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  • How can I bind a custom color to WPF toolkit ColorPicker? [on hold]

    - by tube-builder
    I need to bind the SelectedColor property of ColorPicker to a custom color which is not present in available colors. I created a simple test to show my problem. My xaml: <xctk:ColorPicker SelectedColor="{Binding Path=Test}"></xctk:ColorPicker> Code behind (CurrentStyle.PenColor returns an integer value which equals 13109765): public Color Test { get; set; } public MyClass() { DataContext = this; Test = Color.FromArgb((byte)((CurrentStyle.PenColor >> 24) & 0xFF), (byte)((CurrentStyle.PenColor >> 16) & 0xFF), (byte)((CurrentStyle.PenColor >> 8) & 0xFF), (byte)(CurrentStyle.PenColor & 0xFF)); InitializeComponent(); } And that's how my ColorPicker looks like when the window is loaded (I don't have enough rep to post images so it's just links): http://s22.postimg.org/frzh2fgy9/image.png Though, when I go to Advanced colors I can see that the color has been recognized and set correctly. Here is a pic: http://s13.postimg.org/gjv4cmy07/image.png Hope for your help. Thanks a lot! EDIT I implemented INotifyPropertyChanged, still to no avail. Here's the code: public Color Test { get { return test; } set { if (test != value) { test = value; OnPropertyChanged("Test"); } } } public event PropertyChangedEventHandler PropertyChanged; protected void OnPropertyChanged(string prop) { if (this.PropertyChanged != null) this.PropertyChanged(this, new PropertyChangedEventArgs(prop)); } Maybe I'm doing smth wrong here.

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  • An alternative to a video codec for storing motion changes [on hold]

    - by Andrew Simpson
    I have a 3 dimensional byte array. The 3-d array represents a jpeg image. Each channel/array represents part of the RGB spectrum. I am not interested in retaining black pixels. A black pixel is represented by this atypical arrangement: myarray[0,0,0] =0; myarray[0,0,1] =0; myarray[0,0,2] =0; So, I have flattened this 3d array out to a 1d array by doing this byte[] AFlatArray = new byte[width x height x 3] and then assigning values respective to the coordinate. But like I said I do not want black pixels. So this array has to only contain color pixels with the x,y coordinate. The result I want is to re-represent the image from the i dimension byte array that only contains non-black pixels. How do I do that? It looks like I have to store black pixels as well because of the xy coordinate system. I have tried writing to a binary file but the size of that file is greater than the jpeg file as the jpeg file is compressed. I am using c#.

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  • glTexImage2D not loading my data

    - by Clyde
    Can anyone suggest why this code doesn't work? When I draw using this texture all I get is black. If I use GLUtils.texImage2D() to load a png file, it works correctly. ByteBuffer bb = ByteBuffer.allocateDirect(128*128*4).order(ByteOrder.nativeOrder()); bb.position(0); for(int row = 0; row != 128; row++) { for(int i = 0 ; i != 128 ; i++) { bb.put((byte)0x80); bb.put((byte)0xFF); bb.put((byte)0xFF); bb.put((byte)i); } } int[] handle = new int[1]; GLES20.glEnable(GLES20.GL_TEXTURE_2D); GLES20.glGenTextures(1, handle, 0); DrawAdapter.checkGlError("Gen textures"); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, handle[0]); DrawAdapter.checkGlError("Bind textures"); bb.position(0); GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_RGBA, 128, 128, 0, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, bb); DrawAdapter.checkGlError("glTexImage2D"); return handle[0];

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  • How To Create a Customized Windows 7 Installation Disc With Integrated Updates

    - by Chris Hoffman
    Do you want to save time when installing Windows 7? You can create a customized installation disc and have it perform an installation without asking you questions, integrate updates and drivers, tweak Windows, and remove Windows components. We’ll be using RT Se7en Lite for this – if you’ve used nLite with Windows XP or vLite with Windows Vista in the past, it works similarly. RT Se7en Lite is a sort of vLite or nLite for Windows 7. Image Credit: bfishadow on Flickr How to Get Pro Features in Windows Home Versions with Third Party Tools HTG Explains: Is ReadyBoost Worth Using? HTG Explains: What The Windows Event Viewer Is and How You Can Use It

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  • UV Atlas Generation and Seam Removal

    - by P. Avery
    I'm generating light maps for scene mesh objects using DirectX's UV Atlas Tool( D3DXUVAtlasCreate() ). I've succeeded in generating an atlas, however, when I try to render the mesh object using the atlas the seams are visible on the mesh. Below are images of a lightmap generated for a cube. Here is the code I use to generate a uv atlas for a cube: struct sVertexPosNormTex { D3DXVECTOR3 vPos, vNorm; D3DXVECTOR2 vUV; sVertexPosNormTex(){} sVertexPosNormTex( D3DXVECTOR3 v, D3DXVECTOR3 n, D3DXVECTOR2 uv ) { vPos = v; vNorm = n; vUV = uv; } ~sVertexPosNormTex() { } }; // create a light map texture to fill programatically hr = D3DXCreateTexture( pd3dDevice, 128, 128, 1, 0, D3DFMT_A8R8G8B8, D3DPOOL_MANAGED, &pLightmap ); if( FAILED( hr ) ) { DebugStringDX( "Main", "Failed to D3DXCreateTexture( lightmap )", __LINE__, hr ); return hr; } // get the zero level surface from the texture IDirect3DSurface9 *pS = NULL; pLightmap->GetSurfaceLevel( 0, &pS ); // clear surface pd3dDevice->ColorFill( pS, NULL, D3DCOLOR_XRGB( 0, 0, 0 ) ); // load a sample mesh DWORD dwcMaterials = 0; LPD3DXBUFFER pMaterialBuffer = NULL; V_RETURN( D3DXLoadMeshFromX( L"cube3.x", D3DXMESH_MANAGED, pd3dDevice, &pAdjacency, &pMaterialBuffer, NULL, &dwcMaterials, &g_pMesh ) ); // generate adjacency DWORD *pdwAdjacency = new DWORD[ 3 * g_pMesh->GetNumFaces() ]; g_pMesh->GenerateAdjacency( 1e-6f, pdwAdjacency ); // create light map coordinates LPD3DXMESH pMesh = NULL; LPD3DXBUFFER pFacePartitioning = NULL, pVertexRemapArray = NULL; FLOAT resultStretch = 0; UINT numCharts = 0; hr = D3DXUVAtlasCreate( g_pMesh, 0, 0, 128, 128, 3.5f, 0, pdwAdjacency, NULL, NULL, NULL, NULL, NULL, 0, &pMesh, &pFacePartitioning, &pVertexRemapArray, &resultStretch, &numCharts ); if( SUCCEEDED( hr ) ) { // release and set mesh SAFE_RELEASE( g_pMesh ); g_pMesh = pMesh; // write mesh to file hr = D3DXSaveMeshToX( L"cube4.x", g_pMesh, 0, ( const D3DXMATERIAL* )pMaterialBuffer->GetBufferPointer(), NULL, dwcMaterials, D3DXF_FILEFORMAT_TEXT ); if( FAILED( hr ) ) { DebugStringDX( "Main", "Failed to D3DXSaveMeshToX() at OnD3D9CreateDevice()", __LINE__, hr ); } // fill the the light map hr = BuildLightmap( pS, g_pMesh ); if( FAILED( hr ) ) { DebugStringDX( "Main", "Failed to BuildLightmap()", __LINE__, hr ); } } else { DebugStringDX( "Main", "Failed to D3DXUVAtlasCreate() at OnD3D9CreateDevice()", __LINE__, hr ); } SAFE_RELEASE( pS ); SAFE_DELETE_ARRAY( pdwAdjacency ); SAFE_RELEASE( pFacePartitioning ); SAFE_RELEASE( pVertexRemapArray ); SAFE_RELEASE( pMaterialBuffer ); Here is code to fill lightmap texture: HRESULT BuildLightmap( IDirect3DSurface9 *pS, LPD3DXMESH pMesh ) { HRESULT hr = S_OK; // validate lightmap texture surface and mesh if( !pS || !pMesh ) return E_POINTER; // lock the mesh vertex buffer sVertexPosNormTex *pV = NULL; pMesh->LockVertexBuffer( D3DLOCK_READONLY, ( void** )&pV ); // lock the mesh index buffer WORD *pI = NULL; pMesh->LockIndexBuffer( D3DLOCK_READONLY, ( void** )&pI ); // get the lightmap texture surface description D3DSURFACE_DESC desc; pS->GetDesc( &desc ); // lock the surface rect to fill with color data D3DLOCKED_RECT rct; hr = pS->LockRect( &rct, NULL, 0 ); if( FAILED( hr ) ) { DebugStringDX( "main.cpp:", "Failed to IDirect3DTexture9::LockRect()", __LINE__, hr ); return hr; } // iterate the pixels of the lightmap texture // check each pixel to see if it lies between the uv coordinates of a cube face BYTE *pBuffer = ( BYTE* )rct.pBits; for( UINT y = 0; y < desc.Height; ++y ) { BYTE* pBufferRow = ( BYTE* )pBuffer; for( UINT x = 0; x < desc.Width * 4; x+=4 ) { // determine the pixel's uv coordinate D3DXVECTOR2 p( ( ( float )x / 4.0f ) / ( float )desc.Width + 0.5f / 128.0f, y / ( float )desc.Height + 0.5f / 128.0f ); // for each face of the mesh // check to see if the pixel lies within the face's uv coordinates for( UINT i = 0; i < 3 * pMesh->GetNumFaces(); i +=3 ) { sVertexPosNormTex v[ 3 ]; v[ 0 ] = pV[ pI[ i + 0 ] ]; v[ 1 ] = pV[ pI[ i + 1 ] ]; v[ 2 ] = pV[ pI[ i + 2 ] ]; if( TexcoordIsWithinBounds( v[ 0 ].vUV, v[ 1 ].vUV, v[ 2 ].vUV, p ) ) { // the pixel lies b/t the uv coordinates of a cube face // light contribution functions aren't needed yet //D3DXVECTOR3 vPos = TexcoordToPos( v[ 0 ].vPos, v[ 1 ].vPos, v[ 2 ].vPos, v[ 0 ].vUV, v[ 1 ].vUV, v[ 2 ].vUV, p ); //D3DXVECTOR3 vNormal = v[ 0 ].vNorm; // set the color of this pixel red( for demo ) BYTE ba[] = { 0, 0, 255, 255, }; //ComputeContribution( vPos, vNormal, g_sLight, ba ); // copy the byte array into the light map texture memcpy( ( void* )&pBufferRow[ x ], ( void* )ba, 4 * sizeof( BYTE ) ); } } } // go to next line of the texture pBuffer += rct.Pitch; } // unlock the surface rect pS->UnlockRect(); // unlock mesh vertex and index buffers pMesh->UnlockIndexBuffer(); pMesh->UnlockVertexBuffer(); // write the surface to file hr = D3DXSaveSurfaceToFile( L"LightMap.jpg", D3DXIFF_JPG, pS, NULL, NULL ); if( FAILED( hr ) ) DebugStringDX( "Main.cpp", "Failed to D3DXSaveSurfaceToFile()", __LINE__, hr ); return hr; } bool TexcoordIsWithinBounds( const D3DXVECTOR2 &t0, const D3DXVECTOR2 &t1, const D3DXVECTOR2 &t2, const D3DXVECTOR2 &p ) { // compute vectors D3DXVECTOR2 v0 = t1 - t0, v1 = t2 - t0, v2 = p - t0; float f00 = D3DXVec2Dot( &v0, &v0 ); float f01 = D3DXVec2Dot( &v0, &v1 ); float f02 = D3DXVec2Dot( &v0, &v2 ); float f11 = D3DXVec2Dot( &v1, &v1 ); float f12 = D3DXVec2Dot( &v1, &v2 ); // Compute barycentric coordinates float invDenom = 1 / ( f00 * f11 - f01 * f01 ); float fU = ( f11 * f02 - f01 * f12 ) * invDenom; float fV = ( f00 * f12 - f01 * f02 ) * invDenom; // Check if point is in triangle if( ( fU >= 0 ) && ( fV >= 0 ) && ( fU + fV < 1 ) ) return true; return false; } Screenshot Lightmap I believe the problem comes from the difference between the lightmap uv coordinates and the pixel center coordinates...for example, here are the lightmap uv coordinates( generated by D3DXUVAtlasCreate() ) for a specific face( tri ) within the mesh, keep in mind that I'm using the mesh uv coordinates to write the pixels for the texture: v[ 0 ].uv = D3DXVECTOR2( 0.003581, 0.295631 ); v[ 1 ].uv = D3DXVECTOR2( 0.003581, 0.003581 ); v[ 2 ].uv = D3DXVECTOR2( 0.295631, 0.003581 ); the lightmap texture size is 128 x 128 pixels. The upper-left pixel center coordinates are: float halfPixel = 0.5 / 128 = 0.00390625; D3DXVECTOR2 pixelCenter = D3DXVECTOR2( halfPixel, halfPixel ); will the mapping and sampling of the lightmap texture will require that an offset be taken into account or that the uv coordinates are snapped to the pixel centers..? ...Any ideas on the best way to approach this situation would be appreciated...What are the common practices?

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  • Capturing and Transforming ASP.NET Output with Response.Filter

    - by Rick Strahl
    During one of my Handlers and Modules session at DevConnections this week one of the attendees asked a question that I didn’t have an immediate answer for. Basically he wanted to capture response output completely and then apply some filtering to the output – effectively injecting some additional content into the page AFTER the page had completely rendered. Specifically the output should be captured from anywhere – not just a page and have this code injected into the page. Some time ago I posted some code that allows you to capture ASP.NET Page output by overriding the Render() method, capturing the HtmlTextWriter() and reading its content, modifying the rendered data as text then writing it back out. I’ve actually used this approach on a few occasions and it works fine for ASP.NET pages. But this obviously won’t work outside of the Page class environment and it’s not really generic – you have to create a custom page class in order to handle the output capture. [updated 11/16/2009 – updated ResponseFilterStream implementation and a few additional notes based on comments] Enter Response.Filter However, ASP.NET includes a Response.Filter which can be used – well to filter output. Basically Response.Filter is a stream through which the OutputStream is piped back to the Web Server (indirectly). As content is written into the Response object, the filter stream receives the appropriate Stream commands like Write, Flush and Close as well as read operations although for a Response.Filter that’s uncommon to be hit. The Response.Filter can be programmatically replaced at runtime which allows you to effectively intercept all output generation that runs through ASP.NET. A common Example: Dynamic GZip Encoding A rather common use of Response.Filter hooking up code based, dynamic  GZip compression for requests which is dead simple by applying a GZipStream (or DeflateStream) to Response.Filter. The following generic routines can be used very easily to detect GZip capability of the client and compress response output with a single line of code and a couple of library helper routines: WebUtils.GZipEncodePage(); which is handled with a few lines of reusable code and a couple of static helper methods: /// <summary> ///Sets up the current page or handler to use GZip through a Response.Filter ///IMPORTANT:  ///You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() {     HttpResponse Response = HttpContext.Current.Response;     if(IsGZipSupported())     {         stringAcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"];         if(AcceptEncoding.Contains("deflate"))         {             Response.Filter = newSystem.IO.Compression.DeflateStream(Response.Filter,                                        System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "deflate");         }         else        {             Response.Filter = newSystem.IO.Compression.GZipStream(Response.Filter,                                       System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "gzip");                            }     }     // Allow proxy servers to cache encoded and unencoded versions separately    Response.AppendHeader("Vary", "Content-Encoding"); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } GZipStream and DeflateStream are streams that are assigned to Response.Filter and by doing so apply the appropriate compression on the active Response. Response.Filter content is chunked So to implement a Response.Filter effectively requires only that you implement a custom stream and handle the Write() method to capture Response output as it’s written. At first blush this seems very simple – you capture the output in Write, transform it and write out the transformed content in one pass. And that indeed works for small amounts of content. But you see, the problem is that output is written in small buffer chunks (a little less than 16k it appears) rather than just a single Write() statement into the stream, which makes perfect sense for ASP.NET to stream data back to IIS in smaller chunks to minimize memory usage en route. Unfortunately this also makes it a more difficult to implement any filtering routines since you don’t directly get access to all of the response content which is problematic especially if those filtering routines require you to look at the ENTIRE response in order to transform or capture the output as is needed for the solution the gentleman in my session asked for. So in order to address this a slightly different approach is required that basically captures all the Write() buffers passed into a cached stream and then making the stream available only when it’s complete and ready to be flushed. As I was thinking about the implementation I also started thinking about the few instances when I’ve used Response.Filter implementations. Each time I had to create a new Stream subclass and create my custom functionality but in the end each implementation did the same thing – capturing output and transforming it. I thought there should be an easier way to do this by creating a re-usable Stream class that can handle stream transformations that are common to Response.Filter implementations. Creating a semi-generic Response Filter Stream Class What I ended up with is a ResponseFilterStream class that provides a handful of Events that allow you to capture and/or transform Response content. The class implements a subclass of Stream and then overrides Write() and Flush() to handle capturing and transformation operations. By exposing events it’s easy to hook up capture or transformation operations via single focused methods. ResponseFilterStream exposes the following events: CaptureStream, CaptureString Captures the output only and provides either a MemoryStream or String with the final page output. Capture is hooked to the Flush() operation of the stream. TransformStream, TransformString Allows you to transform the complete response output with events that receive a MemoryStream or String respectively and can you modify the output then return it back as a return value. The transformed output is then written back out in a single chunk to the response output stream. These events capture all output internally first then write the entire buffer into the response. TransformWrite, TransformWriteString Allows you to transform the Response data as it is written in its original chunk size in the Stream’s Write() method. Unlike TransformStream/TransformString which operate on the complete output, these events only see the current chunk of data written. This is more efficient as there’s no caching involved, but can cause problems due to searched content splitting over multiple chunks. Using this implementation, creating a custom Response.Filter transformation becomes as simple as the following code. To hook up the Response.Filter using the MemoryStream version event: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformStream += filter_TransformStream; Response.Filter = filter; and the event handler to do the transformation: MemoryStream filter_TransformStream(MemoryStream ms) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = encoding.GetString(ms.ToArray()); output = FixPaths(output); ms = new MemoryStream(output.Length); byte[] buffer = encoding.GetBytes(output); ms.Write(buffer,0,buffer.Length); return ms; } private string FixPaths(string output) { string path = HttpContext.Current.Request.ApplicationPath; // override root path wonkiness if (path == "/") path = ""; output = output.Replace("\"~/", "\"" + path + "/").Replace("'~/", "'" + path + "/"); return output; } The idea of the event handler is that you can do whatever you want to the stream and return back a stream – either the same one that’s been modified or a brand new one – which is then sent back to as the final response. The above code can be simplified even more by using the string version events which handle the stream to string conversions for you: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; and the event handler to do the transformation calling the same FixPaths method shown above: string filter_TransformString(string output) { return FixPaths(output); } The events for capturing output and capturing and transforming chunks work in a very similar way. By using events to handle the transformations ResponseFilterStream becomes a reusable component and we don’t have to create a new stream class or subclass an existing Stream based classed. By the way, the example used here is kind of a cool trick which transforms “~/” expressions inside of the final generated HTML output – even in plain HTML controls not HTML controls – and transforms them into the appropriate application relative path in the same way that ResolveUrl would do. So you can write plain old HTML like this: <a href=”~/default.aspx”>Home</a>  and have it turned into: <a href=”/myVirtual/default.aspx”>Home</a>  without having to use an ASP.NET control like Hyperlink or Image or having to constantly use: <img src=”<%= ResolveUrl(“~/images/home.gif”) %>” /> in MVC applications (which frankly is one of the most annoying things about MVC especially given the path hell that extension-less and endpoint-less URLs impose). I can’t take credit for this idea. While discussing the Response.Filter issues on Twitter a hint from Dylan Beattie who pointed me at one of his examples which does something similar. I thought the idea was cool enough to use an example for future demos of Response.Filter functionality in ASP.NET next I time I do the Modules and Handlers talk (which was great fun BTW). How practical this is is debatable however since there’s definitely some overhead to using a Response.Filter in general and especially on one that caches the output and the re-writes it later. Make sure to test for performance anytime you use Response.Filter hookup and make sure it' doesn’t end up killing perf on you. You’ve been warned :-}. How does ResponseFilterStream work? The big win of this implementation IMHO is that it’s a reusable  component – so for implementation there’s no new class, no subclassing – you simply attach to an event to implement an event handler method with a straight forward signature to retrieve the stream or string you’re interested in. The implementation is based on a subclass of Stream as is required in order to handle the Response.Filter requirements. What’s different than other implementations I’ve seen in various places is that it supports capturing output as a whole to allow retrieving the full response output for capture or modification. The exception are the TransformWrite and TransformWrite events which operate only active chunk of data written by the Response. For captured output, the Write() method captures output into an internal MemoryStream that is cached until writing is complete. So Write() is called when ASP.NET writes to the Response stream, but the filter doesn’t pass on the Write immediately to the filter’s internal stream. The data is cached and only when the Flush() method is called to finalize the Stream’s output do we actually send the cached stream off for transformation (if the events are hooked up) and THEN finally write out the returned content in one big chunk. Here’s the implementation of ResponseFilterStream: /// <summary> /// A semi-generic Stream implementation for Response.Filter with /// an event interface for handling Content transformations via /// Stream or String. /// <remarks> /// Use with care for large output as this implementation copies /// the output into a memory stream and so increases memory usage. /// </remarks> /// </summary> public class ResponseFilterStream : Stream { /// <summary> /// The original stream /// </summary> Stream _stream; /// <summary> /// Current position in the original stream /// </summary> long _position; /// <summary> /// Stream that original content is read into /// and then passed to TransformStream function /// </summary> MemoryStream _cacheStream = new MemoryStream(5000); /// <summary> /// Internal pointer that that keeps track of the size /// of the cacheStream /// </summary> int _cachePointer = 0; /// <summary> /// /// </summary> /// <param name="responseStream"></param> public ResponseFilterStream(Stream responseStream) { _stream = responseStream; } /// <summary> /// Determines whether the stream is captured /// </summary> private bool IsCaptured { get { if (CaptureStream != null || CaptureString != null || TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Determines whether the Write method is outputting data immediately /// or delaying output until Flush() is fired. /// </summary> private bool IsOutputDelayed { get { if (TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Event that captures Response output and makes it available /// as a MemoryStream instance. Output is captured but won't /// affect Response output. /// </summary> public event Action<MemoryStream> CaptureStream; /// <summary> /// Event that captures Response output and makes it available /// as a string. Output is captured but won't affect Response output. /// </summary> public event Action<string> CaptureString; /// <summary> /// Event that allows you transform the stream as each chunk of /// the output is written in the Write() operation of the stream. /// This means that that it's possible/likely that the input /// buffer will not contain the full response output but only /// one of potentially many chunks. /// /// This event is called as part of the filter stream's Write() /// operation. /// </summary> public event Func<byte[], byte[]> TransformWrite; /// <summary> /// Event that allows you to transform the response stream as /// each chunk of bytep[] output is written during the stream's write /// operation. This means it's possibly/likely that the string /// passed to the handler only contains a portion of the full /// output. Typical buffer chunks are around 16k a piece. /// /// This event is called as part of the stream's Write operation. /// </summary> public event Func<string, string> TransformWriteString; /// <summary> /// This event allows capturing and transformation of the entire /// output stream by caching all write operations and delaying final /// response output until Flush() is called on the stream. /// </summary> public event Func<MemoryStream, MemoryStream> TransformStream; /// <summary> /// Event that can be hooked up to handle Response.Filter /// Transformation. Passed a string that you can modify and /// return back as a return value. The modified content /// will become the final output. /// </summary> public event Func<string, string> TransformString; protected virtual void OnCaptureStream(MemoryStream ms) { if (CaptureStream != null) CaptureStream(ms); } private void OnCaptureStringInternal(MemoryStream ms) { if (CaptureString != null) { string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); OnCaptureString(content); } } protected virtual void OnCaptureString(string output) { if (CaptureString != null) CaptureString(output); } protected virtual byte[] OnTransformWrite(byte[] buffer) { if (TransformWrite != null) return TransformWrite(buffer); return buffer; } private byte[] OnTransformWriteStringInternal(byte[] buffer) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = OnTransformWriteString(encoding.GetString(buffer)); return encoding.GetBytes(output); } private string OnTransformWriteString(string value) { if (TransformWriteString != null) return TransformWriteString(value); return value; } protected virtual MemoryStream OnTransformCompleteStream(MemoryStream ms) { if (TransformStream != null) return TransformStream(ms); return ms; } /// <summary> /// Allows transforming of strings /// /// Note this handler is internal and not meant to be overridden /// as the TransformString Event has to be hooked up in order /// for this handler to even fire to avoid the overhead of string /// conversion on every pass through. /// </summary> /// <param name="responseText"></param> /// <returns></returns> private string OnTransformCompleteString(string responseText) { if (TransformString != null) TransformString(responseText); return responseText; } /// <summary> /// Wrapper method form OnTransformString that handles /// stream to string and vice versa conversions /// </summary> /// <param name="ms"></param> /// <returns></returns> internal MemoryStream OnTransformCompleteStringInternal(MemoryStream ms) { if (TransformString == null) return ms; //string content = ms.GetAsString(); string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); content = TransformString(content); byte[] buffer = HttpContext.Current.Response.ContentEncoding.GetBytes(content); ms = new MemoryStream(); ms.Write(buffer, 0, buffer.Length); //ms.WriteString(content); return ms; } /// <summary> /// /// </summary> public override bool CanRead { get { return true; } } public override bool CanSeek { get { return true; } } /// <summary> /// /// </summary> public override bool CanWrite { get { return true; } } /// <summary> /// /// </summary> public override long Length { get { return 0; } } /// <summary> /// /// </summary> public override long Position { get { return _position; } set { _position = value; } } /// <summary> /// /// </summary> /// <param name="offset"></param> /// <param name="direction"></param> /// <returns></returns> public override long Seek(long offset, System.IO.SeekOrigin direction) { return _stream.Seek(offset, direction); } /// <summary> /// /// </summary> /// <param name="length"></param> public override void SetLength(long length) { _stream.SetLength(length); } /// <summary> /// /// </summary> public override void Close() { _stream.Close(); } /// <summary> /// Override flush by writing out the cached stream data /// </summary> public override void Flush() { if (IsCaptured && _cacheStream.Length > 0) { // Check for transform implementations _cacheStream = OnTransformCompleteStream(_cacheStream); _cacheStream = OnTransformCompleteStringInternal(_cacheStream); OnCaptureStream(_cacheStream); OnCaptureStringInternal(_cacheStream); // write the stream back out if output was delayed if (IsOutputDelayed) _stream.Write(_cacheStream.ToArray(), 0, (int)_cacheStream.Length); // Clear the cache once we've written it out _cacheStream.SetLength(0); } // default flush behavior _stream.Flush(); } /// <summary> /// /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> /// <returns></returns> public override int Read(byte[] buffer, int offset, int count) { return _stream.Read(buffer, offset, count); } /// <summary> /// Overriden to capture output written by ASP.NET and captured /// into a cached stream that is written out later when Flush() /// is called. /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> public override void Write(byte[] buffer, int offset, int count) { if ( IsCaptured ) { // copy to holding buffer only - we'll write out later _cacheStream.Write(buffer, 0, count); _cachePointer += count; } // just transform this buffer if (TransformWrite != null) buffer = OnTransformWrite(buffer); if (TransformWriteString != null) buffer = OnTransformWriteStringInternal(buffer); if (!IsOutputDelayed) _stream.Write(buffer, offset, buffer.Length); } } The key features are the events and corresponding OnXXX methods that handle the event hookups, and the Write() and Flush() methods of the stream implementation. All the rest of the members tend to be plain jane passthrough stream implementation code without much consequence. I do love the way Action<t> and Func<T> make it so easy to create the event signatures for the various events – sweet. A few Things to consider Performance Response.Filter is not great for performance in general as it adds another layer of indirection to the ASP.NET output pipeline, and this implementation in particular adds a memory hit as it basically duplicates the response output into the cached memory stream which is necessary since you may have to look at the entire response. If you have large pages in particular this can cause potentially serious memory pressure in your server application. So be careful of wholesale adoption of this (or other) Response.Filters. Make sure to do some performance testing to ensure it’s not killing your app’s performance. Response.Filter works everywhere A few questions came up in comments and discussion as to capturing ALL output hitting the site and – yes you can definitely do that by assigning a Response.Filter inside of a module. If you do this however you’ll want to be very careful and decide which content you actually want to capture especially in IIS 7 which passes ALL content – including static images/CSS etc. through the ASP.NET pipeline. So it is important to filter only on what you’re looking for – like the page extension or maybe more effectively the Response.ContentType. Response.Filter Chaining Originally I thought that filter chaining doesn’t work at all due to a bug in the stream implementation code. But it’s quite possible to assign multiple filters to the Response.Filter property. So the following actually works to both compress the output and apply the transformed content: WebUtils.GZipEncodePage(); ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; However the following does not work resulting in invalid content encoding errors: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; WebUtils.GZipEncodePage(); In other words multiple Response filters can work together but it depends entirely on the implementation whether they can be chained or in which order they can be chained. In this case running the GZip/Deflate stream filters apparently relies on the original content length of the output and chokes when the content is modified. But if attaching the compression first it works fine as unintuitive as that may seem. Resources Download example code Capture Output from ASP.NET Pages © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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  • JPA - insert and retrieve clob and blob types

    - by pachunoori.vinay.kumar(at)oracle.com
    This article describes about the JPA feature for handling clob and blob data types.You will learn the following in this article. @Lob annotation Client code to insert and retrieve the clob/blob types End to End ADFaces application to retrieve the image from database table and display it in web page. Use Case Description Persisting and reading the image from database using JPA clob/blob type. @Lob annotation By default, TopLink JPA assumes that all persistent data can be represented as typical database data types. Use the @Lob annotation with a basic mapping to specify that a persistent property or field should be persisted as a large object to a database-supported large object type. A Lob may be either a binary or character type. TopLink JPA infers the Lob type from the type of the persistent field or property. For string and character-based types, the default is Clob. In all other cases, the default is Blob. Example Below code shows how to use this annotation to specify that persistent field picture should be persisted as a Blob. public class Person implements Serializable {    @Id    @Column(nullable = false, length = 20)    private String name;    @Column(nullable = false)    @Lob    private byte[] picture;    @Column(nullable = false, length = 20) } Client code to insert and retrieve the clob/blob types Reading a image file and inserting to Database table Below client code will read the image from a file and persist to Person table in database.                       Person p=new Person();                      p.setName("Tom");                      p.setSex("male");                      p.setPicture(writtingImage("Image location"));// - c:\images\test.jpg                       sessionEJB.persistPerson(p); //Retrieving the image from Database table and writing to a file                       List<Person> plist=sessionEJB.getPersonFindAll();//                      Person person=(Person)plist.get(0);//get a person object                      retrieveImage(person.getPicture());   //get picture retrieved from Table //Private method to create byte[] from image file  private static byte[] writtingImage(String fileLocation) {      System.out.println("file lication is"+fileLocation);     IOManager manager=new IOManager();        try {           return manager.getBytesFromFile(fileLocation);                    } catch (IOException e) {        }        return null;    } //Private method to read byte[] from database and write to a image file    private static void retrieveImage(byte[] b) {    IOManager manager=new IOManager();        try {            manager.putBytesInFile("c:\\webtest.jpg",b);        } catch (IOException e) {        }    } End to End ADFaces application to retrieve the image from database table and display it in web page. Please find the application in this link. Following are the j2ee components used in the sample application. ADFFaces(jspx page) HttpServlet Class - Will make a call to EJB and retrieve the person object from person table.Read the byte[] and write to response using Outputstream. SessionEJBBean - This is a session facade to make a local call to JPA entities JPA Entity(Person.java) - Person java class with setter and getter method annotated with @Lob representing the clob/blob types for picture field.

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  • Best way to handle Integer overflow in C#?

    - by byte
    Handling integer overflow is a common task, but what's the best way to handle it in C#? Is there some syntactic sugar to make it simpler than with other languages? Or is this really the best way? int x = foo(); int test = x * common; if(test / common != x) Console.WriteLine("oh noes!"); else Console.WriteLine("safe!");

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  • Adding ComboBoxItem to a combobox inside a user control (XAML/WPF)

    - by byte
    I am currently learning to create custom controls in WPF. I successfully created a simple custom control using a Label and a Text Box. I was able to allow setting the Label text by DependencyProperty. Now I am creating a user control that has a ComboBox. I need to allow adding items to this ComboBox from outside the control. To achieve this, I tried exposing a DependencyProperty of type ItemsCollection and it will allows access to the ComboBox's Items property (the DP in my control sample is named 'CbItems'). But I get errors because Items property of Combobox is ReadOnly. Control XAML <UserControl x:Class="MyWpfApp.Controls.MyControl" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Height="Auto" Width="Auto"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition /> <ColumnDefinition /> </Grid.ColumnDefinitions> <Label Grid.Column="0" Content="{Binding FieldLabel}"></Label> <ComboBox Name="cmb" Grid.Column="1" Width="150"></ComboBox> </Grid> </UserControl> MainWindow XAML <Window x:Class="MyWpfApp.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:ctl="clr-namespace:MyWpfApp.Controls" Title="Window1" Height="300" Width="300"> <Grid> <ctl:MyControl> <ctl:MyControl.CbItems> <ComboBoxItem>Hello</ComboBoxItem> <ComboBoxItem>World</ComboBoxItem> <ComboBoxItem>Hi</ComboBoxItem> </ctl:LobCombox.CbItems> </ctl:LobCombox> </Grid> </Window> I would like to know what the correct way is to achieve this functionality. I believe the answer to this might also help with other controls like GridView etc Many Thanks

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  • Most efficient sorting of calculation on DataTable column calculation

    - by byte
    Lets say you have a DataTable that has columns of "id", "cost", "qty": DataTable dt = new DataTable(); dt.Columns.Add("id", typeof(int)); dt.Columns.Add("cost", typeof(double)); dt.Columns.Add("qty", typeof(int)); And it's keyed on "id": dt.PrimaryKey = new DataColumn[1] { dt.Columns["id"] }; Now what we are interested in is the cost per quantity. So, in other words if you had a row of: id | cost | qty ---------------- 42 | 10.00 | 2 The cost per quantity is 5.00. My question then is, given the preceeding table, assume it's constructed with many thousands of rows, and you're interested in the top 3 cost per quantity rows. The information needed is the id, cost per quantity. You cannot use LINQ. In SQL it would be trivial; how BEST (most efficiently) would you accomplish it in C# without LINQ?

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  • Threads are facing deadlock in socket program [migrated]

    - by ankur.trapasiya
    I am developing one program in which a user can download a number of files. Now first I am sending the list of files to the user. So from the list user selects one file at a time and provides path where to store that file. In turn it also gives the server the path of file where does it exist. I am following this approach because I want to give stream like experience without file size limitation. Here is my code.. 1) This is server which gets started each time I start my application public class FileServer extends Thread { private ServerSocket socket = null; public FileServer() { try { socket = new ServerSocket(Utils.tcp_port); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } @Override public void run() { try { System.out.println("request received"); new FileThread(socket.accept()).start(); } catch (IOException ex) { ex.printStackTrace(); } } } 2) This thread runs for each client separately and sends the requested file to the user 8kb data at a time. public class FileThread extends Thread { private Socket socket; private String filePath; public String getFilePath() { return filePath; } public void setFilePath(String filePath) { this.filePath = filePath; } public FileThread(Socket socket) { this.socket = socket; System.out.println("server thread" + this.socket.isConnected()); //this.filePath = filePath; } @Override public void run() { // TODO Auto-generated method stub try { ObjectInputStream ois=new ObjectInputStream(socket.getInputStream()); try { //************NOTE filePath=(String) ois.readObject(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } File f = new File(this.filePath); byte[] buf = new byte[8192]; InputStream is = new FileInputStream(f); BufferedInputStream bis = new BufferedInputStream(is); ObjectOutputStream oos = new ObjectOutputStream( socket.getOutputStream()); int c = 0; while ((c = bis.read(buf, 0, buf.length)) > 0) { oos.write(buf, 0, c); oos.flush(); // buf=new byte[8192]; } oos.close(); //socket.shutdownOutput(); // client.shutdownOutput(); System.out.println("stop"); // client.shutdownOutput(); ois.close(); // Thread.sleep(500); is.close(); bis.close(); socket.close(); } catch (IOException ex) { ex.printStackTrace(); } } } NOTE: here filePath represents the path of the file where it exists on the server. The client who is connecting to the server provides this path. I am managing this through sockets and I am successfully receiving this path. 3) FileReceiverThread is responsible for receiving the data from the server and constructing file from this buffer data. public class FileReceiveThread extends Thread { private String fileStorePath; private String sourceFile; private Socket socket = null; public FileReceiveThread(String ip, int port, String fileStorePath, String sourceFile) { this.fileStorePath = fileStorePath; this.sourceFile = sourceFile; try { socket = new Socket(ip, port); System.out.println("receive file thread " + socket.isConnected()); } catch (IOException ex) { ex.printStackTrace(); } } @Override public void run() { try { ObjectOutputStream oos = new ObjectOutputStream( socket.getOutputStream()); oos.writeObject(sourceFile); oos.flush(); // oos.close(); File f = new File(fileStorePath); OutputStream os = new FileOutputStream(f); BufferedOutputStream bos = new BufferedOutputStream(os); byte[] buf = new byte[8192]; int c = 0; //************ NOTE ObjectInputStream ois = new ObjectInputStream( socket.getInputStream()); while ((c = ois.read(buf, 0, buf.length)) > 0) { // ois.read(buf); bos.write(buf, 0, c); bos.flush(); // buf = new byte[8192]; } ois.close(); oos.close(); // os.close(); bos.close(); socket.close(); //Thread.sleep(500); } catch (IOException ex) { ex.printStackTrace(); } } } NOTE : Now the problem that I am facing is at the first time when the file is requested the outcome of the program is same as my expectation. I am able to transmit any size of file at first time. Now when the second file is requested (e.g. I have sent file a,b,c,d to the user and user has received file a successfully and now he is requesting file b) the program faces deadlock at this situation. It is waiting for socket's input stream. I put breakpoint and tried to debug it but it is not going in FileThread's run method second time. I could not find out the mistake here. Basically I am making a LAN Messenger which works on LAN. I am using SWT as UI framework.

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  • The Joy Of Hex

    - by Jim Giercyk
    While working on a mainframe integration project, it occurred to me that some basic computer concepts are slipping into obscurity. For example, just about anyone can tell you that a 64-bit processor is faster than a 32-bit processer. A grade school child could tell you that a computer “speaks” in ‘1’s and ‘0’s. Some people can even tell you that there are 8 bits in a byte. However, I have found that even the most seasoned developers often can’t explain the theory behind those statements. That is not a knock on programmers; in the age of IntelliSense, what reason do we have to work with data at the bit level? Many computer theory classes treat bit-level programming as a thing of the past, no longer necessary now that storage space is plentiful. The trouble with that mindset is that the world is full of legacy systems that run programs written in the 1970’s.  Today our jobs require us to extract data from those systems, regardless of the format, and that often involves low-level programming. Because it seems knowledge of the low-level concepts is waning in recent times, I thought a review would be in order.       CHARACTER: See Spot Run HEX: 53 65 65 20 53 70 6F 74 20 52 75 6E DECIMAL: 83 101 101 32 83 112 111 116 32 82 117 110 BINARY: 01010011 01100101 01100101 00100000 01010011 01110000 01101111 01110100 00100000 01010010 01110101 01101110 In this example, I have broken down the words “See Spot Run” to a level computers can understand – machine language.     CHARACTER:  The character level is what is rendered by the computer.  A “Character Set” or “Code Page” contains 256 characters, both printable and unprintable.  Each character represents 1 BYTE of data.  For example, the character string “See Spot Run” is 12 Bytes long, exclusive of the quotation marks.  Remember, a SPACE is an unprintable character, but it still requires a byte.  In the example I have used the default Windows character set, ASCII, which you can see here:  http://www.asciitable.com/ HEX:  Hex is short for hexadecimal, or Base 16.  Humans are comfortable thinking in base ten, perhaps because they have 10 fingers and 10 toes; fingers and toes are called digits, so it’s not much of a stretch.  Computers think in Base 16, with numeric values ranging from zero to fifteen, or 0 – F.  Each decimal place has a possible 16 values as opposed to a possible 10 values in base 10.  Therefore, the number 10 in Hex is equal to the number 16 in Decimal.  DECIMAL:  The Decimal conversion is strictly for us humans to use for calculations and conversions.  It is much easier for us humans to calculate that [30 – 10 = 20] in decimal than it is for us to calculate [1E – A = 14] in Hex.  In the old days, an error in a program could be found by determining the displacement from the entry point of a module.  Since those values were dumped from the computers head, they were in hex. A programmer needed to convert them to decimal, do the equation and convert back to hex.  This gets into relative and absolute addressing, a topic for another day.  BINARY:  Binary, or machine code, is where any value can be expressed in 1s and 0s.  It is really Base 2, because each decimal place can have a possibility of only 2 characters, a 1 or a 0.  In Binary, the number 10 is equal to the number 2 in decimal. Why only 1s and 0s?  Very simply, computers are made up of lots and lots of transistors which at any given moment can be ON ( 1 ) or OFF ( 0 ).  Each transistor is a bit, and the order that the transistors fire (or not fire) is what distinguishes one value from  another in the computers head (or CPU).  Consider 32 bit vs 64 bit processing…..a 64 bit processor has the capability to read 64 transistors at a time.  A 32 bit processor can only read half as many at a time, so in theory the 64 bit processor should be much faster.  There are many more factors involved in CPU performance, but that is the fundamental difference.    DECIMAL HEX BINARY 0 0 0000 1 1 0001 2 2 0010 3 3 0011 4 4 0100 5 5 0101 6 6 0110 7 7 0111 8 8 1000 9 9 1001 10 A 1010 11 B 1011 12 C 1100 13 D 1101 14 E 1110 15 F 1111   Remember that each character is a BYTE, there are 2 HEX characters in a byte (called nibbles) and 8 BITS in a byte.  I hope you enjoyed reading about the theory of data processing.  This is just a high-level explanation, and there is much more to be learned.  It is safe to say that, no matter how advanced our programming languages and visual studios become, they are nothing more than a way to interpret bits and bytes.  There is nothing like the joy of hex to get the mind racing.

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  • Bitmap to Texture2D problem with colors

    - by xnaNewbie89
    I have a small problem with converting a bitmap to a Texture2D. The resulted image of the conversion has the red channel switched with the blue channel :/ I don't know why, because the pixel formats are the same. If someone can help me I will be very happy :) System.Drawing.Image image = System.Drawing.Bitmap.FromFile(ImageFileLoader.filename); System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(image); Texture2D mapTexture = new Texture2D(Screen.Game.GraphicsDevice, bitmap.Width, bitmap.Height,false,SurfaceFormat.Color); System.Drawing.Imaging.BitmapData data = bitmap.LockBits(new System.Drawing.Rectangle( 0, 0, bitmap.Width, bitmap.Height), System.Drawing.Imaging.ImageLockMode.ReadOnly,System.Drawing.Imaging.PixelFormat.Format32bppArgb); byte[] bytes = new byte[data.Height * data.Width*4]; System.Runtime.InteropServices.Marshal.Copy(data.Scan0, bytes, 0, bytes.Length); mapTexture.SetData<byte>(bytes, 0, data.Height * data.Width * 4); bitmap.UnlockBits(data); bitmap.Dispose(); image.Dispose();

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  • Wpf binding with nested properties

    - by byte
    ViewModel I have a property of type Member called KeyMember. The 'Member' type has an ObservableCollection called Addresses. The Address is composed of two strings - street and postcode . View I have a ListBox whose item source need to be set to ViewModels's KeyMember property and it should display the Street of all the Past Addresses in the collection. Question My ViewModel and View relationship is established properly. I am able to write a data template for the above simple case as below <ListBox ItemsSource="{Binding KeyMember.Addresses}"> <ListBox.ItemTemplate> <DataTemplate DataType="Address"> <TextBlock Text="{Binding Street}"/> </DataTemplate> </ListBox.ItemTemplate> </ListBox> How would I write the DataTemplate if I change KeyMember from type Member to ObservableCollection< Member assuming that the collection has only one element. PS: I know that for multiple elements in collection, I will have to implement the Master-Detail pattern/scenario.

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  • TabItems from View collection

    - by byte
    I am using MVVM. I have a tab control. I will have a collection of items. I want to display each of this item in the collection as a tab item. The view in each tab item is different and may have its own viewmodel. How do I achieve this? E.g. I have 3 items in the collection. The Tab item template contains an ItemControl. I would like to now have 3 Tabs created and the ItemControls inside each tabitem may be showing different views. One way I could do is have a single view and viewmodel for each item. Now based on some condition the View will display different UI elements and behave differently. But I am afraide this will make the view quite complex over a period of time.

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  • NetBeans parameter fill after code completion

    - by byte
    This is a particularly annoying problem I'm having, and I can't be the only one to have issue with it. In NetBeans, when you type part of a method, then hit CTRL-SPACE, it displays the code-completion popup, whereupon you can hit tab to finish out the word. This is great, and pretty much how all IDE's operate. Example: Thread.sl < CTRL-SPACE Thread.sleep Yay! Problem is that in this context, once you type in a paren, it auto-fills the parameters for the method with their default names, and inserts a closing paren (regardless of whether you have disabled the option to automatically close them on the preferences page for code completion). This behavior is NOT present if you had manually typed out the full name. How is this helpful to anyone? You've got to type over it your actual variable that you will be passing, and NetBeans gives you no option to prevent the closing paren on code-completion. Does anyone have a way to solve this issue, without having to dive into the netbeans source and build it just for this minor of an issue?

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  • How can I handle multiple views of a data object? Which design pattern is acceptable?

    - by tranquil.byte
    I have a person object. class Person { private $name; ... } I need to be able to change how they are displayed on the front-end ( visitors have control ). They can choose list view, grid view, photo view for example. class PersonDisplay { public function displayList() { // Query database // Output html to display in list mode } public function displayPhoto() { // Query database // Output html to display in photo mode } } Is this an acceptable way to handle the presentation of the items on the front-end or is there a specific design pattern I should be researching to help me with this task? Does anyone have any suggestions or ideas where this could go wrong or if this could potentially make maintenance a nightmare? The Person object was just an example very similiar to what I am using.

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  • Are the following data type allocations analagous?

    - by byte
    I'm very interested in languages and their underpinnings, and I'd like to pose this question to the community. Are the following analagous to eachother in these languages? C# Foo bar = default(Foo); //alloc bar = new Foo(); //init VB.NET Dim bar As Foo = Nothing 'alloc bar = New Foo() 'init Objective-C Foo* bar = [Foo alloc]; //alloc bar = [bar init]; //init

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  • DependencyProperty Orientation problem

    - by byte
    I am learning WPF and am trying to create my first UserControl. My UserControl consists of StackPanel StackPanel contains a Label and TextBox I am trying to create two Dependency Properties Text for the Label Orientation for the StackPanel - The orientation will affect the position of the Label and TextBox effectively I have successfully created a Text dependency property and bind it to my UserControls . But when I created the Orientation property, I seem to get following error in get property The as operator must be used with a reference type or nullable type ('System.Windows.Controls.Orientation' is a non-nullable value type) public static DependencyProperty OrientationProperty = DependencyProperty.Register("Orientation", typeof(System.Windows.Controls.Orientation), typeof(MyControl), new PropertyMetadata((System.Windows.Controls.Orientation)(Orientation.Horizontal))); public Orientation Orientation { get { return GetValue(OrientationProperty) as System.Windows.Controls.Orientation; } set { SetValue(OrientationProperty, value); } } Appreciate your help.

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  • Using block around a static/singleton resource reference

    - by byte
    This is interesting (to me anyway), and I'd like to see if anyone has a good answer and explanation for this behavior. Say you have a singleton database object (or static database object), and you have it stored in a class Foo. public class Foo { public static SqlConnection DBConn = new SqlConnection(ConfigurationManager.ConnectionStrings["BAR"].ConnectionString); } Then, lets say that you are cognizant of the usefulness of calling and disposing your connection (pretend for this example that its a one-time use for purposes of illustration). So you decide to use a 'using' block to take care of the Dispose() call. using (SqlConnection conn = Foo.DBConn) { conn.Open(); using (SqlCommand cmd = new SqlCommand()) { cmd.Connection = conn; cmd.CommandType = System.Data.CommandType.StoredProcedure; cmd.CommandText = "SP_YOUR_PROC"; cmd.ExecuteNonQuery(); } conn.Close(); } This fails, with an error stating that the "ConnectionString property is not initialized". It's not an issue with pulling the connection string from the app.config/web.config. When you investigate in a debug session you see that Foo.DBConn is not null, but contains empty properties. Why is this?

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  • WPF MVVM - Correct way to consume a web service asynchronously

    - by byte
    I have implemented MVVM in my WPF application. I was wondering what is the correct way to consume a Web Service from WPF MVVM app. So far, I have created a DataAccess interface and a class that implements this interface. This would serve as a facade / proxy to the web service. The ViewModel gets a reference to this class as the constructor parameter so it can make any calls to get/set data, in this case it will be a Web service call. I would appreciate if you can guide me with some hints and / or direct me to some online resource.

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  • Why doesn't Java allow for the creaton of generic arrays?

    - by byte
    There are plenty of questions on stackoverflow from people who have attempted to create an array of generics like so: ArrayList<Foo>[] poo = new ArrayList<Foo>[5]; And the answer of course is that the Java specification doesn't allow you to declare an array of generics. My question however is why ? What is the technical reason underlying this restriction in the java language or java vm? It's a technical curiosity I've always wondered about.

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  • Efficient mapping of game entity positions in Java

    - by byte
    In Java (Swing), say I've got a 2D game where I have various types of entities on the screen, such as a player, bad guys, powerups, etc. When the player moves across the screen, in order to do efficient checking of what is in the immediate vicinity of the player, I would think I'd want indexed access to the things that are near the character based on their position. For example, if player 'P' steps onto element 'E' in the following example... | | | | | | | | | |P| | | | |E| | | | | | | | | ... would be to do something like: if(player.getPosition().x == entity.getPosition().x && entity.getPosition.y == thing.getPosition().y) { //do something } And thats fine, but that implies that the entities hold their positions, and therefor if I had MANY entities on the screen I would have to loop through all possible entities available and check each ones position against the player position. This seems really inefficient especially if you start getting tons of entities. So, I would suspect I'd want some sort of map like Map<Point, Entity> map = new HashMap<Point, Entity>(); And store my point information there, so that I could access these entities in constant time. The only problem with that approach is that, if I want to move an entity to a different point on the screen, I'd have to search through the values of the HashMap for the entity I want to move (inefficient since I dont know its Point position ahead of time), and then once I've found it remove it from the HashMap, and re-insert it with the new position information. Any suggestions or advice on what sort of data structure / storage format I ought to be using here in order to have efficient access to Entities based on their position, as well as Position's based on the Entity?

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  • Wpf button click when application window is not active

    - by byte
    I have a WPF application window with a button (ButtonA) which has a command binding to a View Model property. When another application is launched the focus is lost and application window is deactivated. Clicking ButtonA now doesn’t execute the command but instead only activates the window and sets the focus to the button. 2nd click is required to fire the command. The desired functionality is on click of ButtonA while the application window is not active, the application window activates and command associated with ButtonA is executed. I have also tried removing the command and adding a click handler for test purpose but this displays same behaviour. I appreciate any help with this issue.

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