Paul Welter's Weblog

Caching the results from LinqDataSource

pwelter34 — Mon, 13 Aug 2007 20:24:00 GMT

I wanted to be able to cache the results of a query from the LinqDataSource that was used in multiple places on the page. I whipped up this little class to do the work of caching for me. The class, LinqCacheDataSource, handles the Selecting and Selected events. The Selected handler inserts the result of the query into cache. The Selecting handler gets the result from the cache. If it doesn't find the result, the query runs as normal. The caching will only work for selecting data. It works great for dropdowns and other fairly static data.

The Code ...

/// <summary>
/// A LinqDataSource that provides caching for Linq queries.
/// </summary>
public class LinqCacheDataSource : LinqDataSource
{
    /// <summary>
    /// Initializes a new instance of the <see cref="LinqCacheDataSource"/> class.
    /// </summary>
    public LinqCacheDataSource()
        : base()
    {
        this.Selecting += new EventHandler<LinqDataSourceSelectEventArgs>(OnSelecting);
        this.Selected += new EventHandler<LinqDataSourceStatusEventArgs>(OnSelected);
    }
 
    private void OnSelecting(object sender, LinqDataSourceSelectEventArgs e)
    {
        if (!EnableCache)
            return;
 
        string key = GetKey();
        object source = Context.Cache[key];
        if (source == null)
            return;
 
        Debug.WriteLine("Cache Hit: " + key);
        e.Result = source;
    }
 
    private void OnSelected(object sender, LinqDataSourceStatusEventArgs e)
    {
        if (!EnableCache)
            return;
 
        if (e.Exception != null || e.Result == null)
            return;
 
        string key = GetKey();
        object source = Context.Cache[key];
        if (source != null)
            return;
 
        Debug.WriteLine("Cache Insert: " + key);
        Context.Cache.Insert(key, e.Result, null, 
            DateTime.Now.AddSeconds(Duration), Cache.NoSlidingExpiration);
    }
 
    private string GetKey()
    {
        StringBuilder sb = new StringBuilder();
        sb.Append(this.ContextTypeName);
        sb.Append(" from ");
        sb.Append(this.TableName);
 
        if (!string.IsNullOrEmpty(this.Select))
        {
            sb.Append(" select ");
            sb.Append(this.Select);
        }
        if (!string.IsNullOrEmpty(this.Where))
        {
            sb.Append(" where ");
            sb.Append(this.Where);
        }
        if (!string.IsNullOrEmpty(this.OrderBy))
        {
            sb.Append(" OrderBy ");
            sb.Append(this.OrderBy);
        }
        return sb.ToString();
    }
 
    /// <summary>
    /// Gets or sets a value indicating whether query caching is enabled.
    /// </summary>
    [DefaultValue(true)]
    [Category("Cache")]
    [Description("Enable caching the linq query result.")]
    public bool EnableCache
    {
        get
        {
            object result = this.ViewState["EnableCache"];
            if (result != null)
                return (bool)result;
 
            return true;
        }
        set
        {
            this.ViewState["EnableCache"] = value;
        }
    }
 
    /// <summary>
    /// Gets or sets the time, in seconds, that the query is cached.
    /// </summary>
    [DefaultValue(30)]
    [Category("Cache")]
    [Description("The time, in seconds, that the query is cached.")]
    public int Duration
    {
        get
        {
            object result = this.ViewState["Duration"];
            if (result != null)
                return (int)result;
 
            return 30;
        }
        set
        {
            this.ViewState["Duration"] = value;
        }
    }
}

PLINQO - CodeSmith LINQ to SQL Templates

pwelter34 — Fri, 10 Aug 2007 17:36:00 GMT

PLINQO, which stands for Professional LINQ to Objects, is a collection of CodeSmith templates that are meant to replace and extend the LINQ to SQL designers that are included with Visual Studio 2008.

Features

Generate or update a LINQ to SQL dbml file from a database schema.

Includes all tables, stored procedures, functions, and views with the ability to exclude objects based on regex patterns.
Ability to automatically remove object prefix and suffixes (ie. tbl_ and usp_).
Dbml file can still be customized with the normal Visual Studio 2008 designer.
Dbml file can be refreshed based on the current database schema without losing customizations. (See Safe Attributes)

Generation of the LINQ to SQL DataContext class.
Generation of the LINQ to SQL entity classes.

Generates one file per entity instead of one massive file.
Generates partial classes where custom code can be written and won't be overwritten.
Generated entity files are added to the project as code behind files to their corresponding custom entity files.

Generation of entity manager classes.

Adds customizable business rules engine to enforce entity validation, business and security rules.
Provides access to common queries based on primary keys, foreign keys, and indexes.
Common queries are exposed as IQueryable so they can be extended.

All templates can be customized to meet your needs.

Download

http://www.codeplex.com/codesmith/Release/ProjectReleases.aspx

Easier way to page Linq queries.

pwelter34 — Thu, 31 May 2007 22:48:00 GMT

The following query extension will make paging a query more natural then skip and take. Simply append Paginate(page, pageSize) to your query.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace System.Linq
{
    public static class PageQuery
    {
        public static IQueryable<T> Paginate<T>(
            this IQueryable<T> query, int page, int pageSize)
        {
            int skip = Math.Max(pageSize * (page - 1), 0);
            return query.Skip(skip).Take(pageSize);
        }
    }
}

Calculator.NET - Calculator that evaluates math expressions

pwelter34 — Sat, 05 May 2007 21:38:00 GMT

I'd like to announce the release of a little project I've been working on. I call it Calculator.NET. I started this project for a couple reasons. First, I was annoyed that Windows Vista doesn't come with a better calculator. Windows XP has Power Calculator, but that doesn't work on Vista. Next, I was reading a blog about DynCalc by Bart De Smet on how to do mathematical calculations. That gave me the starting point on how to create Calculator.NET.

As part of the project, I created a MathExpressions library that does the bulk of work. The library supports math expressions, functions unit conversion and variables. Below are some examples of using the library directly.

MathEvaluator eval = new MathEvaluator();
//basic math
double result = eval.Evaluate("(2 + 1) * (1 + 2)");
//calling a function
result = eval.Evaluate("sqrt(4)");
//evaluate trigonometric 
result = eval.Evaluate("cos(pi * 45 / 180.0)");
//convert inches to feet
result = eval.Evaluate("12 [in->ft]");
//use variable
result = eval.Evaluate("answer * 10");
//add variable
eval.Variables.Add("x", 10);            
result = eval.Evaluate("x * 10");

Calculator that evaluates math expressions.

Calculator.NET Features

Evaluate math expressions including grouping
Support trigonometry and other function
Common unit conversion of the following types
- Length
- Mass
- Speed
- Temperature
- Time
- Volume
Variable support including last answer

Download Calculator.NET

CodeSmith 4.0 Public Beta Released

pwelter34 — Thu, 19 Oct 2006 16:24:00 GMT

CodeSmith 4.0 Beta 2 has been released and is now available to the public. Here are just a few the new capabilities in CodeSmith 4.0:

CodeSmith Projects (.csp) - This feature makes automating your code generation process really easy and consistent whether you are working from inside of Visual Studio 2005, MSBuild, Windows Explorer, a command line / batch file, or CodeSmith itself.
ActiveSnippets - Imagine Visual Studio 2005 snippets, but with the full power of CodeSmith available to execute any logic or access any complex metadata (including database schema and xml data) to control the output of your snippets.
CodeSmith Maps (.csmap) - This feature will allow you to create dictionary style maps of things like SQL to C# data type mappings.
.netTiers 2.0 - The .netTiers templates have been greatly enhanced and included with CodeSmith 4.0.
Extended Property Management - You can now edit and add new schema extended properties inside of CodeSmith Studio.
Property Persistence - CodeSmith now remembers the property values from the last time you executed a template.

You can read the announcement here.

XML Serializable Generic Dictionary

pwelter34 — Wed, 03 May 2006 17:13:00 GMT

XML Serializable Generic Dictionary

For some reason, the generic Dictionary in .net 2.0 is not XML serializable. The following code snippet is a xml serializable generic dictionary. The dictionary is serialzable by implementing the IXmlSerializable interface.

    using System;
    using System.Collections.Generic;
    using System.Text;
    using System.Xml.Serialization;
 
    [XmlRoot("dictionary")]
    public class SerializableDictionary<TKey, TValue>
        : Dictionary<TKey, TValue>, IXmlSerializable
    {
        #region IXmlSerializable Members
        public System.Xml.Schema.XmlSchema GetSchema()
        {
            return null;
        }
 
        public void ReadXml(System.Xml.XmlReader reader)
        {
            XmlSerializer keySerializer = new XmlSerializer(typeof(TKey));
            XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue));
 
            bool wasEmpty = reader.IsEmptyElement;
            reader.Read();
 
            if (wasEmpty)
                return;
 
            while (reader.NodeType != System.Xml.XmlNodeType.EndElement)
            {
                reader.ReadStartElement("item");
 
                reader.ReadStartElement("key");
                TKey key = (TKey)keySerializer.Deserialize(reader);
                reader.ReadEndElement();
 
                reader.ReadStartElement("value");
                TValue value = (TValue)valueSerializer.Deserialize(reader);
                reader.ReadEndElement();
 
                this.Add(key, value);
 
                reader.ReadEndElement();
                reader.MoveToContent();
            }
            reader.ReadEndElement();
        }
 
        public void WriteXml(System.Xml.XmlWriter writer)
        {
            XmlSerializer keySerializer = new XmlSerializer(typeof(TKey));
            XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue));
 
            foreach (TKey key in this.Keys)
            {
                writer.WriteStartElement("item");
 
                writer.WriteStartElement("key");
                keySerializer.Serialize(writer, key);
                writer.WriteEndElement();
 
                writer.WriteStartElement("value");
                TValue value = this[key];
                valueSerializer.Serialize(writer, value);
                writer.WriteEndElement();
 
                writer.WriteEndElement();
            }
        }
        #endregion
    }

Update: Fixed bug Justin pointed out by adding an extra reader.ReadEndElement() and by checking the IsEmptyElement property.

MSBuild Community Tasks Project releases new version

pwelter34 — Fri, 31 Mar 2006 20:15:00 GMT

Announcement

The MSBuild Community Tasks Project releases version v1.1.0.145. There are many new tasks in this release. Special thanks to all the contributors to the project.

Current Community Tasks

Task	Description
AppPoolController	Allows control for an application pool on a local or remote machine with IIS installed.
AppPoolCreate	Creates a new application pool on a local or remote machine.
AppPoolDelete	Deletes an existing application pool on a local or remote machine.
AssemblyInfo	Generates an AssemblyInfo file using the attributes given.
Attrib	Changes the attributes of files and/or directories
FileUpdate	Replace text in file(s) using a Regular Expression.
FtpUpload	Uploads a file using File Transfer Protocol (FTP).
FxCop	Uses FxCop to analyze managed code assemblies and reports on their design best-practice compliance.
Mail	Sends an email message.
Math.Add	Add numbers.
Math.Divide	Divide numbers.
Math.Multiple	Multiple numbers.
Math.Subtract	Subtract numbers.
Move	Moves files on the filesystem to a new location.
NDoc	Runs NDoc to create documentation.
NUnit	Runs tests using the NUnit.
RegistryRead	Reads a value from the Registry.
RegistryWrite	Writes a value to the Registry.
Script	Executes code contained within the task.
ServiceController	Task that can control a Windows service.
ServiceQuery	Task that can determine the status of a service.
Sleep	A task for sleeping for a specified period of time.
SqlExecute	Executes a SQL command
SvnCheckout	Checkout files from Subversion
SvnClient	Subversion Client
SvnCommit	Commit files to Subversion
SvnExport	Export files from Subversion
SvnInfo	Get Subversion information for a file or directory.
SvnUpdate	Update files from Subversion
SvnVersion	Get Subversion revision number of a local copy
TaskSchema	Generates a XSD schema of the MSBuild tasks in an assembly.
Time	Gets the current date and time.
Unzip	Unzip a file to a target directory.
Version	Increments a four-part version number stored in a text file
VssAdd	Adds files to a Visual SourceSafe database.
VssCheckin	Checks in files to a Visual SourceSafe database.
VssCheckout	Checks out files from a Visual SourceSafe database.
VssClean	Removes Visual SourceSafe binding information and status files from a Visual Studio solution tree.
VssDiff	Generates a diff between two versions of an item in a Visual SourceSafe database.
VssGet	Gets the latest version of a file or project from a Visual SourceSafe database.
VssHistory	Generates an XML file containing the history of an item in a Visual SourceSafe database between two dates or labels.
VssLabel	Labels an item in a Visual SourceSafe database.
VssUndoCheckout	Cancels a checkout of an item from a Visual SourceSafe database.
WebDirectoryCreate	Creates a new web directory on a local or remote machine.
WebDirectoryDelete	Deletes a web directory on a local or remote machine
WebDownload	Downloads a resource with the specified URI to a local file.
XmlRead	Reads a value from a XML document using a XPath.
XmlWrite	Updates a XML document using a XPath.
Xslt	Merge and transform a set of xml files.
Zip	Create a zip file with the files specified.

Join Project

Please join the MSBuild Community Tasks Project and help contribute in building the tasks.

http://msbuildtasks.tigris.org/

Download The Latest Release

The latest binaries, source and installer for Windows can be found in this directory of the Tigris file-sharing area.

MSBuild.Community.Tasks.msi - MSBuild Community Tasks Setup
MSBuild.Community.Tasks.v1.1.0.145.zip - MSBuild Community Tasks v1.1.0.145 Source

Create a Relative path code snippet

pwelter34 — Wed, 08 Feb 2006 07:38:00 GMT

Here is a code snippet that is equivalent to the windows API PathRelativePathTo as native c#. The function creates a relative path from one file or folder to another.

public class PathUtil
{
    /// <summary>
    /// Creates a relative path from one file
    /// or folder to another.
    /// </summary>
    /// <param name="fromDirectory">
    /// Contains the directory that defines the 
    /// start of the relative path.
    /// </param>
    /// <param name="toPath">
    /// Contains the path that defines the
    /// endpoint of the relative path.
    /// </param>
    /// <returns>
    /// The relative path from the start
    /// directory to the end path.
    /// </returns>
    /// <exception cref="ArgumentNullException"></exception>
    public static string RelativePathTo(
        string fromDirectory, string toPath)
    {
        if (fromDirectory == null)
            throw new ArgumentNullException("fromDirectory");
 
        if (toPath == null)
            throw new ArgumentNullException("toPath");
 
        bool isRooted = Path.IsPathRooted(fromDirectory)
            && Path.IsPathRooted(toPath);
 
        if (isRooted)
        {
            bool isDifferentRoot = string.Compare(
                Path.GetPathRoot(fromDirectory),
                Path.GetPathRoot(toPath), true) != 0;
 
            if (isDifferentRoot)
                return toPath;                          
        }                
 
        StringCollection relativePath = new StringCollection();
        string[] fromDirectories = fromDirectory.Split(
            Path.DirectorySeparatorChar);
 
        string[] toDirectories = toPath.Split(
            Path.DirectorySeparatorChar);
 
        int length = Math.Min(
            fromDirectories.Length, 
            toDirectories.Length);
 
        int lastCommonRoot = -1;
 
        // find common root
        for (int x = 0; x < length; x++)
        {
            if (string.Compare(fromDirectories[x], 
                toDirectories[x], true) != 0)
                break;
 
            lastCommonRoot = x;
        }
        if (lastCommonRoot == -1)
            return toPath;
 
        // add relative folders in from path
        for (int x = lastCommonRoot + 1; x < fromDirectories.Length; x++)
            if (fromDirectories[x].Length > 0)
                relativePath.Add("..");
 
        // add to folders to path
        for (int x = lastCommonRoot + 1; x < toDirectories.Length; x++)
            relativePath.Add(toDirectories[x]);
 
        // create relative path
        string[] relativeParts = new string[relativePath.Count];
        relativePath.CopyTo(relativeParts, 0);
 
        string newPath = string.Join(
            Path.DirectorySeparatorChar.ToString(), 
            relativeParts);
 
        return newPath;
    }
 
}

Draco.NET version 1.6.4.0 Released

pwelter34 — Thu, 05 Jan 2006 19:28:00 GMT

I’ve update and released a new version of Draco.NET. This release is mainly to make it compatible with Visual Studio 2005 and MSBuild. The following is a list of changes …

1.6-release-2 (1.6.4.0)

Added MSBuild support
Added Visual Studio 2005 support
Added manual build (no polling) support
Improved project config web page
Fixed bug where error emails were sent repeatedly

What is Draco.NET?

Draco.NET is a Windows service application designed to facilitate continuous integration. Draco.NET monitors your source code repository, automatically rebuilds your project when changes are detected and then emails you the build result along with a list of changes since the last build.

Get the latest

http://sourceforge.net/project/showfiles.php?group_id=66880

~ Paul