我正在使用ASP.NET v4.5和linq实体 我试图按周使用以下代码
对数据进行分组var groupedByWeek = salesOrdersList
.GroupBy(i => i.DueDate.AddDays(-(int)i.DueDate.DayOfWeek));
但是我得到一个“黄色死亡屏幕”，错误是：
LINQ to Entities无法识别方法'System.DateTime AddDays（Double）'方法，并且此方法无法转换为商店表达式。
理想情况下，我想提出
var groupedByWeek = salesOrdersList.GroupBy(i => i.DueDate.WeekNumber);
但生活并不那么容易！
有没有人知道使用Linq to Entities的周数的方法？
答案 0 :(得分：16)
var groupedByWeek = salesOrdersList.GroupBy(i => SqlFunctions.DatePart("week", i.DueDate));
它会将DATEPART sql函数调用添加到生成的SQL查询中。
答案 1 :(得分：1)
每天：
package com.sitetrack.Ui.Camera.fragments
import android.annotation.SuppressLint
import android.content.Intent
import android.content.res.Configuration
import android.graphics.Color
import android.graphics.drawable.ColorDrawable
import android.hardware.display.DisplayManager
import android.media.MediaScannerConnection
import android.net.Uri
import android.os.Build
import android.os.Bundle
import android.util.DisplayMetrics
import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.webkit.MimeTypeMap
import android.widget.ImageButton
import androidx.camera.core.AspectRatio
import androidx.camera.core.Camera
import androidx.camera.core.CameraSelector
import androidx.camera.core.ImageAnalysis
import androidx.camera.core.ImageCapture
import androidx.camera.core.ImageCapture.Metadata
import androidx.camera.core.ImageProxy
import androidx.camera.core.Preview
import androidx.camera.lifecycle.ProcessCameraProvider
import androidx.camera.view.PreviewView
import androidx.constraintlayout.widget.ConstraintLayout
import androidx.core.content.ContextCompat
import androidx.fragment.app.Fragment
import androidx.lifecycle.LifecycleOwner
import androidx.localbroadcastmanager.content.LocalBroadcastManager
import androidx.navigation.Navigation
import com.sitetrack.R
import com.sitetrack.Ui.Camera.CameraScreen
import com.sitetrack.Util.ANIMATION_FAST_MILLIS
import com.sitetrack.Util.ANIMATION_SLOW_MILLIS
import com.sitetrack.Ui.Camera.PreviewActivity
import com.sitetrack.Util.CommonMethods
import com.sitetrack.Util.CommonMethods.Companion.compressImage
import kotlinx.android.synthetic.main.camera_ui_container.*
import java.io.File
import java.nio.ByteBuffer
import java.text.SimpleDateFormat
import java.util.ArrayDeque
import java.util.Locale
import java.util.concurrent.Executor
import java.util.concurrent.Executors
import kotlin.math.abs
import kotlin.math.max
import kotlin.math.min
/** Helper type alias used for analysis use case callbacks */
typealias LumaListener = (luma: Double) -> Unit
/**
* Main fragment for this app. Implements all camera operations including:
* - Viewfinder
* - Photo taking
* - Image analysis
*/
class CameraFragment : Fragment() {
private lateinit var container: ConstraintLayout
private lateinit var viewFinder: PreviewView
private lateinit var outputDirectory: File
private lateinit var broadcastManager: LocalBroadcastManager
private lateinit var displayManager: DisplayManager
private lateinit var mainExecutor: Executor
private lateinit var analysisExecutor: Executor
private var displayId: Int = -1
private var lensFacing: Int = CameraSelector.LENS_FACING_FRONT
private var preview: Preview? = null
private var imageCapture: ImageCapture? = null
private var imageAnalyzer: ImageAnalysis? = null
private var camera: Camera? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
mainExecutor = ContextCompat.getMainExecutor(requireContext())
analysisExecutor = Executors.newSingleThreadExecutor()
}
override fun onResume() {
super.onResume()
// Make sure that all permissions are still present, since the
// user could have removed them while the app was in paused state.
if (!PermissionsFragment.hasPermissions(
requireContext())) {
Navigation.findNavController(requireActivity(), R.id.fragment_container).navigate(
CameraFragmentDirections.actionCameraToPermissions()
)
}
}
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?): View? =
inflater.inflate(R.layout.fragment_camera, container, false)
private fun setGalleryThumbnail(file: File) {
startActivity(Intent(activity, PreviewActivity::class.java)
.putExtra("actualImage",file.absolutePath))
activity!!.overridePendingTransition(R.anim.enter_from_right, R.anim.exit_to_left)
activity!!.finish()
}
/** Define callback that will be triggered after a photo has been taken and saved to disk */
private val imageSavedListener = object : ImageCapture.OnImageSavedCallback {
override fun onError(imageCaptureError: Int, message: String, cause: Throwable?) {
Log.e(TAG, "Photo capture failed: $message", cause)
}
override fun onImageSaved(photoFile: File) {
Log.d(TAG, "Photo capture succeeded: ${photoFile.absolutePath}")
// We can only change the foreground Drawable using API level 23+ API
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
// Update the gallery thumbnail with latest picture taken
setGalleryThumbnail(photoFile)
}
// Implicit broadcasts will be ignored for devices running API level >= 24
// so if you only target API level 24+ you can remove this statement
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) {
requireActivity().sendBroadcast(
Intent(android.hardware.Camera.ACTION_NEW_PICTURE, Uri.fromFile(photoFile))
)
}
// If the folder selected is an external media directory, this is unnecessary
// but otherwise other apps will not be able to access our images unless we
// scan them using [MediaScannerConnection]
val mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(photoFile.extension)
MediaScannerConnection.scanFile(
context, arrayOf(photoFile.absolutePath), arrayOf(mimeType), null
)
}
}
@SuppressLint("MissingPermission")
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
container = view as ConstraintLayout
viewFinder = container.findViewById(R.id.view_finder)
broadcastManager = LocalBroadcastManager.getInstance(view.context)
// Determine the output directory
outputDirectory = CameraScreen.getOutputDirectory(requireContext())
// Wait for the views to be properly laid out
Thread(Runnable {
viewFinder.post {
// Keep track of the display in which this view is attached
displayId = viewFinder.display.displayId
// Build UI controls
updateCameraUi()
// Bind use cases
bindCameraUseCases()
} }).start()
}
/**
* Inflate camera controls and update the UI manually upon config changes to avoid removing
* and re-adding the view finder from the view hierarchy; this provides a seamless rotation
* transition on devices that support it.
*
* NOTE: The flag is supported starting in Android 8 but there still is a small flash on the
* screen for devices that run Android 9 or below.
*/
override fun onConfigurationChanged(newConfig: Configuration) {
super.onConfigurationChanged(newConfig)
updateCameraUi()
}
/** Declare and bind preview, capture and analysis use cases */
private fun bindCameraUseCases() {
// Get screen metrics used to setup camera for full screen resolution
val metrics = DisplayMetrics().also { viewFinder.display.getRealMetrics(it) }
Log.d(TAG, "Screen metrics: ${metrics.widthPixels} x ${metrics.heightPixels}")
val screenAspectRatio = aspectRatio(metrics.widthPixels, metrics.heightPixels)
val rotation = viewFinder.display.rotation
// Bind the CameraProvider to the LifeCycleOwner
val cameraSelector = CameraSelector.Builder().requireLensFacing(lensFacing).build()
val cameraProviderFuture = ProcessCameraProvider.getInstance(requireContext())
cameraProviderFuture.addListener(Runnable {
// CameraProvider
val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()
// Preview
preview = Preview.Builder()
// We request aspect ratio but no resolution
.setTargetAspectRatio(screenAspectRatio)
// Set initial target rotation
.setTargetRotation(rotation)
.build()
// Default PreviewSurfaceProvider
preview?.previewSurfaceProvider = viewFinder.previewSurfaceProvider
// ImageCapture
imageCapture = ImageCapture.Builder()
.setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
// We request aspect ratio but no resolution to match preview config, but letting
// CameraX optimize for whatever specific resolution best fits requested capture mode
.setTargetAspectRatio(screenAspectRatio)
// Set initial target rotation, we will have to call this again if rotation changes
// during the lifecycle of this use case
.setTargetRotation(rotation)
.build()
// ImageAnalysis
imageAnalyzer = ImageAnalysis.Builder()
// We request aspect ratio but no resolution
.setTargetAspectRatio(screenAspectRatio)
// Set initial target rotation, we will have to call this again if rotation changes
// during the lifecycle of this use case
.setTargetRotation(rotation)
.build()
// The analyzer can then be assigned to the instance
.also {
it.setAnalyzer(analysisExecutor,
LuminosityAnalyzer { luma ->
// Values returned from our analyzer are passed to the attached listener
// We log image analysis results here - you should do something useful instead!
Log.d(
TAG, "Average luminosity: $luma"
)
})
}
// Must unbind the use-cases before rebinding them.
cameraProvider.unbindAll()
try {
// A variable number of use-cases can be passed here -
// camera provides access to CameraControl & CameraInfo
camera = cameraProvider.bindToLifecycle(
this as LifecycleOwner, cameraSelector, preview, imageCapture, imageAnalyzer
)
} catch(exc: Exception) {
Log.e(TAG, "Use case binding failed", exc)
}
}, mainExecutor)
}
/**
* [androidx.camera.core.ImageAnalysisConfig] requires enum value of
* [androidx.camera.core.AspectRatio]. Currently it has values of 4:3 & 16:9.
*
* Detecting the most suitable ratio for dimensions provided in @params by counting absolute
* of preview ratio to one of the provided values.
*
* @param width - preview width
* @param height - preview height
* @return suitable aspect ratio
*/
private fun aspectRatio(width: Int, height: Int): Int {
val previewRatio = max(width, height).toDouble() / min(width, height)
if (abs(previewRatio - RATIO_4_3_VALUE) <= abs(previewRatio - RATIO_16_9_VALUE)) {
return AspectRatio.RATIO_4_3
}
return AspectRatio.RATIO_16_9
}
/** Method used to re-draw the camera UI controls, called every time configuration changes. */
private fun updateCameraUi() {
// Remove previous UI if any
container.findViewById<ConstraintLayout>(R.id.camera_ui_container)?.let {
container.removeView(it)
}
// Inflate a new view containing all UI for controlling the camera
val controls = View.inflate(requireContext(), R.layout.camera_ui_container, container)
// Listener for button used to capture photo
controls.findViewById<ImageButton>(R.id.camera_capture_button).setOnClickListener {
camera_capture_button.isEnabled = false
// Get a stable reference of the modifiable image capture use case
imageCapture?.let { imageCapture ->
// Create output file to hold the image
val photoFile =
createFile(outputDirectory, FILENAME, PHOTO_EXTENSION
)
// Setup image capture metadata
val metadata = Metadata().apply {
// Mirror image when using the front camera
isReversedHorizontal = lensFacing == CameraSelector.LENS_FACING_FRONT
}
// Setup image capture listener which is triggered after photo has been taken
imageCapture.takePicture(photoFile, metadata, mainExecutor, imageSavedListener)
// We can only change the foreground Drawable using API level 23+ API
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
// Display flash animation to indicate that photo was captured
container.postDelayed({
container.foreground = ColorDrawable(Color.WHITE)
container.postDelayed(
{ container.foreground = null },
ANIMATION_FAST_MILLIS
)
}, ANIMATION_SLOW_MILLIS)
}
}
}
// Listener for button used to switch cameras
controls.findViewById<ImageButton>(R.id.camera_switch_button).setOnClickListener {
lensFacing = if (CameraSelector.LENS_FACING_FRONT == lensFacing) {
CameraSelector.LENS_FACING_BACK
} else {
CameraSelector.LENS_FACING_FRONT
}
// Bind use cases
bindCameraUseCases()
}
// Listener for button used to view the most recent photo
controls.findViewById<ImageButton>(R.id.close_button).setOnClickListener {
activity!!.finish()
}
}
/**
* Our custom image analysis class.
*
* <p>All we need to do is override the function `analyze` with our desired operations. Here,
* we compute the average luminosity of the image by looking at the Y plane of the YUV frame.
*/
private class LuminosityAnalyzer(listener: LumaListener? = null) : ImageAnalysis.Analyzer {
private val frameRateWindow = 8
private val frameTimestamps = ArrayDeque<Long>(5)
private val listeners = ArrayList<LumaListener>().apply { listener?.let { add(it) } }
private var lastAnalyzedTimestamp = 0L
var framesPerSecond: Double = -1.0
private set
/**
* Used to add listeners that will be called with each luma computed
*/
fun onFrameAnalyzed(listener: LumaListener) = listeners.add(listener)
/**
* Helper extension function used to extract a byte array from an image plane buffer
*/
private fun ByteBuffer.toByteArray(): ByteArray {
rewind() // Rewind the buffer to zero
val data = ByteArray(remaining())
get(data) // Copy the buffer into a byte array
return data // Return the byte array
}
/**
* Analyzes an image to produce a result.
*
* <p>The caller is responsible for ensuring this analysis method can be executed quickly
* enough to prevent stalls in the image acquisition pipeline. Otherwise, newly available
* images will not be acquired and analyzed.
*
* <p>The image passed to this method becomes invalid after this method returns. The caller
* should not store external references to this image, as these references will become
* invalid.
*
* @param image image being analyzed VERY IMPORTANT: Analyzer method implementation must
* call image.close() on received images when finished using them. Otherwise, new images
* may not be received or the camera may stall, depending on back pressure setting.
*
*/
override fun analyze(image: ImageProxy) {
// If there are no listeners attached, we don't need to perform analysis
if (listeners.isEmpty()) {
image.close()
return
}
// Keep track of frames analyzed
val currentTime = System.currentTimeMillis()
frameTimestamps.push(currentTime)
// Compute the FPS using a moving average
while (frameTimestamps.size >= frameRateWindow) frameTimestamps.removeLast()
val timestampFirst = frameTimestamps.peekFirst() ?: currentTime
val timestampLast = frameTimestamps.peekLast() ?: currentTime
framesPerSecond = 1.0 / ((timestampFirst - timestampLast) /
frameTimestamps.size.coerceAtLeast(1).toDouble()) * 1000.0
// Analysis could take an arbitrarily long amount of time
// Since we are running in a different thread, it won't stall other use cases
lastAnalyzedTimestamp = frameTimestamps.first
// Since format in ImageAnalysis is YUV, image.planes[0] contains the luminance plane
val buffer = image.planes[0].buffer
// Extract image data from callback object
val data = buffer.toByteArray()
// Convert the data into an array of pixel values ranging 0-255
val pixels = data.map { it.toInt() and 0xFF }
// Compute average luminance for the image
val luma = pixels.average()
// Call all listeners with new value
listeners.forEach { it(luma) }
image.close()
}
}
companion object {
private const val TAG = "CameraXBasic"
private const val FILENAME = "yyyy-MM-dd-HH-mm-ss-SSS"
private const val PHOTO_EXTENSION = ".jpg"
private const val RATIO_4_3_VALUE = 4.0 / 3.0
private const val RATIO_16_9_VALUE = 16.0 / 9.0
/** Helper function used to create a timestamped file */
private fun createFile(baseFolder: File, format: String, extension: String) =
File(baseFolder, SimpleDateFormat(format, Locale.US)
.format(System.currentTimeMillis()) + extension)
}
}
OR
var daily = salesOrdersList.Where(x => (long)(x.DueDate - new DateTime(1970, 1, 1, 0, 0, 0)).TotalDays == (long)(Datetime.Now.ToLocalTime()- new DateTime(1970, 1, 1, 0, 0, 0)).TotalDays ).ToList();
每周：
var daily = salesOrdersList.Where(x => x.DueDate.Day == Datetime.Now.ToLocalTime().Day).ToList();
每月
var weekly = salesOrdersList.Where(x => (long)(x.DueDate - new DateTime(1970, 1, 1, 0, 0, 0)).TotalDays / 7 == (long)(Datetime.Now.ToLocalTime()- new DateTime(1970, 1, 1, 0, 0, 0)).TotalDays / 7).ToList();
答案 2 :(得分：0)
或者您可以获得该周第一天的日期，然后按该日期分组。
获取一周中第一天的日期。 你可以使用这段代码：
public static class DateTimeExtensions
{
public static DateTime StartOfWeek(this DateTime dt, DayOfWeek startOfWeek)
{
int diff = dt.DayOfWeek - startOfWeek;
if (diff < 0)
{
diff += 7;
}
return dt.AddDays(-1 * diff).Date;
}
}
然后你可以按照这样的第一个星期分组：
var groupedByWeek = salesOrdersList.GroupBy(i => i.DueDate.StartOfWeek(DayOfWeek.Monday));