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bekzod009 wrote: Thanks
And what is your problem?
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I inherited a project at my job, and there is a line of code that is giving me an error. I am having trouble figuring it out.
In the method below, data is being pulled from a table, and put into a CustomerData object. The "Expiration" line, which is a DateTime, is the one that is erroring. If I take out this part: "() => new License()" in the .FirstOrDefault method, it compiles, but when I click on the part that populates the grid I get "Object reference not set to an instance of an object.". If I try to compile with this part: "() =&gt; new License()" it gives me this error: "The type arguments for method 'System.Linq.Enumerable.FirstOrDefault<TSource>(System.Collections.Generic.IEnumerable<TSource>, System.Func<TSource,bool>)' cannot be inferred from the usage. Try specifying the type arguments explicitly."
If I assign "Expiration" to a static DateTime, then it works fine and populates the return with all the same date/time.
So, I think the linq part of the statement is wrong and I am getting null back (when the field is not nullable), or I need to specify the type somewhere in there.
Any help would be appreciated!
internal static IEnumerable<CustomerData> GetCustomers(this HttpRequest request)
{
var dc = new RootDataContext();
return dc.Customers.ToList().Select(c => new CustomerData()
{
CustomerId = c.CustomerID,
StoreNumber = c.StoreNumber,
StoreName = c.StoreName,
OwnerName = c.OwnerName,
City = c.City,
State = c.State,
TimeZone = c.TimeZone,
//Compile time error, "specify type"
//Expiration = c.Licenses.Where(l => l.ProductID > 1002).OrderBy(l => l.Expiration).FirstOrDefault(() => new License()).Expiration,
//Compiles, errors "null reference"
//Expiration = c.Licenses.Where(l => l.ProductID > 1002).OrderBy(l => l.Expiration).FirstOrDefault().Expiration,
//works, all the same datetime
//Expiration = new DateTime(2010, 12, 10),
Trial = c.Licenses.Where(l => l.ProductID > 1002).Any(l => l.Trial),
InventoryDate = c.Products_Database_Eagle != null ? c.Products_Database_Eagle.InventoryDate : default(DateTime),
Upload = c.Products_Database_Eagle != null ? c.Products_Database_Eagle.Upload : false,
Finalize = c.Products_Database_Eagle != null ? c.Products_Database_Eagle.Finalize : false,
Registration = c.RegistrationKey,
});
}
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Looks like the search failure is returning a null license (since you specified FirstOrDefault) whose DateTime member you're trying to access.
/ravi
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So what would I do there?
I cant leave it blank, or else it gives me a object reference exception.
The code that was in there "() => new License()" has a compile time error that says "The type arguments for method 'System.Linq.Enumerable.FirstOrDefault<TSource>(System.Collections.Generic.IEnumerable<TSource>, System.Func<TSource,bool>)' cannot be inferred from the usage. Try specifying the type arguments explicitly."
I guess I need to know how to specify the type explicitly. I think it is trying to create a new License if it cannot find one in the select statement, which is why it leaves it blank if it cannot find one.
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Calvin Bell wrote: So what would I do there?
You need to evaluate your design and decide how the code should work, rather than simply tweaking the code to compile and run under circumstances. What DateTime do you want to do if the license is not found? A null reference, DateTime.MinValue, something else? The choice is yours.
/ravi
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my server implements a reading thread that blocks until data is received.
what I'd like to do is have a designated thread that only writes as data becomes available (an event would be created that contains the TcpClient in the event argument).
Therefore the question: is it possible to use TcpClient.GetStream() twice for the same TcpClient ?
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It's not possible.
'tcpclient.getstream() ' can get all btye[] by server socket sending.
April
Comm100 - Leading Live Chat Software Provider
modified 27-May-14 21:53pm.
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Yes, it's possible.
You can't read or write by two threads, but having a thread that only reads and a thread that only writes is perfectly possible. I always do this but, in fact, I call GetStream only once, and pass the returned stream as the parameter to the threads, but I really think this don't change anything.
Also, be carefull not to close the stream before you finished, as closing the stream will also close the tcp/ip connection.
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passing the TcpClient object around and calling GetStream() once in the read thread and once in the write thread worked just fine.
Since I found this out I have updated my code to use a secure socket and now I'm passing around a NegotiateStream object (but no need to call GetStream) 
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Hi,
In c# i generated HTML report (colored).
I am using Webbrowser control.
I need to print it. But unfortunately i cannot print the color (background color). why?
A sample report is as below.
<html>
<head>
<title>Test</title>
</head>
<body align=center >
<table align=center border=0 width=1000>
<tr>
<td align=center class=title style='border:2px solid red;'>110P-1 PRODUCTION SCHEDULE</td>
</tr>
</table>
<table align=center border=1 width=1000 cellspacing=0 cellpadding=0>
<tr>
<td colspan=3 align=right> <b>TOTALS:</b> </td>
<td align=center ><b>22160.00</b></td>
<td align=center ><b>15828.57</b></td>
<td align=center ><b>18000.09</b></td>
<td align=center><b>2971.36</b></td>
<td align=center><b>33</b></td>
<td > </td>
</tr>
<tr>
<td align=center ><b>DEL.DATE</b></td>
<td align=center ><b>COLOUR</b></td>
<td align=center><b>ADDRESS</b></td>
<td align=center ><b>L/M</b></td>
<td align=center ><b>HOURS@1.4m</b></td>
<td align=center ><b>COMPLETE</b></td>
<td align=center ><b>REMAIN HOURS</b></td>
<td align=center ><b>PACKS</b></td>
<td align=center ><b>STATUS</b></td>
</td>
<tr><td align=center > 20/11/2009</td>
<td align=center style='background-color:#FF8C00;'> </td>
<td align=center > Hamilton Iland</td>
<td align=center > 20310.00</td>
<td align=center > 14507.14</td>
<td align=center> 18000.09</td>
<td align=center > 1649.94</td>
<td align=center > 33</td>
<td align=center > </td></tr>
<tr><td align=center > 16/11/2009</td>
<td align=center style='background-color:#14A0E6;'> </td>
<td align=center > Bankstown</td>
<td align=center > 1250.00</td>
<td align=center > 892.86</td>
<td align=center > 0.00</td>
<td align=center > 892.86</td>
<td align=center > </td>
<td align=center > </td></tr>
</tr>
</table>
</body>
---------------------------------- ---------------------
I am using .NET framework 3.5
I have color printer. and if i changed table border to red, blue, etc for border, it prints in color.
It only does not work with table cell (TD) background color.
Thanks in advance
Shukra
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Because it follows the settings for Internet Explorer, which, by default, doesn't print the background at all.
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To follow up on Dave's response, you don't need to use a WebBrowserControl to print your document. Simply save the HTML to a temporary file and do the .NET equivalent of ShellExecute (..., "print", ...) to print it. The .NET equivalent is Process.Start().
/ravi
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Thanks Ravi,
Will you pls tell me if.
Is there any way to change IE printer settings from c# code?
1.I want to dynamically set page orientation to "Landscape" or "Portrait"
2.I want to remove the header or footer. (I can change the values from registry, but don't know how to disable it?)
Thanks again,
Shukra
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Hi,
I am currently doing some research to see which of these wrappers of OpenCV to use for myfinal year project. I am looking to develop something in C# to recognise the movement of a hand.
Any advice is appreciated.
Cheers!
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Great! Was there a question in there, or did you just want to announce to the world what you're doing?
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My Bad! Engrossed in this thing I cant think straight!
I want to find out which one is better. Thanks in advance for your suggestions!
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The one that meets all of your specifications.
"Better" is a subjective term. The only way you're going to know is to test each one against what you want to do.
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Hi
Is there a way of writing and reading a csv file from C# at the same time?
I mean I have two separated projects; one keeps writing data into a csv file and the other one is to read the data from the same csv that is also being written.
When I tried this, it always says the file can't be accessed because it's being used by another process.
Is there anyway of getting around this?
Many thanks indeed.
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Tony4966 wrote: Is there anyway of getting around this?
The easiest way that comes to mind is to replace the file with a desktop database. You can read/write into the database from multiple points, and export the parts to CSV if you need them.
I are Troll 
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The program that writes the file needs to allow other processes to read it; this is done when the stream is opened.
But, really, this is unlikely to be a good design. Do you really want the file? Or are you only trying to have inter-process communication? If you don't actually need the file; then find a better way.
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You are right. This is probably not a good design but I just want to get this working as quickly as possible and it is just a short term solution.
So please can you be a little bit more specific about how exactly I let the program that writes into the file allow other programs to read the file at the same time?
A quick example of would be
string path = @"C:\Documents and Settings\";
string filename = "tester.csv";
TextWriter writer = new StreamWriter(path + filename, false);
for (int j = 0; j < 10; j++)
writer.WriteLine("{0}, {1}", j,2 * j);
Many thanks indeed.
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You can create a FileStream that allows read access using this[^] constructor:
Stream stream = new FileStream(path + filename, FileAccess.OpenOrCreate, FileAccess.Write, FileShare.Read);
TextWriter writer = new StreamWriter(stream); Also it is a better pratice to dispose of the stream, enclosing them with the using keyword.
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Consider using a message queue. It is robust and flexible, performs well, supports asynchronous processing (if desired) and doesn't take a lot of code so should be as quick to get up and running as messing with the files.
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a service with a queue seems like an awesome idea for production code; you could add logging and keep adding all sorts of features as the requirements of the other applications change.
I personally have used a MemoryMapped file to exchange data between two applications because I hate using the HDD for temporary data.
EDIT: for an example of a memorymapped file: http://msdn.microsoft.com/en-us/library/dd997372%28VS.100%29.aspx[^]
modified on Monday, November 23, 2009 6:45 PM
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