alias method - Page 245

Is there a difference between @ and * when using BIND?

- by nbolton

When configuring a BIND DNS zone, I often wonder why there exists both @ and * to specify an alias for the zone name. Is there a difference between the two?

Running localhost webapp projects under domain name using fiddler2

I have a Tomcat server running on my local dev machine(running Windows8) & I use fiddler2 to assign an alias to localhost as my domain name (www.mydomainName.com), so my application webpages open in the browser like this: http://www.mydomainName.com/myAppName/welcome.html instead of http://localhost:8080/myAppName/welcome.html But I want to my webapp pages urls to omit 'myAppName' & be something like : http://www.mydomainName.com/welcome.html How could I configure to do this ?

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How to restore pre-windows-8 Alt+Shift keyboard behavior?

- by SandRock

Before Windows 8, the Alt+Shift shortcut changed the input method (keyboard layout) for the current app. This permitted to map an input method to each app. For example I could keep the default layout for my apps where I write in english and switch to a french layout in apps where I write in french. This was working great: each app had his keyboard layout. Now with Windows 8 the Alt+Shift key has a global behavior for all applications. This meens I have to change my input method almost each time I change from app to app. Is there a way to restore the pre-Windows-8 behavior? Or is there another shortcut?

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Sync folder outside SkyDrive on OS X

- by Asmodiel

After the recent 25 GB update, I wanted to sync my pictures with SkyDrive as I finally have enough space (My almost 10 GB Dropbox is full with other data and I need more than 10 GB for my pictures alone). Anyway, the symlink (ln -s) option is not really working as it just creates an alias inside the skydrive which is not even synchronised. Is there any other option or do I have to live with moving the pictures folder into SkyDrive (which I wouldn't really want to do).

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Migrating email accounts from FirstClass to Exchange, selectively.

- by TMB

I am moving about 500 users from FirstClass to Exchange; however, we cannot move everyone at once and would like to do so in waves of 100 users. Is there a way to route mail to different servers based on email alias?

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Preventing duplicate Data with ASP.NET AJAX

- by Yousef_Jadallah

Some times you need to prevent User names ,E-mail ID's or other values from being duplicated by a new user during Registration or any other cases,So I will add a simple approach to make the page more user-friendly. Instead the user filled all the Registration fields then press submit after that received a message as a result of PostBack that "THIS USERNAME IS EXIST", Ajax tidies this up by allowing asynchronous querying while the user is still completing the registration form. ASP.NET enables you to create Web services can be accessed from client script in Web pages by using AJAX technology to make Web service calls. Data is exchanged asynchronously between client and server, typically in JSON format. I’ve added an article to show you step by step how to use ASP.NET AJAX with Web Services , you can find it here . Lets go a head with the steps : 1-Create a new project , if you are using VS 2005 you have to create ASP.NET Ajax Enabled Web site. 2-Create your own Database which contain user table that have User_Name field. for Testing I’ve added SQL Server Database that come with Dot Net 2008: Then I’ve created tblUsers: This table and this structure just for our example, you can use your own table to implement this approach. 3-Add new Item to your project or website, Choose Web Service file, lets say WebService.cs .In this Web Service file import System.Data.SqlClient Namespace, Then Add your web method that contain string parameter which received the Username parameter from the Script , Finally don’t forget to qualified the Web Service Class with the ScriptServiceAttribute attribute ([System.Web.Script.Services.ScriptService]) using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Services; using System.Data.SqlClient; [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] [System.Web.Script.Services.ScriptService] public class WebService : System.Web.Services.WebService { [WebMethod] public int CheckDuplicate(string User_Name) { string strConn = @"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\TestDB.mdf;Integrated Security=True;User Instance=True"; string strQuery = "SELECT COUNT(*) FROM tblUsers WHERE User_Name = @User_Name"; SqlConnection con = new SqlConnection(strConn); SqlCommand cmd = new SqlCommand(strQuery, con); cmd.Parameters.Add("User_Name", User_Name); con.Open(); int RetVal= (int)cmd.ExecuteScalar(); con.Close(); return RetVal; } } .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; } Our Web Method here is CheckDuplicate Which accept User_Name String as a parameter and return number of the rows , if the name will found in the database this method will return 1 else it will return 0. I’ve applied [WebMethod] Attribute to our method CheckDuplicate, And applied the ScriptService attribute to a Web Service class named WebService. 4-Add this simple Registration form : <fieldset> <table id="TblRegistratoin" cellpadding="0" cellspacing="0"> <tr> <td> User Name </td> <td> <asp:TextBox ID="txtUserName" onblur="CallWebMethod();" runat="server"></asp:TextBox> </td> <td> <asp:Label ID="lblDuplicate" runat="server" ForeColor="Red" Text=""></asp:Label> </td> </tr> <tr> <td colspan="3"> <asp:Button ID="btnRegistration" runat="server" Text="Registration" /> </td> </tr> </table> </fieldset> .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; } onblur event is added to the Textbox txtUserName, This event Fires when the Textbox loses the input focus, That mean after the user get focus out from the Textbox CallWebMethod function will be fired. CallWebMethod will be implemented in step 6. 5-Add ScriptManager Control to your aspx file then reference the Web service by adding an asp:ServiceReference child element to the ScriptManager control and setting its path attribute to point to the Web service, That generate a JavaScript proxy class for calling the specified Web service from client script. <asp:ScriptManager runat="server" ID="scriptManager"> <Services> <asp:ServiceReference Path="WebService.asmx" /> </Services> </asp:ScriptManager> .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; } 6-Define the JavaScript code to call the Web Service : <script language="javascript" type="text/javascript"> // This function calls the Web service method // passing simple type parameters and the // callback function function CallWebMethod() { var User_Name = document.getElementById('<%=txtUserName.ClientID %>').value; WebService.CheckDuplicate(User_Name, OnSucceeded, OnError); } // This is the callback function invoked if the Web service // succeeded function OnSucceeded(result) { var rsltElement = document.getElementById("lblDuplicate"); if (result == 1) rsltElement.innerHTML = "This User Name is exist"; else rsltElement.innerHTML = ""; } function OnError(error) { // Display the error. alert("Service Error: " + error.get_message()); } </script> .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; } This call references the WebService Class and CheckDuplicate Web Method defined in the service. It passes a User_Name value obtained from a textbox as well as a callback function named OnSucceeded that should be invoked when the asynchronous Web Service call returns. If the Web Service in different Namespace you can refer it before the class name this Main formula may help you : NameSpaceName.ClassName.WebMethdName(Parameters , Success callback function, Error callback function); Parameters: you can pass one or many parameters. Success callback function :handles returned data from the service . Error callback function :Any errors that occur when the Web Service is called will trigger in this function. Using Error Callback function is optional. Hope these steps help you to understand this approach.

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SQL SERVER – Concat Function in SQL Server – SQL Concatenation

- by pinaldave

Earlier this week, I was delivering Advanced BI training on the subject of “SQL Server 2008 R2″. I had great time delivering the session. During the session, we talked about SQL Server 2010 Denali. Suddenly one of the attendees suggested his displeasure for the product. He said, even though, SQL Server is now in moving very fast and have proved many times a good enterprise solution, it does not have some basic functions. I naturally asked him for example and he suggested CONCAT() which exists in MySQL and Oracle. The answer is very simple – the equalent function in SQL Server to CONCAT() is ‘+’ (plus operator without quotes). Method 1: Concatenating two strings SELECT 'FirstName' + ' ' + 'LastName' AS FullName Method 2: Concatenating two Numbers SELECT CAST(1 AS VARCHAR(10)) + 'R' + CAST(2 AS VARCHAR(10)) Method 3: Concatenating values from table columns SELECT FirstName + ' ' + LastName FROM AdventureWorks.Person.Contact Well, this may look very simple but sometime it is very difficult to find the information for simple things only. Do you have any such example which you would like to share with community? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL String, SQL Tips and Tricks, T SQL, Technology

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Preventing duplicate Data with ASP.NET AJAX

- by Yousef_Jadallah

Some times you need to prevent User names ,E-mail ID's or other values from being duplicated by a new user during Registration or any other cases,So I will add a simple approach to make the page more user-friendly. Instead the user filled all the Registration fields then press submit after that received a message as a result of PostBack that "THIS USERNAME IS EXIST", Ajax tidies this up by allowing asynchronous querying while the user is still completing the registration form. ASP.NET enables you to create Web services can be accessed from client script in Web pages by using AJAX technology to make Web service calls. Data is exchanged asynchronously between client and server, typically in JSON format. I’ve added an article to show you step by step how to use ASP.NET AJAX with Web Services , you can find it here . Lets go a head with the steps : 1-Create a new project , if you are using VS 2005 you have to create ASP.NET Ajax Enabled Web site. 2-Create your own Database which contain user table that have User_Name field. for Testing I’ve added SQL Server Database that come with Dot Net 2008: Then I’ve created tblUsers: This table and this structure just for our example, you can use your own table to implement this approach. 3-Add new Item to your project or website, Choose Web Service file, lets say WebService.cs .In this Web Service file import System.Data.SqlClient Namespace, Then Add your web method that contain string parameter which received the Username parameter from the Script , Finally don’t forget to qualified the Web Service Class with the ScriptServiceAttribute attribute ([System.Web.Script.Services.ScriptService]) using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Services; using System.Data.SqlClient; [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] [System.Web.Script.Services.ScriptService] public class WebService : System.Web.Services.WebService { [WebMethod] public int CheckDuplicate(string User_Name) { string strConn = @"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\TestDB.mdf;Integrated Security=True;User Instance=True"; string strQuery = "SELECT COUNT(*) FROM tblUsers WHERE User_Name = @User_Name"; SqlConnection con = new SqlConnection(strConn); SqlCommand cmd = new SqlCommand(strQuery, con); cmd.Parameters.Add("User_Name", User_Name); con.Open(); int RetVal= (int)cmd.ExecuteScalar(); con.Close(); return RetVal; } } .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; } Our Web Method here is CheckDuplicate Which accept User_Name String as a parameter and return number of the rows , if the name will found in the database this method will return 1 else it will return 0. I’ve applied [WebMethod] Attribute to our method CheckDuplicate, And applied the ScriptService attribute to a Web Service class named WebService. 4-Add this simple Registration form : <fieldset> <table id="TblRegistratoin" cellpadding="0" cellspacing="0"> <tr> <td> User Name </td> <td> <asp:TextBox ID="txtUserName" onblur="CallWebMethod();" runat="server"></asp:TextBox> </td> <td> <asp:Label ID="lblDuplicate" runat="server" ForeColor="Red" Text=""></asp:Label> </td> </tr> <tr> <td colspan="3"> <asp:Button ID="btnRegistration" runat="server" Text="Registration" /> </td> </tr> </table> </fieldset> .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; } onblur event is added to the Textbox txtUserName, This event Fires when the Textbox loses the input focus, That mean after the user get focus out from the Textbox CallWebMethod function will be fired. CallWebMethod will be implemented in step 6. 5-Add ScriptManager Control to your aspx file then reference the Web service by adding an asp:ServiceReference child element to the ScriptManager control and setting its path attribute to point to the Web service, That generate a JavaScript proxy class for calling the specified Web service from client script. <asp:ScriptManager runat="server" ID="scriptManager"> <Services> <asp:ServiceReference Path="WebService.asmx" /> </Services> </asp:ScriptManager> .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; } 6-Define the JavaScript code to call the Web Service : <script language="javascript" type="text/javascript"> // This function calls the Web service method // passing simple type parameters and the // callback function function CallWebMethod() { var User_Name = document.getElementById('<%=txtUserName.ClientID %>').value; WebService.CheckDuplicate(User_Name, OnSucceeded, OnError); } // This is the callback function invoked if the Web service // succeeded function OnSucceeded(result) { var rsltElement = document.getElementById("lblDuplicate"); if (result == 1) rsltElement.innerHTML = "This User Name is exist"; else rsltElement.innerHTML = ""; } function OnError(error) { // Display the error. alert("Service Error: " + error.get_message()); } </script> .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; } This call references the WebService Class and CheckDuplicate Web Method defined in the service. It passes a User_Name value obtained from a textbox as well as a callback function named OnSucceeded that should be invoked when the asynchronous Web Service call returns. If the Web Service in different Namespace you can refer it before the class name this Main formula may help you : NameSpaceName.ClassName.WebMethdName(Parameters , Success callback function, Error callback function); Parameters: you can pass one or many parameters. Success callback function :handles returned data from the service . Error callback function :Any errors that occur when the Web Service is called will trigger in this function. Using Error Callback function is optional. Hope these steps help you to understand this approach.

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Access violation in DirectX OMSetRenderTargets

- by IDWMaster

I receive the following error (Unhandled exception at 0x527DAE81 (d3d11_1sdklayers.dll) in Lesson2.Triangles.exe: 0xC0000005: Access violation reading location 0x00000000) when running the Triangle sample application for DirectX 11 in D3D_FEATURE_LEVEL_9_1. This error occurs at the OMSetRenderTargets function, as shown below, and does not happen if I remove that function from the program (but then, the screen is blue, and does not render the triangle) //// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF //// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO //// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A //// PARTICULAR PURPOSE. //// //// Copyright (c) Microsoft Corporation. All rights reserved #include #include #include "DirectXSample.h" #include "BasicMath.h" #include "BasicReaderWriter.h" using namespace Microsoft::WRL; using namespace Windows::UI::Core; using namespace Windows::Foundation; using namespace Windows::ApplicationModel::Core; using namespace Windows::ApplicationModel::Infrastructure; // This class defines the application as a whole. ref class Direct3DTutorialViewProvider : public IViewProvider { private: CoreWindow^ m_window; ComPtr m_swapChain; ComPtr m_d3dDevice; ComPtr m_d3dDeviceContext; ComPtr m_renderTargetView; public: // This method is called on application launch. void Initialize( _In_ CoreWindow^ window, _In_ CoreApplicationView^ applicationView ) { m_window = window; } // This method is called after Initialize. void Load(_In_ Platform::String^ entryPoint) { } // This method is called after Load. void Run() { // First, create the Direct3D device. // This flag is required in order to enable compatibility with Direct2D. UINT creationFlags = D3D11_CREATE_DEVICE_BGRA_SUPPORT; #if defined(_DEBUG) // If the project is in a debug build, enable debugging via SDK Layers with this flag. creationFlags |= D3D11_CREATE_DEVICE_DEBUG; #endif // This array defines the ordering of feature levels that D3D should attempt to create. D3D_FEATURE_LEVEL featureLevels[] = { D3D_FEATURE_LEVEL_11_1, D3D_FEATURE_LEVEL_11_0, D3D_FEATURE_LEVEL_10_1, D3D_FEATURE_LEVEL_10_0, D3D_FEATURE_LEVEL_9_3, D3D_FEATURE_LEVEL_9_1 }; ComPtr d3dDevice; ComPtr d3dDeviceContext; DX::ThrowIfFailed( D3D11CreateDevice( nullptr, // specify nullptr to use the default adapter D3D_DRIVER_TYPE_HARDWARE, nullptr, // leave as nullptr if hardware is used creationFlags, // optionally set debug and Direct2D compatibility flags featureLevels, ARRAYSIZE(featureLevels), D3D11_SDK_VERSION, // always set this to D3D11_SDK_VERSION &d3dDevice, nullptr, &d3dDeviceContext ) ); // Retrieve the Direct3D 11.1 interfaces. DX::ThrowIfFailed( d3dDevice.As(&m_d3dDevice) ); DX::ThrowIfFailed( d3dDeviceContext.As(&m_d3dDeviceContext) ); // After the D3D device is created, create additional application resources. CreateWindowSizeDependentResources(); // Create a Basic Reader-Writer class to load data from disk. This class is examined // in the Resource Loading sample. BasicReaderWriter^ reader = ref new BasicReaderWriter(); // Load the raw vertex shader bytecode from disk and create a vertex shader with it. auto vertexShaderBytecode = reader-ReadData("SimpleVertexShader.cso"); ComPtr vertexShader; DX::ThrowIfFailed( m_d3dDevice-CreateVertexShader( vertexShaderBytecode-Data, vertexShaderBytecode-Length, nullptr, &vertexShader ) ); // Create an input layout that matches the layout defined in the vertex shader code. // For this lesson, this is simply a float2 vector defining the vertex position. const D3D11_INPUT_ELEMENT_DESC basicVertexLayoutDesc[] = { { "POSITION", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0 }, }; ComPtr inputLayout; DX::ThrowIfFailed( m_d3dDevice-CreateInputLayout( basicVertexLayoutDesc, ARRAYSIZE(basicVertexLayoutDesc), vertexShaderBytecode-Data, vertexShaderBytecode-Length, &inputLayout ) ); // Load the raw pixel shader bytecode from disk and create a pixel shader with it. auto pixelShaderBytecode = reader-ReadData("SimplePixelShader.cso"); ComPtr pixelShader; DX::ThrowIfFailed( m_d3dDevice-CreatePixelShader( pixelShaderBytecode-Data, pixelShaderBytecode-Length, nullptr, &pixelShader ) ); // Create vertex and index buffers that define a simple triangle. float3 triangleVertices[] = { float3(-0.5f, -0.5f,13.5f), float3( 0.0f, 0.5f,0), float3( 0.5f, -0.5f,0), }; D3D11_BUFFER_DESC vertexBufferDesc = {0}; vertexBufferDesc.ByteWidth = sizeof(float3) * ARRAYSIZE(triangleVertices); vertexBufferDesc.Usage = D3D11_USAGE_DEFAULT; vertexBufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER; vertexBufferDesc.CPUAccessFlags = 0; vertexBufferDesc.MiscFlags = 0; vertexBufferDesc.StructureByteStride = 0; D3D11_SUBRESOURCE_DATA vertexBufferData; vertexBufferData.pSysMem = triangleVertices; vertexBufferData.SysMemPitch = 0; vertexBufferData.SysMemSlicePitch = 0; ComPtr vertexBuffer; DX::ThrowIfFailed( m_d3dDevice-CreateBuffer( &vertexBufferDesc, &vertexBufferData, &vertexBuffer ) ); // Once all D3D resources are created, configure the application window. // Allow the application to respond when the window size changes. m_window-SizeChanged += ref new TypedEventHandler( this, &Direct3DTutorialViewProvider::OnWindowSizeChanged ); // Specify the cursor type as the standard arrow cursor. m_window-PointerCursor = ref new CoreCursor(CoreCursorType::Arrow, 0); // Activate the application window, making it visible and enabling it to receive events. m_window-Activate(); // Enter the render loop. Note that tailored applications should never exit. while (true) { // Process events incoming to the window. m_window-Dispatcher-ProcessEvents(CoreProcessEventsOption::ProcessAllIfPresent); // Specify the render target we created as the output target. ID3D11RenderTargetView* targets[1] = {m_renderTargetView.Get()}; m_d3dDeviceContext-OMSetRenderTargets( 1, targets, NULL // use no depth stencil ); // Clear the render target to a solid color. const float clearColor[4] = { 0.071f, 0.04f, 0.561f, 1.0f }; //Code fails here m_d3dDeviceContext-ClearRenderTargetView( m_renderTargetView.Get(), clearColor ); m_d3dDeviceContext-IASetInputLayout(inputLayout.Get()); // Set the vertex and index buffers, and specify the way they define geometry. UINT stride = sizeof(float3); UINT offset = 0; m_d3dDeviceContext-IASetVertexBuffers( 0, 1, vertexBuffer.GetAddressOf(), &stride, &offset ); m_d3dDeviceContext-IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST); // Set the vertex and pixel shader stage state. m_d3dDeviceContext-VSSetShader( vertexShader.Get(), nullptr, 0 ); m_d3dDeviceContext-PSSetShader( pixelShader.Get(), nullptr, 0 ); // Draw the cube. m_d3dDeviceContext-Draw(3,0); // Present the rendered image to the window. Because the maximum frame latency is set to 1, // the render loop will generally be throttled to the screen refresh rate, typically around // 60Hz, by sleeping the application on Present until the screen is refreshed. DX::ThrowIfFailed( m_swapChain-Present(1, 0) ); } } // This method is called before the application exits. void Uninitialize() { } private: // This method is called whenever the application window size changes. void OnWindowSizeChanged( _In_ CoreWindow^ sender, _In_ WindowSizeChangedEventArgs^ args ) { m_renderTargetView = nullptr; CreateWindowSizeDependentResources(); } // This method creates all application resources that depend on // the application window size. It is called at app initialization, // and whenever the application window size changes. void CreateWindowSizeDependentResources() { if (m_swapChain != nullptr) { // If the swap chain already exists, resize it. DX::ThrowIfFailed( m_swapChain-ResizeBuffers( 2, 0, 0, DXGI_FORMAT_R8G8B8A8_UNORM, 0 ) ); } else { // If the swap chain does not exist, create it. DXGI_SWAP_CHAIN_DESC1 swapChainDesc = {0}; swapChainDesc.Stereo = false; swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT; swapChainDesc.Scaling = DXGI_SCALING_NONE; swapChainDesc.Flags = 0; // Use automatic sizing. swapChainDesc.Width = 0; swapChainDesc.Height = 0; // This is the most common swap chain format. swapChainDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM; // Don't use multi-sampling. swapChainDesc.SampleDesc.Count = 1; swapChainDesc.SampleDesc.Quality = 0; // Use two buffers to enable flip effect. swapChainDesc.BufferCount = 2; // We recommend using this swap effect for all applications. swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL; // Once the swap chain description is configured, it must be // created on the same adapter as the existing D3D Device. // First, retrieve the underlying DXGI Device from the D3D Device. ComPtr dxgiDevice; DX::ThrowIfFailed( m_d3dDevice.As(&dxgiDevice) ); // Ensure that DXGI does not queue more than one frame at a time. This both reduces // latency and ensures that the application will only render after each VSync, minimizing // power consumption. DX::ThrowIfFailed( dxgiDevice-SetMaximumFrameLatency(1) ); // Next, get the parent factory from the DXGI Device. ComPtr dxgiAdapter; DX::ThrowIfFailed( dxgiDevice-GetAdapter(&dxgiAdapter) ); ComPtr dxgiFactory; DX::ThrowIfFailed( dxgiAdapter-GetParent( __uuidof(IDXGIFactory2), &dxgiFactory ) ); // Finally, create the swap chain. DX::ThrowIfFailed( dxgiFactory-CreateSwapChainForImmersiveWindow( m_d3dDevice.Get(), DX::GetIUnknown(m_window), &swapChainDesc, nullptr, // allow on all displays &m_swapChain ) ); } // Once the swap chain is created, create a render target view. This will // allow Direct3D to render graphics to the window. ComPtr backBuffer; DX::ThrowIfFailed( m_swapChain-GetBuffer( 0, __uuidof(ID3D11Texture2D), &backBuffer ) ); DX::ThrowIfFailed( m_d3dDevice-CreateRenderTargetView( backBuffer.Get(), nullptr, &m_renderTargetView ) ); // After the render target view is created, specify that the viewport, // which describes what portion of the window to draw to, should cover // the entire window. D3D11_TEXTURE2D_DESC backBufferDesc = {0}; backBuffer-GetDesc(&backBufferDesc); D3D11_VIEWPORT viewport; viewport.TopLeftX = 0.0f; viewport.TopLeftY = 0.0f; viewport.Width = static_cast(backBufferDesc.Width); viewport.Height = static_cast(backBufferDesc.Height); viewport.MinDepth = D3D11_MIN_DEPTH; viewport.MaxDepth = D3D11_MAX_DEPTH; m_d3dDeviceContext-RSSetViewports(1, &viewport); } }; // This class defines how to create the custom View Provider defined above. ref class Direct3DTutorialViewProviderFactory : IViewProviderFactory { public: IViewProvider^ CreateViewProvider() { return ref new Direct3DTutorialViewProvider(); } }; [Platform::MTAThread] int main(array^) { auto viewProviderFactory = ref new Direct3DTutorialViewProviderFactory(); Windows::ApplicationModel::Core::CoreApplication::Run(viewProviderFactory); return 0; }

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jQuery Templates and Data Linking (and Microsoft contributing to jQuery)

- by ScottGu

The jQuery library has a passionate community of developers, and it is now the most widely used JavaScript library on the web today. Two years ago I announced that Microsoft would begin offering product support for jQuery, and that we’d be including it in new versions of Visual Studio going forward. By default, when you create new ASP.NET Web Forms and ASP.NET MVC projects with VS 2010 you’ll find jQuery automatically added to your project. A few weeks ago during my second keynote at the MIX 2010 conference I announced that Microsoft would also begin contributing to the jQuery project. During the talk, John Resig -- the creator of the jQuery library and leader of the jQuery developer team – talked a little about our participation and discussed an early prototype of a new client templating API for jQuery. In this blog post, I’m going to talk a little about how my team is starting to contribute to the jQuery project, and discuss some of the specific features that we are working on such as client-side templating and data linking (data-binding). Contributing to jQuery jQuery has a fantastic developer community, and a very open way to propose suggestions and make contributions. Microsoft is following the same process to contribute to jQuery as any other member of the community. As an example, when working with the jQuery community to improve support for templating to jQuery my team followed the following steps: We created a proposal for templating and posted the proposal to the jQuery developer forum (http://forum.jquery.com/topic/jquery-templates-proposal and http://forum.jquery.com/topic/templating-syntax ). After receiving feedback on the forums, the jQuery team created a prototype for templating and posted the prototype at the Github code repository (http://github.com/jquery/jquery-tmpl ). We iterated on the prototype, creating a new fork on Github of the templating prototype, to suggest design improvements. Several other members of the community also provided design feedback by forking the templating code. There has been an amazing amount of participation by the jQuery community in response to the original templating proposal (over 100 posts in the jQuery forum), and the design of the templating proposal has evolved significantly based on community feedback. The jQuery team is the ultimate determiner on what happens with the templating proposal – they might include it in jQuery core, or make it an official plugin, or reject it entirely. My team is excited to be able to participate in the open source process, and make suggestions and contributions the same way as any other member of the community. jQuery Template Support Client-side templates enable jQuery developers to easily generate and render HTML UI on the client. Templates support a simple syntax that enables either developers or designers to declaratively specify the HTML they want to generate. Developers can then programmatically invoke the templates on the client, and pass JavaScript objects to them to make the content rendered completely data driven. These JavaScript objects can optionally be based on data retrieved from a server. Because the jQuery templating proposal is still evolving in response to community feedback, the final version might look very different than the version below. This blog post gives you a sense of how you can try out and use templating as it exists today (you can download the prototype by the jQuery core team at http://github.com/jquery/jquery-tmpl or the latest submission from my team at http://github.com/nje/jquery-tmpl). jQuery Client Templates You create client-side jQuery templates by embedding content within a <script type="text/html"> tag. For example, the HTML below contains a <div> template container, as well as a client-side jQuery “contactTemplate” template (within the <script type="text/html"> element) that can be used to dynamically display a list of contacts: The {{= name }} and {{= phone }} expressions are used within the contact template above to display the names and phone numbers of “contact” objects passed to the template. We can use the template to display either an array of JavaScript objects or a single object. The JavaScript code below demonstrates how you can render a JavaScript array of “contact” object using the above template. The render() method renders the data into a string and appends the string to the “contactContainer” DIV element: When the page is loaded, the list of contacts is rendered by the template. All of this template rendering is happening on the client-side within the browser: Templating Commands and Conditional Display Logic The current templating proposal supports a small set of template commands - including if, else, and each statements. The number of template commands was deliberately kept small to encourage people to place more complicated logic outside of their templates. Even this small set of template commands is very useful though. Imagine, for example, that each contact can have zero or more phone numbers. The contacts could be represented by the JavaScript array below: The template below demonstrates how you can use the if and each template commands to conditionally display and loop the phone numbers for each contact: If a contact has one or more phone numbers then each of the phone numbers is displayed by iterating through the phone numbers with the each template command: The jQuery team designed the template commands so that they are extensible. If you have a need for a new template command then you can easily add new template commands to the default set of commands. Support for Client Data-Linking The ASP.NET team recently submitted another proposal and prototype to the jQuery forums (http://forum.jquery.com/topic/proposal-for-adding-data-linking-to-jquery). This proposal describes a new feature named data linking. Data Linking enables you to link a property of one object to a property of another object - so that when one property changes the other property changes. Data linking enables you to easily keep your UI and data objects synchronized within a page. If you are familiar with the concept of data-binding then you will be familiar with data linking (in the proposal, we call the feature data linking because jQuery already includes a bind() method that has nothing to do with data-binding). Imagine, for example, that you have a page with the following HTML <input> elements: The following JavaScript code links the two INPUT elements above to the properties of a JavaScript “contact” object that has a “name” and “phone” property: When you execute this code, the value of the first INPUT element (#name) is set to the value of the contact name property, and the value of the second INPUT element (#phone) is set to the value of the contact phone property. The properties of the contact object and the properties of the INPUT elements are also linked – so that changes to one are also reflected in the other. Because the contact object is linked to the INPUT element, when you request the page, the values of the contact properties are displayed: More interesting, the values of the linked INPUT elements will change automatically whenever you update the properties of the contact object they are linked to. For example, we could programmatically modify the properties of the “contact” object using the jQuery attr() method like below: Because our two INPUT elements are linked to the “contact” object, the INPUT element values will be updated automatically (without us having to write any code to modify the UI elements): Note that we updated the contact object above using the jQuery attr() method. In order for data linking to work, you must use jQuery methods to modify the property values. Two Way Linking The linkBoth() method enables two-way data linking. The contact object and INPUT elements are linked in both directions. When you modify the value of the INPUT element, the contact object is also updated automatically. For example, the following code adds a client-side JavaScript click handler to an HTML button element. When you click the button, the property values of the contact object are displayed using an alert() dialog: The following demonstrates what happens when you change the value of the Name INPUT element and click the Save button. Notice that the name property of the “contact” object that the INPUT element was linked to was updated automatically: The above example is obviously trivially simple. Instead of displaying the new values of the contact object with a JavaScript alert, you can imagine instead calling a web-service to save the object to a database. The benefit of data linking is that it enables you to focus on your data and frees you from the mechanics of keeping your UI and data in sync. Converters The current data linking proposal also supports a feature called converters. A converter enables you to easily convert the value of a property during data linking. For example, imagine that you want to represent phone numbers in a standard way with the “contact” object phone property. In particular, you don’t want to include special characters such as ()- in the phone number - instead you only want digits and nothing else. In that case, you can wire-up a converter to convert the value of an INPUT element into this format using the code below: Notice above how a converter function is being passed to the linkFrom() method used to link the phone property of the “contact” object with the value of the phone INPUT element. This convertor function strips any non-numeric characters from the INPUT element before updating the phone property. Now, if you enter the phone number (206) 555-9999 into the phone input field then the value 2065559999 is assigned to the phone property of the contact object: You can also use a converter in the opposite direction also. For example, you can apply a standard phone format string when displaying a phone number from a phone property. Combining Templating and Data Linking Our goal in submitting these two proposals for templating and data linking is to make it easier to work with data when building websites and applications with jQuery. Templating makes it easier to display a list of database records retrieved from a database through an Ajax call. Data linking makes it easier to keep the data and user interface in sync for update scenarios. Currently, we are working on an extension of the data linking proposal to support declarative data linking. We want to make it easy to take advantage of data linking when using a template to display data. For example, imagine that you are using the following template to display an array of product objects: Notice the {{link name}} and {{link price}} expressions. These expressions enable declarative data linking between the SPAN elements and properties of the product objects. The current jQuery templating prototype supports extending its syntax with custom template commands. In this case, we are extending the default templating syntax with a custom template command named “link”. The benefit of using data linking with the above template is that the SPAN elements will be automatically updated whenever the underlying “product” data is updated. Declarative data linking also makes it easier to create edit and insert forms. For example, you could create a form for editing a product by using declarative data linking like this: Whenever you change the value of the INPUT elements in a template that uses declarative data linking, the underlying JavaScript data object is automatically updated. Instead of needing to write code to scrape the HTML form to get updated values, you can instead work with the underlying data directly – making your client-side code much cleaner and simpler. Downloading Working Code Examples of the Above Scenarios You can download this .zip file to get with working code examples of the above scenarios. The .zip file includes 4 static HTML page: Listing1_Templating.htm – Illustrates basic templating. Listing2_TemplatingConditionals.htm – Illustrates templating with the use of the if and each template commands. Listing3_DataLinking.htm – Illustrates data linking. Listing4_Converters.htm – Illustrates using a converter with data linking. You can un-zip the file to the file-system and then run each page to see the concepts in action. Summary We are excited to be able to begin participating within the open-source jQuery project. We’ve received lots of encouraging feedback in response to our first two proposals, and we will continue to actively contribute going forward. These features will hopefully make it easier for all developers (including ASP.NET developers) to build great Ajax applications. Hope this helps, Scott P.S. [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu]

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Spritebatch not working in winforms

- by CodingMadeEasy

I'm using the Winforms sample on the app hub and everything is working fine except my spritebatch won't draw anything unless I call Invalidate in the Draw method. I have this in my initialize method: Application.Idle += delegate { Invalidate(); }; I used a breakpoint and it is indeed invalidating my program and it is calling my draw method. I get no errors with the spritebatch and all the textures are loaded I just don't see anything on the screen. Here's the code I have: protected override void Draw() { GraphicsDevice.Clear(Color.CornflowerBlue); spriteBatch.Begin(); tileSheet.Draw(spriteBatch); foreach (Image img in selector) img.Draw(spriteBatch); spriteBatch.End(); } But when I do this: protected override void Draw() { GraphicsDevice.Clear(Color.CornflowerBlue); spriteBatch.Begin(); tileSheet.Draw(spriteBatch); foreach (Image img in selector) img.Draw(spriteBatch); spriteBatch.End(); Invalidate(); } then all of a sudden the drawing starts to work! but the problem is that it freezes everything else and only that control gets updated. What can I do to fix this? It's really frustrating.

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Rendering shadow sprites in cocos2d-x

- by lukeluke

I am writing a 2D game with cocos2d-x. I want to put a "shadow" sprite on a background sprite using the equation: MAX(0, Cd*1 - Cs*S) where Cd is the destination color (that is, a background pixel), Cs is the source color (the shadow pixel) , S is the scale factor (between 0 and 1). The MAX() function is used to avoid negative results. This is a lighting effect: when the shadow sprite pixel is 0, there is no effect on the background pixel, otherwise, the background pixel becomes darker. Now, the only way that comes to my mind is to change the blending equation to GL_FUNC_SUBTRACT, but it doesn't compile with cocos2d-x (can't found it)... I would subclass the CCSprite class in order to implement the draw() method in order to change, when needed, the blending equation, call the original draw() method and restore the blending equation to its previous state at the end of the method. So my questions are two: how to use glBlendEquation() with cocos2d-x? Keep in mind that i am writing a game for iphone/android/windows. are shadows handled this way in 2D games? Thx

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ScrollViewer.EnsureVisible for Windows Phone

- by Daniel Moth

In my Translator By Moth app, on both the current and saved pivot pages the need arose to programmatically scroll to the bottom. In the former, case it is when a translation takes place (if the text is too long, I want to scroll to the bottom of the translation so the user can focus on that, and not their input text for translation). In the latter case it was when a new translation is saved (it is added to the bottom of the list, so scrolling is required to make it visible). On both pages a ScrollViewer is used. In my exploration of the APIs through intellisense and msdn I could not find a method that auto scrolled to the bottom. So I hacked together a solution where I added a blank textblock to the bottom of each page (within the ScrollViewer, but above the translated textblock and the saved list) and tried to make it scroll it into view from code. After searching the web I found a little algorithm that did most of what I wanted (sorry, I do not have the reference handy, but thank you whoever it was) that after minor tweaking I turned into an extension method for the ScrollViewer that is very easy to use: this.Scroller.EnsureVisible(this.BlankText); The method itself I share with you here: public static void EnsureVisible(this System.Windows.Controls.ScrollViewer scroller, System.Windows.UIElement uiElem) { System.Diagnostics.Debug.Assert(scroller != null); System.Diagnostics.Debug.Assert(uiElem != null); scroller.UpdateLayout(); double maxScrollPos = scroller.ExtentHeight - scroller.ViewportHeight; double scrollPos = scroller.VerticalOffset - scroller.TransformToVisual(uiElem).Transform(new System.Windows.Point(0, 0)).Y; if (scrollPos > maxScrollPos) scrollPos = maxScrollPos; else if (scrollPos < 0) scrollPos = 0; scroller.ScrollToVerticalOffset(scrollPos); } I am sure there are better ways, but this "worked for me" :-) Comments about this post by Daniel Moth welcome at the original blog.

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Entity Framework v1 – tips and Tricks Part 3

- by Rohit Gupta

General Tips on Entity Framework v1 & Linq to Entities: ToTraceString() If you need to know the underlying SQL that the EF generates for a Linq To Entities query, then use the ToTraceString() method of the ObjectQuery class. (or use LINQPAD) Note that you need to cast the LINQToEntities query to ObjectQuery before calling TotraceString() as follows: 1: string efSQL = ((ObjectQuery)from c in ctx.Contact 2: where c.Address.Any(a => a.CountryRegion == "US") 3: select c.ContactID).ToTraceString(); ================================================================================ MARS or MultipleActiveResultSet When you create a EDM Model (EDMX file) from the database using Visual Studio, it generates a connection string with the same name as the name of the EntityContainer in CSDL. In the ConnectionString so generated it sets the MultipleActiveResultSet attribute to true by default. So if you are running the following query then it streams multiple readers over the same connection: 1: using (BAEntities context = new BAEntities()) 2: { 3: var cons = 4: from con in context.Contacts 5: where con.FirstName == "Jose" 6: select con; 7: foreach (var c in cons) 8: { 9: if (c.AddDate < new System.DateTime(2007, 1, 1)) 10: { 11: c.Addresses.Load(); 12: } 13: } 14: } ================================================================================= Explicitly opening and closing EntityConnection When you call ToList() or foreach on a LINQToEntities query the EF automatically closes the connection after all the records from the query have been consumed. Thus if you need to run many LINQToEntities queries over the same connection then explicitly open and close the connection as follows: 1: using (BAEntities context = new BAEntities()) 2: { 3: context.Connection.Open(); 4: var cons = from con in context.Contacts where con.FirstName == "Jose" 5: select con; 6: var conList = cons.ToList(); 7: var allCustomers = from con in context.Contacts.OfType<Customer>() 8: select con; 9: var allcustList = allCustomers.ToList(); 10: context.Connection.Close(); 11: } ====================================================================== Dispose ObjectContext only if required After you retrieve entities using the ObjectContext and you are not explicitly disposing the ObjectContext then insure that your code does consume all the records from the LinqToEntities query by calling .ToList() or foreach statement, otherwise the the database connection will remain open and will be closed by the garbage collector when it gets to dispose the ObjectContext. Secondly if you are making updates to the entities retrieved using LinqToEntities then insure that you dont inadverdently dispose of the ObjectContext after the entities are retrieved and before calling .SaveChanges() since you need the SAME ObjectContext to keep track of changes made to the Entities (by using ObjectStateEntry objects). So if you do need to explicitly dispose of the ObjectContext do so only after calling SaveChanges() and only if you dont need to change track the entities retrieved any further. ======================================================================= SQL InjectionAttacks under control with EFv1 LinqToEntities and LinqToSQL queries are parameterized before they are sent to the DB hence they are not vulnerable to SQL Injection attacks. EntitySQL may be slightly vulnerable to attacks since it does not use parameterized queries. However since the EntitySQL demands that the query be valid Entity SQL syntax and valid native SQL syntax at the same time. So the only way one can do a SQLInjection Attack is by knowing the SSDL of the EDM Model and be able to write the correct EntitySQL (note one cannot append regular SQL since then the query wont be a valid EntitySQL syntax) and append it to a parameter. ====================================================================== Improving Performance You can convert the EntitySets and AssociationSets in a EDM Model into precompiled Views using the edmgen utility. for e.g. the Customer Entity can be converted into a precompiled view using edmgen and all LinqToEntities query against the contaxt.Customer EntitySet will use the precompiled View instead of the EntitySet itself (the same being true for relationships (EntityReference & EntityCollections of a Entity)). The advantage being that when using precompiled views the performance will be much better. The syntax for generating precompiled views for a existing EF project is : edmgen /mode:ViewGeneration /inssdl:BAModel.ssdl /incsdl:BAModel.csdl /inmsl:BAModel.msl /p:Chap14.csproj Note that this will only generate precompiled views for EntitySets and Associations and not for existing LinqToEntities queries in the project.(for that use CompiledQuery.Compile<>) Secondly if you have a LinqToEntities query that you need to run multiple times, then one should precompile the query using CompiledQuery.Compile method. The CompiledQuery.Compile<> method accepts a lamda expression as a parameter, which denotes the LinqToEntities query that you need to precompile. The following is a example of a lamda that we can pass into the CompiledQuery.Compile() method 1: Expression<Func<BAEntities, string, IQueryable<Customer>>> expr = (BAEntities ctx1, string loc) => 2: from c in ctx1.Contacts.OfType<Customer>() 3: where c.Reservations.Any(r => r.Trip.Destination.DestinationName == loc) 4: select c; Then we call the Compile Query as follows: 1: var query = CompiledQuery.Compile<BAEntities, string, IQueryable<Customer>>(expr); 2: 3: using (BAEntities ctx = new BAEntities()) 4: { 5: var loc = "Malta"; 6: IQueryable<Customer> custs = query.Invoke(ctx, loc); 7: var custlist = custs.ToList(); 8: foreach (var item in custlist) 9: { 10: Console.WriteLine(item.FullName); 11: } 12: } Note that if you created a ObjectQuery or a Enitity SQL query instead of the LINQToEntities query, you dont need precompilation for e.g. 1: An Example of EntitySQL query : 2: string esql = "SELECT VALUE c from Contacts AS c where c is of(BAGA.Customer) and c.LastName = 'Gupta'"; 3: ObjectQuery<Customer> custs = CreateQuery<Customer>(esql); 1: An Example of ObjectQuery built using ObjectBuilder methods: 2: from c in Contacts.OfType<Customer>().Where("it.LastName == 'Gupta'") 3: select c This is since the Query plan is cached and thus the performance improves a bit, however since the ObjectQuery or EntitySQL query still needs to materialize the results into Entities hence it will take the same amount of performance hit as with LinqToEntities. However note that not ALL EntitySQL based or QueryBuilder based ObjectQuery plans are cached. So if you are in doubt always create a LinqToEntities compiled query and use that instead ============================================================ GetObjectStateEntry Versus GetObjectByKey We can get to the Entity being referenced by the ObjectStateEntry via its Entity property and there are helper methods in the ObjectStateManager (osm.TryGetObjectStateEntry) to get the ObjectStateEntry for a entity (for which we know the EntityKey). Similarly The ObjectContext has helper methods to get an Entity i.e. TryGetObjectByKey(). TryGetObjectByKey() uses GetObjectStateEntry method under the covers to find the object, however One important difference between these 2 methods is that TryGetObjectByKey queries the database if it is unable to find the object in the context, whereas TryGetObjectStateEntry only looks in the context for existing entries. It will not make a trip to the database ============================================================= POCO objects with EFv1: To create POCO objects that can be used with EFv1. We need to implement 3 key interfaces: IEntityWithKey IEntityWithRelationships IEntityWithChangeTracker Implementing IEntityWithKey is not mandatory, but if you dont then we need to explicitly provide values for the EntityKey for various functions (for e.g. the functions needed to implement IEntityWithChangeTracker and IEntityWithRelationships). Implementation of IEntityWithKey involves exposing a property named EntityKey which returns a EntityKey object. Implementation of IEntityWithChangeTracker involves implementing a method named SetChangeTracker since there can be multiple changetrackers (Object Contexts) existing in memory at the same time. 1: public void SetChangeTracker(IEntityChangeTracker changeTracker) 2: { 3: _changeTracker = changeTracker; 4: } Additionally each property in the POCO object needs to notify the changetracker (objContext) that it is updating itself by calling the EntityMemberChanged and EntityMemberChanging methods on the changeTracker. for e.g.: 1: public EntityKey EntityKey 2: { 3: get { return _entityKey; } 4: set 5: { 6: if (_changeTracker != null) 7: { 8: _changeTracker.EntityMemberChanging("EntityKey"); 9: _entityKey = value; 10: _changeTracker.EntityMemberChanged("EntityKey"); 11: } 12: else 13: _entityKey = value; 14: } 15: } 16: ===================== Custom Property ==================================== 17: 18: [EdmScalarPropertyAttribute(IsNullable = false)] 19: public System.DateTime OrderDate 20: { 21: get { return _orderDate; } 22: set 23: { 24: if (_changeTracker != null) 25: { 26: _changeTracker.EntityMemberChanging("OrderDate"); 27: _orderDate = value; 28: _changeTracker.EntityMemberChanged("OrderDate"); 29: } 30: else 31: _orderDate = value; 32: } 33: } Finally you also need to create the EntityState property as follows: 1: public EntityState EntityState 2: { 3: get { return _changeTracker.EntityState; } 4: } The IEntityWithRelationships involves creating a property that returns RelationshipManager object: 1: public RelationshipManager RelationshipManager 2: { 3: get 4: { 5: if (_relManager == null) 6: _relManager = RelationshipManager.Create(this); 7: return _relManager; 8: } 9: } ============================================================ Tip : ProviderManifestToken – change EDMX File to use SQL 2008 instead of SQL 2005 To use with SQL Server 2008, edit the EDMX file (the raw XML) changing the ProviderManifestToken in the SSDL attributes from "2005" to "2008" ============================================================= With EFv1 we cannot use Structs to replace a anonymous Type while doing projections in a LINQ to Entities query. While the same is supported with LINQToSQL, it is not with LinqToEntities. For e.g. the following is not supported with LinqToEntities since only parameterless constructors and initializers are supported in LINQ to Entities. (the same works with LINQToSQL) 1: public struct CompanyInfo 2: { 3: public int ID { get; set; } 4: public string Name { get; set; } 5: } 6: var companies = (from c in dc.Companies 7: where c.CompanyIcon == null 8: select new CompanyInfo { Name = c.CompanyName, ID = c.CompanyId }).ToList(); ;

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LINQ: Single vs. First

- by Paulo Morgado

I’ve witnessed and been involved in several discussions around the correctness or usefulness of the Single method in the LINQ API. The most common argument is that you are querying for the first element on the result set and an exception will be thrown if there’s more than one element. The First method should be used instead, because it doesn’t throw if the result set has more than one item. Although the documentation for Single states that it returns a single, specific element of a sequence of values, it actually returns THE single, specific element of a sequence of ONE value. One you use the Single method in your code you are asserting that your query will result in a scalar result instead of a result set of arbitrary length. On the other hand, the documentation for First states that it returns the first element of a sequence of arbitrary length. Imagine you want to catch a taxi. You go the the taxi line and catch the FIRST one, no matter how many are there. On the other hand, if you go the the parking lot to get your car, you want the SINGLE one specific car that’s yours. If your “query” “returns” more than one car, it’s an exception. Either because it “returned” not only your car or you happen to have more than one car in that parking lot. In either case, you can only drive one car at once and you’ll need to refine your “query”.

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MVC Automatic Menu

- by Nuri Halperin

An ex-colleague of mine used to call his SQL script generator "Super-Scriptmatic 2000". It impressed our then boss little, but was fun to say and use. We called every batch job and script "something 2000" from that day on. I'm tempted to call this one Menu-Matic 2000, except it's waaaay past 2000. Oh well. The problem: I'm developing a bunch of stuff in MVC. There's no PM to generate mounds of requirements and there's no Ux Architect to create wireframe. During development, things change. Specifically, actions get renamed, moved from controller x to y etc. Well, as the site grows, it becomes a major pain to keep a static menu up to date, because the links change. The HtmlHelper doesn't live up to it's name and provides little help. How do I keep this growing list of pesky little forgotten actions reigned in? The general plan is: Decorate every action you want as a menu item with a custom attribute Reflect out all menu items into a structure at load time Render the menu using as CSS friendly <ul><li> HTML. The MvcMenuItemAttribute decorates an action, designating it to be included as a menu item: [AttributeUsage(AttributeTargets.Method, AllowMultiple = true)] public class MvcMenuItemAttribute : Attribute { public string MenuText { get; set; } public int Order { get; set; } public string ParentLink { get; set; } internal string Controller { get; set; } internal string Action { get; set; } #region ctor public MvcMenuItemAttribute(string menuText) : this(menuText, 0) { } public MvcMenuItemAttribute(string menuText, int order) { MenuText = menuText; Order = order; } internal string Link { get { return string.Format("/{0}/{1}", Controller, this.Action); } } internal MvcMenuItemAttribute ParentItem { get; set; } #endregion } The MenuText allows overriding the text displayed on the menu. The Order allows the items to be ordered. The ParentLink allows you to make this item a child of another menu item. An example action could then be decorated thusly: [MvcMenuItem("Tracks", Order = 20, ParentLink = "/Session/Index")] . All pretty straightforward methinks. The challenge with menu hierarchy becomes fairly apparent when you try to render a menu and highlight the "current" item or render a breadcrumb control. Both encounter an ambiguity if you allow a data source to have more than one menu item with the same URL link. The issue is that there is no great way to tell which link a person click. Using referring URL will fail if a user bookmarked the page. Using some extra query string to disambiguate duplicate URLs essentially changes the links, and also ads a chance of collision with other query parameters. Besides, that smells. The stock ASP.Net sitemap provider simply disallows duplicate URLS. I decided not to, and simply pick the first one encountered as the "current". Although it doesn't solve the issue completely – one might say they wanted the second of the 2 links to be "current"- it allows one to include a link twice (home->deals and products->deals etc), and the logic of deciding "current" is easy enough to explain to the customer. Now that we got that out of the way, let's build the menu data structure: public static List<MvcMenuItemAttribute> ListMenuItems(Assembly assembly) { var result = new List<MvcMenuItemAttribute>(); foreach (var type in assembly.GetTypes()) { if (!type.IsSubclassOf(typeof(Controller))) { continue; } foreach (var method in type.GetMethods()) { var items = method.GetCustomAttributes(typeof(MvcMenuItemAttribute), false) as MvcMenuItemAttribute[]; if (items == null) { continue; } foreach (var item in items) { if (String.IsNullOrEmpty(item.Controller)) { item.Controller = type.Name.Substring(0, type.Name.Length - "Controller".Length); } if (String.IsNullOrEmpty(item.Action)) { item.Action = method.Name; } result.Add(item); } } } return result.OrderBy(i => i.Order).ToList(); } Using reflection, the ListMenuItems method takes an assembly (you will hand it your MVC web assembly) and generates a list of menu items. It digs up all the types, and for each one that is an MVC Controller, digs up the methods. Methods decorated with the MvcMenuItemAttribute get plucked and added to the output list. Again, pretty simple. To make the structure hierarchical, a LINQ expression matches up all the items to their parent: public static void RegisterMenuItems(List<MvcMenuItemAttribute> items) { _MenuItems = items; _MenuItems.ForEach(i => i.ParentItem = items.FirstOrDefault(p => String.Equals(p.Link, i.ParentLink, StringComparison.InvariantCultureIgnoreCase))); } The _MenuItems is simply an internal list to keep things around for later rendering. Finally, to package the menu building for easy consumption: public static void RegisterMenuItems(Type mvcApplicationType) { RegisterMenuItems(ListMenuItems(Assembly.GetAssembly(mvcApplicationType))); } To bring this puppy home, a call in Global.asax.cs Application_Start() registers the menu. Notice the ugliness of reflection is tucked away from the innocent developer. All they have to do is call the RegisterMenuItems() and pass in the type of the application. When you use the new project template, global.asax declares a class public class MvcApplication : HttpApplication and that is why the Register call passes in that type. protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes); MvcMenu.RegisterMenuItems(typeof(MvcApplication)); } What else is left to do? Oh, right, render! public static void ShowMenu(this TextWriter output) { var writer = new HtmlTextWriter(output); renderHierarchy(writer, _MenuItems, null); } public static void ShowBreadCrumb(this TextWriter output, Uri currentUri) { var writer = new HtmlTextWriter(output); string currentLink = "/" + currentUri.GetComponents(UriComponents.Path, UriFormat.Unescaped); var menuItem = _MenuItems.FirstOrDefault(m => m.Link.Equals(currentLink, StringComparison.CurrentCultureIgnoreCase)); if (menuItem != null) { renderBreadCrumb(writer, _MenuItems, menuItem); } } private static void renderBreadCrumb(HtmlTextWriter writer, List<MvcMenuItemAttribute> menuItems, MvcMenuItemAttribute current) { if (current == null) { return; } var parent = current.ParentItem; renderBreadCrumb(writer, menuItems, parent); writer.Write(current.MenuText); writer.Write(" / "); } static void renderHierarchy(HtmlTextWriter writer, List<MvcMenuItemAttribute> hierarchy, MvcMenuItemAttribute root) { if (!hierarchy.Any(i => i.ParentItem == root)) return; writer.RenderBeginTag(HtmlTextWriterTag.Ul); foreach (var current in hierarchy.Where(element => element.ParentItem == root).OrderBy(i => i.Order)) { if (ItemFilter == null || ItemFilter(current)) { writer.RenderBeginTag(HtmlTextWriterTag.Li); writer.AddAttribute(HtmlTextWriterAttribute.Href, current.Link); writer.AddAttribute(HtmlTextWriterAttribute.Alt, current.MenuText); writer.RenderBeginTag(HtmlTextWriterTag.A); writer.WriteEncodedText(current.MenuText); writer.RenderEndTag(); // link renderHierarchy(writer, hierarchy, current); writer.RenderEndTag(); // li } } writer.RenderEndTag(); // ul } The ShowMenu method renders the menu out to the provided TextWriter. In previous posts I've discussed my partiality to using well debugged, time test HtmlTextWriter to render HTML rather than writing out angled brackets by hand. In addition, writing out using the actual writer on the actual stream rather than generating string and byte intermediaries (yes, StringBuilder being no exception) disturbs me. To carry out the rendering of an hierarchical menu, the recursive renderHierarchy() is used. You may notice that an ItemFilter is called before rendering each item. I figured that at some point one might want to exclude certain items from the menu based on security role or context or something. That delegate is the hook for such future feature. To carry out rendering of a breadcrumb recursion is used again, this time simply to unwind the parent hierarchy from the leaf node, then rendering on the return from the recursion rather than as we go along deeper. I guess I was stuck in LISP that day.. recursion is fun though. Now all that is left is some usage! Open your Site.Master or wherever you'd like to place a menu or breadcrumb, and plant one of these calls: <% MvcMenu.ShowBreadCrumb(this.Writer, Request.Url); %> to show a breadcrumb trail (notice lack of "=" after <% and the semicolon). <% MvcMenu.ShowMenu(Writer); %> to show the menu. As mentioned before, the HTML output is nested <UL> <LI> tags, which should make it easy to style using abundant CSS to produce anything from static horizontal or vertical to dynamic drop-downs. This has been quite a fun little implementation and I was pleased that the code size remained low. The main crux was figuring out how to pass parent information from the attribute to the hierarchy builder because attributes have restricted parameter types. Once I settled on that implementation, the rest falls into place quite easily.

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Performance Optimization – It Is Faster When You Can Measure It

- by Alois Kraus

Performance optimization in bigger systems is hard because the measured numbers can vary greatly depending on the measurement method of your choice. To measure execution timing of specific methods in your application you usually use Time Measurement Method Potential Pitfalls Stopwatch Most accurate method on recent processors. Internally it uses the RDTSC instruction. Since the counter is processor specific you can get greatly different values when your thread is scheduled to another core or the core goes into a power saving mode. But things do change luckily: Intel's Designer's vol3b, section 16.11.1 "16.11.1 Invariant TSC The time stamp counter in newer processors may support an enhancement, referred to as invariant TSC. Processor's support for invariant TSC is indicated by CPUID.80000007H:EDX[8]. The invariant TSC will run at a constant rate in all ACPI P-, C-. and T-states. This is the architectural behavior moving forward. On processors with invariant TSC support, the OS may use the TSC for wall clock timer services (instead of ACPI or HPET timers). TSC reads are much more efficient and do not incur the overhead associated with a ring transition or access to a platform resource." DateTime.Now Good but it has only a resolution of 16ms which can be not enough if you want more accuracy. Reporting Method Potential Pitfalls Console.WriteLine Ok if not called too often. Debug.Print Are you really measuring performance with Debug Builds? Shame on you. Trace.WriteLine Better but you need to plug in some good output listener like a trace file. But be aware that the first time you call this method it will read your app.config and deserialize your system.diagnostics section which does also take time. In general it is a good idea to use some tracing library which does measure the timing for you and you only need to decorate some methods with tracing so you can later verify if something has changed for the better or worse. In my previous article I did compare measuring performance with quantum mechanics. This analogy does work surprising well. When you measure a quantum system there is a lower limit how accurately you can measure something. The Heisenberg uncertainty relation does tell us that you cannot measure of a quantum system the impulse and location of a particle at the same time with infinite accuracy. For programmers the two variables are execution time and memory allocations. If you try to measure the timings of all methods in your application you will need to store them somewhere. The fastest storage space besides the CPU cache is the memory. But if your timing values do consume all available memory there is no memory left for the actual application to run. On the other hand if you try to record all memory allocations of your application you will also need to store the data somewhere. This will cost you memory and execution time. These constraints are always there and regardless how good the marketing of tool vendors for performance and memory profilers are: Any measurement will disturb the system in a non predictable way. Commercial tool vendors will tell you they do calculate this overhead and subtract it from the measured values to give you the most accurate values but in reality it is not entirely true. After falling into the trap to trust the profiler timings several times I have got into the habit to Measure with a profiler to get an idea where potential bottlenecks are. Measure again with tracing only the specific methods to check if this method is really worth optimizing. Optimize it Measure again. Be surprised that your optimization has made things worse. Think harder Implement something that really works. Measure again Finished! - Or look for the next bottleneck. Recently I have looked into issues with serialization performance. For serialization DataContractSerializer was used and I was not sure if XML is really the most optimal wire format. After looking around I have found protobuf-net which uses Googles Protocol Buffer format which is a compact binary serialization format. What is good for Google should be good for us. A small sample app to check out performance was a matter of minutes: using ProtoBuf; using System; using System.Diagnostics; using System.IO; using System.Reflection; using System.Runtime.Serialization; [DataContract, Serializable] class Data { [DataMember(Order=1)] public int IntValue { get; set; } [DataMember(Order = 2)] public string StringValue { get; set; } [DataMember(Order = 3)] public bool IsActivated { get; set; } [DataMember(Order = 4)] public BindingFlags Flags { get; set; } } class Program { static MemoryStream _Stream = new MemoryStream(); static MemoryStream Stream { get { _Stream.Position = 0; _Stream.SetLength(0); return _Stream; } } static void Main(string[] args) { DataContractSerializer ser = new DataContractSerializer(typeof(Data)); Data data = new Data { IntValue = 100, IsActivated = true, StringValue = "Hi this is a small string value to check if serialization does work as expected" }; var sw = Stopwatch.StartNew(); int Runs = 1000 * 1000; for (int i = 0; i < Runs; i++) { //ser.WriteObject(Stream, data); Serializer.Serialize<Data>(Stream, data); } sw.Stop(); Console.WriteLine("Did take {0:N0}ms for {1:N0} objects", sw.Elapsed.TotalMilliseconds, Runs); Console.ReadLine(); } } The results are indeed promising: Serializer Time in ms N objects protobuf-net 807 1000000 DataContract 4402 1000000 Nearly a factor 5 faster and a much more compact wire format. Lets use it! After switching over to protbuf-net the transfered wire data has dropped by a factor two (good) and the performance has worsened by nearly a factor two. How is that possible? We have measured it? Protobuf-net is much faster! As it turns out protobuf-net is faster but it has a cost: For the first time a type is de/serialized it does use some very smart code-gen which does not come for free. Lets try to measure this one by setting of our performance test app the Runs value not to one million but to 1. Serializer Time in ms N objects protobuf-net 85 1 DataContract 24 1 The code-gen overhead is significant and can take up to 200ms for more complex types. The break even point where the code-gen cost is amortized by its faster serialization performance is (assuming small objects) somewhere between 20.000-40.000 serialized objects. As it turned out my specific scenario involved about 100 types and 1000 serializations in total. That explains why the good old DataContractSerializer is not so easy to take out of business. The final approach I ended up was to reduce the number of types and to serialize primitive types via BinaryWriter directly which turned out to be a pretty good alternative. It sounded good until I measured again and found that my optimizations so far do not help much. After looking more deeper at the profiling data I did found that one of the 1000 calls did take 50% of the time. So how do I find out which call it was? Normal profilers do fail short at this discipline. A (totally undeserved) relatively unknown profiler is SpeedTrace which does unlike normal profilers create traces of your applications by instrumenting your IL code at runtime. This way you can look at the full call stack of the one slow serializer call to find out if this stack was something special. Unfortunately the call stack showed nothing special. But luckily I have my own tracing as well and I could see that the slow serializer call did happen during the serialization of a bool value. When you encounter after much analysis something unreasonable you cannot explain it then the chances are good that your thread was suspended by the garbage collector. If there is a problem with excessive GCs remains to be investigated but so far the serialization performance seems to be mostly ok. When you do profile a complex system with many interconnected processes you can never be sure that the timings you just did measure are accurate at all. Some process might be hitting the disc slowing things down for all other processes for some seconds as well. There is a big difference between warm and cold startup. If you restart all processes you can basically forget the first run because of the OS disc cache, JIT and GCs make the measured timings very flexible. When you are in need of a random number generator you should measure cold startup times of a sufficiently complex system. After the first run you can try again getting different and much lower numbers. Now try again at least two times to get some feeling how stable the numbers are. Oh and try to do the same thing the next day. It might be that the bottleneck you found yesterday is gone today. Thanks to GC and other random stuff it can become pretty hard to find stuff worth optimizing if no big bottlenecks except bloatloads of code are left anymore. When I have found a spot worth optimizing I do make the code changes and do measure again to check if something has changed. If it has got slower and I am certain that my change should have made it faster I can blame the GC again. The thing is that if you optimize stuff and you allocate less objects the GC times will shift to some other location. If you are unlucky it will make your faster working code slower because you see now GCs at times where none were before. This is where the stuff does get really tricky. A safe escape hatch is to create a repro of the slow code in an isolated application so you can change things fast in a reliable manner. Then the normal profilers do also start working again. As Vance Morrison does point out it is much more complex to profile a system against the wall clock compared to optimize for CPU time. The reason is that for wall clock time analysis you need to understand how your system does work and which threads (if you have not one but perhaps 20) are causing a visible delay to the end user and which threads can wait a long time without affecting the user experience at all. Next time: Commercial profiler shootout.

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Passing elapsed time to the update function from the game loop

- by Sri Harsha Chilakapati

I want to pass the time elapsed to the update() method as this would make easy to implement the animations and time related concepts. Here's my game-loop. public void gameLoop(){ boolean running = true; long gameTime = getCurrentTime(); long elapsedTime = 0; long lastUpdateTime = 0; int loops; while (running){ loops = 0; while(getCurrentTime()>gameTime && loops<Global.MAX_FRAMESKIP){ elapsedTime = getCurrentTime() - lastUpdateTime; lastUpdateTime = getCurrentTime(); update(elapsedTime); gameTime += SKIP_STEPS; loops++; } displayGame(); } } getCurrentTime() method public long getCurrentTime(){ return (System.nanoTime()/1000000); } update() method long time = 0; public void update(long elapsedTime){ time += elapsedTime; if (time>=1000){ System.out.println("A second elapsed"); time -= 1000; } } But this is printing the message for 3 seconds. Thanks.

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String.IsNullOrWhiteSpace

- by Scott Dorman

An empty string is different than an unassigned string variable (which is null), and is a string containing no characters between the quotes (""). The .NET Framework provides String.Empty to represent an empty string, and there is no practical difference between ("") and String.Empty. One of the most common string comparisons to perform is to determine if a string variable is equal to an empty string. The fastest and simplest way to determine if a string is empty is to test if the Length property is equal to 0. However, since strings are reference types it is possible for a string variable to be null, which would result in a runtime error when you tried to access the Length property. Since testing to determine if a string is empty is such a common occurrence, the .NET Framework provides the static method String.IsNullOrEmpty method: public static bool IsNullOrEmpty(string value) { if (value != null) { return (value.Length == 0); } return true; } It is also very common to determine if a string is empty and contains more than just whitespace characters. For example, String.IsNullOrEmpty(" ") would return false, since this string is actually made up of three whitespace characters. In some cases, this may be acceptable, but in many others it is not. TO help simplify testing this scenario, the .NET Framework 4 introduces the String.IsNullOrWhiteSpace method: public static bool IsNullOrWhiteSpace(string value) { if (value != null) { for (int i = 0; i < value.Length; i++) { if (!char.IsWhiteSpace(value[i])) { return false; } } } return true; } Using either String.IsNullOrEmpty or String.IsNullOrWhiteSpace helps ensure correctness, readability, and consistency, so they should be used in all situations where you need to determine if a string is null, empty, or contains only whitespace characters. Technorati Tags: .NET,C# 4

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Making a Case For The Command Line

- by Jesse Taber

Originally posted on: http://geekswithblogs.net/GruffCode/archive/2013/06/30/making-a-case-for-the-command-line.aspxI have had an idea percolating in the back of my mind for over a year now that I’ve just recently started to implement. This idea relates to building out “internal tools” to ease the maintenance and on-going support of a software system. The system that I currently work on is (mostly) web-based, so we traditionally we have built these internal tools in the form of pages within the app that are only accessible by our developers and support personnel. These pages allow us to perform tasks within the system that, for one reason or another, we don’t want to let our end users perform (e.g. mass create/update/delete operations on data, flipping switches that turn paid modules of the system on or off, etc). When we try to build new tools like this we often struggle with the level of effort required to build them. Effort Required Creating a whole new page in an existing web application can be a fairly large undertaking. You need to create the page and ensure it will have a layout that is consistent with the other pages in the app. You need to decide what types of input controls need to go onto the page. You need to ensure that everything uses the same style as the rest of the site. You need to figure out what the text on the page should say. Then, when you figure out that you forgot about an input that should really be present you might have to go back and re-work the entire thing. Oh, and in addition to all of that, you still have to, you know, write the code that actually performs the task. Everything other than the code that performs the task at hand is just overhead. We don’t need a fancy date picker control in a nicely styled page for the vast majority of our internal tools. We don’t even really need a page, for that matter. We just need a way to issue a command to the application and have it, in turn, execute the code that we’ve written to accomplish a given task. All we really need is a simple console application! Plumbing Problems A former co-worker of mine, John Sonmez, always advocated the Unix philosophy for building internal tools: start with something that runs at the command line, and then build a UI on top of that if you need to. John’s idea has a lot of merit, and we tried building out some internal tools as simple Console applications. Unfortunately, this was often easier said that done. Doing a “File –> New Project” to build out a tool for a mature system can be pretty daunting because that new project is totally empty. In our case, the web application code had a lot of of “plumbing” built in: it managed authentication and authorization, it handled database connection management for our multi-tenanted architecture, it managed all of the context that needs to follow a user around the application such as their timezone and regional/language settings. In addition, the configuration file for the web application (a web.config in our case because this is an ASP .NET application) is large and would need to be reproduced into a similar configuration file for a Console application. While most of these problems are could be solved pretty easily with some refactoring of the codebase, building Console applications for internal tools still potentially suffers from one pretty big drawback: you’d have to execute them on a machine with network access to all of the needed resources. Obviously, our web servers can easily communicate the the database servers and can publish messages to our service bus, but the same is not true for all of our developer and support personnel workstations. We could have everyone run these tools remotely via RDP or SSH, but that’s a bit cumbersome and certainly a lot less convenient than having the tools built into the web application that is so easily accessible. Mix and Match So we need a way to build tools that are easily accessible via the web application but also don’t require the overhead of creating a user interface. This is where my idea comes into play: why not just build a command line interface into the web application? If it’s part of the web application we get all of the plumbing that comes along with that code, and we’re executing everything on the web servers which means we’ll have access to any external resources that we might need. Rather than having to incur the overhead of creating a brand new page for each tool that we want to build, we can create one new page that simply accepts a command in text form and executes it as a request on the web server. In this way, we can focus on writing the code to accomplish the task. If the tool ends up being heavily used, then (and only then) should we consider spending the time to build a better user experience around it. To be clear, I’m not trying to downplay the importance of building great user experiences into your system; we should all strive to provide the best UX possible to our end users. I’m only advocating this sort of bare-bones interface for internal consumption by the technical staff that builds and supports the software. This command line interface should be the “back end” to a highly polished and eye-pleasing public face. Implementation As I mentioned at the beginning of this post, this is an idea that I’ve had for awhile but have only recently started building out. I’ve outlined some general guidelines and design goals for this effort as follows: Text in, text out: In the interest of keeping things as simple as possible, I want this interface to be purely text-based. Users will submit commands as plain text, and the application will provide responses in plain text. Obviously this text will be “wrapped” within the context of HTTP requests and responses, but I don’t want to have to think about HTML or CSS when taking input from the user or displaying responses back to the user. Task-oriented code only: After building the initial “harness” for this interface, the only code that should need to be written to create a new internal tool should be code that is expressly needed to accomplish the task that the tool is intended to support. If we want to encourage and enable ourselves to build good tooling, we need to lower the barriers to entry as much as possible. Built-in documentation: One of the great things about most command line utilities is the ‘help’ switch that provides usage guidelines and details about the arguments that the utility accepts. Our web-based command line utility should allow us to build the documentation for these tools directly into the code of the tools themselves. I finally started trying to implement this idea when I heard about a fantastic open-source library called CLAP (Command Line Auto Parser) that lets me meet the guidelines outlined above. CLAP lets you define classes with public methods that can be easily invoked from the command line. Here’s a quick example of the code that would be needed to create a new tool to do something within your system: 1: public class CustomerTools 2: { 3: [Verb] 4: public void UpdateName(int customerId, string firstName, string lastName) 5: { 6: //invoke internal services/domain objects/hwatever to perform update 7: } 8: } This is just a regular class with a single public method (though you could have as many methods as you want). The method is decorated with the ‘Verb’ attribute that tells the CLAP library that it is a method that can be invoked from the command line. Here is how you would invoke that code: Parser.Run(args, new CustomerTools()); Note that ‘args’ is just a string[] that would normally be passed passed in from the static Main method of a Console application. Also, CLAP allows you to pass in multiple classes that define [Verb] methods so you can opt to organize the code that CLAP will invoke in any way that you like. You can invoke this code from a command line application like this: SomeExe UpdateName -customerId:123 -firstName:Jesse -lastName:Taber ‘SomeExe’ in this example just represents the name of .exe that is would be created from our Console application. CLAP then interprets the arguments passed in order to find the method that should be invoked and automatically parses out the parameters that need to be passed in. After a quick spike, I’ve found that invoking the ‘Parser’ class can be done from within the context of a web application just as easily as it can from within the ‘Main’ method entry point of a Console application. There are, however, a few sticking points that I’m working around: Splitting arguments into the ‘args’ array like the command line: When you invoke a standard .NET console application you get the arguments that were passed in by the user split into a handy array (this is the ‘args’ parameter referenced above). Generally speaking they get split by whitespace, but it’s also clever enough to handle things like ignoring whitespace in a phrase that is surrounded by quotes. We’ll need to re-create this logic within our web application so that we can give the ‘args’ value to CLAP just like a console application would. Providing a response to the user: If you were writing a console application, you might just use Console.WriteLine to provide responses to the user as to the progress and eventual outcome of the command. We can’t use Console.WriteLine within a web application, so I’ll need to find another way to provide feedback to the user. Preferably this approach would allow me to use the same handler classes from both a Console application and a web application, so some kind of strategy pattern will likely emerge from this effort. Submitting files: Often an internal tool needs to support doing some kind of operation in bulk, and the easiest way to submit the data needed to support the bulk operation is in a file. Getting the file uploaded and available to the CLAP handler classes will take a little bit of effort. Mimicking the console experience: This isn’t really a requirement so much as a “nice to have”. To start out, the command-line interface in the web application will probably be a single ‘textarea’ control with a button to submit the contents to a handler that will pass it along to CLAP to be parsed and run. I think it would be interesting to use some javascript and CSS trickery to change that page into something with more of a “shell” interface look and feel. I’ll be blogging more about this effort in the future and will include some code snippets (or maybe even a full blown example app) as I progress. I also think that I’ll probably end up either submitting some pull requests to the CLAP project or possibly forking/wrapping it into a more web-friendly package and open sourcing that.

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Enum.HasFlag

- by Scott Dorman

An enumerated type, also called an enumeration (or just an enum for short), is simply a way to create a numeric type restricted to a predetermined set of valid values with meaningful names for those values. While most enumerations represent discrete values, or well-known combinations of those values, sometimes you want to combine values in an arbitrary fashion. These enumerations are known as flags enumerations because the values represent flags which can be set or unset. To combine multiple enumeration values, you use the logical OR operator. For example, consider the following: public enum FileAccess { None = 0, Read = 1, Write = 2, } class Program { static void Main(string[] args) { FileAccess access = FileAccess.Read | FileAccess.Write; Console.WriteLine(access); } } The output of this simple console application is: The value 3 is the numeric value associated with the combination of FileAccess.Read and FileAccess.Write. Clearly, this isn’t the best representation. What you really want is for the output to look like: To achieve this result, you simply add the Flags attribute to the enumeration. The Flags attribute changes how the string representation of the enumeration value is displayed when using the ToString() method. Although the .NET Framework does not require it, enumerations that will be used to represent flags should be decorated with the Flags attribute since it provides a clear indication of intent. One “problem” with Flags enumerations is determining when a particular flag is set. The code to do this isn’t particularly difficult, but unless you use it regularly it can be easy to forget. To test if the access variable has the FileAccess.Read flag set, you would use the following code: (access & FileAccess.Read) == FileAccess.Read Starting with .NET 4, a HasFlag static method has been added to the Enum class which allows you to easily perform these tests: access.HasFlag(FileAccess.Read) This method follows one of the “themes” for the .NET Framework 4, which is to simplify and reduce the amount of boilerplate code like this you must write. Technorati Tags: .NET,C# 4

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Game Components, Game Managers and Object Properties

- by George Duckett

I'm trying to get my head around component based entity design. My first step was to create various components that could be added to an object. For every component type i had a manager, which would call every component's update function, passing in things like keyboard state etc. as required. The next thing i did was remove the object, and just have each component with an Id. So an object is defined by components having the same Ids. Now, i'm thinking that i don't need a manager for all my components, for example i have a SizeComponent, which just has a Size property). As a result the SizeComponent doesn't have an update method, and the manager's update method does nothing. My first thought was to have an ObjectProperty class which components could query, instead of having them as properties of components. So an object would have a number of ObjectProperty and ObjectComponent. Components would have update logic that queries the object for properties. The manager would manage calling the component's update method. This seems like over-engineering to me, but i don't think i can get rid of the components, because i need a way for the managers to know what objects need what component logic to run (otherwise i'd just remove the component completely and push its update logic into the manager). Is this (having ObjectProperty, ObjectComponent and ComponentManager classes) over-engineering? What would be a good alternative?

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Stack Trace Logger [migrated]

- by Chris Okyen

I need to write a parent Java class that classes using recursion can extend. The parent class will be be able to realize whenever the call stack changes ( you enter a method, temporarily leave it to go to another method call, or you are are finsihed with the method ) and then print it out. I want it to print on the console, but clear the console as well every time so it shows the stack horizantaly so you can see the height of each stack to see what popped off and what popped on... Also print out if a baseline was reached for recursive functions. First. How can I using the StackTraceElements and Thread classes to detect automatically whenever the stack has popped or pushed an element on without calling it manually? Second, how would I do the clearing thing? For instance , if I had the code: public class recursion(int i) { private static void recursion(int i) { if( i < 10) System.out.println('A'); else { recursion(i / 10 ); System.out.println('B'); } } public static void main(String[] argv) { recursion(102); } } It would need to print out the stack when entering main(), when entering recursion(102) from main(), when it enters recursion(102 / 10), which is recursion(10), from recursion(102), when it enters recursion(10 / 10), which is recursion(1) from recursion(10). Print out a message out when it reaches the baseline recursion(1).. then print out the stacks of reversed revisitation of function recursion(10), recursion(102) and main(). finally print out we are exiting main().

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How to read Scala code with lots of implicits?

- by Petr Pudlák

Consider the following code fragment (adapted from http://stackoverflow.com/a/12265946/1333025): // Using scalaz 6 import scalaz._, Scalaz._ object Example extends App { case class Container(i: Int) def compute(s: String): State[Container, Int] = state { case Container(i) => (Container(i + 1), s.toInt + i) } val d = List("1", "2", "3") type ContainerState[X] = State[Container, X] println( d.traverse[ContainerState, Int](compute) ! Container(0) ) } I understand what it does on high level. But I wanted to trace what exactly happens during the call to d.traverse at the end. Clearly, List doesn't have traverse, so it must be implicitly converted to another type that does. Even though I spent a considerable amount of time trying to find out, I wasn't very successful. First I found that there is a method in scalaz.Traversable traverse[F[_], A, B] (f: (A) => F[B], t: T[A])(implicit arg0: Applicative[F]): F[T[B]] but clearly this is not it (although it's most likely that "my" traverse is implemented using this one). After a lot of searching, I grepped scalaz source codes and I found scalaz.MA's method traverse[F[_], B] (f: (A) => F[B])(implicit a: Applicative[F], t: Traverse[M]): F[M[B]] which seems to be very close. Still I'm missing to what List is converted in my example and if it uses MA.traverse or something else. The question is: What procedure should I follow to find out what exactly is called at d.traverse? Having even such a simple code that is so hard analyze seems to me like a big problem. Am I missing something very simple? How should I proceed when I want to understand such code that uses a lot of imported implicits? Is there some way to ask the compiler what implicits it used? Or is there something like Hoogle for Scala so that I can search for a method just by its name?

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Textures quality issues with Libgdx

- by user1876708

I have drawn several vector objets and characters ( in Adobe Illustrator ) for my game on Android. They are all scalable at any size without any quality losses ( of course it's vector ^^ ). I have tried to simulate my gameboard directly on Illustrator just before setting my assests on libdgx to implement them in my game. I set all the objects at the good size, so that they fit perfectly on my XHDPI device I am running my test on. As you can see it works great ( for me at least ^^ ), the PNG quality is good for me, as expected ! So I have edited all my PNG at this size, set my assets on libgdx and build my game apk. And here is a screenshot of my gameboard ( don't pay attention at the differences of placing and objects, but check at the objets presents on both screenshot ). As you can see, I have a loss of my PNG quality in the game. It can be seen clealry on the hedgehog PNG, but also ( but not as obvious ) on the mushroom ( check at the outline ) and the hole PNG. If you really pay attention, on every objects, you can see pixels that are not visible on my first screenshot. And I just can't figure out why this is happening Oo If you have any ideas, you are very welcome ! Thanks. PS : You can check more clearly the 2 gameboard on this two links ( look at them at 100%, display at high resolution ) : Good quality link, from Illustrator Poor quality link, from the game Second phase of tests : We display an object ( the hedgehog ) on our main menu screen to see how it looks like. The things is that it looks like he is suppose to, which means, high quality with no pixels. The hedgehog PNG is coming from an atlas : layer.addActor(hedgehog); No loss of quality with this method So we think the problem is comming from the method we are using to display it on our gameboard : blocks[9][3] = new Block(TextureUtils.hedgehog, new Vector2(9, 3)); the block is getting the size from the vector we are associating to it, but we have a loss of quality with this method.

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