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  • C# Reflection: How to call method of interface without creating instance?

    - by jitm
    Hello, I have situation where I have to call method of interface using reflection, like this object x = null; MethodInfo method = interfaceExists.GetMethod("ShutDown"); method.Invoke(x, new object[] { 4 }) As you can see I do not create instance of object! And, as I can supposed, I receive exception Non-static method requires a target And Question, Can I call method of interface using reflection without creating instance of interface and if YES, How I can do it ? Thank you.

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  • How to grep curl -I header information

    - by Mint
    Im trying to get the redirect link from a site by using curl -I then grep to "location" and then sed out the location text so that I am left with the URL. But this doesn't work, it will outputs the URL to screen and doesn't put it test=$(curl -I "http://www.redirectURL.com/" 2> /dev/null | grep "location" | sed -E 's/location:[ ]+//g') echo "1..$test..2" Which then outputs: ..2http://www.newURLfromRedirect.com/bla Whats going on?

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  • Automatically generating Guids in Sybase

    - by Daniel Dyson
    I have a table with 42 million records. 32 million have a null value and I would like to generate a new guid for each one. Should I do this in batches? Also, going forward, I would like a new guid added to the field on the insert of a new record. What is the best way to do this? The field is not the primary key, which is an auto-incrementing integer.

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  • Is it thread safe to read a form controls value (but not change it) without using Invoke/BeginInvoke from another thread

    - by goku_da_master
    I know you can read a gui control from a worker thread without using Invoke/BeginInvoke because my app is doing it now. The cross thread exception error is not being thrown and my System.Timers.Timer thread is able to read gui control values just fine (unlike this guy: can a worker thread read a control in the GUI?) Question 1: Given the cardinal rule of threads, should I be using Invoke/BeginInvoke to read form control values? And does this make it more thread-safe? The background to this question stems from a problem my app is having. It seems to randomly corrupt form controls another thread is referencing. (see question 2) Question 2: I have a second thread that needs to update form control values so I Invoke/BeginInvoke to update those values. Well this same thread needs a reference to those controls so it can update them. It holds a list of these controls (say DataGridViewRow objects). Sometimes (not always), the DataGridViewRow reference gets "corrupt". What I mean by corrupt, is the reference is still valid, but some of the DataGridViewRow properties are null (ex: row.Cells). Is this caused by question 1 or can you give me any tips on why this might be happening? Here's some code (the last line has the problem): public partial class MyForm : Form { void Timer_Elapsed(object sender) { // we're on a new thread (this function gets called every few seconds) UpdateUiHelper updateUiHelper = new UpdateUiHelper(this); foreach (DataGridViewRow row in dataGridView1.Rows) { object[] values = GetValuesFromDb(); updateUiHelper.UpdateRowValues(row, values[0]); } // .. do other work here updateUiHelper.UpdateUi(); } } public class UpdateUiHelper { private readonly Form _form; private Dictionary<DataGridViewRow, object> _rows; private delegate void RowDelegate(DataGridViewRow row); private readonly object _lockObject = new object(); public UpdateUiHelper(Form form) { _form = form; _rows = new Dictionary<DataGridViewRow, object>(); } public void UpdateRowValues(DataGridViewRow row, object value) { if (_rows.ContainsKey(row)) _rows[row] = value; else { lock (_lockObject) { _rows.Add(row, value); } } } public void UpdateUi() { foreach (DataGridViewRow row in _rows.Keys) { SetRowValueThreadSafe(row); } } private void SetRowValueThreadSafe(DataGridViewRow row) { if (_form.InvokeRequired) { _form.Invoke(new RowDelegate(SetRowValueThreadSafe), new object[] { row }); return; } // now we're on the UI thread object newValue = _rows[row]; row.Cells[0].Value = newValue; // randomly errors here with NullReferenceException, but row is never null! }

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  • How to get latest files in C#

    - by Newbie
    I have some files with same name but with different dates. Basically we are finding the files with most recent dates The file patterns are <FileNames><YYYYMMDD><FileExtension> e.g. test_20100506.xls indicates <FileNames> = test_ <YYYYMMDD> = 20100506 <FileExtension> = .xls Now in the source folder, the files are standardization_20100503.xls, standardization_20100504.xls, standardization_20100305.xls, replacement_20100505.xls As can be seen that, standardization_.xls are 3 in numbers but replacement_.xls is only 1. The output will be a list of file names whose content will be standardization_20100504.xls and replacement_20100505.xls Because among all the standardization_.xls is the most recent one and replacement_.xls is also the same. I have tried with my own logic but somehow failed. My idea is as under private static void GetLatestFiles(ref List<FileInfo> validFiles) { List<FileInfo> validFilesTemp = new List<FileInfo>(); for (int i = 0; i < validFiles.Count; i++) { for (int j = i+1; j < validFiles.Count; j++) { string getFileTextX = ExtractText(validFiles[i].Name); string getFileTextY = ExtractText(validFiles[j].Name); if (getFileTextX == getFileTextY) { int getFileDatesX = Convert.ToInt32(ExtractNumbers(validFiles[i].Name)); int getFileDatesY = Convert.ToInt32(ExtractNumbers(validFiles[j].Name)); if (getFileDatesX > getFileDatesY) { validFilesTemp.Add(validFiles[i]); } else { validFilesTemp.Add(validFiles[j]); } } } } validFiles.Clear(); validFiles = validFilesTemp; } The ExtractNumbers is: public static string ExtractNumbers(string expr) { return string.Join(null, System.Text.RegularExpressions.Regex.Split(expr, "[^\\d]")); } and the ExtractText is public static string ExtractText(string expr) { return string.Join(null, System.Text.RegularExpressions.Regex.Split(expr, "[\\d]")); } I am using c#3.0 and framework 3.5 Help needed .. it's very urgent Thanks .

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  • How can I do a multi level parent-child sort using Linq?

    - by Tenacious T
    How can I do a multi-level parent-child sort using Linq if I have a table structure like the one below: [Table: Sections] Id Seq Name ParentSectionId 1 1 TOP NULL 2 1 AAAA 1 3 2 SSSS 1 4 3 DDDD 1 5 1 SectionA1 2 6 2 SectionA2 2 7 1 SectionS1 3 8 3 ASummary 2 Expected sort result: TOP AAAA SectionA1 SectionA2 ASummary SSSS SectionS1 DDDD

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  • Ques: Which method will be called and y?

    - by Gaurav
    Ques: Which method will be called and y? public class Test { public void method(Object o){ System.out.println("object"); } public void method(String s) { System.out.println("String"); } public void method() { System.out.println("blank"); } /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Test test=new Test(); test.method(null); } }

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  • Using RedirectToAction with custom type parameter

    - by user170497
    Hi asp.net mvc 2 I have this action in Identity controller public ActionResult Details(string id, MessageUi message) { And I'm trying to redirect to this action from another controller, but I don't know how should I pass the message parameter I was trying with var id = "someidvalue" var message = new MessageUi("somevalue"); return RedirectToAction("Details", "Identity", new { id, message}); } but message parameter is null

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  • Invoking static methods containing Generic Parameters using Reflection.

    - by AJP
    While executing the following code i gets this error "Late bound operations cannot be performed on types or methods for which ContainsGenericParameters is true." class Program { static void Main(string[] args) { MethodInfo MI = typeof(MyClass).GetMethod("TestProc"); MI.MakeGenericMethod(new [] {typeof(string)}); MI.Invoke(null, new [] {"Hello"}); } } class MyClass { public static void TestProc<T>(T prefix) { Console.WriteLine("Hello"); } } Please help.

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  • Can you get a Func<T> (or similar) from a MethodInfo object?

    - by Dan Tao
    I realize that, generally speaking, there are performance implications of using reflection. (I myself am not a fan of reflection at all, actually; this is a purely academic question.) Suppose there exists some class that looks like this: public class MyClass { public string GetName() { return "My Name"; } } Bear with me here. I know that if I have an instance of MyClass called x, I can call x.GetName(). Furthermore, I could set a Func<string> variable to x.GetName. Now here's my question. Let's say I don't know the above class is called MyClass; I've got some object, x, but I have no idea what it is. I could check to see if that object has a GetName method by doing this: MethodInfo getName = x.GetType().GetMethod("GetName"); Suppose getName is not null. Then couldn't I furthermore check if getName.ReturnType == typeof(string) and getName.GetParameters().Length == 0, and at this point, wouldn't I be quite certain that the method represented by my getName object could definitely be cast to a Func<string>, somehow? I realize there's a MethodInfo.Invoke, and I also realize I could always create a Func<string> like: Func<string> getNameFunc = () => getName.Invoke(x, null); I guess what I'm asking is if there's any way to go from a MethodInfo object to the actual method it represents, incurring the performance cost of reflection in the process, but after that point being able to call the method directly (via, e.g., a Func<string> or something similar) without a performance penalty. What I'm envisioning might look something like this: // obviously this would throw an exception if GetActualInstanceMethod returned // something that couldn't be cast to a Func<string> Func<string> getNameFunc = (Func<string>)getName.GetActualInstanceMethod(x); (I realize that doesn't exist; I'm wondering if there's anything like it.) If what I'm asking doesn't make sense, or if I'm being unclear, I'll be happy to attempt to clarify.

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  • Any way to anticipate session timeout ?

    - by Tom
    Hi, Is there a way to "catch" the session timeout event, so as to retrieve data from HttpSession before its invalidated ? We're implementing the Filter Interface, and in the doFilter method, the user we stored in the session object at login is null when session times out. Thanks in advance.

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  • Will my shared variables loose value? (asp.net vb)

    - by Phil
    I have a class includes.vb that holds some variables (sharing them with other pages) like: Public Shared pageid As Integer = 0 I then have a function that does some work with these variables returning them with values; Return pageid When I step through the code, the variables have values (while stepping through the function), but when they are returned to the page, they come back null. Do they loose value everytime a page is loaded? Can you suggest an alternative method? Thanks a lot.

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  • Java looping through array - Optimization

    - by oudouz
    I've got some Java code that runs quite the expected way, but it's taking some amount of time -some seconds- even if the job is just looping through an array. The input file is a Fasta file as shown in the image below. The file I'm using is 2.9Mo, and there are some other Fasta file that can take up to 20Mo. And in the code im trying to loop through it by bunches of threes, e.g: AGC TTT TCA ... etc The code has no functional sens for now but what I want is to append each Amino Acid to it's equivalent bunch of Bases. Example : AGC - Ser / CUG Leu / ... etc So what's wrong with the code ? and Is there any way to do it better ? Any optimization ? Looping through the whole String is taking some time, maybe just seconds, but need to find a better way to do it. import java.io.BufferedReader; import java.io.File; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; public class fasta { public static void main(String[] args) throws IOException { File fastaFile; FileReader fastaReader; BufferedReader fastaBuffer = null; StringBuilder fastaString = new StringBuilder(); try { fastaFile = new File("res/NC_017108.fna"); fastaReader = new FileReader(fastaFile); fastaBuffer = new BufferedReader(fastaReader); String fastaDescription = fastaBuffer.readLine(); String line = fastaBuffer.readLine(); while (line != null) { fastaString.append(line); line = fastaBuffer.readLine(); } System.out.println(fastaDescription); System.out.println(); String currentFastaAcid; for (int i = 0; i < fastaString.length(); i+=3) { currentFastaAcid = fastaString.toString().substring(i, i + 3); System.out.println(currentFastaAcid); } } catch (NullPointerException e) { System.out.println(e.getMessage()); } catch (FileNotFoundException e) { System.out.println(e.getMessage()); } catch (IOException e) { System.out.println(e.getMessage()); } finally { fastaBuffer.close(); } } }

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  • trying to show a variable in my layout

    - by user1400
    hi i have a simple question where is my code wrong ? in index controller and index action i put $this->view->username="user1"; and when i try in my layout i use echo $this->username; i got fllowing error or null value Notice: Trying to get property of non-object in D:\Zend\Apache2\htdocs\test\application\layouts\layout.phtml on line 115 thanks

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  • Another getcwd question...

    - by rubenvb
    Sorry to keep hammering on this, but I'm trying to learn :). Is this any good? And yes, I care about memory leaks. I can't find a decent way of preallocating the char*, because there simply seems to be no cross-platform way. const string getcwd() { char* a_cwd = getcwd(NULL,0); string s_cwd(a_cwd); free(a_cwd); return s_cwd; }

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  • How to set size (width,height) of externally loaded swf

    - by Raj
    Hi, I have loaded swf using following code, var loader:Loader = new Loader(); loader.load(new URLRequest("XYZ.swf")); addChild(loader); How do I control height and width of this loaded swf. I tried var mc = MovieClip(loader.loaderContentInfo.content); mc.width = 320; mc.height = 240; this gives null object error.

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  • Database design

    - by Hadad
    Hello, I've a system, that have two types of users (Companies and individuals).all types have a shared set of properties but they differ in another. What is the best design merge all in one table that allows null for unmatched properties, or separate them in two tables related to a basic table with a one to one relationship. Thanks.

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