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  • vSphere education - What are the downsides of configuring virtual machines with *too* much RAM?

    - by ewwhite
    VMware memory management seems to be a tricky balancing act. With cluster RAM, Resource Pools, VMware's management techniques (TPS, ballooning, host swapping), in-guest RAM utilization, swapping, reservations, shares and limits, there are a lot of variables. I'm in a situation where clients are using dedicated vSphere cluster resources. However, they are configuring the virtual machines as though they were on physical hardware. In turn, this means a standard VM build may have 4 vCPUs and 16GB or more of RAM. I come from the school of starting small (1 vCPU, minimal RAM), checking real-world use and adjusting up as necessary. Some examples from a "problem" cluster. Resource pool summary - Looks almost 4:1 overcommitted. Note the high amount of ballooned RAM. Resource allocation - The Worst Case Allocation column shows that these VMs would have access to less than 50% of their configured RAM under constrained conditions. The real-time memory utilization graph of the top VM in the listing above. 4 vCPU and 64GB RAM allocated. It averages under 9GB use. Summary of the same VM What are the downsides of overcommitting and overconfiguring resources (specifically RAM) in vSphere environments? Assuming that the VMs can run in less RAM, is it fair to say that there's overhead to configuring virtual machines with more RAM than they need? What is the counter-argument to: "if a VM has 16GB of RAM allocated, but only uses 4GB, what's the problem??"? E.g. do customers need to be educated? What specific metric should be used to meter RAM usage. Tracking the peaks of "Active" versus time?

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  • Profile System: User share the same id

    - by Malcolm Frexner
    I have a strange effect on my site when it is under heavy load. I randomly get the properties of other users settings. I have my own implementation of the profile system so I guess I can not blame the profile system itself. I just need a point to start debugging from. I guess there is a cookie-value that maps to an Profile entry somewhere. Is there any chance to see how this mapping works? Here is my profile provider: using System; using System.Text; using System.Configuration; using System.Web; using System.Web.Profile; using System.Collections; using System.Collections.Specialized; using B2CShop.Model; using log4net; using System.Collections.Generic; using System.Diagnostics; using B2CShop.DAL; using B2CShop.Model.RepositoryInterfaces; [assembly: log4net.Config.XmlConfigurator()] namespace B2CShop.Profile { public class B2CShopProfileProvider : ProfileProvider { private static readonly ILog _log = LogManager.GetLogger(typeof(B2CShopProfileProvider)); // Get an instance of the Profile DAL using the ProfileDALFactory private static readonly B2CShop.DAL.UserRepository dal = new B2CShop.DAL.UserRepository(); // Private members private const string ERR_INVALID_PARAMETER = "Invalid Profile parameter:"; private const string PROFILE_USER = "User"; private static string applicationName = B2CShop.Model.Configuration.ApplicationConfiguration.MembershipApplicationName; /// <summary> /// The name of the application using the custom profile provider. /// </summary> public override string ApplicationName { get { return applicationName; } set { applicationName = value; } } /// <summary> /// Initializes the provider. /// </summary> /// <param name="name">The friendly name of the provider.</param> /// <param name="config">A collection of the name/value pairs representing the provider-specific attributes specified in the configuration for this provider.</param> public override void Initialize(string name, NameValueCollection config) { if (config == null) throw new ArgumentNullException("config"); if (string.IsNullOrEmpty(config["description"])) { config.Remove("description"); config.Add("description", "B2C Shop Custom Provider"); } if (string.IsNullOrEmpty(name)) name = "b2c_shop"; if (config["applicationName"] != null && !string.IsNullOrEmpty(config["applicationName"].Trim())) applicationName = config["applicationName"]; base.Initialize(name, config); } /// <summary> /// Returns the collection of settings property values for the specified application instance and settings property group. /// </summary> /// <param name="context">A System.Configuration.SettingsContext describing the current application use.</param> /// <param name="collection">A System.Configuration.SettingsPropertyCollection containing the settings property group whose values are to be retrieved.</param> /// <returns>A System.Configuration.SettingsPropertyValueCollection containing the values for the specified settings property group.</returns> public override SettingsPropertyValueCollection GetPropertyValues(SettingsContext context, SettingsPropertyCollection collection) { string username = (string)context["UserName"]; bool isAuthenticated = (bool)context["IsAuthenticated"]; //if (!isAuthenticated) return null; int uniqueID = dal.GetUniqueID(username, isAuthenticated, false, ApplicationName); SettingsPropertyValueCollection svc = new SettingsPropertyValueCollection(); foreach (SettingsProperty prop in collection) { SettingsPropertyValue pv = new SettingsPropertyValue(prop); switch (pv.Property.Name) { case PROFILE_USER: if (!String.IsNullOrEmpty(username)) { pv.PropertyValue = GetUser(uniqueID); } break; default: throw new ApplicationException(ERR_INVALID_PARAMETER + " name."); } svc.Add(pv); } return svc; } /// <summary> /// Sets the values of the specified group of property settings. /// </summary> /// <param name="context">A System.Configuration.SettingsContext describing the current application usage.</param> /// <param name="collection">A System.Configuration.SettingsPropertyValueCollection representing the group of property settings to set.</param> public override void SetPropertyValues(SettingsContext context, SettingsPropertyValueCollection collection) { string username = (string)context["UserName"]; CheckUserName(username); bool isAuthenticated = (bool)context["IsAuthenticated"]; int uniqueID = dal.GetUniqueID(username, isAuthenticated, false, ApplicationName); if (uniqueID == 0) { uniqueID = dal.CreateProfileForUser(username, isAuthenticated, ApplicationName); } foreach (SettingsPropertyValue pv in collection) { if (pv.PropertyValue != null) { switch (pv.Property.Name) { case PROFILE_USER: SetUser(uniqueID, (UserInfo)pv.PropertyValue); break; default: throw new ApplicationException(ERR_INVALID_PARAMETER + " name."); } } } UpdateActivityDates(username, false); } // Profile gettters // Retrieve UserInfo private static UserInfo GetUser(int userID) { return dal.GetUser(userID); } // Update account info private static void SetUser(int uniqueID, UserInfo user) { user.UserID = uniqueID; dal.SetUser(user); } // UpdateActivityDates // Updates the LastActivityDate and LastUpdatedDate values // when profile properties are accessed by the // GetPropertyValues and SetPropertyValues methods. // Passing true as the activityOnly parameter will update // only the LastActivityDate. private static void UpdateActivityDates(string username, bool activityOnly) { dal.UpdateActivityDates(username, activityOnly, applicationName); } /// <summary> /// Deletes profile properties and information for the supplied list of profiles. /// </summary> /// <param name="profiles">A System.Web.Profile.ProfileInfoCollection of information about profiles that are to be deleted.</param> /// <returns>The number of profiles deleted from the data source.</returns> public override int DeleteProfiles(ProfileInfoCollection profiles) { int deleteCount = 0; foreach (ProfileInfo p in profiles) if (DeleteProfile(p.UserName)) deleteCount++; return deleteCount; } /// <summary> /// Deletes profile properties and information for profiles that match the supplied list of user names. /// </summary> /// <param name="usernames">A string array of user names for profiles to be deleted.</param> /// <returns>The number of profiles deleted from the data source.</returns> public override int DeleteProfiles(string[] usernames) { int deleteCount = 0; foreach (string user in usernames) if (DeleteProfile(user)) deleteCount++; return deleteCount; } // DeleteProfile // Deletes profile data from the database for the specified user name. private static bool DeleteProfile(string username) { CheckUserName(username); return dal.DeleteAnonymousProfile(username, applicationName); } // Verifies user name for sise and comma private static void CheckUserName(string userName) { if (string.IsNullOrEmpty(userName) || userName.Length > 256 || userName.IndexOf(",") > 0) throw new ApplicationException(ERR_INVALID_PARAMETER + " user name."); } /// <summary> /// Deletes all user-profile data for profiles in which the last activity date occurred before the specified date. /// </summary> /// <param name="authenticationOption">One of the System.Web.Profile.ProfileAuthenticationOption values, specifying whether anonymous, authenticated, or both types of profiles are deleted.</param> /// <param name="userInactiveSinceDate">A System.DateTime that identifies which user profiles are considered inactive. If the System.Web.Profile.ProfileInfo.LastActivityDate value of a user profile occurs on or before this date and time, the profile is considered inactive.</param> /// <returns>The number of profiles deleted from the data source.</returns> public override int DeleteInactiveProfiles(ProfileAuthenticationOption authenticationOption, DateTime userInactiveSinceDate) { string[] userArray = new string[0]; dal.GetInactiveProfiles((int)authenticationOption, userInactiveSinceDate, ApplicationName).CopyTo(userArray, 0); return DeleteProfiles(userArray); } /// <summary> /// Retrieves profile information for profiles in which the user name matches the specified user names. /// </summary> /// <param name="authenticationOption">One of the System.Web.Profile.ProfileAuthenticationOption values, specifying whether anonymous, authenticated, or both types of profiles are returned.</param> /// <param name="usernameToMatch">The user name to search for.</param> /// <param name="pageIndex">The index of the page of results to return.</param> /// <param name="pageSize">The size of the page of results to return.</param> /// <param name="totalRecords">When this method returns, contains the total number of profiles.</param> /// <returns>A System.Web.Profile.ProfileInfoCollection containing user-profile information // for profiles where the user name matches the supplied usernameToMatch parameter.</returns> public override ProfileInfoCollection FindProfilesByUserName(ProfileAuthenticationOption authenticationOption, string usernameToMatch, int pageIndex, int pageSize, out int totalRecords) { CheckParameters(pageIndex, pageSize); return GetProfileInfo(authenticationOption, usernameToMatch, null, pageIndex, pageSize, out totalRecords); } /// <summary> /// Retrieves profile information for profiles in which the last activity date occurred on or before the specified date and the user name matches the specified user name. /// </summary> /// <param name="authenticationOption">One of the System.Web.Profile.ProfileAuthenticationOption values, specifying whether anonymous, authenticated, or both types of profiles are returned.</param> /// <param name="usernameToMatch">The user name to search for.</param> /// <param name="userInactiveSinceDate">A System.DateTime that identifies which user profiles are considered inactive. If the System.Web.Profile.ProfileInfo.LastActivityDate value of a user profile occurs on or before this date and time, the profile is considered inactive.</param> /// <param name="pageIndex">The index of the page of results to return.</param> /// <param name="pageSize">The size of the page of results to return.</param> /// <param name="totalRecords">When this method returns, contains the total number of profiles.</param> /// <returns>A System.Web.Profile.ProfileInfoCollection containing user profile information for inactive profiles where the user name matches the supplied usernameToMatch parameter.</returns> public override ProfileInfoCollection FindInactiveProfilesByUserName(ProfileAuthenticationOption authenticationOption, string usernameToMatch, DateTime userInactiveSinceDate, int pageIndex, int pageSize, out int totalRecords) { CheckParameters(pageIndex, pageSize); return GetProfileInfo(authenticationOption, usernameToMatch, userInactiveSinceDate, pageIndex, pageSize, out totalRecords); } /// <summary> /// Retrieves user profile data for all profiles in the data source. /// </summary> /// <param name="authenticationOption">One of the System.Web.Profile.ProfileAuthenticationOption values, specifying whether anonymous, authenticated, or both types of profiles are returned.</param> /// <param name="pageIndex">The index of the page of results to return.</param> /// <param name="pageSize">The size of the page of results to return.</param> /// <param name="totalRecords">When this method returns, contains the total number of profiles.</param> /// <returns>A System.Web.Profile.ProfileInfoCollection containing user-profile information for all profiles in the data source.</returns> public override ProfileInfoCollection GetAllProfiles(ProfileAuthenticationOption authenticationOption, int pageIndex, int pageSize, out int totalRecords) { CheckParameters(pageIndex, pageSize); return GetProfileInfo(authenticationOption, null, null, pageIndex, pageSize, out totalRecords); } /// <summary> /// Retrieves user-profile data from the data source for profiles in which the last activity date occurred on or before the specified date. /// </summary> /// <param name="authenticationOption">One of the System.Web.Profile.ProfileAuthenticationOption values, specifying whether anonymous, authenticated, or both types of profiles are returned.</param> /// <param name="userInactiveSinceDate">A System.DateTime that identifies which user profiles are considered inactive. If the System.Web.Profile.ProfileInfo.LastActivityDate of a user profile occurs on or before this date and time, the profile is considered inactive.</param> /// <param name="pageIndex">The index of the page of results to return.</param> /// <param name="pageSize">The size of the page of results to return.</param> /// <param name="totalRecords">When this method returns, contains the total number of profiles.</param> /// <returns>A System.Web.Profile.ProfileInfoCollection containing user-profile information about the inactive profiles.</returns> public override ProfileInfoCollection GetAllInactiveProfiles(ProfileAuthenticationOption authenticationOption, DateTime userInactiveSinceDate, int pageIndex, int pageSize, out int totalRecords) { CheckParameters(pageIndex, pageSize); return GetProfileInfo(authenticationOption, null, userInactiveSinceDate, pageIndex, pageSize, out totalRecords); } /// <summary> /// Returns the number of profiles in which the last activity date occurred on or before the specified date. /// </summary> /// <param name="authenticationOption">One of the System.Web.Profile.ProfileAuthenticationOption values, specifying whether anonymous, authenticated, or both types of profiles are returned.</param> /// <param name="userInactiveSinceDate">A System.DateTime that identifies which user profiles are considered inactive. If the System.Web.Profile.ProfileInfo.LastActivityDate of a user profile occurs on or before this date and time, the profile is considered inactive.</param> /// <returns>The number of profiles in which the last activity date occurred on or before the specified date.</returns> public override int GetNumberOfInactiveProfiles(ProfileAuthenticationOption authenticationOption, DateTime userInactiveSinceDate) { int inactiveProfiles = 0; ProfileInfoCollection profiles = GetProfileInfo(authenticationOption, null, userInactiveSinceDate, 0, 0, out inactiveProfiles); return inactiveProfiles; } //Verifies input parameters for page size and page index. private static void CheckParameters(int pageIndex, int pageSize) { if (pageIndex < 1 || pageSize < 1) throw new ApplicationException(ERR_INVALID_PARAMETER + " page index."); } //GetProfileInfo //Retrieves a count of profiles and creates a //ProfileInfoCollection from the profile data in the //database. Called by GetAllProfiles, GetAllInactiveProfiles, //FindProfilesByUserName, FindInactiveProfilesByUserName, //and GetNumberOfInactiveProfiles. //Specifying a pageIndex of 0 retrieves a count of the results only. private static ProfileInfoCollection GetProfileInfo(ProfileAuthenticationOption authenticationOption, string usernameToMatch, object userInactiveSinceDate, int pageIndex, int pageSize, out int totalRecords) { ProfileInfoCollection profiles = new ProfileInfoCollection(); totalRecords = 0; // Count profiles only. if (pageSize == 0) return profiles; int counter = 0; int startIndex = pageSize * (pageIndex - 1); int endIndex = startIndex + pageSize - 1; DateTime dt = new DateTime(1900, 1, 1); if (userInactiveSinceDate != null) dt = (DateTime)userInactiveSinceDate; /* foreach(CustomProfileInfo profile in dal.GetProfileInfo((int)authenticationOption, usernameToMatch, dt, applicationName, out totalRecords)) { if(counter >= startIndex) { ProfileInfo p = new ProfileInfo(profile.UserName, profile.IsAnonymous, profile.LastActivityDate, profile.LastUpdatedDate, 0); profiles.Add(p); } if(counter >= endIndex) { break; } counter++; } */ return profiles; } } } This is how I use it in the controller: public ActionResult AddTyreToCart(CartViewModel model) { string profile = Request.IsAuthenticated ? Request.AnonymousID : User.Identity.Name; } I would like to debug: How can 2 users who provide different cookies get the same profileid? EDIT Here is the code for getuniqueid public int GetUniqueID(string userName, bool isAuthenticated, bool ignoreAuthenticationType, string appName) { SqlParameter[] parms = { new SqlParameter("@Username", SqlDbType.VarChar, 256), new SqlParameter("@ApplicationName", SqlDbType.VarChar, 256)}; parms[0].Value = userName; parms[1].Value = appName; if (!ignoreAuthenticationType) { Array.Resize(ref parms, parms.Length + 1); parms[2] = new SqlParameter("@IsAnonymous", SqlDbType.Bit) { Value = !isAuthenticated }; } int userID; object retVal = null; retVal = SqlHelper.ExecuteScalar(ConfigurationManager.ConnectionStrings["SQLOrderB2CConnString"].ConnectionString, CommandType.StoredProcedure, "getProfileUniqueID", parms); if (retVal == null) userID = CreateProfileForUser(userName, isAuthenticated, appName); else userID = Convert.ToInt32(retVal); return userID; } And this is the SP: CREATE PROCEDURE [dbo].[getProfileUniqueID] @Username VarChar( 256), @ApplicationName VarChar( 256), @IsAnonymous bit = null AS BEGIN SET NOCOUNT ON; /* [getProfileUniqueID] created 08.07.2009 mf Retrive unique id for current user */ SELECT UniqueID FROM dbo.Profiles WHERE Username = @Username AND ApplicationName = @ApplicationName AND IsAnonymous = @IsAnonymous or @IsAnonymous = null END

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  • Could not load type 'Default.DataMatch' in DataMatch.aspx file

    - by salvationishere
    I am developing a C# VS 2008 / SQL Server 2008 website, but now I am getting the above error when I build it. I included the Default.aspx, Default.aspx.cs, DataMatch.aspx, and DataMatch.aspx.cs files below. What do I need to do to fix this? Default.aspx: <%@ Page Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" Title="Untitled Page" %> ... DataMatch.aspx: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="DataMatch.aspx.cs" Inherits="_Default.DataMatch" %> ... Default.aspx.cs: using System; using System.Collections; using System.Configuration; using System.Data; using System.Linq; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.HtmlControls; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Xml.Linq; using System.Collections.Generic; using System.IO; using System.Drawing; using System.ComponentModel; using System.Data.SqlClient; using ADONET_namespace; using System.Security.Principal; //using System.Windows; public partial class _Default : System.Web.UI.Page //namespace AddFileToSQL { //protected System.Web.UI.HtmlControls.HtmlInputFile uploadFile; //protected System.Web.UI.HtmlControls.HtmlInputButton btnOWrite; //protected System.Web.UI.HtmlControls.HtmlInputButton btnAppend; protected System.Web.UI.WebControls.Label Label1; protected static string inputfile = ""; public static string targettable; public static string selection; // Number of controls added to view state protected int default_NumberOfControls { get { if (ViewState["default_NumberOfControls"] != null) { return (int)ViewState["default_NumberOfControls"]; } else { return 0; } } set { ViewState["default_NumberOfControls"] = value; } } protected void uploadFile_onclick(object sender, EventArgs e) { } protected void Load_GridData() { //GridView1.DataSource = ADONET_methods.DisplaySchemaTables(); //GridView1.DataBind(); } protected void btnOWrite_Click(object sender, EventArgs e) { if (uploadFile.PostedFile.ContentLength > 0) { feedbackLabel.Text = "You do not have sufficient access to overwrite table records."; } else { feedbackLabel.Text = "This file does not contain any data."; } } protected void btnAppend_Click(object sender, EventArgs e) { string fullpath = Page.Request.PhysicalApplicationPath; string path = uploadFile.PostedFile.FileName; if (File.Exists(path)) { // Create a file to write to. try { StreamReader sr = new StreamReader(path); string s = ""; while (sr.Peek() > 0) s = sr.ReadLine(); sr.Close(); } catch (IOException exc) { Console.WriteLine(exc.Message + "Cannot open file."); return; } } if (uploadFile.PostedFile.ContentLength > 0) { inputfile = System.IO.File.ReadAllText(path); Session["Message"] = inputfile; Response.Redirect("DataMatch.aspx"); } else { feedbackLabel.Text = "This file does not contain any data."; } } protected void Page_Load(object sender, EventArgs e) { if (Request.IsAuthenticated) { WelcomeBackMessage.Text = "Welcome back, " + User.Identity.Name + "!"; // Reference the CustomPrincipal / CustomIdentity CustomIdentity ident = User.Identity as CustomIdentity; if (ident != null) WelcomeBackMessage.Text += string.Format(" You are the {0} of {1}.", ident.Title, ident.CompanyName); AuthenticatedMessagePanel.Visible = true; AnonymousMessagePanel.Visible = false; if (!Page.IsPostBack) { Load_GridData(); } } else { AuthenticatedMessagePanel.Visible = false; AnonymousMessagePanel.Visible = true; } } protected void GridView1_SelectedIndexChanged(object sender, EventArgs e) { GridViewRow row = GridView1.SelectedRow; targettable = row.Cells[2].Text; } } DataMatch.aspx.cs: using System; using System.Collections; using System.Collections.Generic; using System.Data; using System.Data.SqlClient; using System.Diagnostics; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using ADONET_namespace; //using MatrixApp; //namespace AddFileToSQL //{ public partial class DataMatch : AddFileToSQL._Default { protected System.Web.UI.WebControls.PlaceHolder phTextBoxes; protected System.Web.UI.WebControls.PlaceHolder phDropDownLists; protected System.Web.UI.WebControls.Button btnAnotherRequest; protected System.Web.UI.WebControls.Panel pnlCreateData; protected System.Web.UI.WebControls.Literal lTextData; protected System.Web.UI.WebControls.Panel pnlDisplayData; protected static string inputfile2; static string[] headers = null; static string[] data = null; static string[] data2 = null; static DataTable myInputFile = new DataTable("MyInputFile"); static string[] myUserSelections; static bool restart = false; private DropDownList[] newcol; int @temp = 0; string @tempS = ""; string @tempT = ""; // a Property that manages a counter stored in ViewState protected int NumberOfControls { get { return (int)ViewState["NumControls"]; } set { ViewState["NumControls"] = value; } } private Hashtable ddl_ht { get { return (Hashtable)ViewState["ddl_ht"]; } set { ViewState["ddl_ht"] = value; } } // Page Load private void Page_Load(object sender, System.EventArgs e) { if (!Page.IsPostBack) { ddl_ht = new Hashtable(); this.NumberOfControls = 0; } } // This data comes from input file private void PopulateFileInputTable() { myInputFile.Columns.Clear(); string strInput, newrow; string[] oneRow; DataColumn myDataColumn; DataRow myDataRow; int result, numRows; //Read the input file strInput = Session["Message"].ToString(); data = strInput.Split('\r'); //Headers headers = data[0].Split('|'); //Data for (int i = 0; i < data.Length; i++) { newrow = data[i].TrimStart('\n'); data[i] = newrow; } result = String.Compare(data[data.Length - 1], ""); numRows = data.Length; if (result == 0) { numRows = numRows - 1; } data2 = new string[numRows]; for (int a = 0, b = 0; a < numRows; a++, b++) { data2[b] = data[a]; } // Create columns for (int col = 0; col < headers.Length; col++) { @temp = (col + 1); @tempS = @temp.ToString(); @tempT = "@col"+ @temp.ToString(); myDataColumn = new DataColumn(); myDataColumn.DataType = Type.GetType("System.String"); myDataColumn.ColumnName = headers[col]; myInputFile.Columns.Add(myDataColumn); ddl_ht.Add(@tempT, headers[col]); } // Create new DataRow objects and add to DataTable. for (int r = 0; r < numRows - 1; r++) { oneRow = data2[r + 1].Split('|'); myDataRow = myInputFile.NewRow(); for (int c = 0; c < headers.Length; c++) { myDataRow[c] = oneRow[c]; } myInputFile.Rows.Add(myDataRow); } NumberOfControls = headers.Length; myUserSelections = new string[NumberOfControls]; } //Create display panel private void CreateDisplayPanel() { btnSubmit.Style.Add("top", "auto"); btnSubmit.Style.Add("left", "auto"); btnSubmit.Style.Add("position", "absolute"); btnSubmit.Style.Add("top", "200px"); btnSubmit.Style.Add("left", "400px"); newcol = CreateDropDownLists(); for (int counter = 0; counter < NumberOfControls; counter++) { pnlDisplayData.Controls.Add(newcol[counter]); pnlDisplayData.Controls.Add(new LiteralControl("<br><br><br>")); pnlDisplayData.Visible = true; pnlDisplayData.FindControl(newcol[counter].ID); } } //Recreate display panel private void RecreateDisplayPanel() { btnSubmit.Style.Add("top", "auto"); btnSubmit.Style.Add("left", "auto"); btnSubmit.Style.Add("position", "absolute"); btnSubmit.Style.Add("top", "200px"); btnSubmit.Style.Add("left", "400px"); newcol = RecreateDropDownLists(); for (int counter = 0; counter < NumberOfControls; counter++) { pnlDisplayData.Controls.Add(newcol[counter]); pnlDisplayData.Controls.Add(new LiteralControl("<br><br><br>")); pnlDisplayData.Visible = true; pnlDisplayData.FindControl(newcol[counter].ID); } } // Add DropDownList Control to Placeholder private DropDownList[] CreateDropDownLists() { DropDownList[] dropDowns = new DropDownList[NumberOfControls]; for (int counter = 0; counter < NumberOfControls; counter++) { DropDownList ddl = new DropDownList(); SqlDataReader dr2 = ADONET_methods.DisplayTableColumns(targettable); ddl.ID = "DropDownListID" + counter.ToString(); int NumControls = targettable.Length; DataTable dt = new DataTable(); dt.Load(dr2); ddl.DataValueField = "COLUMN_NAME"; ddl.DataTextField = "COLUMN_NAME"; ddl.DataSource = dt; ddl.SelectedIndexChanged += new EventHandler(ddlList_SelectedIndexChanged); ddl.DataBind(); ddl.AutoPostBack = true; ddl.EnableViewState = true; //Preserves View State info on Postbacks dr2.Close(); ddl.Items.Add("IGNORE"); dropDowns[counter] = ddl; } return dropDowns; } protected void ddlList_SelectedIndexChanged(object sender, EventArgs e) { DropDownList ddl = (DropDownList)sender; string ID = ddl.ID; } // Add TextBoxes Control to Placeholder private DropDownList[] RecreateDropDownLists() { DropDownList[] dropDowns = new DropDownList[NumberOfControls]; for (int counter = 0; counter < NumberOfControls; counter++) { DropDownList ddl = new DropDownList(); SqlDataReader dr2 = ADONET_methods.DisplayTableColumns(targettable); ddl.ID = "DropDownListID" + counter.ToString(); int NumControls = targettable.Length; DataTable dt = new DataTable(); dt.Load(dr2); ddl.DataValueField = "COLUMN_NAME"; ddl.DataTextField = "COLUMN_NAME"; ddl.DataSource = dt; ddl.SelectedIndexChanged += new EventHandler(ddlList_SelectedIndexChanged); ddl.DataBind(); ddl.AutoPostBack = true; ddl.EnableViewState = false; //Preserves View State info on Postbacks dr2.Close(); ddl.Items.Add("IGNORE"); dropDowns[counter] = ddl; } return dropDowns; } private void CreateLabels() { for (int counter = 0; counter < NumberOfControls; counter++) { Label lbl = new Label(); lbl.ID = "Label" + counter.ToString(); lbl.Text = headers[counter]; lbl.Style["position"] = "absolute"; lbl.Style["top"] = 60 * counter + 10 + "px"; lbl.Style["left"] = 250 + "px"; pnlDisplayData.Controls.Add(lbl); pnlDisplayData.Controls.Add(new LiteralControl("<br><br><br>")); } } // Add TextBoxes Control to Placeholder private void RecreateLabels() { for (int counter = 0; counter < NumberOfControls; counter++) { Label lbl = new Label(); lbl.ID = "Label" + counter.ToString(); lbl.Text = headers[counter]; lbl.Style["position"] = "absolute"; lbl.Style["top"] = 60 * counter + 10 + "px"; lbl.Style["left"] = 250 + "px"; pnlDisplayData.Controls.Add(lbl); pnlDisplayData.Controls.Add(new LiteralControl("<br><br><br>")); } } // Create TextBoxes and DropDownList data here on postback. protected override void CreateChildControls() { // create the child controls if the server control does not contains child controls this.EnsureChildControls(); // Creates a new ControlCollection. this.CreateControlCollection(); // Here we are recreating controls to persist the ViewState on every post back if (Page.IsPostBack) { RecreateDisplayPanel(); RecreateLabels(); } // Create these conrols when asp.net page is created else { PopulateFileInputTable(); CreateDisplayPanel(); CreateLabels(); } // Prevent dropdownlists and labels from being created again. if (restart == false) { this.ChildControlsCreated = true; } else if (restart == true) { this.ChildControlsCreated = false; } } private void AppendRecords() { switch (targettable) { case "ContactType": for (int r = 0; r < myInputFile.Rows.Count; r++) { resultLabel.Text = ADONET_methods.AppendDataCT(myInputFile.Rows[r], ddl_ht); } break; case "Contact": for (int r = 0; r < myInputFile.Rows.Count; r++) { resultLabel.Text = ADONET_methods.AppendDataC(myInputFile.Rows[r], ddl_ht); } break; case "AddressType": for (int r = 0; r < myInputFile.Rows.Count; r++) { resultLabel.Text = ADONET_methods.AppendDataAT(myInputFile.Rows[r], ddl_ht); } break; default: resultLabel.Text = "You do not have access to modify this table. Please select a different target table and try again."; restart = true; break; //throw new ArgumentOutOfRangeException("targettable type", targettable); } } // Read all the data from TextBoxes and DropDownLists protected void btnSubmit_Click(object sender, System.EventArgs e) { //int cnt = FindOccurence("DropDownListID"); AppendRecords(); pnlDisplayData.Visible = false; btnSubmit.Visible = false; resultLabel.Attributes.Add("style", "align:center"); btnSubmit.Style.Add("top", "auto"); btnSubmit.Style.Add("left", "auto"); btnSubmit.Style.Add("position", "absolute"); int bSubmitPosition = NumberOfControls; btnSubmit.Style.Add("top", System.Convert.ToString(bSubmitPosition)+"px"); resultLabel.Visible = true; Instructions.Visible = false; if (restart == true) { CreateChildControls(); } } private int FindOccurence(string substr) { string reqstr = Request.Form.ToString(); return ((reqstr.Length - reqstr.Replace(substr, "").Length) / substr.Length); } #region Web Form Designer generated code override protected void OnInit(EventArgs e) { // // CODEGEN: This call is required by the ASP.NET Web Form Designer. // InitializeComponent(); base.OnInit(e); } /// <summary> /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// </summary> private void InitializeComponent() { } #endregion } //}

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  • Using C# 4.0’s DynamicObject as a Stored Procedure Wrapper

    - by EltonStoneman
    [Source: http://geekswithblogs.net/EltonStoneman] Overview Ignoring the fashion, I still make a lot of use of DALs – typically when inheriting a codebase with an established database schema which is full of tried and trusted stored procedures. In the DAL a collection of base classes have all the scaffolding, so the usual pattern is to create a wrapper class for each stored procedure, giving typesafe access to parameter values and output. DAL calls then looks like instantiate wrapper-populate parameters-execute call:       using (var sp = new uspGetManagerEmployees())     {         sp.ManagerID = 16;         using (var reader = sp.Execute())         {             //map entities from the output         }     }   Or rolling it all into a fluent DAL call – which is nicer to read and implicitly disposes the resources:   This is fine, the wrapper classes are very simple to handwrite or generate. But as the codebase grows, you end up with a proliferation of very small wrapper classes: The wrappers don't add much other than encapsulating the stored procedure call and giving you typesafety for the parameters. With the dynamic extension in .NET 4.0 you have the option to build a single wrapper class, and get rid of the one-to-one stored procedure to wrapper class mapping. In the dynamic version, the call looks like this:       dynamic getUser = new DynamicSqlStoredProcedure("uspGetManagerEmployees", Database.AdventureWorks);     getUser.ManagerID = 16;       var employees = Fluently.Load<List<Employee>>()                             .With<EmployeeMap>()                             .From(getUser);   The important difference is that the ManagerId property doesn't exist in the DynamicSqlStoredProcedure class. Declaring the getUser object with the dynamic keyword allows you to dynamically add properties, and the DynamicSqlStoredProcedure class intercepts when properties are added and builds them as stored procedure parameters. When getUser.ManagerId = 16 is executed, the base class adds a parameter call (using the convention that parameter name is the property name prefixed by "@"), specifying the correct SQL Server data type (mapping it from the type of the value the property is set to), and setting the parameter value. Code Sample This is worked through in a sample project on github – Dynamic Stored Procedure Sample – which also includes a static version of the wrapper for comparison. (I'll upload this to the MSDN Code Gallery once my account has been resurrected). Points worth noting are: DynamicSP.Data – database-independent DAL that has all the data plumbing code. DynamicSP.Data.SqlServer – SQL Server DAL, thin layer on top of the generic DAL which adds SQL Server specific classes. Includes the DynamicSqlStoredProcedure base class. DynamicSqlStoredProcedure.TrySetMember. Invoked when a dynamic member is added. Assumes the property is a parameter named after the SP parameter name and infers the SqlDbType from the framework type. Adds a parameter to the internal stored procedure wrapper and sets its value. uspGetManagerEmployees – the static version of the wrapper. uspGetManagerEmployeesTest – test fixture which shows usage of the static and dynamic stored procedure wrappers. The sample uses stored procedures from the AdventureWorks database in the SQL Server 2008 Sample Databases. Discussion For this scenario, the dynamic option is very favourable. Assuming your DAL is itself wrapped by a higher layer, the stored procedure wrapper classes have very little reuse. Even if you're codegening the classes and test fixtures, it's still additional effort for very little value. The main consideration with dynamic classes is that the compiler ignores all the members you use, and evaluation only happens at runtime. In this case where scope is strictly limited that's not an issue – but you're relying on automated tests rather than the compiler to find errors, but that should just encourage better test coverage. Also you can codegen the dynamic calls at a higher level. Performance may be a consideration, as there is a first-time-use overhead when the dynamic members of an object are bound. For a single run, the dynamic wrapper took 0.2 seconds longer than the static wrapper. The framework does a good job of caching the effort though, so for 1,000 calls the dynamc version still only takes 0.2 seconds longer than the static: You don't get IntelliSense on dynamic objects, even for the declared members of the base class, and if you've been using class names as keys for configuration settings, you'll lose that option if you move to dynamics. The approach may make code more difficult to read, as you can't navigate through dynamic members, but you do still get full debugging support.     var employees = Fluently.Load<List<Employee>>()                             .With<EmployeeMap>()                             .From<uspGetManagerEmployees>                             (                                 i => i.ManagerID = 16,                                 x => x.Execute()                             );

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  • Getting a Web Resource Url in non WebForms Applications

    - by Rick Strahl
    WebResources in ASP.NET are pretty useful feature. WebResources are resources that are embedded into a .NET assembly and can be loaded from the assembly via a special resource URL. WebForms includes a method on the ClientScriptManager (Page.ClientScript) and the ScriptManager object to retrieve URLs to these resources. For example you can do: ClientScript.GetWebResourceUrl(typeof(ControlResources), ControlResources.JQUERY_SCRIPT_RESOURCE); GetWebResourceUrl requires a type (which is used for the assembly lookup in which to find the resource) and the resource id to lookup. GetWebResourceUrl() then returns a nasty old long URL like this: WebResource.axd?d=-b6oWzgbpGb8uTaHDrCMv59VSmGhilZP5_T_B8anpGx7X-PmW_1eu1KoHDvox-XHqA1EEb-Tl2YAP3bBeebGN65tv-7-yAimtG4ZnoWH633pExpJor8Qp1aKbk-KQWSoNfRC7rQJHXVP4tC0reYzVw2&t=634533278261362212 While lately excessive resource usage has been frowned upon especially by MVC developers who tend to opt for content distributed as files, I still think that Web Resources have their place even in non-WebForms applications. Also if you have existing assemblies that include resources like scripts and common image links it sure would be nice to access them from non-WebForms pages like MVC views or even in plain old Razor Web Pages. Where's my Page object Dude? Unfortunately natively ASP.NET doesn't have a mechanism for retrieving WebResource Urls outside of the WebForms engine. It's a feature that's specifically baked into WebForms and that relies specifically on the Page HttpHandler implementation. Both Page.ClientScript (obviously) and ScriptManager rely on a hosting Page object in order to work and the various methods off these objects require control instances passed. The reason for this is that the script managers can inject scripts and links into Page content (think RegisterXXXX methods) and for that a Page instance is required. However, for many other methods - like GetWebResourceUrl() - that simply return resources or resource links the Page reference is really irrelevant. While there's a separate ClientScriptManager class, it's marked as sealed and doesn't have any public constructors so you can't create your own instance (without Reflection). Even if it did the internal constructor it does have requires a Page reference. No good… So, can we get access to a WebResourceUrl generically without running in a WebForms Page instance? We just have to create a Page instance ourselves and use it internally. There's nothing intrinsic about the use of the Page class in ClientScript, at least for retrieving resources and resource Urls so it's easy to create an instance of a Page for example in a static method. For our needs of retrieving ResourceUrls or even actually retrieving script resources we can use a canned, non-configured Page instance we create on our own. The following works just fine: public static string GetWebResourceUrl(Type type, string resource ) { Page page = new Page(); return page.ClientScript.GetWebResourceUrl(type, resource); } A slight optimization for this might be to cache the created Page instance. Page tends to be a pretty heavy object to create each time a URL is required so you might want to cache the instance: public class WebUtils { private static Page CachedPage { get { if (_CachedPage == null) _CachedPage = new Page(); return _CachedPage; } } private static Page _CachedPage; public static string GetWebResourceUrl(Type type, string resource) { return CachedPage.ClientScript.GetWebResourceUrl(type, resource); } } You can now use GetWebResourceUrl in a Razor page like this: <!DOCTYPE html> <html <head> <script src="@WebUtils.GetWebResourceUrl(typeof(ControlResources),ControlResources.JQUERY_SCRIPT_RESOURCE)"> </script> </head> <body> <div class="errordisplay"> <img src="@WebUtils.GetWebResourceUrl(typeof(ControlResources),ControlResources.WARNING_ICON_RESOURCE)" /> This is only a Test! </div> </body> </html> And voila - there you have WebResources served from a non-Page based application. WebResources may be a on the way out, but legacy apps have them embedded and for some situations, like fallback scripts and some common image resources I still like to use them. Being able to use them from non-WebForms applications should have been built into the core ASP.NETplatform IMHO, but seeing that it's not this workaround is easy enough to implement.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  MVC   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • TDD and WCF behavior

    - by Frederic Hautecoeur
    Some weeks ago I wanted to develop a WCF behavior using TDD. I have lost some time trying to use mocks. After a while i decided to just use a host and a client. I don’t like this approach but so far I haven’t found a good and fast solution to use Unit Test for testing a WCF behavior. To Implement my solution I had to : Create a Dummy Service Definition; Create the Dummy Service Implementation; Create a host; Create a client in my test; Create and Add the behavior; Dummy Service Definition This is just a simple service, composed of an Interface and a simple implementation. The structure is aimed to be easily customizable for my future needs.   Using Clauses : 1: using System.Runtime.Serialization; 2: using System.ServiceModel; 3: using System.ServiceModel.Channels; The DataContract: 1: [DataContract()] 2: public class MyMessage 3: { 4: [DataMember()] 5: public string MessageString; 6: } The request MessageContract: 1: [MessageContract()] 2: public class RequestMessage 3: { 4: [MessageHeader(Name = "MyHeader", Namespace = "http://dummyservice/header", Relay = true)] 5: public string myHeader; 6:  7: [MessageBodyMember()] 8: public MyMessage myRequest; 9: } The response MessageContract: 1: [MessageContract()] 2: public class ResponseMessage 3: { 4: [MessageHeader(Name = "MyHeader", Namespace = "http://dummyservice/header", Relay = true)] 5: public string myHeader; 6:  7: [MessageBodyMember()] 8: public MyMessage myResponse; 9: } The ServiceContract: 1: [ServiceContract(Name="DummyService", Namespace="http://dummyservice",SessionMode=SessionMode.Allowed )] 2: interface IDummyService 3: { 4: [OperationContract(Action="Perform", IsOneWay=false, ProtectionLevel=System.Net.Security.ProtectionLevel.None )] 5: ResponseMessage DoThis(RequestMessage request); 6: } Dummy Service Implementation 1: public class DummyService:IDummyService 2: { 3: #region IDummyService Members 4: public ResponseMessage DoThis(RequestMessage request) 5: { 6: ResponseMessage response = new ResponseMessage(); 7: response.myHeader = "Response"; 8: response.myResponse = new MyMessage(); 9: response.myResponse.MessageString = 10: string.Format("Header:<{0}> and Request was <{1}>", 11: request.myHeader, request.myRequest.MessageString); 12: return response; 13: } 14: #endregion 15: } Host Creation The most simple host implementation using a Named Pipe binding. The GetBinding method will create a binding for the host and can be used to create the same binding for the client. 1: public static class TestHost 2: { 3: 4: internal static string hostUri = "net.pipe://localhost/dummy"; 5:  6: // Create Host method. 7: internal static ServiceHost CreateHost() 8: { 9: ServiceHost host = new ServiceHost(typeof(DummyService)); 10:  11: // Creating Endpoint 12: Uri namedPipeAddress = new Uri(hostUri); 13: host.AddServiceEndpoint(typeof(IDummyService), GetBinding(), namedPipeAddress); 14:  15: return host; 16: } 17:  18: // Binding Creation method. 19: internal static Binding GetBinding() 20: { 21: NamedPipeTransportBindingElement namedPipeTransport = new NamedPipeTransportBindingElement(); 22: TextMessageEncodingBindingElement textEncoding = new TextMessageEncodingBindingElement(); 23:  24: return new CustomBinding(textEncoding, namedPipeTransport); 25: } 26:  27: // Close Method. 28: internal static void Close(ServiceHost host) 29: { 30: if (null != host) 31: { 32: host.Close(); 33: host = null; 34: } 35: } 36: } Checking the service A simple test tool check the plumbing. 1: [TestMethod] 2: public void TestService() 3: { 4: using (ServiceHost host = TestHost.CreateHost()) 5: { 6: host.Open(); 7:  8: using (ChannelFactory<IDummyService> channel = 9: new ChannelFactory<IDummyService>(TestHost.GetBinding() 10: , new EndpointAddress(TestHost.hostUri))) 11: { 12: IDummyService svc = channel.CreateChannel(); 13: try 14: { 15: RequestMessage request = new RequestMessage(); 16: request.myHeader = Guid.NewGuid().ToString(); 17: request.myRequest = new MyMessage(); 18: request.myRequest.MessageString = "I want some beer."; 19:  20: ResponseMessage response = svc.DoThis(request); 21: } 22: catch (Exception ex) 23: { 24: Assert.Fail(ex.Message); 25: } 26: } 27: host.Close(); 28: } 29: } Running the service should show that the client and the host are running fine. So far so good. Adding the Behavior Add a reference to the Behavior project and add the using entry in the test class. We just need to add the behavior to the service host : 1: [TestMethod] 2: public void TestService() 3: { 4: using (ServiceHost host = TestHost.CreateHost()) 5: { 6: host.Description.Behaviors.Add(new MyBehavior()); 7: host.Open();¨ 8: …  If you set a breakpoint in your behavior and run the test in debug mode, you will hit the breakpoint. In this case I used a ServiceBehavior. To add an Endpoint behavior you have to add it to the endpoints. 1: host.Description.Endpoints[0].Behaviors.Add(new MyEndpointBehavior()) To add a contract or an operation behavior a custom attribute should work on the service contract definition. I haven’t tried that yet.   All the code provided in this blog and in the following files are for sample use. Improvements I don’t like to instantiate a client and a service to test my behaviors. But so far I have' not found an easy way to do it. Today I am passing a type of endpoint to the host creator and it creates the right binding type. This allows me to easily switch between bindings at will. I have used the same approach to test Mex Endpoints, another post should come later for this. Enjoy !

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  • Event Logging in LINQ C# .NET

    The first thing you'll want to do before using this code is to create a table in your database called TableHistory: CREATE TABLE [dbo].[TableHistory] (     [TableHistoryID] [int] IDENTITY NOT NULL ,     [TableName] [varchar] (50) NOT NULL ,     [Key1] [varchar] (50) NOT NULL ,     [Key2] [varchar] (50) NULL ,     [Key3] [varchar] (50) NULL ,     [Key4] [varchar] (50) NULL ,     [Key5] [varchar] (50) NULL ,     [Key6] [varchar] (50)NULL ,     [ActionType] [varchar] (50) NULL ,     [Property] [varchar] (50) NULL ,     [OldValue] [varchar] (8000) NULL ,     [NewValue] [varchar] (8000) NULL ,     [ActionUserName] [varchar] (50) NOT NULL ,     [ActionDateTime] [datetime] NOT NULL ) Once you have created the table, you'll need to add it to your custom LINQ class (which I will refer to as DboDataContext), thus creating the TableHistory class. Then, you'll need to add the History.cs file to your project. You'll also want to add the following code to your project to get the system date: public partial class DboDataContext{ [Function(Name = "GetDate", IsComposable = true)] public DateTime GetSystemDate() { MethodInfo mi = MethodBase.GetCurrentMethod() as MethodInfo; return (DateTime)this.ExecuteMethodCall(this, mi, new object[] { }).ReturnValue; }}private static Dictionary<type,> _cachedIL = new Dictionary<type,>();public static T CloneObjectWithIL<t>(T myObject){ Delegate myExec = null; if (!_cachedIL.TryGetValue(typeof(T), out myExec)) { // Create ILGenerator DynamicMethod dymMethod = new DynamicMethod("DoClone", typeof(T), new Type[] { typeof(T) }, true); ConstructorInfo cInfo = myObject.GetType().GetConstructor(new Type[] { }); ILGenerator generator = dymMethod.GetILGenerator(); LocalBuilder lbf = generator.DeclareLocal(typeof(T)); //lbf.SetLocalSymInfo("_temp"); generator.Emit(OpCodes.Newobj, cInfo); generator.Emit(OpCodes.Stloc_0); foreach (FieldInfo field in myObject.GetType().GetFields( System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.NonPublic)) { // Load the new object on the eval stack... (currently 1 item on eval stack) generator.Emit(OpCodes.Ldloc_0); // Load initial object (parameter) (currently 2 items on eval stack) generator.Emit(OpCodes.Ldarg_0); // Replace value by field value (still currently 2 items on eval stack) generator.Emit(OpCodes.Ldfld, field); // Store the value of the top on the eval stack into // the object underneath that value on the value stack. // (0 items on eval stack) generator.Emit(OpCodes.Stfld, field); } // Load new constructed obj on eval stack -> 1 item on stack generator.Emit(OpCodes.Ldloc_0); // Return constructed object. --> 0 items on stack generator.Emit(OpCodes.Ret); myExec = dymMethod.CreateDelegate(typeof(Func<t,>)); _cachedIL.Add(typeof(T), myExec); } return ((Func<t,>)myExec)(myObject);}I got both of the above methods off of the net somewhere (maybe even from CodeProject), but it's been long enough that I can't recall where I got them.Explanation of the History ClassThe History class records changes by creating a TableHistory record, inserting the values for the primary key for the table being modified into the Key1, Key2, ..., Key6 columns (if you have more than 6 values that make up a primary key on any table, you'll want to modify this), setting the type of change being made in the ActionType column (INSERT, UPDATE, or DELETE), old value and new value if it happens to be an update action, and the date and Windows identity of the user who made the change.Let's examine what happens when a call is made to the RecordLinqInsert method:public static void RecordLinqInsert(DboDataContext dbo, IIdentity user, object obj){ TableHistory hist = NewHistoryRecord(obj); hist.ActionType = "INSERT"; hist.ActionUserName = user.Name; hist.ActionDateTime = dbo.GetSystemDate(); dbo.TableHistories.InsertOnSubmit(hist);}private static TableHistory NewHistoryRecord(object obj){ TableHistory hist = new TableHistory(); Type type = obj.GetType(); PropertyInfo[] keys; if (historyRecordExceptions.ContainsKey(type)) { keys = historyRecordExceptions[type].ToArray(); } else { keys = type.GetProperties().Where(o => AttrIsPrimaryKey(o)).ToArray(); } if (keys.Length > KeyMax) throw new HistoryException("object has more than " + KeyMax.ToString() + " keys."); for (int i = 1; i <= keys.Length; i++) { typeof(TableHistory) .GetProperty("Key" + i.ToString()) .SetValue(hist, keys[i - 1].GetValue(obj, null).ToString(), null); } hist.TableName = type.Name; return hist;}protected static bool AttrIsPrimaryKey(PropertyInfo pi){ var attrs = from attr in pi.GetCustomAttributes(typeof(ColumnAttribute), true) where ((ColumnAttribute)attr).IsPrimaryKey select attr; if (attrs != null && attrs.Count() > 0) return true; else return false;}RecordLinqInsert takes as input a data context which it will use to write to the database, the user, and the LINQ object to be recorded (a single object, for instance, a Customer or Order object if you're using AdventureWorks). It then calls the NewHistoryRecord method, which uses LINQ to Objects in conjunction with the AttrIsPrimaryKey method to pull all the primary key properties, set the Key1-KeyN properties of the TableHistory object, and return the new TableHistory object. The code would be called in an application, like so: Continue span.fullpost {display:none;}

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  • ASP.NET WebAPI Security 4: Examples for various Authentication Scenarios

    - by Your DisplayName here!
    The Thinktecture.IdentityModel.Http repository includes a number of samples for the various authentication scenarios. All the clients follow a basic pattern: Acquire client credential (a single token, multiple tokens, username/password). Call Service. The service simply enumerates the claims it finds on the request and returns them to the client. I won’t show that part of the code, but rather focus on the step 1 and 2. Basic Authentication This is the most basic (pun inteneded) scenario. My library contains a class that can create the Basic Authentication header value. Simply set username and password and you are good to go. var client = new HttpClient { BaseAddress = _baseAddress }; client.DefaultRequestHeaders.Authorization = new BasicAuthenticationHeaderValue("alice", "alice"); var response = client.GetAsync("identity").Result; response.EnsureSuccessStatusCode();   SAML Authentication To integrate a Web API with an existing enterprise identity provider like ADFS, you can use SAML tokens. This is certainly not the most efficient way of calling a “lightweight service” ;) But very useful if that’s what it takes to get the job done. private static string GetIdentityToken() {     var factory = new WSTrustChannelFactory(         new WindowsWSTrustBinding(SecurityMode.Transport),         _idpEndpoint);     factory.TrustVersion = TrustVersion.WSTrust13;     var rst = new RequestSecurityToken     {         RequestType = RequestTypes.Issue,         KeyType = KeyTypes.Bearer,         AppliesTo = new EndpointAddress(Constants.Realm)     };     var token = factory.CreateChannel().Issue(rst) as GenericXmlSecurityToken;     return token.TokenXml.OuterXml; } private static Identity CallService(string saml) {     var client = new HttpClient { BaseAddress = _baseAddress };     client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("SAML", saml);     var response = client.GetAsync("identity").Result;     response.EnsureSuccessStatusCode();     return response.Content.ReadAsAsync<Identity>().Result; }   SAML to SWT conversion using the Azure Access Control Service Another possible options for integrating SAML based identity providers is to use an intermediary service that allows converting the SAML token to the more compact SWT (Simple Web Token) format. This way you only need to roundtrip the SAML once and can use the SWT afterwards. The code for the conversion uses the ACS OAuth2 endpoint. The OAuth2Client class is part of my library. private static string GetServiceTokenOAuth2(string samlToken) {     var client = new OAuth2Client(_acsOAuth2Endpoint);     return client.RequestAccessTokenAssertion(         samlToken,         SecurityTokenTypes.Saml2TokenProfile11,         Constants.Realm).AccessToken; }   SWT Authentication When you have an identity provider that directly supports a (simple) web token, you can acquire the token directly without the conversion step. Thinktecture.IdentityServer e.g. supports the OAuth2 resource owner credential profile to issue SWT tokens. private static string GetIdentityToken() {     var client = new OAuth2Client(_oauth2Address);     var response = client.RequestAccessTokenUserName("bob", "abc!123", Constants.Realm);     return response.AccessToken; } private static Identity CallService(string swt) {     var client = new HttpClient { BaseAddress = _baseAddress };     client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", swt);     var response = client.GetAsync("identity").Result;     response.EnsureSuccessStatusCode();     return response.Content.ReadAsAsync<Identity>().Result; }   So you can see that it’s pretty straightforward to implement various authentication scenarios using WebAPI and my authentication library. Stay tuned for more client samples!

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  • Breaking through the class sealing

    - by Jason Crease
    Do you understand 'sealing' in C#?  Somewhat?  Anyway, here's the lowdown. I've done this article from a C# perspective, but I've occasionally referenced .NET when appropriate. What is sealing a class? By sealing a class in C#, you ensure that you ensure that no class can be derived from that class.  You do this by simply adding the word 'sealed' to a class definition: public sealed class Dog {} Now writing something like " public sealed class Hamster: Dog {} " you'll get a compile error like this: 'Hamster: cannot derive from sealed type 'Dog' If you look in an IL disassembler, you'll see a definition like this: .class public auto ansi sealed beforefieldinit Dog extends [mscorlib]System.Object Note the addition of the word 'sealed'. What about sealing methods? You can also seal overriding methods.  By adding the word 'sealed', you ensure that the method cannot be overridden in a derived class.  Consider the following code: public class Dog : Mammal { public sealed override void Go() { } } public class Mammal { public virtual void Go() { } } In this code, the method 'Go' in Dog is sealed.  It cannot be overridden in a subclass.  Writing this would cause a compile error: public class Dachshund : Dog { public override void Go() { } } However, we can 'new' a method with the same name.  This is essentially a new method; distinct from the 'Go' in the subclass: public class Terrier : Dog { public new void Go() { } } Sealing properties? You can also seal seal properties.  You add 'sealed' to the property definition, like so: public sealed override string Name {     get { return m_Name; }     set { m_Name = value; } } In C#, you can only seal a property, not the underlying setters/getters.  This is because C# offers no override syntax for setters or getters.  However, in underlying IL you seal the setter and getter methods individually - a property is just metadata. Why bother sealing? There are a few traditional reasons to seal: Invariance. Other people may want to derive from your class, even though your implementation may make successful derivation near-impossible.  There may be twisted, hacky logic that could never be second-guessed by another developer.  By sealing your class, you're protecting them from wasting their time.  The CLR team has sealed most of the framework classes, and I assume they did this for this reason. Security.  By deriving from your type, an attacker may gain access to functionality that enables him to hack your system.  I consider this a very weak security precaution. Speed.  If a class is sealed, then .NET doesn't need to consult the virtual-function-call table to find the actual type, since it knows that no derived type can exist.  Therefore, it could emit a 'call' instead of 'callvirt' or at least optimise the machine code, thus producing a performance benefit.  But I've done trials, and have been unable to demonstrate this If you have an example, please share! All in all, I'm not convinced that sealing is interesting or important.  Anyway, moving-on... What is automatically sealed? Value types and structs.  If they were not always sealed, all sorts of things would go wrong.  For instance, structs are laid-out inline within a class.  But what if you assigned a substruct to a struct field of that class?  There may be too many fields to fit. Static classes.  Static classes exist in C# but not .NET.  The C# compiler compiles a static class into an 'abstract sealed' class.  So static classes are already sealed in C#. Enumerations.  The CLR does not track the types of enumerations - it treats them as simple value types.  Hence, polymorphism would not work. What cannot be sealed? Interfaces.  Interfaces exist to be implemented, so sealing to prevent implementation is dumb.  But what if you could prevent interfaces from being extended (i.e. ban declarations like "public interface IMyInterface : ISealedInterface")?  There is no good reason to seal an interface like this.  Sealing finalizes behaviour, but interfaces have no intrinsic behaviour to finalize Abstract classes.  In IL you can create an abstract sealed class.  But C# syntax for this already exists - declaring a class as a 'static', so it forces you to declare it as such. Non-override methods.  If a method isn't declared as override it cannot be overridden, so sealing would make no difference.  Note this is stated from a C# perspective - the words are opposite in IL.  In IL, you have four choices in total: no declaration (which actually seals the method), 'virtual' (called 'override' in C#), 'sealed virtual' ('sealed override' in C#) and 'newslot virtual' ('new virtual' or 'virtual' in C#, depending on whether the method already exists in a base class). Methods that implement interface methods.  Methods that implement an interface method must be virtual, so cannot be sealed. Fields.  A field cannot be overridden, only hidden (using the 'new' keyword in C#), so sealing would make no sense.

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  • How to build a Singleton-like dependency injector replacement (Php)

    - by Erparom
    I know out there are a lot of excelent containers, even frameworks almost entirely DI based with good strong IoC classes. However, this doesn't help me to "define" a new pattern. (This is Php code but understandable to anyone) Supose we have: //Declares the singleton class bookSingleton { private $author; private static $bookInstance; private static $isLoaned = FALSE; //The private constructor private function __constructor() { $this->author = "Onecrappy Writer Ofcheap Novels"; } //Sets the global isLoaned state and also gets self instance public static function loanBook() { if (self::$isLoaned === FALSE) { //Book already taken, so return false return FALSE; } else { //Ok, not loaned, lets instantiate (if needed and loan) if (!isset(self::$bookInstance)) { self::$bookInstance = new BookSingleton(); } self::$isLoaned = TRUE; } } //Return loaned state to false, so another book reader can take the book public function returnBook() { $self::$isLoaned = FALSE; } public function getAuthor() { return $this->author; } } Then we get the singelton consumtion class: //Consumes the Singleton class BookBorrower() { private $borrowedBook; private $haveBookState; public function __construct() { this->haveBookState = FALSE; } //Use the singelton-pattern behavior public function borrowBook() { $this->borrowedBook = BookSingleton::loanBook(); //Check if was successfully borrowed if (!this->borrowedBook) { $this->haveBookState = FALSE; } else { $this->haveBookState = TRUE; } } public function returnBook() { $this->borrowedBook->returnBook(); $this->haveBookState = FALSE; } public function getBook() { if ($this->haveBookState) { return "The book is loaned, the author is" . $this->borrowedbook->getAuthor(); } else { return "I don't have the book, perhaps someone else took it"; } } } At last, we got a client, to test the behavior function __autoload($class) { require_once $class . '.php'; } function write ($whatever,$breaks) { for($break = 0;$break<$breaks;$break++) { $whatever .= "\n"; } echo nl2br($whatever); } write("Begin Singleton test", 2); $borrowerJuan = new BookBorrower(); $borrowerPedro = new BookBorrower(); write("Juan asks for the book", 1); $borrowerJuan->borrowBook(); write("Book Borrowed? ", 1); write($borrowerJuan->getAuthorAndTitle(),2); write("Pedro asks for the book", 1); $borrowerPedro->borrowBook(); write("Book Borrowed? ", 1); write($borrowerPedro->getAuthorAndTitle(),2); write("Juan returns the book", 1); $borrowerJuan->returnBook(); write("Returned Book Juan? ", 1); write($borrowerJuan->getAuthorAndTitle(),2); write("Pedro asks again for the book", 1); $borrowerPedro->borrowBook(); write("Book Borrowed? ", 1); write($borrowerPedro->getAuthorAndTitle(),2); This will end up in the expected behavior: Begin Singleton test Juan asks for the book Book Borrowed? The book is loaned, the author is = Onecrappy Writer Ofcheap Novels Pedro asks for the book Book Borrowed? I don't have the book, perhaps someone else took it Juan returns the book Returned Book Juan? I don't have the book, perhaps someone else took it Pedro asks again for the book Book Borrowed? The book is loaned, the author is = Onecrappy Writer Ofcheap Novels So I want to make a pattern based on the DI technique able to do exactly the same, but without singleton pattern. As far as I'm aware, I KNOW I must inject the book inside "borrowBook" function instead of taking a static instance: public function borrowBook(BookNonSingleton $book) { if (isset($this->borrowedBook) || $book->isLoaned()) { $this->haveBook = FALSE; return FALSE; } else { $this->borrowedBook = $book; $this->haveBook = TRUE; return TRUE; } } And at the client, just handle the book: $borrowerJuan = new BookBorrower(); $borrowerJuan-borrowBook(new NonSingletonBook()); Etc... and so far so good, BUT... Im taking the responsability of "single instance" to the borrower, instead of keeping that responsability inside the NonSingletonBook, that since it has not anymore a private constructor, can be instantiated as many times... making instances on each call. So, What does my NonSingletonBook class MUST be in order to never allow borrowers to have this same book twice? (aka) keep the single instance. Because the dependency injector part of the code (borrower) does not solve me this AT ALL. Is it needed the container with an "asShared" method builder with static behavior? No way to encapsulate this functionallity into the Book itself? "Hey Im a book and I shouldn't be instantiated more than once, I'm unique"

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  • Functional Adaptation

    - by Charles Courchaine
    In real life and OO programming we’re often faced with using adapters, DVI to VGA, 1/4” to 1/8” audio connections, 110V to 220V, wrapping an incompatible interface with a new one, and so on.  Where the adapter pattern is generally considered for interfaces and classes a similar technique can be applied to method signatures.  To be fair, this adaptation is generally used to reduce the number of parameters but I’m sure there are other clever possibilities to be had.  As Jan questioned in the last post, how can we use a common method to execute an action if the action has a differing number of parameters, going back to the greeting example it was suggested having an AddName method that takes a first and last name as parameters.  This is exactly what we’ll address in this post. Let’s set the stage with some review and some code changes.  First, our method that handles the setup/tear-down infrastructure for our WCF service: 1: private static TResult ExecuteGreetingFunc<TResult>(Func<IGreeting, TResult> theGreetingFunc) 2: { 3: IGreeting aGreetingService = null; 4: try 5: { 6: aGreetingService = GetGreetingChannel(); 7: return theGreetingFunc(aGreetingService); 8: } 9: finally 10: { 11: CloseWCFChannel((IChannel)aGreetingService); 12: } 13: } Our original AddName method: 1: private static string AddName(string theName) 2: { 3: return ExecuteGreetingFunc<string>(theGreetingService => theGreetingService.AddName(theName)); 4: } Our new AddName method: 1: private static int AddName(string firstName, string lastName) 2: { 3: return ExecuteGreetingFunc<int>(theGreetingService => theGreetingService.AddName(firstName, lastName)); 4: } Let’s change the AddName method, just a little bit more for this example and have it take the greeting service as a parameter. 1: private static int AddName(IGreeting greetingService, string firstName, string lastName) 2: { 3: return greetingService.AddName(firstName, lastName); 4: } The new signature of AddName using the Func delegate is now Func<IGreeting, string, string, int>, which can’t be used with ExecuteGreetingFunc as is because it expects Func<IGreeting, TResult>.  Somehow we have to eliminate the two string parameters before we can use this with our existing method.  This is where we need to adapt AddName to match what ExecuteGreetingFunc expects, and we’ll do so in the following progression. 1: Func<IGreeting, string, string, int> -> Func<IGreeting, string, int> 2: Func<IGreeting, string, int> -> Func<IGreeting, int>   For the first step, we’ll create a method using the lambda syntax that will “eliminate” the last name parameter: 1: string lastNameToAdd = "Smith"; 2: //Func<IGreeting, string, string, int> -> Func<IGreeting, string, int> 3: Func<IGreeting, string, int> addName = (greetingService, firstName) => AddName(greetingService, firstName, lastNameToAdd); The new addName method gets us one step close to the signature we need.  Let’s say we’re going to call this in a loop to add several names, we’ll take the final step from Func<IGreeting, string, int> -> Func<IGreeting, int> in line as a lambda passed to ExecuteGreetingFunc like so: 1: List<string> firstNames = new List<string>() { "Bob", "John" }; 2: int aID; 3: foreach (string firstName in firstNames) 4: { 5: //Func<IGreeting, string, int> -> Func<IGreeting, int> 6: aID = ExecuteGreetingFunc<int>(greetingService => addName(greetingService, firstName)); 7: Console.WriteLine(GetGreeting(aID)); 8: } If for some reason you needed to break out the lambda on line 6 you could replace it with 1: aID = ExecuteGreetingFunc<int>(ApplyAddName(addName, firstName)); and use this method: 1: private static Func<IGreeting, int> ApplyAddName(Func<IGreeting, string, int> addName, string lastName) 2: { 3: return greetingService => addName(greetingService, lastName); 4: } Splitting out a lambda into its own method is useful both in this style of coding as well as LINQ queries to improve the debugging experience.  It is not strictly necessary to break apart the steps & functions as was shown above; the lambda in line 6 (of the foreach example) could include both the last name and first name instead of being composed of two functions.  The process demonstrated above is one of partially applying functions, this could have also been done with Currying (also see Dustin Campbell’s excellent post on Currying for the canonical curried add example).  Matthew Podwysocki also has some good posts explaining both Currying and partial application and a follow up post that further clarifies the difference between Currying and partial application.  In either technique the ultimate goal is to reduce the number of parameters passed to a function.  Currying makes it a single parameter passed at each step, where partial application allows one to use multiple parameters at a time as we’ve done here.  This technique isn’t for everyone or every problem, but can be extremely handy when you need to adapt a call to something you don’t control.

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  • Issues with ILMerge, Lambda Expressions and VS2010 merging?

    - by John Blumenauer
    A little Background For quite some time now, it’s been possible to merge multiple .NET assemblies into a single assembly using ILMerge in Visual Studio 2008.  This is especially helpful when writing wrapper assemblies for 3rd-party libraries where it’s desirable to minimize the number of assemblies for distribution.  During the merge process, ILMerge will take a set of assemblies and merge them into a single assembly.  The resulting assembly can be either an executable or a DLL and is identified as the primary assembly. Issue During a recent project, I discovered using ILMerge to merge assemblies containing lambda expressions in Visual Studio 2010 is resulting in invalid primary assemblies.  The code below is not where the initial issue was identified, I will merely use it to illustrate the problem at hand. In order to describe the issue, I created a console application and a class library for calculating a few math functions utilizing lambda expressions.  The code is available for download at the bottom of this blog entry. MathLib.cs using System; namespace MathLib { public static class MathHelpers { public static Func<double, double, double> Hypotenuse = (x, y) => Math.Sqrt(x * x + y * y); static readonly Func<int, int, bool> divisibleBy = (int a, int b) => a % b == 0; public static bool IsPrimeNumber(int x) { { for (int i = 2; i <= x / 2; i++) if (divisibleBy(x, i)) return false; return true; }; } } } Program.cs using System; using MathLib; namespace ILMergeLambdasConsole { class Program { static void Main(string[] args) { int n = 19; if (MathHelpers.IsPrimeNumber(n)) { Console.WriteLine(n + " is prime"); } else { Console.WriteLine(n + " is not prime"); } Console.ReadLine(); } } } Not surprisingly, the preceding code compiles, builds and executes without error prior to running the ILMerge tool.   ILMerge Setup In order to utilize ILMerge, the following changes were made to the project. The MathLib.dll assembly was built in release configuration and copied to the MathLib folder.  The following folder hierarchy was used for this example:   The project file for ILMergeLambdasConsole project file was edited to add the ILMerge post-build configuration.  The following lines were added near the bottom of the project file:  <Target Name="AfterBuild" Condition="'$(Configuration)' == 'Release'"> <Exec Command="&quot;..\..\lib\ILMerge\Ilmerge.exe&quot; /ndebug /out:@(MainAssembly) &quot;@(IntermediateAssembly)&quot; @(ReferenceCopyLocalPaths->'&quot;%(FullPath)&quot;', ' ')" /> <Delete Files="@(ReferenceCopyLocalPaths->'$(OutDir)%(DestinationSubDirectory)%(Filename)%(Extension)')" /> </Target> The ILMergeLambdasConsole project was modified to reference the MathLib.dll located in the MathLib folder above. ILMerge and ILMerge.exe.config was copied into the ILMerge folder shown above.  The contents of ILMerge.exe.config are: <?xml version="1.0" encoding="utf-8" ?> <configuration> <startup useLegacyV2RuntimeActivationPolicy="true"> <requiredRuntime safemode="true" imageVersion="v4.0.30319" version="v4.0.30319"/> </startup> </configuration> Post-ILMerge After compiling and building, the MathLib.dll assembly will be merged into the ILMergeLambdasConsole executable.  Unfortunately, executing ILMergeLambdasConsole.exe now results in a crash.  The ILMerge documentation recommends using PEVerify.exe to validate assemblies after merging.  Executing PEVerify.exe against the ILMergeLambdasConsole.exe assembly results in the following error:    Further investigation by using Reflector reveals the divisibleBy method in the MathHelpers class looks a bit questionable after the merge.     Prior to using ILMerge, the same divisibleBy method appeared as the following in Reflector: It’s pretty obvious something has gone awry during the merge process.  However, this is only occurring when building within the Visual Studio 2010 environment.  The same code and configuration built within Visual Studio 2008 executes fine.  I’m still investigating the issue.  If anyone has already experienced this situation and solved it, I would love to hear from you.  However, as of right now, it looks like something has gone terribly wrong when executing ILMerge against assemblies containing Lambdas in Visual Studio 2010. Solution Files ILMergeLambdaExpression

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  • TFS API Change WorkItem CreatedDate And ChangedDate To Historic Dates

    - by Tarun Arora
    There may be times when you need to modify the value of the fields “System.CreatedDate” and “System.ChangedDate” on a work item. Richard Hundhausen has a great blog with ample of reason why or why not you should need to set the values of these fields to historic dates. In this blog post I’ll show you, Create a PBI WorkItem linked to a Task work item by pre-setting the value of the field ‘System.ChangedDate’ to a historic date Change the value of the field ‘System.Created’ to a historic date Simulate the historic burn down of a task type work item in a sprint Explain the impact of updating values of the fields CreatedDate and ChangedDate on the Sprint burn down chart Rules of Play      1. You need to be a member of the Project Collection Service Accounts              2. You need to use ‘WorkItemStoreFlags.BypassRules’ when you instantiate the WorkItemStore service // Instanciate Work Item Store with the ByPassRules flag _wis = new WorkItemStore(_tfs, WorkItemStoreFlags.BypassRules);      3. You cannot set the ChangedDate         - Less than the changed date of previous revision         - Greater than current date Walkthrough The walkthrough contains 5 parts 00 – Required References 01 – Connect to TFS Programmatically 02 – Create a Work Item Programmatically 03 – Set the values of fields ‘System.ChangedDate’ and ‘System.CreatedDate’ to historic dates 04 – Results of our experiment Lets get started………………………………………………… 00 – Required References Microsoft.TeamFoundation.dll Microsoft.TeamFoundation.Client.dll Microsoft.TeamFoundation.Common.dll Microsoft.TeamFoundation.WorkItemTracking.Client.dll 01 – Connect to TFS Programmatically I have a in depth blog post on how to connect to TFS programmatically in case you are interested. However, the code snippet below will enable you to connect to TFS using the Team Project Picker. // Services I need access to globally private static TfsTeamProjectCollection _tfs; private static ProjectInfo _selectedTeamProject; private static WorkItemStore _wis; // Connect to TFS Using Team Project Picker public static bool ConnectToTfs() { var isSelected = false; // The user is allowed to select only one project var tfsPp = new TeamProjectPicker(TeamProjectPickerMode.SingleProject, false); tfsPp.ShowDialog(); // The TFS project collection _tfs = tfsPp.SelectedTeamProjectCollection; if (tfsPp.SelectedProjects.Any()) { // The selected Team Project _selectedTeamProject = tfsPp.SelectedProjects[0]; isSelected = true; } return isSelected; } 02 – Create a Work Item Programmatically In the below code snippet I have create a Product Backlog Item and a Task type work item and then link them together as parent and child. Note – You will have to set the ChangedDate to a historic date when you created the work item. Remember, If you try and set the ChangedDate to a value earlier than last assigned you will receive the following exception… TF26212: Team Foundation Server could not save your changes. There may be problems with the work item type definition. Try again or contact your Team Foundation Server administrator. If you notice below I have added a few seconds each time I have modified the ‘ChangedDate’ just to avoid running into the exception listed above. // Create Linked Work Items and return Ids private static List<int> CreateWorkItemsProgrammatically() { // Instantiate Work Item Store with the ByPassRules flag _wis = new WorkItemStore(_tfs, WorkItemStoreFlags.BypassRules); // List of work items to return var listOfWorkItems = new List<int>(); // Create a new Product Backlog Item var p = new WorkItem(_wis.Projects[_selectedTeamProject.Name].WorkItemTypes["Product Backlog Item"]); p.Title = "This is a new PBI"; p.Description = "Description"; p.IterationPath = string.Format("{0}\\Release 1\\Sprint 1", _selectedTeamProject.Name); p.AreaPath = _selectedTeamProject.Name; p["Effort"] = 10; // Just double checking that ByPassRules is set to true if (_wis.BypassRules) { p.Fields["System.ChangedDate"].Value = Convert.ToDateTime("2012-01-01"); } if (p.Validate().Count == 0) { p.Save(); listOfWorkItems.Add(p.Id); } else { Console.WriteLine(">> Following exception(s) encountered during work item save: "); foreach (var e in p.Validate()) { Console.WriteLine(" - '{0}' ", e); } } var t = new WorkItem(_wis.Projects[_selectedTeamProject.Name].WorkItemTypes["Task"]); t.Title = "This is a task"; t.Description = "Task Description"; t.IterationPath = string.Format("{0}\\Release 1\\Sprint 1", _selectedTeamProject.Name); t.AreaPath = _selectedTeamProject.Name; t["Remaining Work"] = 10; if (_wis.BypassRules) { t.Fields["System.ChangedDate"].Value = Convert.ToDateTime("2012-01-01"); } if (t.Validate().Count == 0) { t.Save(); listOfWorkItems.Add(t.Id); } else { Console.WriteLine(">> Following exception(s) encountered during work item save: "); foreach (var e in t.Validate()) { Console.WriteLine(" - '{0}' ", e); } } var linkTypEnd = _wis.WorkItemLinkTypes.LinkTypeEnds["Child"]; p.Links.Add(new WorkItemLink(linkTypEnd, t.Id) {ChangedDate = Convert.ToDateTime("2012-01-01").AddSeconds(20)}); if (_wis.BypassRules) { p.Fields["System.ChangedDate"].Value = Convert.ToDateTime("2012-01-01").AddSeconds(20); } if (p.Validate().Count == 0) { p.Save(); } else { Console.WriteLine(">> Following exception(s) encountered during work item save: "); foreach (var e in p.Validate()) { Console.WriteLine(" - '{0}' ", e); } } return listOfWorkItems; } 03 – Set the value of “Created Date” and Change the value of “Changed Date” to Historic Dates The CreatedDate can only be changed after a work item has been created. If you try and set the CreatedDate to a historic date at the time of creation of a work item, it will not work. // Lets do a work item effort burn down simulation by updating the ChangedDate & CreatedDate to historic Values private static void WorkItemChangeSimulation(IEnumerable<int> listOfWorkItems) { foreach (var id in listOfWorkItems) { var wi = _wis.GetWorkItem(id); switch (wi.Type.Name) { case "ProductBacklogItem": if (wi.State.ToLower() == "new") wi.State = "Approved"; // Advance the changed date by few seconds wi.Fields["System.ChangedDate"].Value = Convert.ToDateTime(wi.Fields["System.ChangedDate"].Value).AddSeconds(10); // Set the CreatedDate to Changed Date wi.Fields["System.CreatedDate"].Value = Convert.ToDateTime(wi.Fields["System.ChangedDate"].Value).AddSeconds(10); wi.Save(); break; case "Task": // Advance the changed date by few seconds wi.Fields["System.ChangedDate"].Value = Convert.ToDateTime(wi.Fields["System.ChangedDate"].Value).AddSeconds(10); // Set the CreatedDate to Changed date wi.Fields["System.CreatedDate"].Value = Convert.ToDateTime(wi.Fields["System.ChangedDate"].Value).AddSeconds(10); wi.Save(); break; } } // A mock sprint start date var sprintStart = DateTime.Today.AddDays(-5); // A mock sprint end date var sprintEnd = DateTime.Today.AddDays(5); // What is the total Sprint duration var totalSprintDuration = (sprintEnd - sprintStart).Days; // How much of the sprint have we already covered var noOfDaysIntoSprint = (DateTime.Today - sprintStart).Days; // Get the effort assigned to our tasks var totalEffortRemaining = QueryTaskTotalEfforRemaining(listOfWorkItems); // Defining how much effort to burn every day decimal dailyBurnRate = totalEffortRemaining / totalSprintDuration < 1 ? 1 : totalEffortRemaining / totalSprintDuration; // we have just created one task var totalNoOfTasks = 1; var simulation = sprintStart; var currentDate = DateTime.Today.Date; // Carry on till effort has been burned down from sprint start to today while (simulation.Date != currentDate.Date) { var dailyBurnRate1 = dailyBurnRate; // A fixed amount needs to be burned down each day while (dailyBurnRate1 > 0) { // burn down bit by bit from all unfinished task type work items foreach (var id in listOfWorkItems) { var wi = _wis.GetWorkItem(id); var isDirty = false; // Set the status to in progress if (wi.State.ToLower() == "to do") { wi.State = "In Progress"; isDirty = true; } // Ensure that there is enough effort remaining in tasks to burn down the daily burn rate if (QueryTaskTotalEfforRemaining(listOfWorkItems) > dailyBurnRate1) { // If there is less than 1 unit of effort left in the task, burn it all if (Convert.ToDecimal(wi["Remaining Work"]) <= 1) { wi["Remaining Work"] = 0; dailyBurnRate1 = dailyBurnRate1 - Convert.ToDecimal(wi["Remaining Work"]); isDirty = true; } else { // How much to burn from each task? var toBurn = (dailyBurnRate / totalNoOfTasks) < 1 ? 1 : (dailyBurnRate / totalNoOfTasks); // Check that the task has enough effort to allow burnForTask effort if (Convert.ToDecimal(wi["Remaining Work"]) >= toBurn) { wi["Remaining Work"] = Convert.ToDecimal(wi["Remaining Work"]) - toBurn; dailyBurnRate1 = dailyBurnRate1 - toBurn; isDirty = true; } else { wi["Remaining Work"] = 0; dailyBurnRate1 = dailyBurnRate1 - Convert.ToDecimal(wi["Remaining Work"]); isDirty = true; } } } else { dailyBurnRate1 = 0; } if (isDirty) { if (Convert.ToDateTime(wi.Fields["System.ChangedDate"].Value).Date == simulation.Date) { wi.Fields["System.ChangedDate"].Value = Convert.ToDateTime(wi.Fields["System.ChangedDate"].Value).AddSeconds(20); } else { wi.Fields["System.ChangedDate"].Value = simulation.AddSeconds(20); } wi.Save(); } } } // Increase date by 1 to perform daily burn down by day simulation = Convert.ToDateTime(simulation).AddDays(1); } } // Get the Total effort remaining in the current sprint private static decimal QueryTaskTotalEfforRemaining(List<int> listOfWorkItems) { var unfinishedWorkInCurrentSprint = _wis.GetQueryDefinition( new Guid(QueryAndGuid.FirstOrDefault(c => c.Key == "Unfinished Work").Value)); var parameters = new Dictionary<string, object> { { "project", _selectedTeamProject.Name } }; var q = new Query(_wis, unfinishedWorkInCurrentSprint.QueryText, parameters); var results = q.RunLinkQuery(); var wis = new List<WorkItem>(); foreach (var result in results) { var _wi = _wis.GetWorkItem(result.TargetId); if (_wi.Type.Name == "Task" && listOfWorkItems.Contains(_wi.Id)) wis.Add(_wi); } return wis.Sum(r => Convert.ToDecimal(r["Remaining Work"])); }   04 – The Results If you are still reading, the results are beautiful! Image 1 – Create work item with Changed Date pre-set to historic date Image 2 – Set the CreatedDate to historic date (Same as the ChangedDate) Image 3 – Simulate of effort burn down on a task via the TFS API   Image 4 – The history of changes on the Task. So, essentially this task has burned 1 hour per day Sprint Burn Down Chart – What’s not possible? The Sprint burn down chart is calculated from the System.AuthorizedDate and not the System.ChangedDate/System.CreatedDate. So, though you can change the System.ChangedDate and System.CreatedDate to historic dates you will not be able to synthesize the sprint burn down chart. Image 1 – By changing the Created Date and Changed Date to ‘18/Oct/2012’ you would have expected the burn down to have been impacted, but it won’t be, because the sprint burn down chart uses the value of field ‘System.AuthorizedDate’ to calculate the unfinished work points. The AsOf queries that are used to calculate the unfinished work points use the value of the field ‘System.AuthorizedDate’. Image 2 – Using the above code I burned down 1 hour effort per day over 5 days from the task work item, I would have expected the sprint burn down to show a constant burn down, instead the burn down shows the effort exhausted on the 24th itself. Simply because the burn down is calculated using the ‘System.AuthorizedDate’. Now you would ask… “Can I change the value of the field System.AuthorizedDate to a historic date” Unfortunately that’s not possible! You will run into the exception ValidationException –  “TF26194: The value for field ‘Authorized Date’ cannot be changed.” Conclusion - You need to be a member of the Project Collection Service account group in order to set the fields ‘System.ChangedDate’ and ‘System.CreatedDate’ to historic dates - You need to instantiate the WorkItemStore using the flag ByPassValidation - The System.ChangedDate needs to be set to a historic date at the time of work item creation. You cannot reset the ChangedDate to a date earlier than the existing ChangedDate and you cannot reset the ChangedDate to a date greater than the current date time. - The System.CreatedDate can only be reset after a work item has been created. You cannot set the CreatedDate at the time of work item creation. The CreatedDate cannot be greater than the current date. You can however reset the CreatedDate to a date earlier than the existing value. - You will not be able to synthesize the Sprint burn down chart by changing the value of System.ChangedDate and System.CreatedDate to historic dates, since the burn down chart uses AsOf queries to calculate the unfinished work points which internally uses the System.AuthorizedDate and NOT the System.ChangedDate & System.CreatedDate - System.AuthorizedDate cannot be set to a historic date using the TFS API Read other posts on using the TFS API here… Enjoy!

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  • What Keeps You from Changing Your Public IP Address and Wreaking Havoc on the Internet?

    - by Jason Fitzpatrick
    What exactly is preventing you (or anyone else) from changing their IP address and causing all sorts of headaches for ISPs and other Internet users? Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites. The Question SuperUser reader Whitemage is curious about what’s preventing him from wantonly changing his IP address and causing trouble: An interesting question was asked of me and I did not know what to answer. So I’ll ask here. Let’s say I subscribed to an ISP and I’m using cable internet access. The ISP gives me a public IP address of 60.61.62.63. What keeps me from changing this IP address to, let’s say, 60.61.62.75, and messing with another consumer’s internet access? For the sake of this argument, let’s say that this other IP address is also owned by the same ISP. Also, let’s assume that it’s possible for me to go into the cable modem settings and manually change the IP address. Under a business contract where you are allocated static addresses, you are also assigned a default gateway, a network address and a broadcast address. So that’s 3 addresses the ISP “loses” to you. That seems very wasteful for dynamically assigned IP addresses, which the majority of customers are. Could they simply be using static arps? ACLs? Other simple mechanisms? Two things to investigate here, why can’t we just go around changing our addresses, and is the assignment process as wasteful as it seems? The Answer SuperUser contributor Moses offers some insight: Cable modems aren’t like your home router (ie. they don’t have a web interface with simple point-and-click buttons that any kid can “hack” into). Cable modems are “looked up” and located by their MAC address by the ISP, and are typically accessed by technicians using proprietary software that only they have access to, that only runs on their servers, and therefore can’t really be stolen. Cable modems also authenticate and cross-check settings with the ISPs servers. The server has to tell the modem whether it’s settings (and location on the cable network) are valid, and simply sets it to what the ISP has it set it for (bandwidth, DHCP allocations, etc). For instance, when you tell your ISP “I would like a static IP, please.”, they allocate one to the modem through their servers, and the modem allows you to use that IP. Same with bandwidth changes, for instance. To do what you are suggesting, you would likely have to break into the servers at the ISP and change what it has set up for your modem. Could they simply be using static arps? ACLs? Other simple mechanisms? Every ISP is different, both in practice and how close they are with the larger network that is providing service to them. Depending on those factors, they could be using a combination of ACL and static ARP. It also depends on the technology in the cable network itself. The ISP I worked for used some form of ACL, but that knowledge was a little beyond my paygrade. I only got to work with the technician’s interface and do routine maintenance and service changes. What keeps me from changing this IP address to, let’s say, 60.61.62.75 and mess with another consumer’s internet access? Given the above, what keeps you from changing your IP to one that your ISP hasn’t specifically given to you is a server that is instructing your modem what it can and can’t do. Even if you somehow broke into the modem, if 60.61.62.75 is already allocated to another customer, then the server will simply tell your modem that it can’t have it. David Schwartz offers some additional insight with a link to a white paper for the really curious: Most modern ISPs (last 13 years or so) will not accept traffic from a customer connection with a source IP address they would not route to that customer were it the destination IP address. This is called “reverse path forwarding”. See BCP 38. Have something to add to the explanation? Sound off in the the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.     

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  • Opposite Force to Apply to a Collided Rigid Body?

    - by Milo
    I'm working on the physics for my GTA2-like game so I can learn more about game physics. The collision detection and resolution are working great. I'm now just unsure how to compute the force to apply to a body after it collides with a wall. My rigid body looks like this: /our simulation object class RigidBody extends Entity { //linear private Vector2D velocity = new Vector2D(); private Vector2D forces = new Vector2D(); private float mass; private Vector2D v = new Vector2D(); //angular private float angularVelocity; private float torque; private float inertia; //graphical private Vector2D halfSize = new Vector2D(); private Bitmap image; private Matrix mat = new Matrix(); private float[] Vector2Ds = new float[2]; private Vector2D tangent = new Vector2D(); private static Vector2D worldRelVec = new Vector2D(); private static Vector2D relWorldVec = new Vector2D(); private static Vector2D pointVelVec = new Vector2D(); private static Vector2D acceleration = new Vector2D(); public RigidBody() { //set these defaults so we don't get divide by zeros mass = 1.0f; inertia = 1.0f; setLayer(LAYER_OBJECTS); } protected void rectChanged() { if(getWorld() != null) { getWorld().updateDynamic(this); } } //intialize out parameters public void initialize(Vector2D halfSize, float mass, Bitmap bitmap) { //store physical parameters this.halfSize = halfSize; this.mass = mass; image = bitmap; inertia = (1.0f / 20.0f) * (halfSize.x * halfSize.x) * (halfSize.y * halfSize.y) * mass; RectF rect = new RectF(); float scalar = 10.0f; rect.left = (int)-halfSize.x * scalar; rect.top = (int)-halfSize.y * scalar; rect.right = rect.left + (int)(halfSize.x * 2.0f * scalar); rect.bottom = rect.top + (int)(halfSize.y * 2.0f * scalar); setRect(rect); } public void setLocation(Vector2D position, float angle) { getRect().set(position.x,position.y, getWidth(), getHeight(), angle); rectChanged(); } public Vector2D getPosition() { return getRect().getCenter(); } @Override public void update(float timeStep) { doUpdate(timeStep); } public void doUpdate(float timeStep) { //integrate physics //linear acceleration.x = forces.x / mass; acceleration.y = forces.y / mass; velocity.x += (acceleration.x * timeStep); velocity.y += (acceleration.y * timeStep); //velocity = Vector2D.add(velocity, Vector2D.scalarMultiply(acceleration, timeStep)); Vector2D c = getRect().getCenter(); v.x = getRect().getCenter().getX() + (velocity.x * timeStep); v.y = getRect().getCenter().getY() + (velocity.y * timeStep); setCenter(v.x, v.y); forces.x = 0; //clear forces forces.y = 0; //angular float angAcc = torque / inertia; angularVelocity += angAcc * timeStep; setAngle(getAngle() + angularVelocity * timeStep); torque = 0; //clear torque } //take a relative Vector2D and make it a world Vector2D public Vector2D relativeToWorld(Vector2D relative) { mat.reset(); Vector2Ds[0] = relative.x; Vector2Ds[1] = relative.y; mat.postRotate(JMath.radToDeg(getAngle())); mat.mapVectors(Vector2Ds); relWorldVec.x = Vector2Ds[0]; relWorldVec.y = Vector2Ds[1]; return relWorldVec; } //take a world Vector2D and make it a relative Vector2D public Vector2D worldToRelative(Vector2D world) { mat.reset(); Vector2Ds[0] = world.x; Vector2Ds[1] = world.y; mat.postRotate(JMath.radToDeg(-getAngle())); mat.mapVectors(Vector2Ds); worldRelVec.x = Vector2Ds[0]; worldRelVec.y = Vector2Ds[1]; return worldRelVec; } //velocity of a point on body public Vector2D pointVelocity(Vector2D worldOffset) { tangent.x = -worldOffset.y; tangent.y = worldOffset.x; pointVelVec.x = (tangent.x * angularVelocity) + velocity.x; pointVelVec.y = (tangent.y * angularVelocity) + velocity.y; return pointVelVec; } public void applyForce(Vector2D worldForce, Vector2D worldOffset) { //add linear force forces.x += worldForce.x; forces.y += worldForce.y; //add associated torque torque += Vector2D.cross(worldOffset, worldForce); } @Override public void draw( GraphicsContext c) { c.drawRotatedScaledBitmap(image, getPosition().x, getPosition().y, getWidth(), getHeight(), getAngle()); } public Vector2D getVelocity() { return velocity; } public void setVelocity(Vector2D velocity) { this.velocity = velocity; } } The way it is given force is by the applyForce method, this method considers angular torque. I'm just not sure how to come up with the vectors in the case where: RigidBody hits static entity RigidBody hits other RigidBody that may or may not be in motion. Would anyone know a way (without too complex math) that I could figure out the opposite force I need to apply to the car? I know the normal it is colliding with and how deep it collided. My main goal is so that say I hit a building from the side, well the car should not just stay there, it should slowly rotate out of it if I'm more than 45 degrees. Right now when I hit a wall I only change the velocity directly which does not consider angular force. Thanks!

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  • [Windows 8] An application bar toggle button

    - by Benjamin Roux
    To stay in the application bar stuff, here’s another useful control which enable to create an application bar button that can be toggled between two different contents/styles/commands (used to create a favorite/unfavorite or a play/pause button for example). namespace Indeed.Controls { public class AppBarToggleButton : Button { public bool IsChecked { get { return (bool)GetValue(IsCheckedProperty); } set { SetValue(IsCheckedProperty, value); } } public static readonly DependencyProperty IsCheckedProperty = DependencyProperty.Register("IsChecked", typeof(bool), typeof(AppBarToggleButton), new PropertyMetadata(false, (o, e) => (o as AppBarToggleButton).IsCheckedChanged())); public string CheckedContent { get { return (string)GetValue(CheckedContentProperty); } set { SetValue(CheckedContentProperty, value); } } public static readonly DependencyProperty CheckedContentProperty = DependencyProperty.Register("CheckedContent", typeof(string), typeof(AppBarToggleButton), null); public ICommand CheckedCommand { get { return (ICommand)GetValue(CheckedCommandProperty); } set { SetValue(CheckedCommandProperty, value); } } public static readonly DependencyProperty CheckedCommandProperty = DependencyProperty.Register("CheckedCommand", typeof(ICommand), typeof(AppBarToggleButton), null); public Style CheckedStyle { get { return (Style)GetValue(CheckedStyleProperty); } set { SetValue(CheckedStyleProperty, value); } } public static readonly DependencyProperty CheckedStyleProperty = DependencyProperty.Register("CheckedStyle", typeof(Style), typeof(AppBarToggleButton), null); public bool AutoToggle { get { return (bool)GetValue(AutoToggleProperty); } set { SetValue(AutoToggleProperty, value); } } public static readonly DependencyProperty AutoToggleProperty = DependencyProperty.Register("AutoToggle", typeof(bool), typeof(AppBarToggleButton), null); private object content; private ICommand command; private Style style; private void IsCheckedChanged() { if (IsChecked) { // backup the current content and command content = Content; command = Command; style = Style; if (CheckedStyle == null) Content = CheckedContent; else Style = CheckedStyle; Command = CheckedCommand; } else { if (CheckedStyle == null) Content = content; else Style = style; Command = command; } } protected override void OnTapped(Windows.UI.Xaml.Input.TappedRoutedEventArgs e) { base.OnTapped(e); if (AutoToggle) IsChecked = !IsChecked; } } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } To use it, it’s very simple. <ic:AppBarToggleButton Style="{StaticResource PlayAppBarButtonStyle}" CheckedStyle="{StaticResource PauseAppBarButtonStyle}" Command="{Binding Path=PlayCommand}" CheckedCommand="{Binding Path=PauseCommand}" IsChecked="{Binding Path=IsPlaying}" /> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } When the IsPlaying property (in my ViewModel) is true the button becomes a Pause button, when it’s false it becomes a Play button. Warning: Just make sure that the IsChecked property is set in last in your control !! If you don’t use style you can alternatively use Content and CheckedContent. Furthermore you can set the AutoToggle to true if you don’t want to control is IsChecked property through binding. With this control and the AppBarPopupButton, you can now create awesome application bar for your apps ! Stay tuned for more awesome Windows 8 tricks !

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  • Example: Controlling randomizer using code contracts

    - by DigiMortal
    One cool addition to Visual Studio 2010 is support for code contracts. Code contracts make sure that all conditions under what method is supposed to run correctly are met. Those who are familiar with unit tests will find code contracts easy to use. In this posting I will show you simple example about static contract checking (example solution is included). To try out code contracts you need at least Visual Studio 2010 Standard Edition. Also you need code contracts package. You can download package from DevLabs Code Contracts page. NB! Speakers, you can use the example solution in your presentations as long as you mention me and this blog in your sessions. Solution has readme.txt file that gives you steps to go through when presenting solution in sessions. This blog posting is companion posting for Visual Studio solution referred below. As an example let’s look at the following class. public class Randomizer {     public static int GetRandomFromRange(int min, int max)     {         var rnd = new Random();         return rnd.Next(min, max);     }       public static int GetRandomFromRangeContracted(int min, int max)     {         Contract.Requires(min < max, "Min must be less than max");           var rnd = new Random();         return rnd.Next(min, max);     } } GetRandomFromRange() method returns results without any checking. GetRandomFromRangeContracted() uses one code contract that makes sure that minimum value is less than maximum value. Now let’s run the following code. class Program {     static void Main(string[] args)     {         var random1 = Randomizer.GetRandomFromRange(0, 9);         Console.WriteLine("Random 1: " + random1);           var random2 = Randomizer.GetRandomFromRange(1, 1);         Console.WriteLine("Random 2: " + random2);           var random3 = Randomizer.GetRandomFromRangeContracted(5, 5);         Console.WriteLine("Random 3: " + random3);           Console.WriteLine(" ");         Console.WriteLine("Press any key to exit ...");         Console.ReadKey();     } } As we have not turned on support for code contracts the code runs without any problems and we get no warnings by Visual Studio that something is wrong. Now let’s turn on static checking for code contracts. As you can see then code still compiles without any errors but Visual Studio warns you about possible problems with contracts. Click on image to see it at original size.  When we open Error list and run our application we get the following output to errors list. Note that these messages are not shown immediately. There is little delay between application starting and appearance of these messages. So wait couple of seconds before going out of your mind. Click on image to see it at original size.  If you look at these warnings you can see that warnings show you illegal calls and also contracts against what they are going. Third warning points to GetRandomFromRange() method and shows that there should be also problem that can be detected by contract. Download Code Contracts example VS2010 solution | 30KB

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  • await, WhenAll, WaitAll, oh my!!

    - by cibrax
    If you are dealing with asynchronous work in .NET, you might know that the Task class has become the main driver for wrapping asynchronous calls. Although this class was officially introduced in .NET 4.0, the programming model for consuming tasks was much more simplified in C# 5.0 in .NET 4.5 with the addition of the new async/await keywords. In a nutshell, you can use these keywords to make asynchronous calls as if they were sequential, and avoiding in that way any fork or callback in the code. The compiler takes care of the rest. I was yesterday writing some code for making multiple asynchronous calls to backend services in parallel. The code looked as follow, var allResults = new List<Result>(); foreach(var provider in providers) { var results = await provider.GetResults(); allResults.AddRange(results); } return allResults; You see, I was using the await keyword to make multiple calls in parallel. Something I did not consider was the overhead this code implied after being compiled. I started an interesting discussion with some smart folks in twitter. One of them, Tugberk Ugurlu, had the brilliant idea of actually write some code to make a performance comparison with another approach using Task.WhenAll. There are two additional methods you can use to wait for the results of multiple calls in parallel, WhenAll and WaitAll. WhenAll creates a new task and waits for results in that new task, so it does not block the calling thread. WaitAll, on the other hand, blocks the calling thread. This is the code Tugberk initially wrote, and I modified afterwards to also show the results of WaitAll. class Program { private static Func<Stopwatch, Task>[] funcs = new Func<Stopwatch, Task>[] { async (watch) => { watch.Start(); await Task.Delay(1000); Console.WriteLine("1000 one has been completed."); }, async (watch) => { await Task.Delay(1500); Console.WriteLine("1500 one has been completed."); }, async (watch) => { await Task.Delay(2000); Console.WriteLine("2000 one has been completed."); watch.Stop(); Console.WriteLine(watch.ElapsedMilliseconds + "ms has been elapsed."); } }; static void Main(string[] args) { Console.WriteLine("Await in loop work starts..."); DoWorkAsync().ContinueWith(task => { Console.WriteLine("Parallel work starts..."); DoWorkInParallelAsync().ContinueWith(t => { Console.WriteLine("WaitAll work starts..."); WaitForAll(); }); }); Console.ReadLine(); } static async Task DoWorkAsync() { Stopwatch watch = new Stopwatch(); foreach (var func in funcs) { await func(watch); } } static async Task DoWorkInParallelAsync() { Stopwatch watch = new Stopwatch(); await Task.WhenAll(funcs[0](watch), funcs[1](watch), funcs[2](watch)); } static void WaitForAll() { Stopwatch watch = new Stopwatch(); Task.WaitAll(funcs[0](watch), funcs[1](watch), funcs[2](watch)); } } After running this code, the results were very concluding. Await in loop work starts... 1000 one has been completed. 1500 one has been completed. 2000 one has been completed. 4532ms has been elapsed. Parallel work starts... 1000 one has been completed. 1500 one has been completed. 2000 one has been completed. 2007ms has been elapsed. WaitAll work starts... 1000 one has been completed. 1500 one has been completed. 2000 one has been completed. 2009ms has been elapsed. The await keyword in a loop does not really make the calls in parallel.

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  • Thread.Interrupt Is Evil

    - by Alois Kraus
    Recently I have found an interesting issue with Thread.Interrupt during application shutdown. Some application was crashing once a week and we had not really a clue what was the issue. Since it happened not very often it was left as is until we have got some memory dumps during the crash. A memory dump usually means WindDbg which I really like to use (I know I am one of the very few fans of it).  After a quick analysis I did find that the main thread already had exited and the thread with the crash was stuck in a Monitor.Wait. Strange Indeed. Running the application a few thousand times under the debugger would potentially not have shown me what the reason was so I decided to what I call constructive debugging. I did create a simple Console application project and try to simulate the exact circumstances when the crash did happen from the information I have via memory dump and source code reading. The thread that was  crashing was actually MS code from an old version of the Microsoft Caching Application Block. From reading the code I could conclude that the main thread did call the Dispose method on the CacheManger class which did call Thread.Interrupt on the cache scavenger thread which was just waiting for work to do. My first version of the repro looked like this   static void Main(string[] args) { Thread t = new Thread(ThreadFunc) { IsBackground = true, Name = "Test Thread" }; t.Start(); Console.WriteLine("Interrupt Thread"); t.Interrupt(); } static void ThreadFunc() { while (true) { object value = Dequeue(); // block until unblocked or awaken via ThreadInterruptedException } } static object WaitObject = new object(); static object Dequeue() { object lret = "got value"; try { lock (WaitObject) { } } catch (ThreadInterruptedException) { Console.WriteLine("Got ThreadInterruptException"); lret = null; } return lret; } I do start a background thread and call Thread.Interrupt on it and then directly let the application terminate. The thread in the meantime does plenty of Monitor.Enter/Leave calls to simulate work on it. This first version did not crash. So I need to dig deeper. From the memory dump I did know that the finalizer thread was doing just some critical finalizers which were closing file handles. Ok lets add some long running finalizers to the sample. class FinalizableObject : CriticalFinalizerObject { ~FinalizableObject() { Console.WriteLine("Hi we are waiting to finalize now and block the finalizer thread for 5s."); Thread.Sleep(5000); } } class Program { static void Main(string[] args) { FinalizableObject fin = new FinalizableObject(); Thread t = new Thread(ThreadFunc) { IsBackground = true, Name = "Test Thread" }; t.Start(); Console.WriteLine("Interrupt Thread"); t.Interrupt(); GC.KeepAlive(fin); // prevent finalizing it too early // After leaving main the other thread is woken up via Thread.Abort // while we are finalizing. This causes a stackoverflow in the CLR ThreadAbortException handling at this time. } With this changed Main method and a blocking critical finalizer I did get my crash just like the real application. The funny thing is that this is actually a CLR bug. When the main method is left the CLR does suspend all threads except the finalizer thread and declares all objects as garbage. After the normal finalizers were called the critical finalizers are executed to e.g. free OS handles (usually). Remember that I did call Thread.Interrupt as one of the last methods in the Main method. The Interrupt method is actually asynchronous and does wake a thread up and throws a ThreadInterruptedException only once unlike Thread.Abort which does rethrow the exception when an exception handling clause is left. It seems that the CLR does not expect that a frozen thread does wake up again while the critical finalizers are executed. While trying to raise a ThreadInterrupedException the CLR goes down with an stack overflow. Ups not so nice. Why has this nobody noticed for years is my next question. As it turned out this error does only happen on the CLR for .NET 4.0 (x86 and x64). It does not show up in earlier or later versions of the CLR. I have reported this issue on connect here but so far it was not confirmed as a CLR bug. But I would be surprised if my console application was to blame for a stack overflow in my test thread in a Monitor.Wait call. What is the moral of this story? Thread.Abort is evil but Thread.Interrupt is too. It is so evil that even the CLR of .NET 4.0 contains a race condition during the CLR shutdown. When the CLR gurus can get it wrong the chances are high that you get it wrong too when you use this constructs. If you do not believe me see what Patrick Smacchia does blog about Thread.Abort and List.Sort. Not only the CLR creators can get it wrong. The BCL writers do sometimes have a hard time with correct exception handling as well. If you do tell me that you use Thread.Abort frequently and never had problems with it I do suspect that you do not have looked deep enough into your application to find such sporadic errors.

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  • Inside BackgroundWorker

    - by João Angelo
    The BackgroundWorker is a reusable component that can be used in different contexts, but sometimes with unexpected results. If you are like me, you have mostly used background workers while doing Windows Forms development due to the flexibility they offer for running a background task. They support cancellation and give events that signal progress updates and task completion. When used in Windows Forms, these events (ProgressChanged and RunWorkerCompleted) get executed back on the UI thread where you can freely access your form controls. However, the logic of the progress changed and worker completed events being invoked in the thread that started the background worker is not something you get directly from the BackgroundWorker, but instead from the fact that you are running in the context of Windows Forms. Take the following example that illustrates the use of a worker in three different scenarios: – Console Application or Windows Service; – Windows Forms; – WPF. using System; using System.ComponentModel; using System.Threading; using System.Windows.Forms; using System.Windows.Threading; class Program { static AutoResetEvent Synch = new AutoResetEvent(false); static void Main() { var bw1 = new BackgroundWorker(); var bw2 = new BackgroundWorker(); var bw3 = new BackgroundWorker(); Console.WriteLine("DEFAULT"); var unspecializedThread = new Thread(() => { OutputCaller(1); SynchronizationContext.SetSynchronizationContext( new SynchronizationContext()); bw1.DoWork += (sender, e) => OutputWork(1); bw1.RunWorkerCompleted += (sender, e) => OutputCompleted(1); // Uses default SynchronizationContext bw1.RunWorkerAsync(); }); unspecializedThread.IsBackground = true; unspecializedThread.Start(); Synch.WaitOne(); Console.WriteLine(); Console.WriteLine("WINDOWS FORMS"); var windowsFormsThread = new Thread(() => { OutputCaller(2); SynchronizationContext.SetSynchronizationContext( new WindowsFormsSynchronizationContext()); bw2.DoWork += (sender, e) => OutputWork(2); bw2.RunWorkerCompleted += (sender, e) => OutputCompleted(2); // Uses WindowsFormsSynchronizationContext bw2.RunWorkerAsync(); Application.Run(); }); windowsFormsThread.IsBackground = true; windowsFormsThread.SetApartmentState(ApartmentState.STA); windowsFormsThread.Start(); Synch.WaitOne(); Console.WriteLine(); Console.WriteLine("WPF"); var wpfThread = new Thread(() => { OutputCaller(3); SynchronizationContext.SetSynchronizationContext( new DispatcherSynchronizationContext()); bw3.DoWork += (sender, e) => OutputWork(3); bw3.RunWorkerCompleted += (sender, e) => OutputCompleted(3); // Uses DispatcherSynchronizationContext bw3.RunWorkerAsync(); Dispatcher.Run(); }); wpfThread.IsBackground = true; wpfThread.SetApartmentState(ApartmentState.STA); wpfThread.Start(); Synch.WaitOne(); } static void OutputCaller(int workerId) { Console.WriteLine( "bw{0}.{1} | Thread: {2} | IsThreadPool: {3}", workerId, "RunWorkerAsync".PadRight(18), Thread.CurrentThread.ManagedThreadId, Thread.CurrentThread.IsThreadPoolThread); } static void OutputWork(int workerId) { Console.WriteLine( "bw{0}.{1} | Thread: {2} | IsThreadPool: {3}", workerId, "DoWork".PadRight(18), Thread.CurrentThread.ManagedThreadId, Thread.CurrentThread.IsThreadPoolThread); } static void OutputCompleted(int workerId) { Console.WriteLine( "bw{0}.{1} | Thread: {2} | IsThreadPool: {3}", workerId, "RunWorkerCompleted".PadRight(18), Thread.CurrentThread.ManagedThreadId, Thread.CurrentThread.IsThreadPoolThread); Synch.Set(); } } Output: //DEFAULT //bw1.RunWorkerAsync | Thread: 3 | IsThreadPool: False //bw1.DoWork | Thread: 4 | IsThreadPool: True //bw1.RunWorkerCompleted | Thread: 5 | IsThreadPool: True //WINDOWS FORMS //bw2.RunWorkerAsync | Thread: 6 | IsThreadPool: False //bw2.DoWork | Thread: 5 | IsThreadPool: True //bw2.RunWorkerCompleted | Thread: 6 | IsThreadPool: False //WPF //bw3.RunWorkerAsync | Thread: 7 | IsThreadPool: False //bw3.DoWork | Thread: 5 | IsThreadPool: True //bw3.RunWorkerCompleted | Thread: 7 | IsThreadPool: False As you can see the output between the first and remaining scenarios is somewhat different. While in Windows Forms and WPF the worker completed event runs on the thread that called RunWorkerAsync, in the first scenario the same event runs on any thread available in the thread pool. Another scenario where you can get the first behavior, even when on Windows Forms or WPF, is if you chain the creation of background workers, that is, you create a second worker in the DoWork event handler of an already running worker. Since the DoWork executes in a thread from the pool the second worker will use the default synchronization context and the completed event will not run in the UI thread.

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  • spliiting code in java-don't know what's wrong [closed]

    - by ???? ?????
    I'm writing a code to split a file into many files with a size specified in the code, and then it will join these parts later. The problem is with the joining code, it doesn't work and I can't figure what is wrong! This is my code: import java.io.*; import java.util.*; public class StupidSplit { static final int Chunk_Size = 10; static int size =0; public static void main(String[] args) throws IOException { String file = "b.txt"; int chunks = DivideFile(file); System.out.print((new File(file)).delete()); System.out.print(JoinFile(file, chunks)); } static boolean JoinFile(String fname, int nChunks) { /* * Joins the chunks together. Chunks have been divided using DivideFile * function so the last part of filename will ".partxxxx" Checks if all * parts are together by matching number of chunks found against * "nChunks", then joins the file otherwise throws an error. */ boolean successful = false; File currentDirectory = new File(System.getProperty("user.dir")); // File[] fileList = currentDirectory.listFiles(); /* populate only the files having extension like "partxxxx" */ List<File> lst = new ArrayList<File>(); // Arrays.sort(fileList); for (File file : fileList) { if (file.isFile()) { String fnm = file.getName(); int lastDot = fnm.lastIndexOf('.'); // add to list which match the name given by "fname" and have //"partxxxx" as extension" if (fnm.substring(0, lastDot).equalsIgnoreCase(fname) && (fnm.substring(lastDot + 1)).substring(0, 4).equals("part")) { lst.add(file); } } } /* * sort the list - it will be sorted by extension only because we have * ensured that list only contains those files that have "fname" and * "part" */ File[] files = (File[]) lst.toArray(new File[0]); Arrays.sort(files); System.out.println("size ="+files.length); System.out.println("hello"); /* Ensure that number of chunks match the length of array */ if (files.length == nChunks-1) { File ofile = new File(fname); FileOutputStream fos; FileInputStream fis; byte[] fileBytes; int bytesRead = 0; try { fos = new FileOutputStream(ofile,true); for (File file : files) { fis = new FileInputStream(file); fileBytes = new byte[(int) file.length()]; bytesRead = fis.read(fileBytes, 0, (int) file.length()); assert(bytesRead == fileBytes.length); assert(bytesRead == (int) file.length()); fos.write(fileBytes); fos.flush(); fileBytes = null; fis.close(); fis = null; } fos.close(); fos = null; } catch (FileNotFoundException fnfe) { System.out.println("Could not find file"); successful = false; return successful; } catch (IOException ioe) { System.out.println("Cannot write to disk"); successful = false; return successful; } /* ensure size of file matches the size given by server */ successful = (ofile.length() == StupidSplit.size) ? true : false; } else { successful = false; } return successful; } static int DivideFile(String fname) { File ifile = new File(fname); FileInputStream fis; String newName; FileOutputStream chunk; //int fileSize = (int) ifile.length(); double fileSize = (double) ifile.length(); //int nChunks = 0, read = 0, readLength = Chunk_Size; int nChunks = 0, read = 0, readLength = Chunk_Size; byte[] byteChunk; try { fis = new FileInputStream(ifile); StupidSplit.size = (int)ifile.length(); while (fileSize > 0) { if (fileSize <= Chunk_Size) { readLength = (int) fileSize; } byteChunk = new byte[readLength]; read = fis.read(byteChunk, 0, readLength); fileSize -= read; assert(read==byteChunk.length); nChunks++; //newName = fname + ".part" + Integer.toString(nChunks - 1); newName = String.format("%s.part%09d", fname, nChunks - 1); chunk = new FileOutputStream(new File(newName)); chunk.write(byteChunk); chunk.flush(); chunk.close(); byteChunk = null; chunk = null; } fis.close(); System.out.println(nChunks); // fis = null; } catch (FileNotFoundException fnfe) { System.out.println("Could not find the given file"); System.exit(-1); } catch (IOException ioe) { System.out .println("Error while creating file chunks. Exiting program"); System.exit(-1); }System.out.println(nChunks); return nChunks; } } }

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  • Project Euler #15

    - by Aistina
    Hey everyone, Last night I was trying to solve challenge #15 from Project Euler: Starting in the top left corner of a 2×2 grid, there are 6 routes (without backtracking) to the bottom right corner. How many routes are there through a 20×20 grid? I figured this shouldn't be so hard, so I wrote a basic recursive function: const int gridSize = 20; // call with progress(0, 0) static int progress(int x, int y) { int i = 0; if (x < gridSize) i += progress(x + 1, y); if (y < gridSize) i += progress(x, y + 1); if (x == gridSize && y == gridSize) return 1; return i; } I verified that it worked for a smaller grids such as 2×2 or 3×3, and then set it to run for a 20×20 grid. Imagine my surprise when, 5 hours later, the program was still happily crunching the numbers, and only about 80% done (based on examining its current position/route in the grid). Clearly I'm going about this the wrong way. How would you solve this problem? I'm thinking it should be solved using an equation rather than a method like mine, but that's unfortunately not a strong side of mine. Update: I now have a working version. Basically it caches results obtained before when a n×m block still remains to be traversed. Here is the code along with some comments: // the size of our grid static int gridSize = 20; // the amount of paths available for a "NxM" block, e.g. "2x2" => 4 static Dictionary<string, long> pathsByBlock = new Dictionary<string, long>(); // calculate the surface of the block to the finish line static long calcsurface(long x, long y) { return (gridSize - x) * (gridSize - y); } // call using progress (0, 0) static long progress(long x, long y) { // first calculate the surface of the block remaining long surface = calcsurface(x, y); long i = 0; // zero surface means only 1 path remains // (we either go only right, or only down) if (surface == 0) return 1; // create a textual representation of the remaining // block, for use in the dictionary string block = (gridSize - x) + "x" + (gridSize - y); // if a same block has not been processed before if (!pathsByBlock.ContainsKey(block)) { // calculate it in the right direction if (x < gridSize) i += progress(x + 1, y); // and in the down direction if (y < gridSize) i += progress(x, y + 1); // and cache the result! pathsByBlock[block] = i; } // self-explanatory :) return pathsByBlock[block]; } Calling it 20 times, for grids with size 1×1 through 20×20 produces the following output: There are 2 paths in a 1 sized grid 0,0110006 seconds There are 6 paths in a 2 sized grid 0,0030002 seconds There are 20 paths in a 3 sized grid 0 seconds There are 70 paths in a 4 sized grid 0 seconds There are 252 paths in a 5 sized grid 0 seconds There are 924 paths in a 6 sized grid 0 seconds There are 3432 paths in a 7 sized grid 0 seconds There are 12870 paths in a 8 sized grid 0,001 seconds There are 48620 paths in a 9 sized grid 0,0010001 seconds There are 184756 paths in a 10 sized grid 0,001 seconds There are 705432 paths in a 11 sized grid 0 seconds There are 2704156 paths in a 12 sized grid 0 seconds There are 10400600 paths in a 13 sized grid 0,001 seconds There are 40116600 paths in a 14 sized grid 0 seconds There are 155117520 paths in a 15 sized grid 0 seconds There are 601080390 paths in a 16 sized grid 0,0010001 seconds There are 2333606220 paths in a 17 sized grid 0,001 seconds There are 9075135300 paths in a 18 sized grid 0,001 seconds There are 35345263800 paths in a 19 sized grid 0,001 seconds There are 137846528820 paths in a 20 sized grid 0,0010001 seconds 0,0390022 seconds in total I'm accepting danben's answer, because his helped me find this solution the most. But upvotes also to Tim Goodman and Agos :) Bonus update: After reading Eric Lippert's answer, I took another look and rewrote it somewhat. The basic idea is still the same but the caching part has been taken out and put in a separate function, like in Eric's example. The result is some much more elegant looking code. // the size of our grid const int gridSize = 20; // magic. static Func<A1, A2, R> Memoize<A1, A2, R>(this Func<A1, A2, R> f) { // Return a function which is f with caching. var dictionary = new Dictionary<string, R>(); return (A1 a1, A2 a2) => { R r; string key = a1 + "x" + a2; if (!dictionary.TryGetValue(key, out r)) { // not in cache yet r = f(a1, a2); dictionary.Add(key, r); } return r; }; } // calculate the surface of the block to the finish line static long calcsurface(long x, long y) { return (gridSize - x) * (gridSize - y); } // call using progress (0, 0) static Func<long, long, long> progress = ((Func<long, long, long>)((long x, long y) => { // first calculate the surface of the block remaining long surface = calcsurface(x, y); long i = 0; // zero surface means only 1 path remains // (we either go only right, or only down) if (surface == 0) return 1; // calculate it in the right direction if (x < gridSize) i += progress(x + 1, y); // and in the down direction if (y < gridSize) i += progress(x, y + 1); // self-explanatory :) return i; })).Memoize(); By the way, I couldn't think of a better way to use the two arguments as a key for the dictionary. I googled around a bit, and it seems this is a common solution. Oh well.

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  • Confusing Java syntax...

    - by posfan12
    I'm trying to convert the following code (from Wikipedia) from Java to JavaScript: /* * 3 June 2003, [[:en:User:Cyp]]: * Maze, generated by my algorithm * 24 October 2006, [[:en:User:quin]]: * Source edited for clarity * 25 January 2009, [[:en:User:DebateG]]: * Source edited again for clarity and reusability * 1 June 2009, [[:en:User:Nandhp]]: * Source edited to produce SVG file when run from the command-line * * This program was originally written by [[:en:User:Cyp]], who * attached it to the image description page for an image generated by * it on en.wikipedia. The image was licensed under CC-BY-SA-3.0/GFDL. */ import java.awt.*; import java.applet.*; import java.util.Random; /* Define the bit masks */ class Constants { public static final int WALL_ABOVE = 1; public static final int WALL_BELOW = 2; public static final int WALL_LEFT = 4; public static final int WALL_RIGHT = 8; public static final int QUEUED = 16; public static final int IN_MAZE = 32; } public class Maze extends java.applet.Applet { /* The width and height (in cells) of the maze */ private int width; private int height; private int maze[][]; private static final Random rnd = new Random(); /* The width in pixels of each cell */ private int cell_width; /* Construct a Maze with the default width, height, and cell_width */ public Maze() { this(20,20,10); } /* Construct a Maze with specified width, height, and cell_width */ public Maze(int width, int height, int cell_width) { this.width = width; this.height = height; this.cell_width = cell_width; } /* Initialization method that will be called when the program is * run from the command-line. Maze will be written as SVG file. */ public static void main(String[] args) { Maze m = new Maze(); m.createMaze(); m.printSVG(); } /* Initialization method that will be called when the program is * run as an applet. Maze will be displayed on-screen. */ public void init() { createMaze(); } /* The maze generation algorithm. */ private void createMaze(){ int x, y, n, d; int dx[] = { 0, 0, -1, 1 }; int dy[] = { -1, 1, 0, 0 }; int todo[] = new int[height * width], todonum = 0; /* We want to create a maze on a grid. */ maze = new int[width][height]; /* We start with a grid full of walls. */ for (x = 0; x < width; ++x) { for (y = 0; y < height; ++y) { if (x == 0 || x == width - 1 || y == 0 || y == height - 1) { maze[x][y] = Constants.IN_MAZE; } else { maze[x][y] = 63; } } } /* Select any square of the grid, to start with. */ x = 1 + rnd.nextInt (width - 2); y = 1 + rnd.nextInt (height - 2); /* Mark this square as connected to the maze. */ maze[x][y] &= ~48; /* Remember the surrounding squares, as we will */ for (d = 0; d < 4; ++d) { if ((maze[][d][][d] & Constants.QUEUED) != 0) { /* want to connect them to the maze. */ todo[todonum++] = ((x + dx[d]) << Constants.QUEUED) | (y + dy[d]); maze[][d][][d] &= ~Constants.QUEUED; } } /* We won't be finished until all is connected. */ while (todonum > 0) { /* We select one of the squares next to the maze. */ n = rnd.nextInt (todonum); x = todo[n] >> 16; /* the top 2 bytes of the data */ y = todo[n] & 65535; /* the bottom 2 bytes of the data */ /* We will connect it, so remove it from the queue. */ todo[n] = todo[--todonum]; /* Select a direction, which leads to the maze. */ do { d = rnd.nextInt (4); } while ((maze[][d][][d] & Constants.IN_MAZE) != 0); /* Connect this square to the maze. */ maze[x][y] &= ~((1 << d) | Constants.IN_MAZE); maze[][d][][d] &= ~(1 << (d ^ 1)); /* Remember the surrounding squares, which aren't */ for (d = 0; d < 4; ++d) { if ((maze[][d][][d] & Constants.QUEUED) != 0) { /* connected to the maze, and aren't yet queued to be. */ todo[todonum++] = ((x + dx[d]) << Constants.QUEUED) | (y + dy[d]); maze[][d][][d] &= ~Constants.QUEUED; } } /* Repeat until finished. */ } /* Add an entrance and exit. */ maze[1][1] &= ~Constants.WALL_ABOVE; maze[width - 2][height - 2] &= ~Constants.WALL_BELOW; } /* Called by the applet infrastructure to display the maze on-screen. */ public void paint(Graphics g) { drawMaze(g); } /* Called to write the maze to an SVG file. */ public void printSVG() { System.out.format("<svg width=\"%d\" height=\"%d\" version=\"1.1\"" + " xmlns=\"http://www.w3.org/2000/svg\">\n", width*cell_width, height*cell_width); System.out.println(" <g stroke=\"black\" stroke-width=\"1\"" + " stroke-linecap=\"round\">"); drawMaze(null); System.out.println(" </g>\n</svg>"); } /* Main maze-drawing loop. */ public void drawMaze(Graphics g) { int x, y; for (x = 1; x < width - 1; ++x) { for (y = 1; y < height - 1; ++y) { if ((maze[x][y] & Constants.WALL_ABOVE) != 0) drawLine( x * cell_width, y * cell_width, (x + 1) * cell_width, y * cell_width, g); if ((maze[x][y] & Constants.WALL_BELOW) != 0) drawLine( x * cell_width, (y + 1) * cell_width, (x + 1) * cell_width, (y + 1) * cell_width, g); if ((maze[x][y] & Constants.WALL_LEFT) != 0) drawLine( x * cell_width, y * cell_width, x * cell_width, (y + 1) * cell_width, g); if ((maze[x][y] & Constants.WALL_RIGHT) != 0) drawLine((x + 1) * cell_width, y * cell_width, (x + 1) * cell_width, (y + 1) * cell_width, g); } } } /* Draw a line, either in the SVG file or on the screen. */ public void drawLine(int x1, int y1, int x2, int y2, Graphics g) { if ( g != null ) g.drawLine(x1, y1, x2, y2); else System.out.format(" <line x1=\"%d\" y1=\"%d\"" + " x2=\"%d\" y2=\"%d\" />\n", x1, y1, x2, y2); } } Anyway, I was chugging along fairly quickly when I came to a bit that I just don't understand: /* Remember the surrounding squares, as we will */ for (var d = 0; d < 4; ++d) { if ((maze[][d][][d] & Constants.QUEUED) != 0) { /* want to connect them to the maze. */ todo[todonum++] = ((x + dx[d]) << Constants.QUEUED) | (y + dy[d]); maze[][d][][d] &= ~Constants.QUEUED; } } What I don't get is why there are four sets of brackets following the "maze" parameter instead of just two, since "maze" is a two dimensional array, not a four dimensional array. I'm sure there's a good reason for this. Problem is, I just don't get it. Thanks!

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  • How to display a JSON error message?

    - by Tiny Giant Studios
    I'm currently developing a tumblr theme and have built a jQuery JSON thingamabob that uses the Tumblr API to do the following: The user would click on the "post type" link (e.g. Video Posts), at which stage jQuery would use JSON to grab all the posts that's related to that type and then dynamically display them in a designated area. Now everything works absolutely peachy, except that with Tumblr being Tumblr and their servers taking a knock every now and then, the Tumblr API thingy is sometimes offline. Now I can't foresee when this function will be down, which is why I want to display some generic error message if JSON (for whatever reason) was unable to load the post. You'll see I've already written some code to show an error message when jQuery can't find any posts related to that post type BUT it doesn't cover any server errors. Note: I sometimes get this error: Failed to load resource: the server responded with a status of 503 (Service Temporarily Unavailable) It is for this 503 Error message that I need to write some code, but I'm slightly clueless :) Here's the jQuery JSON code: $('ul.right li').find('a').click(function() { var postType = this.className; var count = 0; byCategory(postType); return false; function byCategory(postType, callback) { $.getJSON('{URL}/api/read/json?type=' + postType + '&callback=?', function(data) { var article = []; $.each(data.posts, function(i, item) { // i = index // item = data for a particular post switch(item.type) { case 'photo': article[i] = '<div class="post_wrap"><div class="photo" style="padding-bottom:5px;">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/XSTldh6ds/photo_icon.png" alt="type_icon"/></a>' + '<a href="' + item.url + '" title="{Title}"><img src="' + item['photo-url-500'] + '"alt="image" /></a></div></div>'; count = 1; break; case 'video': article[i] = '<div class="post_wrap"><div class="video" style="padding-bottom:5px;">' + '<a href="' + item.url + '" title="{Title}" class="type_icon">' + '<img src="http://static.tumblr.com/ewjv7ap/nuSldhclv/video_icon.png" alt="type_icon"/></a>' + '<span style="margin: auto;">' + item['video-player'] + '</span>' + '</div></div>'; count = 1; break; case 'audio': if (use_IE == true) { article[i] = '<div class="post_wrap"><div class="regular">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/R50ldh5uj/audio_icon.png" alt="type_icon"/></a>' + '<h3><a href="' + item.url + '">' + item['id3-artist'] +' - ' + item['id3-title'] + '</a></h3>' + '</div></div>'; } else { article[i] = '<div class="post_wrap"><div class="regular">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/R50ldh5uj/audio_icon.png" alt="type_icon"/></a>' + '<h3><a href="' + item.url + '">' + item['id3-artist'] +' - ' + item['id3-title'] + '</a></h3><div class="player">' + item['audio-player'] + '</div>' + '</div></div>'; }; count = 1; break; case 'regular': article[i] = '<div class="post_wrap"><div class="regular">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/dwxldhck1/regular_icon.png" alt="type_icon"/></a><h3><a href="' + item.url + '">' + item['regular-title'] + '</a></h3><div class="description_container">' + item['regular-body'] + '</div></div></div>'; count = 1; break; case 'quote': article[i] = '<div class="post_wrap"><div class="quote">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/loEldhcpr/quote_icon.png" alt="type_icon"/></a><blockquote><h3><a href="' + item.url + '" title="{Title}">' + item['quote-text'] + '</a></h3></blockquote><cite>- ' + item['quote-source'] + '</cite></div></div>'; count = 1; break; case 'conversation': article[i] = '<div class="post_wrap"><div class="chat">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/MVuldhcth/conversation_icon.png" alt="type_icon"/></a><h3><a href="' + item.url + '">' + item['conversation-title'] + '</a></h3></div></div>'; count = 1; break; case 'link': article[i] = '<div class="post_wrap"><div class="link">' + '<a href="' + item.url + '" title="{Title}" class="type_icon"><img src="http://static.tumblr.com/ewjv7ap/EQGldhc30/link_icon.png" alt="type_icon"/></a><h3><a href="' + item['link-url'] + '" target="_blank">' + item['link-text'] + '</a></h3></div></div>'; count = 1; break; default: alert('No Entries Found.'); }; }) // end each if (!(count == 0)) { $('#content_right') .hide('fast') .html('<div class="first_div"><span class="left_corner"></span><span class="right_corner"></span><h2>Displaying ' + postType + ' Posts Only</h2></div>' + article.join('')) .slideDown('fast') } else { $('#content_right') .hide('fast') .html('<div class="first_div"><span class="left_corner"></span><span class="right_corner"></span><h2>Hmmm, currently there are no ' + postType + ' posts to display</h2></div>') .slideDown('fast') } // end getJSON }); // end byCategory } }); If you'd like to see the demo in action, check out Elegantem but do note that everything might work absolutely fine for you (or not), depending on Tumblr's temperament.

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  • Maze not generating properly. Out of bounds exception. need quick fix

    - by Dan Joseph Porcioncula
    My maze generator seems to have a problem. I am trying to generate something like the maze from http://mazeworks.com/mazegen/mazetut/index.htm . My program displays this http://a1.sphotos.ak.fbcdn.net/hphotos-ak-snc7/s320x320/374060_426350204045347_100000111130260_1880768_1572427285_n.jpg and the error Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1 at Grid.genRand(Grid.java:73) at Grid.main(Grid.java:35) How do I fix my generator program? import java.awt.*; import java.awt.Color; import java.awt.Component; import java.awt.Graphics; import javax.swing.*; import java.util.ArrayList; public class Grid extends Canvas { Cell[][] maze; int size; int pathSize; double width, height; ArrayList<int[]> coordinates = new ArrayList<int[]>(); public Grid(int size, int h, int w) { this.size = size; maze = new Cell[size][size]; for(int i = 0; i<size; i++){ for(int a =0; a<size; a++){ maze[i][a] = new Cell(); } } setPreferredSize(new Dimension(h, w)); } public static void main(String[] args) { JFrame y = new JFrame(); y.setLayout(new BorderLayout()); Grid f = new Grid(25, 400, 400); y.add(f, BorderLayout.CENTER); y.setSize(450, 450); y.setVisible(true); y.setDefaultCloseOperation(y.EXIT_ON_CLOSE); f.genRand(); f.repaint(); } public void push(int[] xy) { coordinates.add(xy); int i = coordinates.size(); coordinates.ensureCapacity(i++); } public int[] pop() { int[] x = coordinates.get((coordinates.size())-1); coordinates.remove((coordinates.size())-1); return x; } public int[] top() { return coordinates.get((coordinates.size())-1); } public void genRand(){ // create a CellStack (LIFO) to hold a list of cell locations [x] // set TotalCells = number of cells in grid int TotalCells = size*size; // choose a cell at random and call it CurrentCell int m = randomInt(size); int n = randomInt(size); Cell curCel = maze[m][n]; // set VisitedCells = 1 int visCel = 1,d=0; int[] q; int h,o = 0,p = 0; // while VisitedCells < TotalCells while( visCel < TotalCells){ // find all neighbors of CurrentCell with all walls intact if(maze[m-1][n].countWalls() == 4){d++;} if(maze[m+1][n].countWalls() == 4){d++;} if(maze[m][n-1].countWalls() == 4){d++;} if(maze[m][n+1].countWalls() == 4){d++;} // if one or more found if(d!=0){ Point[] ls = new Point[4]; ls[0] = new Point(m-1,n); ls[1] = new Point(m+1,n); ls[2] = new Point(m,n-1); ls[3] = new Point(m,n+1); // knock down the wall between it and CurrentCell h = randomInt(3); switch(h){ case 0: o = (int)(ls[0].getX()); p = (int)(ls[0].getY()); curCel.destroyWall(2); maze[o][p].destroyWall(1); break; case 1: o = (int)(ls[1].getX()); p = (int)(ls[1].getY()); curCel.destroyWall(1); maze[o][p].destroyWall(2); break; case 2: o = (int)(ls[2].getX()); p = (int)(ls[2].getY()); curCel.destroyWall(3); maze[o][p].destroyWall(0); break; case 3: o = (int)(ls[3].getX()); p = (int)(ls[3].getY()); curCel.destroyWall(0); maze[o][p].destroyWall(3); break; } // push CurrentCell location on the CellStack push(new int[] {m,n}); // make the new cell CurrentCell m = o; n = p; curCel = maze[m][n]; // add 1 to VisitedCells visCel++; } // else else{ // pop the most recent cell entry off the CellStack q = pop(); m = q[0]; n = q[1]; curCel = maze[m][n]; // make it CurrentCell // endIf } // endWhile } } public int randomInt(int s) { return (int)(s* Math.random());} public void paint(Graphics g) { int k, j; width = getSize().width; height = getSize().height; double htOfRow = height / (size); double wdOfRow = width / (size); //checks verticals - destroys east border of cell for (k = 0; k < size; k++) { for (j = 0; j < size; j++) { if(maze[k][j].checkWall(2)){ g.drawLine((int) (k * wdOfRow), (int) (j * htOfRow), (int) (k * wdOfRow), (int) ((j+1) * htOfRow)); }} } //checks horizontal - destroys north border of cell for (k = 0; k < size; k++) { for (j = 0; j < size; j++) { if(maze[k][j].checkWall(3)){ g.drawLine((int) (k * wdOfRow), (int) (j * htOfRow), (int) ((k+1) * wdOfRow), (int) (j * htOfRow)); }} } } } class Cell { private final static int NORTH = 0; private final static int EAST = 1; private final static int WEST = 2; private final static int SOUTH = 3; private final static int NO = 4; private final static int START = 1; private final static int END = 2; boolean[] wall = new boolean[4]; boolean[] border = new boolean[4]; boolean[] backtrack = new boolean[4]; boolean[] solution = new boolean[4]; private boolean isVisited = false; private int Key = 0; public Cell(){ for(int i=0;i<4;i++){wall[i] = true;} } public int countWalls(){ int i, k =0; for(i=0; i<4; i++) { if (wall[i] == true) {k++;} } return k;} public boolean checkWall(int x){ switch(x){ case 0: return wall[0]; case 1: return wall[1]; case 2: return wall[2]; case 3: return wall[3]; } return true; } public void destroyWall(int x){ switch(x){ case 0: wall[0] = false; break; case 1: wall[1] = false; break; case 2: wall[2] = false; break; case 3: wall[3] = false; break; } } public void setStart(int i){Key = i;} public int getKey(){return Key;} public boolean checkVisit(){return isVisited;} public void visitCell(){isVisited = true;} }

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