I am trying to splice the work on multiple threads using ThreadPooling. I wanna use every available thread to assign (and calculate in a different part of the program down the line) the output of an array member to another array members.
It does work, but it is much slower than just adding them on a single thread. Is my usage wrong or is this operation too simple for multithreading?
arrayI and arrayX variables are in classScope, i couldnt pass them as QueueUserWorkItem argument without converting them in setNeuronInput.
if (layerType != 0)
{
for (arrayI = 0; arrayI < layerSize -1 ; arrayI++)
{
for (arrayX = 0; arrayX < network.Layers[layerIndex - 1].layerSize - 1; arrayX++)
{
ThreadPool.QueueUserWorkItem(new WaitCallback(setNeuronInput), null);
//Neurons[i].input[x] = _network.Layers[layerIndex - 1].Neurons[x].output;
}
}
}
//ThreadPool.GetAvailableThreads(out availableThreads, out placeHolder);
//while (availableThreads != maxThreads)
//{
// ThreadPool.GetAvailableThreads(out availableThreads, out placeHolder);
//}
//return;
}
public void setNeuronInput(object o)
{
try
{
//Console.WriteLine("Thread is working");
Neurons[arrayI].input[arrayX] = network.Layers[layerIndex - 1].Neurons[arrayX].output;
}
catch(Exception e)
{
Console.WriteLine(e);
Console.WriteLine("ArrayI is : " + arrayI);
Console.WriteLine("ArrayX is : " + arrayX);
Console.ReadLine();
}
}
Hello I'm trying to update my chart(s) every second, all chart(s) should be always at the same time. For better understanding I'll include an image but first off I'm gonna explain what actually happens.
So I'm ping requests are sent, every time an result is there, it writes it down in an data point array called file. Everything fine, works as expected.
At the same time, two timers are running, one timer calls a method that prepares the data (let's say at a specific time no data is found in the array -> it should just set value 0). The prepared data is than in a buffer.
The second timer is updating the UI and reading from the tempData but this isn't quite working as expected or wished.
Timers:
myTimer.Interval = 1000;
myTimer.Tick += FileReadFunction;
aTimer.Elapsed += new System.Timers.ElapsedEventHandler(prepData);
aTimer.Interval = 1000;
Button Click which starts timers:
private void _tbStartAll_Click(object sender, EventArgs e)
{
lock (_hosts)
{
foreach (HostPinger hp in _hosts)
hp.Start();
myTimer.Start();
aTimer.Enabled = true;
}
}
Method for preparing Data in Form Class:
public void prepData(object objectInfo, EventArgs e)
{
foreach (NetPinger.source.AddGraph b in graphList)
{
b.prepareData();
}
}
Prep Data Method:
public void prepareData()
{
double unixTimestamp = (Int32)(DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1))).TotalSeconds;
for (double i = unixTimestamp; unixTimestamp - graphSizing < i; i--)
{
bool exists;
try
{
exists = Array.Exists(file, element => element.XValue == i);
exists = true;
}
catch
{
exists = false;
}
try
{
if (exists == false)
{
TempBuffer = TempBuffer.Skip(1).Concat(new DataPoint[] { new DataPoint(i, 0) }).ToArray();
}
else
{
DataPoint point = Array.Find(file, element => element.XValue == i);
TempBuffer = TempBuffer.Skip(1).Concat(new DataPoint[] { (point) }).ToArray();
}
}
catch (Exception ex)
{
//just for debugging...
}
}
}
File Read Method in Form Class:
private void FileReadFunction(object objectInfo, EventArgs e)
{
foreach (NetPinger.source.AddGraph b in graphList)
{
b.fileRead();
}
}
Method FileRead / Update Chart:
public void fileRead()
{
//double unixTimestamp = (Int32)(DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1))).TotalSeconds;
chart_holder.Series[0].Points.Clear();
foreach (DataPoint a in TempBuffer)
{
chart_holder.Series[0].Points.Add(a);
}
}
Image Example of what I mean with time synchronization:
I'm kinda out of ideas why it's not working out, is it because a thread is faster than another? Or what is the reason and how could I fix it? I'm very thankful for your help.
Greetings C.User
I solved the problem by changing the code a bit. To keep it synchronized I prepare the data first, before displaying it at all. After the data is prepared than all the data is getting displayed. Also I only use one timer now instead of two.
Is there any possibility to read Data from 2 RS232 Ports parallel?
It seems, that when i have 2 DataReceived-Events there are blocking each other.
I have also tried to set the SerialPort.ReceivedBytesThreshold to a value of 50/100
class DataCollector
{
private SerialPort _serialPort;
List<String> Data;
private bool _finished = false;
private bool _handshake = true;
public DataCollector(SerialPort serialPort, bool handshake=true)
{
Data = new List<String>();
_serialPort = serialPort;
_serialPort.DataReceived += SerialPortDataReceived;
_handshake = handshake;
if (_serialPort.IsOpen)
{
_serialPort.DiscardInBuffer();
}
}
~DataCollector()
{
if (_serialPort.IsOpen)
{
_serialPort.DiscardInBuffer();
}
Data.Clear();
}
private void SerialPortDataReceived(object sender, SerialDataReceivedEventArgs e)
{
if (_handshake == false)
{
String str =_serialPort.ReadLine();
str.Insert(str.Length, "\n");
Data.Add(str);
if (Data.Count == 48)
{
_finished = true;
}
}
else
{
Char readedByte = (char)_serialPort.ReadByte();
if ((readedByte != (char)5) && Data.Count == 0)
{
return;
}
if (readedByte.CompareTo((char)2) == 0)
{
readLine();
sendAck();
}
else if (readedByte.CompareTo((char)5) == 0)
{
Data.Add(((char)5).ToString());
sendAck();
}
else if (readedByte == (char)4)
{
_finished = true;
}
}
private void sendAck()
{
if (_serialPort.IsOpen )
{
Byte[] bytes = {6};
_serialPort.Write(bytes,0,1);
}
}
private void readLine(){
String str = _serialPort.ReadLine();
Data.Add(str);
}
}
There are 2 defined in the Main:
_inputCollector = new DataCollector(_RS232Input);
_inputSecondCollector = new DataCollector(_RS232SecondInput, false);
Comment
I would seriously reconsider that implementation of only having a single thread - you should realistically have two separate threads each dealing with its own serial port (as currently, the program will 'freeze' if a large message was passed in - meaning the second port will be 'unusable' until this msg has finished).
Answer
Your system is currently running on a single thread. But implementing a muti-threading system - one which will listen to the first port, and another to listen to the second port. That way, they can both work at the same time.
Currently, (on this single thread) if data is received on one port, (and the other receives also) the thread will 'freeze' until the first message has been received/dealt with - and THEN will read the second port (that is, if it has not already timed out). So by using two threads, both ports can be written/read simultaneously (or, seem to be anyway).
The following code was a proof of concept for a message batching routine. Do I avoid goto like the plague and rewrite this code? Or do you think the goto is an expressive way to get this done?
If you'd rewrite please post some code...
var queue = new Queue<TraceItem>(this.batch);
while (this.connected)
{
byte[] buffer = null;
try
{
socket.Recv(out buffer);
}
catch
{
// ignore the exception we get when the socket is shut down from another thread
// the connected flag will be set to false and we'll break the loop
}
HaveAnotherMessage:
if (buffer != null)
{
try
{
var item = TraceItemSerializer.FromBytes(buffer);
if (item != null)
{
queue.Enqueue(item);
buffer = null;
if (queue.Count < this.batch && socket.Recv(out buffer, ZMQ.NOBLOCK))
{
goto HaveAnotherMessage;
}
}
}
catch (Exception ex)
{
this.ReceiverPerformanceCounter.IncrementDiagnosticExceptions();
this.tracer.TraceException(TraceEventType.Error, 0, ex);
}
}
// queue processing code
}
Pretty much sums up my thoughts on "goto."
Goto is bad programming practice for many reasons. Chief among them is that there is almost never a reason for it. Someone posted a do..while loop, use that. Use a boolean to check if you should continue. Use a while loop. Goto's are for interpreted languages and a call back to assembler days (JMP anyone?). You're using a high level language for a reason. So that you and everyone else doesn't look at your code and get lost.
To keep this answer somewhat current I'd like to point out that a combination of goto and bracing errors caused a major SSL bug in iOS and OS X.
Replace the goto with a do-while, or simply a while loop if you don't want the "always run once" functionality you have right now.
var queue = new Queue<TraceItem>(this.batch);
while (this.connected)
{
byte[] buffer = null;
try
{
socket.Recv(out buffer);
}
catch
{
// ignore the exception we get when the socket is shut down from another thread
// the connected flag will be set to false and we'll break the loop
}
do {
if (buffer != null)
{
try
{
var item = TraceItemSerializer.FromBytes(buffer);
if (item != null)
{
queue.Enqueue(item);
buffer = null;
}
}
catch (Exception ex)
{
this.ReceiverPerformanceCounter.IncrementDiagnosticExceptions();
this.tracer.TraceException(TraceEventType.Error, 0, ex);
}
}
} while(queue.Count < this.batch && socket.Recv(out buffer, ZMQ.NOBLOCK))
// queue processing code
}
It's so amazingly easy to rid yourself of GOTO in this situation it makes me cry:
var queue = new Queue<TraceItem>(this.batch);
while (this.connected)
{
byte[] buffer = null;
try
{
socket.Recv(out buffer);
}
catch
{
// ignore the exception we get when the socket is shut down from another thread
// the connected flag will be set to false and we'll break the loop
}
bool hasAnotherMessage = true
while(hasAnotherMessage)
{
hasAnotherMessage = false;
if (buffer != null)
{
try
{
var item = TraceItemSerializer.FromBytes(buffer);
if (item != null)
{
queue.Enqueue(item);
buffer = null;
if (queue.Count < this.batch && socket.Recv(out buffer, ZMQ.NOBLOCK))
{
hasAnotherMessage = true;
}
}
}
catch (Exception ex)
{
this.ReceiverPerformanceCounter.IncrementDiagnosticExceptions();
this.tracer.TraceException(TraceEventType.Error, 0, ex);
}
}
}
// queue processing code
}
I guess the goto is SLIGHTLY more readable intuitively... But if you WANTED to avoid it I think all you'd have to do is throw the code in a while(true) loop, and then have a break statement at the end of the loop for a normal iteration. And the goto could be replaced with a continue statement.
Eventually you just learn to read and write loops and other control flow structures instead of using goto statements, at least in my experience.
Kind of related to Josh K post but I'm writing it here since comments doesn't allow code.
I can think of a good reason: While traversing some n-dimensional construct to find something. Example for n=3 //...
for (int i = 0; i < X; i++)
for (int j = 0; j < Y; j++)
for (int k = 0; k < Z; k++)
if ( array[i][j][k] == someValue )
{
//DO STUFF
goto ENDFOR; //Already found my value, let's get out
}
ENDFOR: ;
//MORE CODE HERE...
I know you can use "n" whiles and booleans to see if you should continue.. or you can create a function that maps that n-dimensional array to just one dimension and just use one while but i believe that the nested for its far more readable.
By the way I'm not saying we should all use gotos but in this specific situation i would do it the way i just mentioned.
You could refactor is to something like this.
while (queue.Count < this.batch && buffer != null)
{
try
{
var item = TraceItemSerializer.FromBytes(buffer);
buffer = null;
if (item != null)
{
queue.Enqueue(item);
socket.Recv(out buffer, ZMQ.NOBLOCK)
}
}
catch (Exception ex)
{
this.ReceiverPerformanceCounter.IncrementDiagnosticExceptions();
this.tracer.TraceException(TraceEventType.Error, 0, ex);
}
}
Umm, I'm not really sure you want to goto out of a try block. I'm pretty sure that is not a safe thing to do, though I'm not 100% sure on that. That just doesn't look very safe...
Wrap the "HaveAnotherMessage" into a method that takes in the buffer and may call itself recursively. That would seem to be the easiest way to fix this.
I would avoid goto in this case, and refactor it. The method reads too long in my opinion.
I think your method is too big. It mixes different levels of abstraction, like error processing, message retrieval and message processing.
If you refactor it in different methods, the goto naturally goes away (note: I assume your main method is called Process):
...
private byte[] buffer;
private Queue<TraceItem> queue;
public void Process() {
queue = new Queue<TraceItem>(batch);
while (connected) {
ReceiveMessage();
TryProcessMessage();
}
}
private void ReceiveMessage() {
try {
socket.Recv(out buffer);
}
catch {
// ignore the exception we get when the socket is shut down from another thread
// the connected flag will be set to false and we'll break the processing
}
}
private void TryProcessMessage() {
try {
ProcessMessage();
}
catch (Exception ex) {
ProcessError(ex);
}
}
private void ProcessMessage() {
if (buffer == null) return;
var item = TraceItemSerializer.FromBytes(buffer);
if (item == null) return;
queue.Enqueue(item);
if (HasMoreData()) {
TryProcessMessage();
}
}
private bool HasMoreData() {
return queue.Count < batch && socket.Recv(out buffer, ZMQ.NOBLOCK);
}
private void ProcessError(Exception ex) {
ReceiverPerformanceCounter.IncrementDiagnosticExceptions();
tracer.TraceException(TraceEventType.Error, 0, ex);
}
...
I've been creating a small application that allows a user to convert images to various sizes and formats. I've been struggling on getting a good solid design with this application. I have the application up and running, but it does integrate good Object-Oriented design. Since this is a personal project, I've been wanting to learn more about integrating interfaces, good class inheritance, object composition, and other elements of OO design.
However, I've been struggling to do so. Don't get me wrong, I know about OO design and what it is, I just don't know how to implement good OO design in projects. Of course its easy to look at class Examples that you read in books, or online. Examples may have simple scenarios such as the following.
Interface IPerson has member functions Walk(), Run() . Abstract Class Person uses IPerson Interface. Class Man and Class Female inherit from Abstract Class Person.
but when it comes to Real Projects I struggle to implement good design. I was hoping for some insight. Here is what I currently have.
Interface:
interface IPicture
{
Bitmap ReturnImage(string path, int width, int height);
}
Main Class that Holds Picture Information. This class basically stores information about the image passed, and information about the new values the user wants (i.e. new size, new file location, new pic format, etc.)
public class MyPictures : IPicture
{
//All Private variables below are properties. Property get/set's have been removed
//for the sake of space
private int _NewWidth;
private int _NewHeight;
private string _NewImgName;
private string _NewImgPath;
private string _NewImgFullPath;
private ImageFormat _NewImgFormat;
//Declare variables to hold values that have been determined
private int _OldWidth;
private int _OldHeight;
private string _OldImgName;
private string _OldImgPath;
//Old Image Format is in String format because of certain extension scenarios.
private string _OldImgFormat;
public MyPictures(Image img, string file)
{
ClearProperties();
//...set properties based on passed variables in constructor...
}
public void ClearProperties()
{
_NewWidth = 0;
_NewHeight = 0;
_NewImgName = "";
_NewImgPath = "";
_NewImgFullPath = "";
_NewImgFormat = null;
_OldWidth = 0;
_OldHeight = 0;
_OldImgName = "";
_OldImgPath = "";
_OldImgFormat = null;
}
public override string ToString()
{
return _OldImgPath;
}
public void ImageSave()
{
Bitmap tempBmp = new Bitmap(_OldImgPath);
Bitmap bmp = new Bitmap(tempBmp, _NewWidth, _NewHeight);
bmp.Save(_NewImgPath + #"\" + _NewImgName + "." + _NewImgFormat.ToString().ToLower(), _NewImgFormat);
}
public Bitmap ImageClone()
{
Bitmap bmp = new Bitmap(_OldImgPath);
return bmp;
}
Bitmap IPicture.ReturnImage(string path, int width, int height)
{
return new Bitmap(new Bitmap(path), width, height);
}
}
Main Class; Starting point of application. This definatly needs some work...
public partial class Form1 : Form
{
static bool hasThreadBeenStopped = false;
static bool imageProcessingComplete = false;
static bool imgConstrained = false;
//Default text when user selects 'All' checkbox for new image name
static string newNameDefault = "'Name' + #";
Utility.Validation.Validate valid = new Utility.Validation.Validate();
public Form1()
{
InitializeComponent();
//Populate Combo Box With Possible Image Formats...
//Conditionally show Image Properties...
ImgPropertiesEnabled();
//Set static progress bar properties...
progressBar1.Minimum = 0;
progressBar1.Step = 1;
}
private void Form1_Load(object sender, EventArgs e)
{
lblImgProcessed.Text = "";
lblFile.Text = "";
txtContentFolder.Text = "";
}
//Delegate declarations. Used for multi-thread processing
public delegate void PopulateTextboxDelegate(Label lbl, string text);
public delegate void ThreadWorkDelegate(Label lbl, string text);
public delegate void ImageDisplayDelegate(Image i);
public delegate void ProgressBarDelegate(ProgressBar p, int step, int value);
//Populate textbox fields with image processed, and image path being processed
public void PopulateTextbox(Label lbl, string text)
{
lbl.Text = "";
lbl.Text = text;
}
public void ThreadWork(Label lbl, string text)
{
this.Invoke(new PopulateTextboxDelegate(PopulateTextbox),
new object[] { lbl, text });
}
//Display Currently Processed Image
public void ImageDisplay(Image i)
{
pbMain.Image = null;
pbMain.Image = i;
}
public void ThreadWorkImg(Image i)
{
this.Invoke(new ImageDisplayDelegate(ImageDisplay),
new object[] {i});
}
//Increment Progress Bar
public void ProgressBarDisplay(ProgressBar pg, int max, int value)
{
//Dynamically set the Progress Bar properties
pg.Maximum = max;
pg.Value = value;
}
public void ThreadProgress(ProgressBar p, int max, int value)
{
this.Invoke(new ProgressBarDelegate(ProgressBarDisplay),
new object[] { p, max, value });
}
private void btnStart_Click(object sender, EventArgs e)
{
string IsValidResult = IsValid();
//If string is empty, Utility passed
if (IsValidResult == "")
{
Thread t = new Thread(new ThreadStart(ProcessFiles));
t.Start();
}
else
{
MessageBox.Show(IsValidResult);
}
}
public void ProcessFiles()
{
int count = 0;
ThreadWorkDelegate w = ThreadWork;
ImageDisplayDelegate im = ThreadWorkImg;
ProgressBarDelegate pb = ThreadProgress;
try
{
foreach (MyPictures mp in lstHold.Items)
{
try
{
if (hasThreadBeenStopped == false)
{
//Disable certain controls during process. We will use the generic
//MethodInvoker, which Represents a delegate that can execute any method
//in managed code that is declared void and takes no parameters.
//Using the MethodInvoker is good when simple delegates are needed. Ironically,
//this way of multi-thread delegation was used because the traditional way as used
//by the rest of the delegates in this method, was not working.
btnApply.Invoke(new MethodInvoker(delegate { btnApply.Enabled = false; }));
btnStart.Invoke(new MethodInvoker(delegate { btnStart.Enabled = false; }));
//Call delegate to show current picture being processed
im.BeginInvoke(mp.ImageClone(), null, null);
mp.ImageSave();
//Increment Count; Image has been processed
count++;
//Invoke Img Proceessed Output
w.BeginInvoke(lblImgProcessed, count.ToString() +
" of " + lstHold.Items.Count.ToString() + " processed",
null, null);
//Invoke File Process Output
w.BeginInvoke(lblFile, mp.NewImgPath, null, null);
//Invoke Progressbar output. Delegate is passed The count of images,
//which will be set as the progressbar max value. the 'count' variable is
//passed to determine the current value.
pb.BeginInvoke(progressBar1, lstHold.Items.Count, count, null, null);
}
else //Thread has been called to stop
{
MessageBox.Show("Image Processing Stopped: " + count + "of " +
lstHold.Items.Count + " processed");
//Enable controls after process
btnApply.Invoke(new MethodInvoker(delegate { btnApply.Enabled = true; }));
btnStart.Invoke(new MethodInvoker(delegate { btnStart.Enabled = true; }));
break;
}
}
catch (Exception ex)
{
MessageBox.Show("Error while processing pictures");
break;
}
}
}
catch (Exception ex)
{
MessageBox.Show("Error while attempting to execute pictures: " + ex.ToString());
}
finally
{
//Loop has ended:
//In finally statement, re-enable disabled controls
//Enable certain controls during process
btnApply.Invoke(new MethodInvoker(delegate { btnApply.Enabled = true; }));
btnStart.Invoke(new MethodInvoker(delegate { btnStart.Enabled = true; }));
//Reset class variables
hasThreadBeenStopped = false;
imageProcessingComplete = false;
}
}
private void btnContent_Click(object sender, EventArgs e)
{
string selection = null;
string[] files = null;
lstAll.Items.Clear();
contentBrowser.ShowDialog();
selection = contentBrowser.SelectedPath;
txtContentFolder.Text = selection;
if (selection != "" || selection != null)
{
try
{
files = System.IO.Directory.GetFiles(selection.Trim());
foreach (string file in files)
{
lstAll.Items.Add(file);
}
}
catch (Exception ex)
{
// MessageBox.Show(ex.ToString());
}
}
}
private void btnGo_Click(object sender, EventArgs e)
{
//Grab files from folder based on user input in the textbox.
string selection = txtContentFolder.Text.Trim();
string[] files = null;
lstAll.Items.Clear();
if (valid.IsNull(selection) == false || valid.IsEmpty(selection) == false)
{
try
{
files = System.IO.Directory.GetFiles(selection);
foreach (string file in files)
{
lstAll.Items.Add(file);
}
}
catch (Exception ex)
{
MessageBox.Show("Invalid Directory");
}
}
txtContentFolder.Text = selection;
}
private void btnDestination_Click(object sender, EventArgs e)
{
string selection = null;
destinationBrowser.ShowDialog();
selection = destinationBrowser.SelectedPath;
txtNewImgPath.Text = selection;
}
private void exitToolStripMenuItem_Click(object sender, EventArgs e)
{
this.Close();
}
private void btnStop_Click(object sender, EventArgs e)
{
//Flag variable that the stop button has been called. This variable is checked
//conditionally when looping over each picture.
hasThreadBeenStopped = true;
}
public string IsValid()
{
StringBuilder sb = new StringBuilder("");
if (lstHold.Items.Count <= 0)
{
return "No items exist to process";
}
//Validate that there is a value in each field for every object in lstHold. All the fields will be
//validated. Note: If there is one invalid field, the rest do not need to be considered.
foreach (MyPictures mp in lstHold.Items)
{
if (mp.NewImgName == "")
{
sb.Append(mp.OldImgPath + ", ");
}
else if (mp.NewImgPath == "")
{
sb.Append(mp.OldImgPath + ", ");
}
else if (mp.NewImgFormat == null)
{
sb.Append(mp.OldImgPath + ", ");
}
else if (mp.NewWidth == 0)
{
sb.Append(mp.OldImgPath + ", ");
}
else if (mp.NewHeight == 0)
{
sb.Append(mp.OldImgPath + ", ");
}
}
//If the returned string is empty, the image is valid. The check for the listbox's count
//will return a string immediatly if false. Because of this, we know that the returning
//string at this level will either be empty (validation passed) or filled with image paths
//of images missing required values. If image is not valid, return this concatenated string of image paths
//that are missing values, and insert a prefixed string literal to this list.
if (sb.ToString() != "")
{
sb.Insert(0, "The following images are missing required values: ");
return sb.ToString();
}
else //String is empty and has passed validation
{
return sb.ToString();
}
}
private void btnMoveOne_Click(object sender, EventArgs e)
{
//Loop through All strings in the lstAll list box. Then use each picture path to convert
//each picture into their own class
foreach (string file in lstAll.SelectedItems)
{
//isImgExistFlag is a flag indicating wheter the image coming from lstAll already exists
//in lstHold. By default, the variable is false. It is set to true if an image does exist
//This variable must be re-created within the scope of the main foreach loop to ensure a proper
//reset of the variable for each image comparison.
bool isImgExistFlag = false;
try
{
Image img;
img = Image.FromFile(file);
MyPictures mp = new MyPictures(img,file);
//If lstHold contains no items, add the item with no validation check.
if (lstHold.Items.Count == 0)
{
lstHold.Items.Add(mp);
}
else
{
//Run through each object in the lstHold to determine if the newly created object
//already exists in list box lstHold.
for (int i = 0; i < lstHold.Items.Count; i++)
{
MyPictures p = (MyPictures)lstHold.Items[i];
//Unique objects will be identified by their Original Image Path, because
//this value will be unique
if (p.OldImgPath == mp.OldImgPath)
{
isImgExistFlag = true;
}
}
//If isImgExistFlag is false, the current Image object doesnt currently exist
//in list box. Therefore, add it to the list.
if (isImgExistFlag == false)
{
lstHold.Items.Add(mp);
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
}
private void btnMoveAll_Click(object sender, EventArgs e)
{
//This event has the same functionality as btnMoveOne_Click, except the main foreach loop
//is based on all of lstAll's items, rather than just the selected items.
foreach (string file in lstAll.Items)
{
bool isImgExistFlag = false;
try
{
Image img;
img = Image.FromFile(file);
MyPictures mp = new MyPictures(img, file);
if (lstHold.Items.Count == 0)
{
lstHold.Items.Add(mp);
}
else
{
for (int i = 0; i < lstHold.Items.Count; i++)
{
MyPictures p = (MyPictures)lstHold.Items[i];
if (p.OldImgPath == mp.OldImgPath)
{
isImgExistFlag = true;
}
}
if (isImgExistFlag == false)
{
lstHold.Items.Add(mp);
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
}
private void btnRemoveOne_Click(object sender, EventArgs e)
{
/*
Create a seperate List to populate:
This is necessary because if you explicitly remove an item from the listbox
you will get the following error:
"List that this enumerator is bound to has been modified. An enumerator can
only be used if the list does not change."
*/
//This variable will keep track of the first index processed.
int first_index = 0;
int count = 0;
List<MyPictures> TempMp = new List<MyPictures>();
if (lstHold.Items.Count >= 1)
{
try
{
foreach (MyPictures mp in lstHold.SelectedItems)
{
if (count == 0)
{
first_index = lstHold.SelectedIndex;
}
//Add objects to be removed
TempMp.Add(mp);
}
foreach (MyPictures mp2 in TempMp)
{
lstHold.Items.Remove(mp2);
}
}
catch (Exception ex)
{
//Hide Error: MessageBox.Show(ex.ToString());
}
//Select new item in list if possible, as long as there is a item in the list
if (lstHold.Items.Count >= 1)
{
//If the first_index variable = the amount of items in the list, the new selected index
//should be the first index -1. This is because the variable first_index would be the
//index of the now deleted item in the list. Therefore we must subtract the variable by 1
//before assigning it to the selected value. Otherwise, we'll be assigning a selected index that
//no longer exists.
//There is also a check to make sure there is more than one item in the list. Otherwise, we could
//potentially assign a selected index of -1.
if (first_index == lstHold.Items.Count && lstHold.Items.Count != 1)
{
lstHold.SelectedIndex = first_index - 1;
}
else if (lstHold.Items.Count == 1)
{
lstHold.SelectedIndex = 0;
}
else
{
lstHold.SelectedIndex = first_index;
}
}
else
{
ClearTextBoxes();
}
}
}
private void btnRemoveAll_Click(object sender, EventArgs e)
{
lstHold.Items.Clear();
ClearTextBoxes();
ImgPropertiesEnabled();
}
private void lstHold_SelectedIndexChanged(object sender, EventArgs e)
{
//This prevents trying to access a negative index. This can happen when a item is removed.
if (lstHold.SelectedIndex >= 0)
{
try
{
MyPictures mp = (MyPictures)lstHold.Items[lstHold.SelectedIndex];
txtOldName.Text = mp.OldImgName;
txtOldImgPath.Text = mp.OldImgPath;
txtOldImgFormat.Text = mp.OldImgFormat.ToString();
txtOldWidth.Text = mp.OldWidth.ToString();
txtOldHeight.Text = mp.OldHeight.ToString();
txtNewName.Text = mp.NewImgName;
cbFormat.SelectedItem = mp.NewImgFormat;
txtNewWidth.Text = mp.NewWidth.ToString();
txtNewHeight.Text = mp.NewHeight.ToString();
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
//Call function to determine which controls should be enabled/disabled
ImgPropertiesEnabled();
}
private void btnApply_Click(object sender, EventArgs e)
{
//Reset color. It could be grey depending on if user changed default name.
txtNewName.ForeColor = Color.Black;
if (lstHold.SelectedIndex == -1)
{
MessageBox.Show("Picture not selected. Select picture to apply properties to.");
}
else if (lstHold.SelectedIndex >= 0)
{
MyPictures mp = (MyPictures)lstHold.Items[lstHold.SelectedIndex];
//User wants to apply a generated name to all pictures within the list
if (chkNewPicName.Checked == true)
{
int count = 0;
foreach (MyPictures pic in lstHold.Items)
{
pic.NewImgName = txtNewName.Text + count.ToString();
++count;
}
txtNewName.Text = mp.NewImgName;
}
//User wants to apply a custom name to this picture only
else
{
mp.NewImgName = txtNewName.Text;
}
//User wants to apply this path to all pictures within the list
if (chkNewPicPath.Checked == true)
{
foreach (MyPictures pic in lstHold.Items)
{
pic.NewImgPath = txtNewImgPath.Text;
}
txtNewImgPath.Text = mp.NewImgPath;
}
//User wants to apply this path to this picture only
else
{
mp.NewImgPath = txtNewImgPath.Text;
}
//User wants to apply this image format to all pictures within the list
if (chkNewPicFormat.Checked == true)
{
foreach (MyPictures pic in lstHold.Items)
{
pic.NewImgFormat = (ImageFormat)cbFormat.SelectedItem;
}
}
//User wants to apply this image format to this picture only
else
{
mp.NewImgFormat = (ImageFormat)cbFormat.SelectedItem;
}
//User wants to apply this size to all pictures
if (chkNewSize.Checked == true)
{
foreach (MyPictures pic in lstHold.Items)
{
pic.NewWidth = Convert.ToInt32(txtNewWidth.Text);
pic.NewHeight = Convert.ToInt32(txtNewHeight.Text);
}
txtNewWidth.Text = mp.NewWidth.ToString();
txtNewHeight.Text = mp.NewHeight.ToString();
}
//User wants to apply this size to this picture only
else
{
mp.NewWidth = Convert.ToInt32(txtNewWidth.Text);
mp.NewHeight = Convert.ToInt32(txtNewHeight.Text);
}
mp.NewImgName = txtNewName.Text;
mp.NewImgFormat = (ImageFormat)cbFormat.SelectedItem;
mp.NewWidth = Convert.ToInt32(txtNewWidth.Text);
mp.NewHeight = Convert.ToInt32(txtNewHeight.Text);
}
}
private void checkBox1_CheckedChanged(object sender, EventArgs e)
{
if (chkSelectAll.Checked)
{
chkNewPicName.Checked = true;
chkNewPicPath.Checked = true;
chkNewPicFormat.Checked = true;
chkNewSize.Checked = true;
}
else
{
chkNewPicName.Checked = false;
chkNewPicPath.Checked = false;
chkNewPicFormat.Checked = false;
chkNewSize.Checked = false;
}
}
private void previewToolStripMenuItem_Click(object sender, EventArgs e)
{
MessageBox.Show("hi there!");
}
private void btnPreview_Click(object sender, EventArgs e)
{
try
{
if (lstHold.Items.Count <= 0)
{
MessageBox.Show("No pictures are available to preview");
}
else if (lstHold.SelectedItem == null)
{
MessageBox.Show("No picture is selected to preview");
}
else
{
MyPictures mp = (MyPictures)lstHold.SelectedItem;
//Bitmap bmp = new Bitmap(mp.OldImgPath);
Form2 frm = new Form2(mp);
frm.Show();
}
}
catch (Exception ex)
{
MessageBox.Show("An Error has occured:\n " + ex.ToString());
}
}
public void ImgPropertiesEnabled()
{
//Enable Image properties when an image is selected
if (lstHold.SelectedIndex >= 0)
{
gbCheckAll.Enabled = true;
gbImgProperties.Enabled = true;
}
else
{
//Disable Image properties when an image is not selected
gbCheckAll.Enabled = false;
gbImgProperties.Enabled = false;
}
//Preview buttons enablement will depend on the same conditions
btnPreview.Enabled = gbImgProperties.Enabled;
}
public void ClearTextBoxes()
{
txtNewImgPath.Text = "";
txtNewName.Text = "";
txtNewHeight.Text = Convert.ToString(0);
txtNewWidth.Text = Convert.ToString(0);
cbFormat.SelectedItem = null;
chkSelectAll.Checked = false;
}
}
Having scanned through the code, yes it is eleborate... maybe a little to much ;)
One thing that i noticed was your naming conventions. Even though it does not change anything in runtime it does make an API/code-maintenance easier.
So, instead of having an IPicture, i would make it something like `IResizableImage´ (reading your spec, thats what it is. Not just a picture, but a resizable one)
Instead of ´ReturnImage()´ i would use something like ´Scale()´. 'ImageSave()' to 'Save()'
Your code will start to read (Which added symantical information by naming convention)
IResizableImage myImg = new ResizableImage( orignalBitmap );
Image rescaledImg = myImg.Scale( "new path", 320,240 );
resccaledImg.Save();
instead of:
IPicture myImg = new MyPictures();
Image rescaled = myImg.ReturnImage( "newpath", 320, 240 );
rescaledImg.ImageSave();
So, Generally classes are nouns, methods are verbs, adjetives are properties/fields. Try to minimize duplication or redancy. "ImageSave" is a method on your Image. Isn't "Image.Save()" clearer than "Image.ImageSave()"?
Just some of my thoughts;
In coding guidelines there is no absolute right or wrong.
Think of being another person when USING the API versus WRITING the API. Jump out of the box of "i know what it does" and imagine being a user never having seen this API before. Does it feel natural and easy accesible?
Hope this helps,
Here are some improvements for you code and design. This tips are not all OO related but you should be aware that good design is not just OO design.
1.Avoid commenting what is obvious.
//Declare variables to hold values that have been determined
private int _OldWidth;
This comment is superfluous because any programmers will understand that is a declaration.
2.Avoid giving wrong name. For example the class "MyPictures" is not really correct because:
Is holds just one picture, while the name suggests many pictures.
It contains "My" which, in my opinion is not correct since if I read your code is not my class. It is yours ;)
3.Avoid concatenating strings. Use string.Format or, for paths, Path.Combine
bmp.Save(_NewImgPath + #"\" + _NewImgName + "." + _NewImgFormat.ToString().ToLower(), _NewImgFormat);
4.Keep methods short. It is hard to keep all methods to 5 lines of code but 30 lines (if my count is correct - without comments and empty lines) for ProcessFiles is a little bit too much.
5.Don't use design elements just because you want to have them. I see no reason to use the interface in your code. In your case it just increases the complexity of your code. Even more, you haven't used it(!!!). You just implemented it and that's all. Use interfaces when you have multiple types that share common functionality (the ones in interface) and you want to treat them all similar without being aware of the actual implementation.
interface IImage
{
void DrawLine(Point startPoint, Point endPoint);
}
class MonochromeImage:IImage
{
void DrawLine(Point startPoint, Point endPoint)
{
//Draw a monochrome line on images with one channel
}
}
class ColorImage:IImage
{
void DrawLine(Point startPoint, Point endPoint)
{
//Draw a red line on images with three channels
}
}
...
void DrawLineOnImage()
{
List<IImage> images = new List<IImage>();
images.Add(new ColorImage());
images.Add(new MonochromeImage());
//I am not aware of what kind of images actually have
//all it matters is to have a draw line method
foreach(IImage image in images)
{
image.DrawLine(p1,p2)
}
}
6.As others already mentioned, try to separate the presentation (graphical user interface - GUI) from the logic. Make it in such a way that you can replace the GUI without changing logic code.
7.Make single responsibility functions. btnMoveOne_Click has more than one responsibility: it checks if file exists and it handles elements on user interface.
8.You image class is coupled to the file system. What happens if I want to store images created in memory? What is the path then? Here is where you can improve the design of the class. Make it in such a way it doesn't matter if files are from disk (HINT: in a FileStream) or from memory (HINT: in a MemoryStream) or any other place.
That's all for now. Hope this information will help you.
To achieve good design you need to apply TDD (Test Driven Design).
You will soon find then testability requires separating the project to layers, such as presentation and business logic.
Start covering your project with tests, and you won't believe how fast you will find design inconsistences with it.
Things will just stand up and scream: "No way you will test me!"
The worst anemy nere is the code buried in the WinForms.
What you can do is making a view "humble". http://codebetter.com/blogs/jeremy.miller/archive/2007/05/23/build-your-own-cab-part-2-the-humble-dialog-box.aspx
As for the project samples, you have to look at architectural patterns, not the OOP samples.
The keywords you will be lookign for are MVC, MVP, MVVM.
Well, here's what I'd do. It's probably different than what many people would do, but I think it's a pretty good, flexible design.
public abstract class AbstractConverter : IImageHandler
{
public AbstractConverter(IImageHandler nextHandler)
{
output = nextHandler;
}
public void HandleImage(Bitmap b)
{
var outBitmap = Convert(b);
output.HandleImage(outBitmap);
}
protected abstract Bitmap Convert(Bitmap input);
private IImageHandler output;
}
public interface IImageHandler
{
void HandleImage(Bitmap b);
}
Now, the rest of your app is:
Creating implementations of AbstractConverter to handle the individual transformations you want
Creating something that can build and wire converters together
Getting the initial Bitmap, and writing the final result out.