C# Discussion Boards - CodeProject

OriginalGriff11-Jul-13 23:58

OriginalGriff

11-Jul-13 23:58

No, there is no way to "miss out" a value in a IEnumerable iteration.
You could use double.MinValue instead:

var ks = d.Max(v => v.Value == null ? double.MinValue : v.Value[0]);

var ks = d.Max(v => { if (v.Value == null) return null; return v.Value[0]; });

But then you need to check for null in the ks variable as a list with all nulls with return a null instead of a double value.

The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)

Richard Deeming12-Jul-13 1:51

Richard Deeming

12-Jul-13 1:51

OriginalGriff wrote:
No, there is no way to "miss out" a value in a IEnumerable iteration.

Ahem![^]

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

OriginalGriff12-Jul-13 3:37

OriginalGriff

12-Jul-13 3:37

Hadn't thought of Where - good point!

The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)

Richard Deeming12-Jul-13 1:50

Richard Deeming

12-Jul-13 1:50

You can use the Where method[^] to skip the null items:

var ks = d.Where(v => v.Value != null).Max(v => v.Value[0]);

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Read Minidumps through Native Code

Jay Nardev12-Jul-13 1:11

Jay Nardev

12-Jul-13 1:11

use like this

Dictionary<string, Nullable<double>[]> d = new Dictionary<string, Nullable<double>[]>();
d.Add("a", new Nullable<double>[2] { 100, 102 });
d.Add("b", null);
d.Add("v", new Nullable<double>[2] { 99, 101 }); ;

It would help you. Smile | :)

Zach.Saunders11-Jul-13 6:02

Zach.Saunders

11-Jul-13 6:02

I am revisiting a project that I have wanted to do for a long time. I am trying to read Minidumps much like BlueScreenView just with C# code. I was pointed to using

[DllImport("dbghelp.dll", SetLastError = true)]
public static extern bool MiniDumpReadDumpStream(IntPtr BaseOfDump,
   int StreamNumber,
   ref MINIDUMP_DIRECTORY Dir,
   ref IntPtr StreamPointer,
   ref UInt32 StreamSize);

And after much digging, I found this
http://www.symbolsource.org/Public/Metadata/NuGet/Project/Microsoft.Samples.Debugging.CorApi/1.4.0.0/Release/Default/Microsoft.Samples.Debugging.Native/Microsoft.Samples.Debugging.Native/DumpReader.cs[ ]

But I am having an issue with being able to pass in a string to the DumpReader and then read the return value. It appears that I need to pass a targetaddress and the length to the ReadMemory but I am getting an exception. I am very new to the whole native code thing. I like my .Net Libraries.

From DumpReader.CS

public byte[] ReadMemory(ulong targetAddress, int length)
{
    byte[] buffer = new byte[length];
    ReadMemory(targetAddress, buffer);
    return buffer;
}

From My Code:

DumpReader dr = new DumpReader(PathToDump);
dr.ReadMemory(??, ??);

Eddy Vluggen11-Jul-13 8:32

Eddy Vluggen

11-Jul-13 8:32

There's an easier example here[^]. I've got it working using the 4.0 runtime, seems the VS-IDE doesn't read them that well for the 2.0 runtime.

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

Zach.Saunders11-Jul-13 9:52

Zach.Saunders

11-Jul-13 9:52

I see that the link in your post describes how to create a MiniDump but what I am looking to be able to do is read them. I am not interested in reading them in VS but through code like BlueScreenView

Mycroft Holmes11-Jul-13 14:01

11-Jul-13 14:01

Zach.Saunders wrote:
I am not interested in reading them in VS but through code like BlueScreenView

And yet you ask the question in a C# forum!

What do you mean by code like BlueScreenView.

Never underestimate the power of human stupidity
RAH

Zach.Saunders11-Jul-13 15:33

Zach.Saunders

11-Jul-13 15:33

I would like to be able to open up the .dmp files programmatically in a C# application and read the output to a form. I am trying to literally make a program that behaves just like Nirsoft's BlueScreenView.

Latest built installer for a project doesn't show up in Add/Remove Programs

Eddy Vluggen14-Jul-13 2:59

Eddy Vluggen

14-Jul-13 2:59

Zach.Saunders wrote:
I would like to be able to open up the .dmp files programmatically in a C# application and read the output to a form.

Here's[^] the file format for a Windows CE 5 structure to give an idea how it looks. I don't know where the one for Windows 7/8 is, or even if it's publicly available.

You'd have to research that Smile | :)

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

stingray2711-Jul-13 2:59

stingray27

11-Jul-13 2:59

I noticed within the past week or two my latest builds of a specific project are not showing up in Add/Remove programs.

I am using Visual Studio 2010, Windows 7 64 bit (though I've also tried 2 32 bit machines). All latest service packs and updates are installed. The solution is made up of several projects with various references. The Setup and Deployment project is not the Install Shield version, but the built in Microsoft project.

Previous versions of the software installed fine, and still do... but if I pull down a tagged earlier version from CVS, and rebuild the installer for those versions, they do not work either.

I've opened the MSI in Orca, and I can see that the ARPNOREMOVE, ARPSYSTEMCOMPONENT are both set to 1. When the project gets installed, a registry entry SystemComponent Dword value is created. If I remove that registry entry, the application shows up. Based on everything I've read and researched I have found people that WANTED this funcitonality but were told Visual Studio can not do this on its own and their solutions were to use Orca to add the ARPNOREMOVE or ARPSYSTEMCOMPONENT. At this point, all of the people who had my problem that I can find either had a basic default installer and they didn't know what name they were looking for in Add/Remove Programs or some other basic error that doesn't apply in my situation.

I've tried all of the following.

-Previous versions of tagged versions on CVS
-Multiple development machines
-Multiple computers to verify none show up in Add/Remove programs -Resetting all Visual Studio settings
-Building from a clean development environment
-Removing Installer project from the solution and creating a new installer project

The weird part is that if I create a new solution and just create a setup and deployment project within, that installs fine.

Re: Latest built installer for a project doesn't show up in Add/Remove Programs

stingray2711-Jul-13 4:14

stingray27

11-Jul-13 4:14

Since I'm in desperate mode, I wrote a post build event to modify the installer... all it is doing is removing the entry 'ARPSYSTEMCOMPONENT'. I suppose I'll also need to the do the same with the ARPNOREMOVE, and the others...

Surely I'm not the first person this has happened to.

Re: Latest built installer for a project doesn't show up in Add/Remove Programs

stingray2712-Jul-13 1:53

stingray27

12-Jul-13 1:53

So this is what I found out. We are using National Instruments Measurement Studio for .Net and the legacy controls. When using the legacy controls a certain merge module gets recognized as a dependency. For whatever reason, now this merge module change the behavior of the installer that is compiled. I've contacted National Instruments and am now working with them.

Remove / delete MemoryMappedFile

Member 333503211-Jul-13 1:32

Member 3335032

11-Jul-13 1:32

I create MemoryMappedFile like this :

mmf = MemoryMappedFile.CreateFromFile(filename, FileMode.OpenOrCreate, name, length, MemoryMappedFileAccess.ReadWrite);

but after use if i try to remove file from disk it is "in use" :

mmf.Dispose();
mmf = null;
File.Delete(filename); // cause exception

how i can remove it without end of application ? All reader/writer are disposed too.

Re: Remove / delete MemoryMappedFile

Garth J Lancaster11-Jul-13 1:54

Garth J Lancaster

11-Jul-13 1:54

have you tried using Finalize() instead of Dispose() ? (just wondering if that would make a difference)

your

mmf = ...

line is probably better served wrapped in a 'using' block btw

'g'

Re: Remove / delete MemoryMappedFile

Member 333503211-Jul-13 2:01

Member 3335032

11-Jul-13 2:01

mff has no Finalize() member Frown | :(

and all MemoryMappedViewAccessor's are wrapped into 'using' blocks, but mmf is "global" and will be accessed from different parts of code.

Design Question

Kevin Marois10-Jul-13 16:07

10-Jul-13 16:07

What's the best way to notify the front end of a business rule or possible FK violation? For example, I have a lookup called PayType, and so far my DeletePayType looks like this:

public static void DeletePayType(int PayTypeId)
{
    using (var dc = getDataContext())
    {

        bool inUse = isPayTypeInUse(PayTypeId);

        if (inUse)
        {
            //TODO: Handle this differently
            throw new Exception("Pay Type is in use and cannot be deleted");
        }
        else
        {
            var payType = (from ca in dc.PayTypes
                            where ca.PayTypeId == PayTypeId
                            select ca).FirstOrDefault();

            if (payType != null)
            {
                dc.PayTypes.DeleteOnSubmit(payType);

                try
                {
                    dc.SubmitChanges();
                }
                catch (Exception e)
                {
                    throw e;
                }
            }
        }
    }
}

Throwing an exception doesn't seem right, but I need the client to know that the pay type is in use and can't be deleted.

Thanks

If it's not broken, fix it until it is

Mycroft Holmes10-Jul-13 17:16

10-Jul-13 17:16

Yup programming by error - try and delete the record and then inform the user when it fails - start looking for some other employment.

Here is one reason I ALWAYS use a stored proc, the delete procedure check the FK table and only deletes the record if there is no constraint.

Never underestimate the power of human stupidity
RAH

Kevin Marois10-Jul-13 17:31

10-Jul-13 17:31

Mycroft Holmes wrote:
Yup programming by error - try and delete the record and then inform the user
when it fails - start looking for some other employment.

I guess I don't get what you mean.

Deleting the record is possible if it's not in use. This isn't programming by error, it's making sure that a FK violation won't occur.

Mycroft Holmes wrote:
Here is one reason I ALWAYS use a stored proc, the delete procedure check the FK
table and only deletes the record if there is no constraint.

Using a sproc won't solve the issue - just move the code that deletes it.

Ant any rate, the user needs to be notified if they cannot delete the record. This is a perfectly normal business rule.

If it's not broken, fix it until it is

Mycroft Holmes10-Jul-13 18:22

10-Jul-13 18:22

Ok a little more detail is required. you have 2 options with this scenario.

You can try and delete the record and hit the constraint and then deal with it by informing the user. This imposes an error on the DB.
You can also query the DB to see if the record can be deleted using an if EXIST query on the related table(s).

The first method is programming by error and is generally used by lazy sods who have no craftsmanship.

The second requires 2 or more round trips to the database and IMHO is a waste of effort. I write a delete procedure that does the checking before it deletes (or deletes the FK children BEFORE it tries to delete the master record). The proc returns the number of master records deleted (1) or failed (0) or if it is not deleting the children and one exists then it returns (-1). This moves the decision into the database and requires one 1 round trip and supplies the feedback to the user if there is an active constraint.

Never underestimate the power of human stupidity
RAH

Kevin Marois10-Jul-13 18:58

10-Jul-13 18:58

You're still missing what I'm aiming for...

I want to find out IF the PayType record can be deleted. If its PK is in use in another table, then I don't want to try to delete it. I DO however want to tell the user it's in use.

If it's not broken, fix it until it is

Mycroft Holmes10-Jul-13 19:34

10-Jul-13 19:34

So how are going to find out if the PayType records is in use by another table(s)? Query the related tables and see if the ID is in use!

You could write a generic procedure that queries sysobjects to identify the PKs and their related fields and then query the tables and return a boolean if you can delete the record. A matter of fact that sounds like an excellent widget to build, why is there not one of those?

Never underestimate the power of human stupidity
RAH

Kevin Marois10-Jul-13 19:57

10-Jul-13 19:57

All that's fine, and is what I am already doing... querying the tables that use the PK.

My original question still is "What's the best way to notify the front end of a business rule or possible FK violation?"

Raise an exception? Return a string?

How does the UI find out that the backend can't delete the row?

If it's not broken, fix it until it is