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Re: MemoryMappedFiles / MemoryMappedViewAccessor

Dave Kreskowiak14-Jun-13 7:24

Dave Kreskowiak

14-Jun-13 7:24

Don't flush every record. Just do the write and flush at then end when you're done with the entire file. An "atomic" operation (this is not really what "atomic" means!) is not going to save your data if the power fails during the write to the drive. The power failing is not going to wait for the write of 50 bytes to the drive to complete before going dead.

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Dave Kreskowiak

Re: MemoryMappedFiles / MemoryMappedViewAccessor

Member 333503216-Jun-13 20:29

Member 3335032

16-Jun-13 20:29

Yes, i know it, prefomance impact at flush every record is huge, but i write small datapackeges asynchrone from different threads and i will be sure, that this is as much as possible power fail safe ... I vod't wahnt lost last 10k entries in OS bufer.

Re: MemoryMappedFiles / MemoryMappedViewAccessor

Dave Kreskowiak17-Jun-13 1:05

Dave Kreskowiak

17-Jun-13 1:05

That what a Uninterruptible Power Supply is for. Use the correct tool for the job. You can't solve everything in software.

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Dave Kreskowiak

Fixed first column position in datagridview in c#

Sneha Bisht13-Jun-13 21:15

Sneha Bisht

13-Jun-13 21:15

Hi,
i am using vs2010 with c#.
i have a problem in datagridview,
is it possible that we fixed the position of first column of datagridview,
means all other columns scroll horizontally but first column fixed at his place.

Thanks

Re: Fixed first column position in datagridview in c#

Rasukumar13-Jun-13 21:56

Rasukumar

13-Jun-13 21:56

Check did you set anywhere Frozen property as true
in code behind as well as in designer side
else add this in your code
DataGridViewColumn column = dataGridView.Columns[0];
column.Frozen = False;

-RaSu,CAS

Entity Framework table names

kruegs3513-Jun-13 10:19

kruegs35

13-Jun-13 10:19

I want to create a procedure to load data from a table using Entity Framework, but without knowing the name of the table until runtime. The idea is that list of table names will be displayed for the user to select. When a table name is selected, the string value of the name is passed into the procedure. Is there a way use a string to reference the table class?

Re: Entity Framework table names

Richard Deeming13-Jun-13 11:46

Richard Deeming

13-Jun-13 11:46

This might help:
http://weblogs.asp.net/ricardoperes/archive/2013/06/11/entity-framework-metadata.aspx[^]

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

Linq - Get Previous Item By Dtae

Kevin Marois13-Jun-13 5:09

Kevin Marois

13-Jun-13 5:09

I have a List<accountdataitems> called AllDataItems. An AccountDataItem has a BillingDate. I pull all the AccountDataItems from AllDataItems where the BillingDate equals the SelectedBillingDate.

Now, for each item in AllDataItems, if I didn't find one because that matches the SeletedBillingDate, I need to find the previous one by the BillingDate.

I'd like to do this with Linq, rather than loops, but I'm not sure how to code this. Could someone help with the Linq for this?

Thanks

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

Re: Linq - Get Previous Item By Dtae

Ennis Ray Lynch, Jr.13-Jun-13 5:22

Ennis Ray Lynch, Jr.

13-Jun-13 5:22

Linq is loops.
Dictionary<accountId, SortedList<DataItem>> populateMeSortDescending;

Need custom software developed? I do custom programming based primarily on MS tools with an emphasis on C# development and consulting.

"And they, since they Were not the one dead, turned to their affairs" -- Robert Frost

"All users always want Excel" --Ennis Lynch

WPF MVVM Threads and a Log

cjb11013-Jun-13 2:38

cjb110

13-Jun-13 2:38

I've got a MVVM WPF app that launches multiple threads via Tasks and I'd like the app to have a basic log UI feature, that is updated asynchronously as the tasks update.

I've been playing with Dispatchers, SyncContexts, various rewrites of ObsverableCollections and basically getting not very far.

I've currently got a ObservableCollection<string>, and each log entry is basically a new item, but I don't care if its just a textblock or anything else if it works Smile | :)

.

Updating the collection works async, but it only displays on the ui once all the tasks have finished (and not all the entries are displayed even then, I have to call OnPropertyChanged again...).

Can anyone point me to an working example?

Re: WPF MVVM Threads and a Log

Pete O'Hanlon13-Jun-13 2:54

Pete O'Hanlon

13-Jun-13 2:54

I answered a question a while back about using log4net to log to the UI. I blogged about how to do it here[^].

I was brought up to respect my elders. I don't respect many people nowadays.

CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier

Re: WPF MVVM Threads and a Log

cjb11013-Jun-13 3:03

cjb110

13-Jun-13 3:03

ah, that looks interesting. I'll give that a go, plus it looks like it might provide a base for more larger apps.

Thanks

Re: WPF MVVM Threads and a Log

Pete O'Hanlon13-Jun-13 5:13

Pete O'Hanlon

13-Jun-13 5:13

You're welcome.

I was brought up to respect my elders. I don't respect many people nowadays.

CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier

how to customize datatable.Select

jojoba201112-Jun-13 17:36

jojoba2011

12-Jun-13 17:36

I am writing a windows desktop application in C# 2008 and i wanna to have select for datatable :

IEnumerable<string> idsInA = dtd.AsEnumerable().Select(row => (string)row["ID"]);

it filters only on one row (ex.ID) but the thing i wanna is for three rows (ex:ID , Title , Path)
Ho i can do that ?

Re: how to customize datatable.Select

Ron Beyer12-Jun-13 18:10

Ron Beyer

12-Jun-13 18:10

IEnumerable<string> idsInA =
    (from row in dtd
     where row["ID"] = idFilter && row["Title"] = titleFilter && row["Path"] = pathFilter
     select row["ID"]).AsEnumerable();

But this only returns one column, if you want all the columns, you would use something like this:

var rowsInA =
    (from row in dtd
     where row["ID"] = idFilter && row["Title"] = titleFilter && row["Path"] = pathFilter
     select row);

and then rowsInA is an IEnumerable that contains the row objects.

Re: how to customize datatable.Select

jojoba201112-Jun-13 20:26

jojoba2011

12-Jun-13 20:26

thanks in advnaced!
But i wanna to return all cells of my datatable !
(Not filter some !!! [No where])

Re: how to customize datatable.Select

Ron Beyer13-Jun-13 2:52

Ron Beyer

13-Jun-13 2:52

Then just remove the where part of the second example I gave.

C# accessing a windows api

classy_dog12-Jun-13 12:17

classy_dog

12-Jun-13 12:17

I am writing a windows desktop application in C# 2010 that will be calling a windows api. The user will enter some information, hit the submit button, and the windows api will be called.

My question is would you show me code on how to call the windows api, tell the windows api what you are looking for, and return any optional values obtained from the windows api?

Re: C# accessing a windows api

Ron Beyer12-Jun-13 12:30

Ron Beyer

12-Jun-13 12:30

This will give you just about any API info you need, with code[^]

Re: C# accessing a windows api

Richard MacCutchan12-Jun-13 21:15

Richard MacCutchan

12-Jun-13 21:15

classy_dog wrote:
show me code on how to call the windows api

An impossible task, since the code for each function is unique to that function. Go to MSDN, search for the function you are interested in, and read the documentation.

Use the best guess

Re: C# accessing a windows api

DaveyM6913-Jun-13 2:45

DaveyM69

13-Jun-13 2:45

What functions in the Windows API are you wanting to call?

Dave

Binging is like googling, it just feels dirtier.
Please take your VB.NET out of our nice case sensitive forum.
Astonish us. Be exceptional. (Pete O'Hanlon)

BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)

Re: C# accessing a windows api

classy_dog13-Jun-13 9:08

classy_dog

13-Jun-13 9:08

I will get calling an windows api that another programmer at work is 'writing'? Should I ask her how to call the windows api?

Re: C# accessing a windows api

Pete O'Hanlon13-Jun-13 9:48

Pete O'Hanlon

13-Jun-13 9:48

Unless you are working for Microsoft, the other programmer is not writing a Windows API. And yes, you should ask her how her "API" should be called.

I was brought up to respect my elders. I don't respect many people nowadays.

CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier

Re: C# accessing a windows api

DaveyM6913-Jun-13 9:52

DaveyM69

13-Jun-13 9:52

The Windows API is Microsoft's own API for windows that they provide to allow you to call functions within the OS: http://msdn.microsoft.com/en-us/library/windows/desktop/ff818516(v=vs.85).aspx[^]

If someone else is writing a library and they are providing an API then they should be providing documentation for it's use.

Re: C# accessing a windows api

Eddy Vluggen13-Jun-13 9:53

Eddy Vluggen

13-Jun-13 9:53

classy_dog wrote:
Should I ask her how to call the windows api?

Let's dub it the "Classy API" Cool | :cool:

using System.Windows.Forms;
using Microsoft.Win32;
using Classy;
using Classy.Dog;
using Classy.Core;

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