Develop Reference

Index was outside the bounds of the array while reading from a file

I hope all of you are having a nice day. So I fixed one error of my program but there's another :/
So here's the code where I create my and read the data from a file:
void ReadData(string fileName, Branch[] branches)
{
string shopsName = null;
using (StreamReader reader = new StreamReader(#fileName))
{
string line = null;
line = reader.ReadLine();
if (line != null)
{
shopsName = line;
}
Branch tempBranches = TempBranch(branches, shopsName);
string address = reader.ReadLine();
string phoneNumber = reader.ReadLine();
while (null != (line = reader.ReadLine()))
{
string[] values = line.Split(';');
string facturer = values[0];
string model = values[1];
double capacity = double.Parse(values[2]);
string energyClass = values[3];
string assemblyType = values[4];
string color = values[5];
string attribute = values[6];
double cost = double.Parse(values[7]);
Fridges fridge = new Fridges(facturer, model, capacity, energyClass, assemblyType, color, attribute, cost);
tempBranches.fridges.AddFridge(fridge);
}
}
And there's the code where I use the TempBranch method. The error is in this line: if (branches[i].ShopsName == shopsName). Hopefully you can help me, cuz I was trying to fix this yesterday for 30 minutes and it still wasn't working :D
private static Branch TempBranch(Branch[] branches, string shopsName)
{
for (int i = 0; i < MaxNumberOfFridges; i++)
{
if (branches[i].ShopsName == shopsName)
{
return branches[i];
}
}
return null;
}

If you replace MaxNumberOfFridges with branches.Length it will only try to find a Branch that's within the range of the branches array. The reason it's not working is because you're trying to access an index which is greater than the Length of the array.

Try this one. Use foreach, if you dont know the lenght of array.
private static Branch TempBranch(Branch[] branches, string shopsName)
{
foreach(var branch in branches)
{
if (branch.ShopsName == shopsName)
{
return branch;
}
}
return null;
}

You can also try to make use of a LINQ query,
return branches.Where(b => b.ShopsName == shopsName).FirstOrDefault();
EDIT:
To NullReferenceError which occurs in your new post occurs due to null being returned in your function where your shop gets created. This due to not finding the given shopname.
So it tries to add an fridge to an shop which does not exist, which is not possible. You will have to add a check so that this does not occur.

This raised error because MaxNumberOfFridges is bigger than branches length.. to simplify it, assume MaxNumberOfFridges is 20 but arry length is 10, so you are trying to access element 11 in array which is outside of array length.
to fix it
for (int i = 0; i < branches.Length; i++)
{
if (branches[i].ShopsName == shopsName)
{
return branches[i];
}
}
other option is to use foreach loop
foreach(var b in branches)
{
if (b.ShopsName == shopsName)
{
return branches[i];
}
}

OutOfMemoryException when updating a large list?

I have a large list and I would like to overwrite one value if required. To do this, I create two subsets of the list which seems to give me an OutOfMemoryException. Here is my code snippet:
if (ownRG != "")
{
List<string> maclist = ownRG.Split(',').ToList();
List<IVFile> temp = powlist.Where(a => maclist.Contains(a.Machine)).ToList();
powlist = powlist.Where(a => !maclist.Contains(a.Machine)).ToList(); // OOME Here
temp.ForEach(a => { a.ReportingGroup = ownRG; });
powlist.AddRange(temp);
}
Essentially I'm splitting the list into the part that needs updating and the part that doesn't, then I perform the update and put the list back together. This works fine for smaller lists, but breaks with an OutOfMemoryException on the third row within the if for a large list. Can I make this more efficient?
NOTE
powlist is the large list (>1m) items. maclist only has between 1 and 10 but even with 1 item this breaks.

Solving your issue
Here is how to rearrange your code using the enumerator code from my answer:
if (!string.IsNullOrEmpty(ownRG))
{
var maclist = new CommaSeparatedStringEnumerable(str);
var temp = powlist.Where(a => maclist.Contains(a.Machine));
foreach (var p in temp)
{
p.ReportingGroup = ownRG;
}
}
You should not use ToList in your code.
You don't need to remove thee contents of temp from powlist (you are re-adding them anyway)
Streaming over a large comma-separated string
You can iterate over the list manually instead of doing what you do now, by looking for , characters and remembering the position of the last found one and the one before. This will definitely make your app work because then it won't need to store the entire set in the memory at once.
Code example:
var str = "aaa,bbb,ccc";
var previousComma = -1;
var currentComma = 0;
for (; (currentComma = str.IndexOf(',', previousComma + 1)) != -1; previousComma = currentComma)
{
var currentItem = str.Substring(previousComma + 1, currentComma - previousComma - 1);
Console.WriteLine(currentItem);
}
var lastItem = str.Substring(previousComma + 1);
Console.WriteLine(lastItem);
Custom iterator
If you want to do it 'properly' in a fancy way, you can even write a custom enumerator:
public class CommaSeparatedStringEnumerator : IEnumerator<string>
{
int previousComma = -1;
int currentComma = -1;
string bigString = null;
bool atEnd = false;
public CommaSeparatedStringEnumerator(string s)
{
if (s == null)
throw new ArgumentNullException("s");
bigString = s;
this.Reset();
}
public string Current { get; private set; }
public void Dispose() { /* No need to do anything here */ }
object IEnumerator.Current { get { return this.Current; } }
public bool MoveNext()
{
if (atEnd)
return false;
atEnd = (currentComma = bigString.IndexOf(',', previousComma + 1)) == -1;
if (!atEnd)
Current = bigString.Substring(previousComma + 1, currentComma - previousComma - 1);
else
Current = bigString.Substring(previousComma + 1);
previousComma = currentComma;
return true;
}
public void Reset()
{
previousComma = -1;
currentComma = -1;
atEnd = false;
this.Current = null;
}
}
public class CommaSeparatedStringEnumerable : IEnumerable<string>
{
string bigString = null;
public CommaSeparatedStringEnumerable(string s)
{
if (s == null)
throw new ArgumentNullException("s");
bigString = s;
}
public IEnumerator<string> GetEnumerator()
{
return new CommaSeparatedStringEnumerator(bigString);
}
IEnumerator IEnumerable.GetEnumerator()
{
return this.GetEnumerator();
}
}
Then you can iterate over it like this:
var str = "aaa,bbb,ccc";
var enumerable = new CommaSeparatedStringEnumerable(str);
foreach (var item in enumerable)
{
Console.WriteLine(item);
}
Other thoughts
Can I make this more efficient?
Yes, you can. I suggest to either work with a more efficient data format (you can take a look around databases or XML, JSON, etc. depending on your needs). If you really want to work with comma-separated items, see my code examples above.

There's no need to create a bunch of sub-lists from powlist and reconstruct it. Simply loop over the powlist and update the ReportingGroup property accordingly.
var maclist = new HashSet<string>( ownRG.Split(',') );
foreach( var item in powlist) {
if( maclist.Contains( item.Machine ) ){
item.ReportingGroup = ownRG;
}
}
Since this changes powlist in place, you won't allocate any extra memory and shouldn't run into an OutOfMemoryException.

In a loop find the next ',' char. Take the substring between the ',' and the previous ',' position. At the end of the loop save a reference to the previous ',' position (which is initially set to 0). So you parse the items one-by-one rather than all at once.

You can try looping the items of your lists, but this will increase processing time.
foreach(var item in powlist)
{
//do your opeartions
}

Trouble finding tab character in list objects

I am working in C#, winforms application.
I am reading from a text file where each row has fields divided by tabs:
I am putting each row in a list named tic_string. From here I am trying to search each list object, find the tabs, and put each field in its own array. So there will be an array for column a, column b, column c ... etc.
The problem is when I try to find the tabs in my list objects, it finds nothing. Here is my code:
string[] tic_num = new string[row_counter];
string[] tic_title = new string[row_counter];
string[] tic_owner = new string[row_counter];
string[] tic_open_date = new string[row_counter];
int last_tab = 0;
int char_counter = 0;
int feild_counter = 1;
int feild_char_count = 1;
int current_row=0;
string temp_feild = "";
char temp_char;
char tab_char = '\t';
foreach (string tic_string_value in tic_string)
{
temp_char = tic_string_value[char_counter];
if (temp_char == tab_char)
{
Console.WriteLine("tab_found");
if (feild_char_count == 1)
{
temp_feild = "";
}
else
{
temp_feild = tic_string_value.Substring(last_tab, feild_char_count);
}
last_tab = char_counter;
feild_char_count = 0;
switch (feild_counter)
{
case 1:
tic_num[current_row] = temp_feild;
break;
case 2:
tic_title[current_row] = temp_feild;
break;
case 3:
tic_owner[current_row] = temp_feild;
break;
case 4:
tic_open_date[current_row] = temp_feild;
break;
}
}
current_row++;
feild_char_count++;
char_counter++;
if (feild_counter == 5)
feild_counter = 1;
}

Your code seems to be too complicated for such simple task. Do not parse each line char by char, just use helper functions like String.Split etc.:
foreach (string tic_string_value in tic_string)
{
var parts = tic_string_value.Split(new [] { '\t' },
StringSplitOptions.RemoveEmptyEntries);
tic_num[current_row] = parts[0];
tic_title[current_row] = parts[1];
tic_owner[current_row] = parts[2];
tic_open_date[current_row] = parts[3];
current_row++;
}

First of all, I deduce from the style of your code that you are probably familiar with C/C++ and are new to C#, because this code has a particularly "C++" flavour to it. It reminds me very much of my own C# code when I first made the jump myself.
I am glad that you described the problem you are trying to solve rather than simply posting the code and asking where to find the bug because I think you can actually solve your problem much more simply.
Considering the following code (this assumes that you're iterating over each of the rows outside this code, and I omit some of the declaring of variables that you had already specified):
int field_counter = 0;
foreach (var field in tic_string.Split('\t')) {
switch (field_counter++) {
case 0:
tic_num[current_row] = field;
break;
case 1:
tic_title[current_row] = field;
break;
case 2:
tic_owner[current_row] = field;
break;
case 3:
tic_open_date[current_row] = field;
break;
}
}
This leverages the succinctness of C# and removes quite a few lines of code, which is always good. The String.Split method will take care of most of the string splitting for you, so there's no need to do it all manually and keep track of characters.
Note: I kept your original naming of some of the field names, although generally it is preferable to use CamelCase in C# code.
Now I notice from your original code that it's possible you don't have "rows" in your data in an actual sense (i.e. split by newline characters) but rather you may have the data entirely tab separated and are using the fact that you have a fixed number of columns per row to split up rows.
If this was the case, might I suggest the following code block could help you:
int i = 0;
foreach (var group in tic_string.GroupBy(x => i++ % 4)) {
int current_row = 0;
foreach (var field in group) {
switch (group.Key) {
case 0:
tic_num[current_row] = field;
break;
case 1:
tic_title[current_row] = field;
break;
case 2:
tic_owner[current_row] = field;
break;
case 3:
tic_open_date[current_row] = field;
break;
}
current_row++;
}
}
Now of course you may need to adapt these blocks to your code rather than use it verbatim. I hope that they at least demonstrate a different way of thinking about the problem. In particular, learning to use the various LINQ extension methods and LINQ queries will also be very helpful - they are part of what allows C# code to be so quick and easy to develop.
Best of luck in solving your problem!

You could also use a list instead of 4 string arrays:
public class ObjectToBeUsed
{
public Person(int num, string title, string owner, string opendate)
{
this.Num = num;
this.Title = title;
this.Owner = owner;
this.OpenDate = opendate;
}
private int _num;
public int Num
{
get { return _num; }
set { _num = value; }
}
private string _title;
public string Title
{
get { return _title; }
set { _title = value; }
}
private string _owner;
public string Owner
{
get { return _owner; }
set { _owner = value; }
}
private string _opendate;
public string OpenDate
{
get { return _opendate; }
set { _opendate = value; }
}
}
This is the class which describes each row in your text file.
System.IO.StreamReader file = new System.IO.StreamReader("test.txt");
string currentLine = null;
List<ObjectToBeUsed> peopleList = new List<ObjectToBeUsed>();
while ((currentLine = file.ReadLine()) != null)
{
string[] tokens = Regex.Split(currentLine, #"\t");
peopleList.Add(new ObjectToBeUsed(Convert.ToInt32(tokens[0]), tokens[1], tokens[2], tokens[3]));
}
The code is pretty self-explanatory, but if you need any further explaining, go ahead.

Code folding in RichTextBox

I am working on a Code Editor derived from Winforms RichTextBox using C#. I have already implemented autocompletion and syntax hilighting, but code folding is somewhat a different approach. What I want to achieve is:
The code below:
public static SomeFunction(EventArgs e)
{
//Some code
//Some code
//Some code
//Some code
//Some code
//Some code
}
Should become:
public static SomeFunction(EventArgs e)[...]
Where[...] is a shortened code that is displayed in a tooltip when you hover over at [...]
Any ideas or suggestions how to do it, either using Regex or procedural code?

I have created a parser that will return the indices of code folding locations.
Folding delimiters are defined by regular expressions.
You can specify a start and ending index so that you don't have to check the entire code when one area is updated.
It will throw exceptions if the code is not properly formatted, feel free to change that behavior. One alternative could be that it keeps moving up the stack until an appropriate end token is found.
Fold Finder
public class FoldFinder
{
public static FoldFinder Instance { get; private set; }
static FoldFinder()
{
Instance = new FoldFinder();
}
public List<SectionPosition> Find(string code, List<SectionDelimiter> delimiters, int start = 0,
int end = -1)
{
List<SectionPosition> positions = new List<SectionPosition>();
Stack<SectionStackItem> stack = new Stack<SectionStackItem>();
int regexGroupIndex;
bool isStartToken;
SectionDelimiter matchedDelimiter;
SectionStackItem currentItem;
Regex scanner = RegexifyDelimiters(delimiters);
foreach (Match match in scanner.Matches(code, start))
{
// the pattern for every group is that 0 corresponds to SectionDelimter, 1 corresponds to Start
// and 2, corresponds to End.
regexGroupIndex =
match.Groups.Cast<Group>().Select((g, i) => new {
Success = g.Success,
Index = i
})
.Where(r => r.Success && r.Index > 0).First().Index;
matchedDelimiter = delimiters[(regexGroupIndex - 1) / 3];
isStartToken = match.Groups[regexGroupIndex + 1].Success;
if (isStartToken)
{
stack.Push(new SectionStackItem()
{
Delimter = matchedDelimiter,
Position = new SectionPosition() { Start = match.Index }
});
}
else
{
currentItem = stack.Pop();
if (currentItem.Delimter == matchedDelimiter)
{
currentItem.Position.End = match.Index + match.Length;
positions.Add(currentItem.Position);
// if searching for an end, and we've passed it, and the stack is empty then quit.
if (end > -1 && currentItem.Position.End >= end && stack.Count == 0) break;
}
else
{
throw new Exception(string.Format("Invalid Ending Token at {0}", match.Index));
}
}
}
if (stack.Count > 0) throw new Exception("Not enough closing symbols.");
return positions;
}
public Regex RegexifyDelimiters(List<SectionDelimiter> delimiters)
{
return new Regex(
string.Join("|", delimiters.Select(d =>
string.Format("(({0})|({1}))", d.Start, d.End))));
}
}
public class SectionStackItem
{
public SectionPosition Position;
public SectionDelimiter Delimter;
}
public class SectionPosition
{
public int Start;
public int End;
}
public class SectionDelimiter
{
public string Start;
public string End;
}
Sample Find
The sample below matches folds delimited by {,}, [,], and right after a symbol until a ;. I don't see too many IDE's that fold for each line, but it might be handy at long pieces of code, like a LINQ query.
var sectionPositions =
FoldFinder.Instance.Find("abc { def { qrt; ghi [ abc ] } qrt }", new List<SectionDelimiter>(
new SectionDelimiter[3] {
new SectionDelimiter() { Start = "\\{", End = "\\}" },
new SectionDelimiter() { Start = "\\[", End = "\\]" },
new SectionDelimiter() { Start = "(?<=\\[|\\{|;|^)[^[{;]*(?=;)", End = ";" },
}));

Sending a list of doubles as strings to the database

Just quite confused with the piece of code below.
I have class like below
public class Counter
{
public Double NormalCounter { get; set; }
public Double SATCounter { get; set; }
public Double SUNCounter { get; set; }
}
in my main class i have method to do some calculation to fill the counter
Counter CountHrs = GetBookedHours(resourceBkg, PrevEvent);
var lstExpResult = new List<string> {CountHrs.NormalCounter.ToString(),
CountHrs.SATCounter.ToString(),
CountHrs.SUNCounter.ToString()};
UpdateBooking(bookingSesid, lstExpResult);
Just assume i have the value like below in the counter
NormalCounter =4
SATCounter=10
SUNCounter=6
am trying to add in to string list and update the database.is that the right way to do ? or any other options i have please.
my update booking method is below to give clear idea.
public static bool UpdateBooking(string BookingSesid,List<string>HoursByRate)
{
SchedwinEntities db = new SchedwinEntities();
string value = string.Empty;
for (int i = 0; i < 5; i++)
{
string str = " ";
if (i < HoursByRate.Count())
{
str = HoursByRate[i];
value += str + ((char)13).ToString() + ((char)10).ToString();
}
}
var query =
from SEVTs in db.SEVTs
where
SEVTs.SESID.Trim() == BookingSesid//SESID
select SEVTs;
foreach (var SEVTs in query)
{
SEVTs.USER3 = value;//value
}
try
{
db.SaveChanges();
return true;
}
catch (UpdateException ex)
{
return false;
}
}

Rather than passing a list of strings that represent doubles, you should pass a list of key-value pairs, construct a parametersized statement from them, and use the list of key-value-pairs to bind parameter values, like this:
class SqlParamBinding {
string Name {get;set;}
object Value {get;set;}
}
var lstExpResult = new List<SqlParamBinding> {
new SqlParamBinding { Name = "NormalCounter", Value = CountHrs.NormalCounter}
, new SqlParamBinding { Name = "SATCounter", Value = CountHrs.SATCounter}
, new SqlParamBinding { Name = "SUNCounter", Value = CountHrs.SUNCounter}
};
UpdateBooking(bookingSesid, lstExpResult);
Now that lstExpResult separates names from values, your UpdateBooking code could format the SQL expression as
WHERE NormalCounter=#NormalCounter AND SATCounter=#SATCounter AND ...
and then bind #NormalCounter, #SATCounter, and #SUNCounter to the values passed in the lstExpResult list.

If it is going to list of Counter classes then have List instead of List. Looks like you might be having bunch of Counter objects that might be getting updated or sent to the database.
Counter c = new Counter();
c. NormalCounter = 4
c.SATCounter = 10
c.SunCounter = 10
List<Counter> listCounter = new List<Counter>
listCounter.Add(c);
Code is more maintainable and readable.
If you are sending one object at a time, then no need of list at all. You can pass in the counter object to your UpdateMethod and parse it while updating the database.