComponent for data. A specific example would be my battle system. Each "team" is given a 3x3 grid they can move around in. See here: Skills target these cells, and not the player, so I would need a way for my systems to determine which cells are occupied and which are not. Basically I need a way for two way communication between Systems and my HUD. I know it's recommended (by some people, anyways) to take your HUD out of the ECS. Is that appropriate in my case?

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  • JPA - Entity design problem

    - by Yatendra Goel
    I am developing a Java Desktop Application and using JPA for persistence. I have a problem mentioned below: I have two entities: Country City Country has the following attribute: CountryName (PK) City has the following attribute: CityName Now as there can be two cities with same name in two different countries, the primaryKey for City table in the datbase is a composite primary key composed of CityName and CountryName. Now my question is How to implement the primary key of the City as an Entity in Java @Entity public class Country implements Serializable { private String countryName; @Id public String getCountryName() { return this.countryName; } } @Entity public class City implements Serializable { private CityPK cityPK; private Country country; @EmbeddedId public CityPK getCityPK() { return this.cityPK; } } @Embeddable public class CityPK implements Serializable { public String cityName; public String countryName; } Now as we know that the relationship from Country to City is OneToMany and to show this relationship in the above code, I have added a country variable in City class. But then we have duplicate data(countryName) stored in two places in the City class: one in the country object and other in the cityPK object. But on the other hand, both are necessary: countryName in cityPK object is necessary because we implement composite primary keys in this way. countryName in country object is necessary because it is the standard way of showing relashionship between objects. How to get around this problem?

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  • Entity Framework and WCf

    - by Nihilist
    Hi I am little confused on designing WCf services with EF. When using WCf and EF, where do we draw this line on what properties to return and what not to with the entity. Here is my scenario I have User. Here are the relations. User [1 to many] Address, User [ 1 to many] Email, User [ 1 to many] Phone So now on the webform, on page1 I can edit user information. say I can edit few properties on the user entity and can also edit address, phone, email entities[ like add / delete and update any] On page2, i can only update user properties and nothing related to navigation properties [ address, email, phone]. So when I return the User Entity [ OR DTO] should i be returning the navigation properties too? Or should the client make multiple calls to get navigation properites. Also, how does it go with Save? Like should the client make multiple calls to save user and related entites or just one call to save the graph? Lets say, if I just have a Save(User user) [ where user has all the related entities too] both page1 and page2 will call save and pass me the user. but one page1 i will need a lot more information. but on page2 i just need the user primitive properties. So my question is, where do we draw this line, how do we design theses services ? Is the WCF operation designed on the page and the fields it has ? I am hoping i explained my problem well enough.

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  • SceneManagers as systems in entity system or as a core class used by a system?

    - by Hatoru Hansou
    It seems entity systems are really popular here. Links posted by other users convinced me of the power of such system and I decided to try it. (Well, that and my original code getting messy) In my project, I originally had a SceneManager class that maintained needed logic and structures to organize the scene (QuadTree, 2D game). Before rendering I call selectRect() and pass the x,y of the camera and the width and height of the screen and then obtain a minimized list containing only visible entities ordered from back to front. Now with Systems, originally in my first attempt my Render system required to get added all entities it should handle. This may sound like the correct approach but I realized this was not efficient. Trying to optimize It I reused the SceneManager class internally in the Renderer system, but then I realized I needed methods such as selectRect() in others systems too (AI principally) and make the SceneManager accessible globally again. Currently I converted SceneManager to a system, and ended up with the following interface (only relevant methods): /// Base system interface class System { public: virtual void tick (double delta_time) = 0; // (methods to add and remove entities) }; typedef std::vector<Entity*> EntitiesVector; /// Specialized system interface to allow query the scene class SceneManager: public System { public: virtual EntitiesVector& cull () = 0; /// Sets the entity to be used as the camera and replaces previous ones. virtual void setCamera (Entity* entity) = 0; }; class SceneRenderer // Not a system { vitual void render (EntitiesVector& entities) = 0; }; Also I could not guess how to convert renderers to systems. My game separates logic updates from screen updates, my main class have a tick() method and a render() method that may not be called the same times. In my first attempt renderers were systems but they was saved in a separated manager, updated only in render() and not in tick() like all other systems. I realized that was silly and simply created a SceneRenderer interface and give up about converting them to systems, but that may be for another question. Then... something does not feel right, isn't it? If I understood correctly a system should not depend on another or even count with another system exposing an specific interface. Each system should care only about its entities, or nodes (as optimization, so they have direct references to relevant components without having to constantly call the component() or getComponent() method of the entity).

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  • Entity Framework and distributed Systems

    - by Dirk Beckmann
    I need some help or maybe only a hint for the right direction. I've got a system that is sperated into two applications. An existing VB.NET desktop client using Entity Framework 5 with code first approach and a asp.net Web Api client in C# that will be refactored right yet. It should be possible to deliver OData. The system and the datamodel is still involving and so migrations will happen in undefined intervalls. So I'm now struggling how to manage my database access on the web api system. So my favourd approch would be us Entity Framework on both systems but I'm running into trouble while creating new migrations. Two solutions I've thought about: Shared Data Access dll The first idea was to separate the data access layer to a seperate project an reference from each of the systems. The context would be the same as long as the dll is up to date in each system. This way both soulutions would be able to make a migration. The main problem ist that it is much more complicate to update a web api system than it is with the client Click Once Update Solution and not every migration is important for the web api. This would couse more update trouble and out of sync libraries Database First on Web Api The second idea was just to use the database first approch an on web api side. But it seems that all annotations will be lost by each model update. Other solutions with stored procedures have been discarded because of missing OData support and maintainability. Does anyone run into same conflicts or has any advices how such a problem can be solved!

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  • Have a program/winform that outputs name and classes in message box, my objective is to write the cl

    - by JB
    Here is my Get Schedule Class: using System; using System.IO; using System.Data; using System.Text; using System.Drawing; using System.Data.OleDb; using System.Collections; using System.ComponentModel; using System.Windows.Forms; using System.Drawing.Printing; using System.Collections.Generic; namespace Eagle_Eye_Class_Finder { public class GetSchedule { public string GetDataFromNumber(string ID) { IDnumber[] IDnumbers = new IDnumber[3]; foreach (IDnumber IDCandidateMatch in IDnumbers) { if (IDCandidateMatch.ID == ID) { StringBuilder myData = new StringBuilder(); myData.AppendLine(IDCandidateMatch.Name); myData.AppendLine(": "); myData.AppendLine(IDCandidateMatch.ID); myData.AppendLine(IDCandidateMatch.year); myData.AppendLine(IDCandidateMatch.class1); myData.AppendLine(IDCandidateMatch.class2); myData.AppendLine(IDCandidateMatch.class3); myData.AppendLine(IDCandidateMatch.class4); //return myData; return myData.ToString(); } } return ""; } public GetSchedule() { IDnumber[] IDnumbers = new IDnumber[3]; IDnumbers[0] = new IDnumber() { Name = "Joshua Banks", ID = "900456317", year = "Senior", class1 = "TEET 4090", class2 = "TEET 3020", class3 = "TEET 3090", class4 = "TEET 4290" }; IDnumbers[1] = new IDnumber() { Name = "Sean Ward", ID = "900456318", year = "Junior", class1 = "ENGNR 4090", class2 = "ENGNR 3020", class3 = "ENGNR 3090", class4 = "ENGNR 4290" }; IDnumbers[2] = new IDnumber() { Name = "Terrell Johnson", ID = "900456319", year = "Sophomore", class1 = "BUS 4090", class2 = "BUS 3020", class3 = "BUS 3090", class4 = "BUS 4290" }; } public class IDnumber { public string Name { get; set; } public string ID { get; set; } public string year { get; set; } public string class1 { get; set; } public string class2 { get; set; } public string class3 { get; set; } public string class4 { get; set; } public static void ProcessNumber(IDnumber myNum) { StringBuilder myData = new StringBuilder(); myData.AppendLine(myNum.Name); myData.AppendLine(": "); myData.AppendLine(myNum.ID); myData.AppendLine(myNum.year); myData.AppendLine(myNum.class1); myData.AppendLine(myNum.class2); myData.AppendLine(myNum.class3); myData.AppendLine(myNum.class4); MessageBox.Show(myData.ToString()); } } } } Here is my Form 1 class: using System; using System.IO; using System.Data; using System.Text; using System.Drawing; using System.Data.OleDb; using System.Collections; using System.Windows.Forms; using System.ComponentModel; using System.Drawing.Printing; using System.Collections.Generic; namespace Eagle_Eye_Class_Finder { /// This form is the entry form, it is the first form the user will see when the app is run. /// public class Form1 : System.Windows.Forms.Form { private System.Windows.Forms.TextBox textBox1; private System.Windows.Forms.ProgressBar progressBar1; private System.Windows.Forms.PictureBox pictureBox1; private System.Windows.Forms.Button button2; private System.Windows.Forms.DateTimePicker dateTimePicker1; private IContainer components; private Timer timer1; private BindingSource form1BindingSource; public static Form Mainform = null; // creates new instance of second form YOURCLASSSCHEDULE SecondForm = new YOURCLASSSCHEDULE(); public Form1() { InitializeComponent(); // TODO: Add any constructor code after InitializeComponent call } /// Clean up any resources being used. protected override void Dispose(bool disposing) { if (disposing) { if (components != null) { components.Dispose(); } } base.Dispose(disposing); } #region Windows Form Designer generated code /// <summary> /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// </summary> private void InitializeComponent() { this.components = new System.ComponentModel.Container(); System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(Form1)); this.textBox1 = new System.Windows.Forms.TextBox(); this.progressBar1 = new System.Windows.Forms.ProgressBar(); this.pictureBox1 = new System.Windows.Forms.PictureBox(); this.button2 = new System.Windows.Forms.Button(); this.dateTimePicker1 = new System.Windows.Forms.DateTimePicker(); this.timer1 = new System.Windows.Forms.Timer(this.components); this.form1BindingSource = new System.Windows.Forms.BindingSource(this.components); ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit(); ((System.ComponentModel.ISupportInitialize)(this.form1BindingSource)).BeginInit(); this.SuspendLayout(); // // textBox1 // this.textBox1.BackColor = System.Drawing.SystemColors.ActiveCaption; this.textBox1.DataBindings.Add(new System.Windows.Forms.Binding("Text", this.form1BindingSource, "Text", true, System.Windows.Forms.DataSourceUpdateMode.OnValidation, null, "900456317")); this.textBox1.Location = new System.Drawing.Point(328, 280); this.textBox1.Name = "textBox1"; this.textBox1.Size = new System.Drawing.Size(208, 20); this.textBox1.TabIndex = 2; this.textBox1.TextChanged += new System.EventHandler(this.textBox1_TextChanged); // // progressBar1 // this.progressBar1.Location = new System.Drawing.Point(258, 410); this.progressBar1.MarqueeAnimationSpeed = 10; this.progressBar1.Name = "progressBar1"; this.progressBar1.Size = new System.Drawing.Size(344, 8); this.progressBar1.TabIndex = 3; this.progressBar1.Click += new System.EventHandler(this.progressBar1_Click); // // pictureBox1 // this.pictureBox1.BackColor = System.Drawing.SystemColors.ControlLightLight; this.pictureBox1.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D; this.pictureBox1.Image = ((System.Drawing.Image)(resources.GetObject("pictureBox1.Image"))); this.pictureBox1.Location = new System.Drawing.Point(680, 400); this.pictureBox1.Name = "pictureBox1"; this.pictureBox1.Size = new System.Drawing.Size(120, 112); this.pictureBox1.TabIndex = 4; this.pictureBox1.TabStop = false; this.pictureBox1.Click += new System.EventHandler(this.pictureBox1_Click); // // button2 // this.button2.Font = new System.Drawing.Font("Mistral", 15.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); this.button2.Image = ((System.Drawing.Image)(resources.GetObject("button2.Image"))); this.button2.Location = new System.Drawing.Point(699, 442); this.button2.Name = "button2"; this.button2.Size = new System.Drawing.Size(78, 28); this.button2.TabIndex = 5; this.button2.Text = "OK"; this.button2.Click += new System.EventHandler(this.button2_Click); // // dateTimePicker1 // this.dateTimePicker1.Location = new System.Drawing.Point(336, 104); this.dateTimePicker1.Name = "dateTimePicker1"; this.dateTimePicker1.Size = new System.Drawing.Size(200, 20); this.dateTimePicker1.TabIndex = 6; this.dateTimePicker1.ValueChanged += new System.EventHandler(this.dateTimePicker1_ValueChanged); // // timer1 // this.timer1.Tick += new System.EventHandler(this.timer1_Tick); // // form1BindingSource // this.form1BindingSource.DataSource = typeof(Eagle_Eye_Class_Finder.Form1); // // Form1 // this.AcceptButton = this.button2; this.AutoScaleBaseSize = new System.Drawing.Size(5, 13); this.BackgroundImage = ((System.Drawing.Image)(resources.GetObject("$this.BackgroundImage"))); this.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Stretch; this.ClientSize = new System.Drawing.Size(856, 556); this.Controls.Add(this.dateTimePicker1); this.Controls.Add(this.button2); this.Controls.Add(this.pictureBox1); this.Controls.Add(this.progressBar1); this.Controls.Add(this.textBox1); this.Name = "Form1"; this.Text = "Eagle Eye Class Finder"; this.Load += new System.EventHandler(this.Form1_Load); ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit(); ((System.ComponentModel.ISupportInitialize)(this.form1BindingSource)).EndInit(); this.ResumeLayout(false); this.PerformLayout(); } #endregion /// The main entry point for the application. [STAThread] static void Main() { Application.Run(new Form1()); } public void Form1_Load(object sender, System.EventArgs e) { } public void textBox1_TextChanged(object sender, System.EventArgs e) { //allows only numbers to be entered in textbox string Str = textBox1.Text.Trim(); double Num; bool isNum = double.TryParse(Str, out Num); if (isNum) Console.ReadLine(); else MessageBox.Show("Enter A Valid ID Number!"); } public void button2_Click(object sender, System.EventArgs e) { string text = textBox1.Text; Mainform = this; this.Hide(); GetSchedule myScheduleFinder = new GetSchedule(); string result = myScheduleFinder.GetDataFromNumber(text); if (!string.IsNullOrEmpty(result)) { MessageBox.Show(result); } else { MessageBox.Show("Enter A Valid ID Number!"); } } public void dateTimePicker1_ValueChanged(object sender, System.EventArgs e) { } public void pictureBox1_Click(object sender, System.EventArgs e) { } public void progressBar1_Click(object sender, EventArgs e) { //this.progressBar1 = new System.progressBar1(); //progressBar1.Maximum = 200; //progressBar1.Minimum = 0; //progressBar1.Step = 20; } private void timer1_Tick(object sender, EventArgs e) { //if (progressBar1.Value >= 200 ) //{ //progressBar1.Value = 0; //} //return; //} //progressBar1.Value != 20; } } } here is my form 2 class: using System; using System.Drawing; using System.Collections; using System.ComponentModel; using System.Windows.Forms; namespace Eagle_Eye_Class_Finder { /// <summary> /// Summary description for Form2. /// </summary> public class YOURCLASSSCHEDULE : System.Windows.Forms.Form { public System.Windows.Forms.LinkLabel linkLabel1; public System.Windows.Forms.LinkLabel linkLabel2; public System.Windows.Forms.LinkLabel linkLabel3; public System.Windows.Forms.LinkLabel linkLabel4; private Button button1; /// Required designer variable. public System.ComponentModel.Container components = null; public YOURCLASSSCHEDULE() { // InitializeComponent(); // TODO: Add any constructor code after InitializeComponent call } /// Clean up any resources being used. protected override void Dispose(bool disposing) { if (disposing) { if (components != null) { components.Dispose(); } } base.Dispose(disposing); } #region Windows Form Designer generated code /// <summary> /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// </summary> private void InitializeComponent() { System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(YOURCLASSSCHEDULE)); this.linkLabel1 = new System.Windows.Forms.LinkLabel(); this.linkLabel2 = new System.Windows.Forms.LinkLabel(); this.linkLabel3 = new System.Windows.Forms.LinkLabel(); this.linkLabel4 = new System.Windows.Forms.LinkLabel(); this.button1 = new System.Windows.Forms.Button(); this.SuspendLayout(); // // linkLabel1 // this.linkLabel1.BackColor = System.Drawing.SystemColors.ActiveCaption; this.linkLabel1.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D; this.linkLabel1.Font = new System.Drawing.Font("Times New Roman", 14.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); this.linkLabel1.LinkArea = new System.Windows.Forms.LinkArea(0, 7); this.linkLabel1.LinkBehavior = System.Windows.Forms.LinkBehavior.HoverUnderline; this.linkLabel1.Location = new System.Drawing.Point(41, 123); this.linkLabel1.Name = "linkLabel1"; this.linkLabel1.Size = new System.Drawing.Size(288, 32); this.linkLabel1.TabIndex = 1; this.linkLabel1.TabStop = true; this.linkLabel1.Text = "Class 1"; this.linkLabel1.TextAlign = System.Drawing.ContentAlignment.MiddleCenter; this.linkLabel1.LinkClicked += new System.Windows.Forms.LinkLabelLinkClickedEventHandler(this.linkLabel1_LinkClicked); // // linkLabel2 // this.linkLabel2.BackColor = System.Drawing.SystemColors.ActiveCaption; this.linkLabel2.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D; this.linkLabel2.Font = new System.Drawing.Font("Times New Roman", 14.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); this.linkLabel2.LinkBehavior = System.Windows.Forms.LinkBehavior.HoverUnderline; this.linkLabel2.Location = new System.Drawing.Point(467, 123); this.linkLabel2.Name = "linkLabel2"; this.linkLabel2.Size = new System.Drawing.Size(288, 32); this.linkLabel2.TabIndex = 2; this.linkLabel2.TabStop = true; this.linkLabel2.Text = "Class 2"; this.linkLabel2.TextAlign = System.Drawing.ContentAlignment.MiddleCenter; this.linkLabel2.VisitedLinkColor = System.Drawing.Color.Navy; this.linkLabel2.LinkClicked += new System.Windows.Forms.LinkLabelLinkClickedEventHandler(this.linkLabel2_LinkClicked); // // linkLabel3 // this.linkLabel3.BackColor = System.Drawing.SystemColors.ActiveCaption; this.linkLabel3.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D; this.linkLabel3.Font = new System.Drawing.Font("Times New Roman", 14.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); this.linkLabel3.LinkBehavior = System.Windows.Forms.LinkBehavior.HoverUnderline; this.linkLabel3.Location = new System.Drawing.Point(41, 311); this.linkLabel3.Name = "linkLabel3"; this.linkLabel3.Size = new System.Drawing.Size(288, 32); this.linkLabel3.TabIndex = 3; this.linkLabel3.TabStop = true; this.linkLabel3.Text = "Class 3"; this.linkLabel3.TextAlign = System.Drawing.ContentAlignment.MiddleCenter; this.linkLabel3.LinkClicked += new System.Windows.Forms.LinkLabelLinkClickedEventHandler(this.linkLabel3_LinkClicked); // // linkLabel4 // this.linkLabel4.BackColor = System.Drawing.SystemColors.ActiveCaption; this.linkLabel4.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D; this.linkLabel4.Font = new System.Drawing.Font("Times New Roman", 14.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); this.linkLabel4.LinkBehavior = System.Windows.Forms.LinkBehavior.HoverUnderline; this.linkLabel4.Location = new System.Drawing.Point(467, 311); this.linkLabel4.Name = "linkLabel4"; this.linkLabel4.Size = new System.Drawing.Size(288, 32); this.linkLabel4.TabIndex = 4; this.linkLabel4.TabStop = true; this.linkLabel4.Text = "Class 4"; this.linkLabel4.TextAlign = System.Drawing.ContentAlignment.MiddleCenter; this.linkLabel4.LinkClicked += new System.Windows.Forms.LinkLabelLinkClickedEventHandler(this.linkLabel4_LinkClicked); // // button1 // this.button1.BackColor = System.Drawing.SystemColors.ActiveCaptionText; this.button1.FlatAppearance.BorderColor = System.Drawing.Color.FromArgb(((int)(((byte)(0)))), ((int)(((byte)(0)))), ((int)(((byte)(64))))); this.button1.FlatStyle = System.Windows.Forms.FlatStyle.Popup; this.button1.Font = new System.Drawing.Font("Pristina", 12F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(0))); this.button1.ForeColor = System.Drawing.SystemColors.ActiveCaption; this.button1.ImageAlign = System.Drawing.ContentAlignment.TopCenter; this.button1.Location = new System.Drawing.Point(358, 206); this.button1.Name = "button1"; this.button1.Size = new System.Drawing.Size(101, 25); this.button1.TabIndex = 5; this.button1.Text = "Go Back"; this.button1.UseVisualStyleBackColor = false; this.button1.Click += new System.EventHandler(this.button1_Click); // // YOURCLASSSCHEDULE // this.AutoScaleBaseSize = new System.Drawing.Size(6, 15); this.BackgroundImage = ((System.Drawing.Image)(resources.GetObject("$this.BackgroundImage"))); this.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Stretch; this.ClientSize = new System.Drawing.Size(790, 482); this.Controls.Add(this.button1); this.Controls.Add(this.linkLabel4); this.Controls.Add(this.linkLabel3); this.Controls.Add(this.linkLabel2); this.Controls.Add(this.linkLabel1); this.Font = new System.Drawing.Font("OldDreadfulNo7 BT", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); this.Name = "YOURCLASSSCHEDULE"; this.Text = "Your Classes"; this.Load += new System.EventHandler(this.Form2_Load); this.ResumeLayout(false); } #endregion public void Form2_Load(object sender, System.EventArgs e) { // if (text == "900456317") // { //} } public void linkLabel1_LinkClicked(object sender, System.Windows.Forms.LinkLabelLinkClickedEventArgs e) { System.Diagnostics.Process.Start("http://www.georgiasouthern.edu/map/"); } private void linkLabel2_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e) { System.Diagnostics.Process.Start("http://www.georgiasouthern.edu/map/"); } private void linkLabel3_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e) { System.Diagnostics.Process.Start("http://www.georgiasouthern.edu/map/"); } private void linkLabel4_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e) { System.Diagnostics.Process.Start("http://www.georgiasouthern.edu/map/"); } private void button1_Click(object sender, EventArgs e) { Form1 form1 = new Form1(); form1.Show(); this.Hide(); } } }

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  • Using MVC2 to update an Entity Framework v4 object with foreign keys fails

    - by jbjon
    With the following simple relational database structure: An Order has one or more OrderItems, and each OrderItem has one OrderItemStatus. Entity Framework v4 is used to communicate with the database and entities have been generated from this schema. The Entities connection happens to be called EnumTestEntities in the example. The trimmed down version of the Order Repository class looks like this: public class OrderRepository { private EnumTestEntities entities = new EnumTestEntities(); // Query Methods public Order Get(int id) { return entities.Orders.SingleOrDefault(d => d.OrderID == id); } // Persistence public void Save() { entities.SaveChanges(); } } An MVC2 app uses Entity Framework models to drive the views. I'm using the EditorFor feature of MVC2 to drive the Edit view. When it comes to POSTing back any changes to the model, the following code is called: [HttpPost] public ActionResult Edit(int id, FormCollection formValues) { // Get the current Order out of the database by ID Order order = orderRepository.Get(id); var orderItems = order.OrderItems; try { // Update the Order from the values posted from the View UpdateModel(order, ""); // Without the ValueProvider suffix it does not attempt to update the order items UpdateModel(order.OrderItems, "OrderItems.OrderItems"); // All the Save() does is call SaveChanges() on the database context orderRepository.Save(); return RedirectToAction("Details", new { id = order.OrderID }); } catch (Exception e) { return View(order); // Inserted while debugging } } The second call to UpdateModel has a ValueProvider suffix which matches the auto-generated HTML input name prefixes that MVC2 has generated for the foreign key collection of OrderItems within the View. The call to SaveChanges() on the database context after updating the OrderItems collection of an Order using UpdateModel generates the following exception: "The operation failed: The relationship could not be changed because one or more of the foreign-key properties is non-nullable. When a change is made to a relationship, the related foreign-key property is set to a null value. If the foreign-key does not support null values, a new relationship must be defined, the foreign-key property must be assigned another non-null value, or the unrelated object must be deleted." When debugging through this code, I can still see that the EntityKeys are not null and seem to be the same value as they should be. This still happens when you are not changing any of the extracted Order details from the database. Also the entity connection to the database doesn't change between the act of Getting and the SaveChanges so it doesn't appear to be a Context issue either. Any ideas what might be causing this problem? I know EF4 has done work on foreign key properties but can anyone shed any light on how to use EF4 and MVC2 to make things easy to update; rather than having to populate each property manually. I had hoped the simplicity of EditorFor and DisplayFor would also extend to Controllers updating data. Thanks

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  • Upgrading Entity Framework 1.0 to 4.0 to include foreign keys

    - by duthiega
    Currently I've been working with Entity Framework 1.0 which is located under a service façade. Below is one of the save methods I've created to either update or insert the device in question. This currently works but, I can't help feel that its a bit of a hack having to set the referenced properties to null then re-attach them just to get an insert to work. The changedDevice already holds these values, so why do I need to assign them again. So, I thought I'll update the model to EF4. That way I can just directly access the foreign keys. However, on doing this I've found that there doesn't seem to be an easy way to add the foreign keys except by removing the entity from the diagram and re-adding it. I don't want to do this as I've already been through all the entity properties renaming them from the DB column names. Can anyone help? /// <summary> /// Saves the non network device. /// </summary> /// <param name="nonNetworkDeviceDto">The non network device dto.</param> public void SaveNonNetworkDevice(NonNetworkDeviceDto nonNetworkDeviceDto) { using (var context = new AssetNetworkEntities2()) { var changedDevice = TransformationHelper.ConvertNonNetworkDeviceDtoToEntity(nonNetworkDeviceDto); if (!nonNetworkDeviceDto.DeviceId.Equals(-1)) { var originalDevice = context.NonNetworkDevices.Include("Status").Include("NonNetworkType").FirstOrDefault( d => d.DeviceId.Equals(nonNetworkDeviceDto.DeviceId)); context.ApplyAllReferencedPropertyChanges(originalDevice, changedDevice); context.ApplyCurrentValues(originalDevice.EntityKey.EntitySetName, changedDevice); } else { var maxNetworkDevice = context.NonNetworkDevices.OrderBy("it.DeviceId DESC").First(); changedDevice.DeviceId = maxNetworkDevice.DeviceId + 1; var status = changedDevice.Status; var nonNetworkType = changedDevice.NonNetworkType; changedDevice.Status = null; changedDevice.NonNetworkType = null; context.AttachTo("DeviceStatuses", status); if (nonNetworkType != null) { context.AttachTo("NonNetworkTypes", nonNetworkType); } changedDevice.Status = status; changedDevice.NonNetworkType = nonNetworkType; context.AddToNonNetworkDevices(changedDevice); } context.SaveChanges(); } }

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  • entity framework and dirty reads

    - by bryanjonker
    I have Entity Framework (.NET 4.0) going against SQL Server 2008. The database is (theoretically) getting updated during business hours -- delete, then insert, all through a transaction. Practically, it's not going to happen that often. But, I need to make sure I can always read data in the database. The application I'm writing will never do any types of writes to the data -- read-only. If I do a dirty read, I can always access the data; the worst that happens is I get old data (which is acceptable). However, can I tell Entity Framework to always use dirty reads? Are there performance or data integrity issues I need to worry about if I set up EF this way? Or should I take a step back and see about rewriting the process that's doing the delete/insert process?

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  • ASP.NET MVC CRUD Validation

    - by Ricardo Peres
    One thing I didn’t refer on my previous post on ASP.NET MVC CRUD with AJAX was how to retrieve model validation information into the client. We want to send any model validation errors to the client in the JSON object that contains the ProductId, RowVersion and Success properties, specifically, if there are any errors, we will add an extra Errors collection property. Here’s how: 1: [HttpPost] 2: [AjaxOnly] 3: [Authorize] 4: public JsonResult Edit(Product product) 5: { 6: if (this.ModelState.IsValid == true) 7: { 8: using (ProductContext ctx = new ProductContext()) 9: { 10: Boolean success = false; 11:  12: ctx.Entry(product).State = (product.ProductId == 0) ? EntityState.Added : EntityState.Modified; 13:  14: try 15: { 16: success = (ctx.SaveChanges() == 1); 17: } 18: catch (DbUpdateConcurrencyException) 19: { 20: ctx.Entry(product).Reload(); 21: } 22:  23: return (this.Json(new { Success = success, ProductId = product.ProductId, RowVersion = Convert.ToBase64String(product.RowVersion) })); 24: } 25: } 26: else 27: { 28: Dictionary<String, String> errors = new Dictionary<String, String>(); 29:  30: foreach (KeyValuePair<String, ModelState> keyValue in this.ModelState) 31: { 32: String key = keyValue.Key; 33: ModelState modelState = keyValue.Value; 34:  35: foreach (ModelError error in modelState.Errors) 36: { 37: errors[key] = error.ErrorMessage; 38: } 39: } 40:  41: return (this.Json(new { Success = false, ProductId = 0, RowVersion = String.Empty, Errors = errors })); 42: } 43: } As for the view, we need to change slightly the onSuccess JavaScript handler on the Single view: 1: function onSuccess(ctx) 2: { 3: if (typeof (ctx.Success) != 'undefined') 4: { 5: $('input#ProductId').val(ctx.ProductId); 6: $('input#RowVersion').val(ctx.RowVersion); 7:  8: if (ctx.Success == false) 9: { 10: var errors = ''; 11:  12: if (typeof (ctx.Errors) != 'undefined') 13: { 14: for (var key in ctx.Errors) 15: { 16: errors += key + ': ' + ctx.Errors[key] + '\n'; 17: } 18:  19: window.alert('An error occurred while updating the entity: the model contained the following errors.\n\n' + errors); 20: } 21: else 22: { 23: window.alert('An error occurred while updating the entity: it may have been modified by third parties. Please try again.'); 24: } 25: } 26: else 27: { 28: window.alert('Saved successfully'); 29: } 30: } 31: else 32: { 33: if (window.confirm('Not logged in. Login now?') == true) 34: { 35: document.location.href = '<% 1: : FormsAuthentication.LoginUrl %>?ReturnURL=' + document.location.pathname; 36: } 37: } 38: } The logic is as this: If the Edit action method is called for a new entity (the ProductId is 0) and it is valid, the entity is saved, and the JSON results contains a Success flag set to true, a ProductId property with the database-generated primary key and a RowVersion with the server-generated ROWVERSION; If the model is not valid, the JSON result will contain the Success flag set to false and the Errors collection populated with all the model validation errors; If the entity already exists in the database (ProductId not 0) and the model is valid, but the stored ROWVERSION is different that the one on the view, the result will set the Success property to false and will return the current (as loaded from the database) value of the ROWVERSION on the RowVersion property. On a future post I will talk about the possibilities that exist for performing model validation, stay tuned!

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  • Entity Component System, weapon

    - by Heorhiy
    I'm new to game programming and currently trying to understand Entity Component System design by implementing simple 2d game. By ECS I mean design, described here for example In my game I have different kind of weapons: automatic, gun, grenade, etc... Each type of weapon has it's own affect area (gun shots along the straight line and grenade explodes and covers some spherical area) , damage impact, visual effect and bullet amount, delay between shots. So I don't completely understand how to implement weapons. Should weapon be an Entity or it should be a component? And how the player should pick up a weapon, switch between different types of weapons and etc.

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  • Making more complicated systems(entity-component-system model question)

    - by winch
    I'm using a model where entities are collections of components and components are just data. All the logic goes into systems which operate on components. Making basic systems(for Rendering and handling collision) was easy. But how do I do more compilcated systems? For example, in a CollisionSystem I can check if entity A collides with entity B. I have this code in CollisionSystem for checking if B damages A: if(collides(a, b)) { HealthComponent* hc = a->get<HealthComponent(); hc.reduceHealth(b->get<DamageComponent>()->getDamage()); But I feel that this code shouldn't belong to Collision system. Where should code like this be and which additional systems should I create to make this code generic?

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  • Rendering order in an Entity System

    - by Daedalus
    Say I use a basic ES approach, and also inside Systems I hold lists of all entities that Systems are required to process. How do I maintain this list of entities in desired rendering order, i.e. for a dumb 2D RenderingSystem? I saw this discussion, and what they suggest is to do something like Z ordering - what I would probably do is just to store a "layer" int in DrawableComponent and then, inside RenderingSystem, just sort entities by mentioned "layer" whenever the entity list for RenderingSystem changes. They also say we could just delete and recreate the entity whenever we want it on the top, but it seems too inflexible to me. How is this problem usually solved?

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  • Entity framework architecture

    - by user1741807
    I want to make a entity framework application in Winforms C#. I'm new to entity framework, and don't know how to make the architecture. I want to have the model in a class library, and a GUI layer, and maybe a controller layer. I'm used to that architecture, but don't know have to handle the objects in other layers than the model. Have do I manage objects in the gui layer, when I can't have a reference to the model? I'm used to have some kind of dto, but what's the best way?

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  • Adding existing entity to navigation property of a different entity

    - by Shay Friedman
    I'm using EF4 and I'm running into a problem when I try to do something that looks quite trivial to me. I have two entities, let's call them A and B. These entities have a many-to-many association between them with a navigation property on A that contains a list of related B entities. What I want to do is to add existing B entities to a new A entity. When I try to do that, I get an exception: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges. Has anyone run into such a problem?

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  • Deleting entity with child relationships using .Net Entity Framework problem

    - by Am
    My God, EF is so frustrating. I can't seem to be able to get my head around what I need to do so I can delete an object. I seem to be able to remove the object but not the related child objects. Can anyone tell me what is the rule of thumb when you want to delete all related child objects of a given object? I've tried loading all related objects like this: if (!object.childobjects.IsLoaded) object.childobjects.Load(); but once I do the following I get errors related to the relationships: modelcontext.DeleteObject(object); modelcontext.SaveChanges(); Why can't I just load the object using modelcontext.GetObjectByKey and remove it along with its child objects? My other question is can I delete an object using Entity command like so? DELETE e from objectset as e where e.id = 12 I've tried few variations and all of them throw exceptions.

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  • RIA Services - Two entity models share an entity name

    - by Alex
    I have two entity models hooked up to two different databases. However, the two databases both have a table named 'brand', for example. As such, there is a naming conflict in my models. Now, I've been able to add a namespace to each model, via Custom Tool Namespace in the model's properties, but the generated code in my Silverlight project will try to use both namespaces, and come up with this, Imports MyProject.ModelA Imports MyProject.ModelB Public ReadOnly Property brands() As EntitySet(Of brand) Get Return MyBase.EntityContainer.GetEntitySet(Of brand) End Get End Property giving me this exception: 'Error 1 'brand' is ambiguous, imported from the namespaces or types 'MyProject.ModelA,MyProject.ModelB'. Has anyone had experience with naming conflicts like this using RIA services? How did you solve it?

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  • Entity Framework 4.1 auto generate with DbContext when creating ADO.NET Entity Data Model

    - by smudgedlens
    I would like to work with DbContext instead of ObjectContext. I updated EF so now I have the DbContext, but I want to generate my strongly-typed context based on the DbContext and not the ObjectContext. When I add new ADO.NET Entity Data Model, it is still based on the ObjectContext. Is it not possible to have it base off of DbContext in Visual Studio 2010 with EF 4.1? UPDATE: Okay, I followed the directions in this link and was able to generate the DbContext template objects. However, now it is saying there is ambiguity between the template entities and the entities in my .edmx file. How do I resovle this? Do I blow away the ones in the .edmx file?

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  • Role of an entity state in a component based system?

    - by Paul
    Component-based entity systems are all the rage these days; everyone seems to agree they are the way to go, but no one really has a definitive implementation of such a system. I was wondering, what role do entity states (walking-left, standing, jumping, etc) have in a CBS? Do they act like controllers (i.e. they handle events and change the entity's attributes based on those events)? What about cases where a state would, for example, require that the entity enters no-clip mode? Should, that state, when it enters, maybe set the CollisionComponent of the entity to a null pointer or something? (Then, on exit, the state should restore the entity's CollisionComponent to its previous state.) Also, I guess it's the current state's job to change the entity's state to something else, right?

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  • Entity Framework - Foreign key constraints not added for inherited entity

    - by Tri Q
    Hello, It appears to me that a strange phenomenon is occurring with inherited entities (TPT) in EF4. I have three entities. 1. Asset 2. Property 3. Activity Property is a derived-type of Asset. Property has many activities (many-to-many) When modeling this in my EDMX, everything seems fine until I try to insert a new Property into the database. If the property does not contain any Activity, it works, but all hell breaks loose when I add some new activities to the new Property. As it turns out after 2 days of crawling the web and fiddling around, I noticed that in the EF store (SSDL) some of the constraints between entities were not picked up during the update process. Property_Activity table which links properties and activities show only one constraint FK_Property_Activity_Activity but FK_Property_Activity_Property was missing. I knew this is an Entity Framework anomoly because when I switched the relationship in the database to: Asset <-- Asset_Activity <-- Activity After an update, all foreign key constraints are picked up and the save is successful, with or without activities in the new property. Is this intended or a bug in EF? How do I get around this problem? Should I abandon inheritance altogether?

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  • Entity Framework and differences between Contains between SQL and objects using ToLower

    - by John Ptacek
    I have run into an "issue" I am not quite sure I understand with Entity Framework. I am using Entity Framework 4 and have tried to utilize a TDD approach. As a result, I recently implemented a search feature using a Repository pattern. For my test project, I am implementing my repository interface and have a set of "fake" object data I am using for test purposes. I ran into an issue trying to get the Contains clause to work for case invariant search. My code snippet for both my test and the repository class used against the database is as follows: if (!string.IsNullOrEmpty(Description)) { items = items.Where(r => r.Description.ToLower().Contains(Description.ToLower())); } However, when I ran my test cases the results where not populated if my case did not match the underlying data. I tried looking into what I thought was an issue for a while. To clear my mind, I went for a run and wondered if the same code with EF would work against a SQL back end database, since SQL will explicitly support the like command and it executed as I expected, using the same logic. I understand why EF against the database back end supports the Contains clause. However, I was surprised that my unit tests did not. Any ideas why other than the SQL server support of the like clause when I use objects I populate in a collection instead of against the database server? Thanks! John

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  • Seeding many to many tables with Entity Framework

    - by Doozer1979
    I have a meeting entity and a users entity which have a many to many relationship. I'm using Autopoco to create seed data for the Users and meetings How do i seed the UserMeetings linking table that is created by EntityFramework with seed data? The linking table has two fields in it; User_Id, and Meeting_ID. I'm looping through the list of users that autopoco creates and attaching a random number of meetings Here's what i've got so far. foreach (var user in userList) { var rand = new Random(); var amountOfMeetingsToAdd = rand.Next(1, 300); for (var i = 0; i <= amountOfMeetingsToAdd; i++) { var randomMeeting = rand.Next(1, MeetingRecords); //Error occurs on This line user.Meetings.Add(_meetings[randomMeeting]); } } I got an 'Object reference not set to an instance of an object.' even though the meeting record that i'm trying to attach does exist. For info all this is happening prior to me saving the context to the DB.

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  • Entity Framework one-to-one relationship mapping flattened in code

    - by Josh Close
    I have a table structure like so. Address: AddressId int not null primary key identity ...more columns AddressContinental: AddressId int not null primary key identity foreign key to pk of Address County State AddressInternational: AddressId int not null primary key identity foreign key to pk of Address ProvinceRegion I don't have control over schema, this is just the way it is. Now, what I want to do is have a single Address object. public class Address { public int AddressId { get; set; } public County County { get; set; } public State State { get; set } public ProvinceRegion { get; set; } } I want to have EF pull it out of the database as a single entity. When saving, I want to save the single entity and have EF know to split it into the three tables. How would I map this in EF 4.1 Code First? I've been searching around and haven't found anything that meets my case yet. UPDATE An address record will have a record in Address and one in either AddressContinental or AddressInternational, but not both.

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