C# Discussion Boards - CodeProject

mikey_g5-Jan-05 1:20

5-Jan-05 1:20

Hi guys,

I have just been fiddling with a DataGrid for the first time and have managed to display pretty much what I want, except that it always highlights cell 0,0.

Is there an option somewhere that will stop this as it makes the grid look really nasty. The only option I could find that stopped it was DataGrid1.enabled = false but of course this has lots of other unwanted side-effects such as the columns cannot be resized by the user.

Any ideas would be much appreciated

Mike

Read data directly from harddrive

lindan5-Jan-05 0:57

lindan

5-Jan-05 0:57

I am programming in C# and I want to get direct access to the harddrive to read data and maybe later also write data.
I have looked at msdn but I dont really know what to search for. Maybe someone know what native functions I should call?, or point me in the right direction.

Thanks! // Anders

------------------------------
http://www.anderslinder.se

Re: Read data directly from harddrive

Paul Ingles5-Jan-05 1:08

Paul Ingles

5-Jan-05 1:08

It's not accessing the hard drive directly, but you could call functions from the Win32 API. The page below covers the functions you can use. If you go to http://www.pinvoke.net/ you ought to be able to find the P/Invoke signatures to let you use them. Alternatively, you could created a class wrapper in Managed C++ that called the functions directly, and then consume that within your C# app.

http://jan.netcomp.monash.edu.au/ssw/files/win32.html[^]

--
Paul
"Put the key of despair into the lock of apathy. Turn the knob of mediocrity slowly and open the gates of despondency - welcome to a day in the average office."
- David Brent, from "The Office"

MS Messenger: paul@oobaloo.co.uk
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Re: Read data directly from harddrive

lindan5-Jan-05 1:53

lindan

5-Jan-05 1:53

Thanks for the fast answer. I think I know what I should do now.
// Anders

------------------------------
http://www.anderslinder.se

Gentle.NET and Cascade Deletes

devvvy4-Jan-05 23:46

devvvy

4-Jan-05 23:46

Has anyone tried Gentle.NET? Does it supports cascades DELETE's? Can INSERT/UPDATE/DELETE/SELECT be mapped to stored procedures?

Reference: http://www.mertner.com/mm/gentle/[^]

Thanks in advance.

Norman Fung

Re: Gentle.NET and Cascade Deletes

Paul Ingles5-Jan-05 0:58

Paul Ingles

5-Jan-05 0:58

I've not got any experience with Gentle.NET, have you considered NHibernate? It's still in Alpha but I believe that what it does provide is pretty stable and reasonably well tested (i.e. production quality), and I also believe it supports cascading deletes. As for a default mapping of commands to stored procedures, I don't know. You may also want to take a look at iBATIS.NET.

--
Paul
"Put the key of despair into the lock of apathy. Turn the knob of mediocrity slowly and open the gates of despondency - welcome to a day in the average office."
- David Brent, from "The Office"

MS Messenger: paul@oobaloo.co.uk
Download my PGP public key

Re: Gentle.NET and Cascade Deletes

devvvy5-Jan-05 3:45

devvvy

5-Jan-05 3:45

Seems like there're plenty of Object-Relational mapping tools around. Some of the desirable features includes:

1. transaction
2. referential integrity, cascade deletes...
3. auto-increment, uid generation
4. inheritance
5. supports used of stored procedures
6. database/provider independent access
7. generation of SQL scripts from UML
...

What important feature have I omitted here? For our project, [1], [2], [3] are basic requirements. [4], [5], [7] are "nice-to-have". [6] ... we're just working with SQL server, but the rest of our application are built pretty robustly that ... we'd prefer OR mapping tools to be data provider independent... so, let's say [6] is also a requirement.

Anyway, anyone familiar with history of OR mapping tools? Which are the most popular OR tools around?

Norman Fung

c# GDI+ Photoshop like filters

vansen4-Jan-05 23:37

vansen

4-Jan-05 23:37

Hi Everyone,

i got a big problem here. I need to reproduce the behaviour of the Photoshop layer blending mode "Hard Light". If I use Photoshop load up a picture and put a layer with a solid color on top of that picture and set this layers Blending Mode to "Hard Light" then the Color of the layer seems to be mixed with the lights and darks of the underlying picture.

Then i went to my c# application:
I thought well take the overlapping pixels of the picture and the layer and mix the HSV Values together. But whatever i do i can't make it look like photoshop.

Does anyone have a clue or hint that could point me into the right direction to be able to reproduce that blending in C# ???

Any help greatly appreciated !!!
Thanks,

Oliver

Re: c# GDI+ Photoshop like filters

Nick Parker5-Jan-05 8:02

Nick Parker

5-Jan-05 8:02

Check out the series by Christian Graus on Image Processing with C# and GDI+:

Image Processing for Dummies with C# and GDI+ Part 1 - Per Pixel Filters[^]
Image Processing for Dummies with C# and GDI+ Part 2 - Convolution Filters[^]
Image Processing for Dummies with C# and GDI+ Part 3 - Edge Detection Filters[^]
Image Processing for Dummies with C# and GDI+ Part 4 - Bilinear Filters and Resizing[^]
Image Processing for Dummies with C# and GDI+ Part 5 - Displacement filters, including swirl[^]
Image Processing for Dummies with C# and GDI+ Part 6 - The HSL color space[^]

or any of the other imaging articles here[^]

- Nick Parker
Microsoft MVP - Visual C#
My Blog | My Articles

Creating Interop Wrapper

DHARMA.R4-Jan-05 23:23

DHARMA.R

4-Jan-05 23:23

Hi All,

I've a class file written using VB 6.0.
The class file has some complex methods.

Now I need to use that methods in my C# project.
It is too hard to convert the Vb code to C#.

By googling I came to know that, we can create interop wrapper to attain this goal.But I'm not aware of interop wrapper even what is that.

Pls. can anyone give me the urls or sample code on this topic ?.

Your help would be greatly appreciated.

DHARMA.R

Re: Creating Interop Wrapper

Paul Ingles4-Jan-05 23:40

Paul Ingles

4-Jan-05 23:40

You'll have to expose the VB code as an ActiveX DLL, enabling you to use .NET's COM interop support.

Here's an MSDN article that talks you through it:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vcwlkCOMInteropPart1CClientTutorial.asp[^]

You'll need to scroll down a bit, to where it says Example 1: Using Tlbimp. This imports the type library, creating a managed gateway to the COM interfaces implemented by the server. All you have to do then is ensure you reference the generated assembly when compiling.

Alternatively, (if you want) you can actually declare the interfaces and GUIDs inside C# through applying attributes. Again, this is documented inside the MSDN article. However, if you've got a large interface you will probably prefer the automated approach.

For more information about .NET's interoperability, you'll definitely want to check out this section in MSDN:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconinteroperatingwithunmanagedcode.asp[^]

It covers things like threading, marshaling of types, lifecycle etc.

--
Paul
"Put the key of despair into the lock of apathy. Turn the knob of mediocrity slowly and open the gates of despondency - welcome to a day in the average office."
- David Brent, from "The Office"

MS Messenger: paul@oobaloo.co.uk
Download my PGP public key

error shown while working on xmltextreader

dhol4-Jan-05 23:06

dhol

4-Jan-05 23:06

Hi
I have to read any schema file, and according to their datatype, it should load values for about 200 into a new xml file.

ie, a rough xml(first file -resulatant file)
<name>john1</name>
<salary>8100</salary>
<name>john2</name>
<salary>8200</salary>
<name>john3</name>
<salary>8300</salary>
<name>john4</name>
<salary>8400</salary>
like so on.. for about 200 values.

Now I have another xml file which has same "name" field all meaningful values for about 50.
(second xml file)
<name>john milton</name>
<name>stephen</name>
<name>george</name>
<name>thomas</name>
<name>paul</name> like so on for about 50 data's.

Now coming to my program, when it reads the schema, and when the schema file has the field"name" then it should read the second file and insert the data's from second file into the first xml (resultant file) for that particular field.

This is my requirement.
and this is my coding done, after running this program, i find that an error showing as "An unhandled exception system.argument exception occured"
please explain why is it occuring and how to rectify it.
Here is that part of the coding

private void button2_Click(object sender, System.EventArgs e)
{
dataSet1.ReadXmlSchema(txtSchema.Text);
foreach (DataTable dTbl in dataSet1.Tables)
{
object[] oValues = new object[dTbl.Columns.Count];
int i = 0;
XmlTextReader xtr = new XmlTextReader("C:\\CDEV\\testdatagenerator\\billtoname.xml");
while(xtr.Read())
{
foreach (DataColumn dColmn in dTbl.Columns)
{
oValues[i] = "";
if((xtr.NodeType == XmlNodeType.Element) && (xtr.Name == dColmn.ColumnName.ToString()))
{
switch(dColmn.DataType.ToString())
{
case "System.String":
oValues[i] = (string) "sachin" + i;
break;
case "System.Int32":
oValues[i] = (int) 100 + i;
break;
case "System.DateTime":
oValues[i] = new DateTime(2004,01,30).AddDays(i * 1);
break;
case "System.Decimal":
oValues[i] = new Decimal(10000900.99) + i;
break;
case "System.Int16":
oValues[i] = (short) 32767 - i;
break;
case "System.Int64":
oValues[i] = (long) 400 - i;
break;
case "System.Double":
oValues[i] = (double) 888888 - i;
break;
case "System.Single":
oValues[i] = (float) 4.5f + i;
break;
}
}
}
}
i = i+1;
dTbl.Rows.Add(oValues);
}
}

private void button3_Click(object sender, System.EventArgs e)
{
dataSet1.WriteXml(txtXml.Text,XmlWriteMode.IgnoreSchema );
MessageBox.Show("Saved");
}
}
}

Re: error shown while working on xmltextreader

exhaulted5-Jan-05 0:09

exhaulted

5-Jan-05 0:09

Try stepping into the code to see which line throws the exception and repost.
If i remember correctly a System.ArgumentException is thrown when one of your
arguments passed into a function are of the incorrect type.

Kev

Installing and Starting Services

exhaulted4-Jan-05 22:55

exhaulted

4-Jan-05 22:55

I've been asked to create an installer package for a service this morning.
Now, installing the service is nice and easy, InstallUtil "ServiceName.exe"
But i have to start the service automatically as well, anyone know how to do it?

I was hoping there would be an exe i can run or an optional parameter with
InstallUtil but i can't find anything.

Cheers

Kev

Ole Automation

Jason Xie4-Jan-05 21:29

Jason Xie

4-Jan-05 21:29

How to let my .net program supporting Ole Automation?
Give some examples for best.

me

Re: Ole Automation

Heath Stewart4-Jan-05 21:56

Heath Stewart

4-Jan-05 21:56

Read Interoperating with Unmanaged Code[^] in the .NET Framework, especially sections about importing COM typelibs into .NET, and exposing your .NET assemblies to COM clients.

There are many articles here on Code Project that discuss this that you can searching using the textbox directly below the logo at the top of every page on this site, and you can click "Search comments" above this forum to search for the hundreds of threads we've discussed previous.

Start by reading those links from above to get a better understand. If you have any specific questions, please ask. This forum is not a suitable place to get an overview of a technology, but to ask questions that we can answe without writing a book (which, BTW, many books on COM interop with .NET already exist - just search Amazon.com[^]).

This posting is provided "AS IS" with no warranties, and confers no rights.

Software Design Engineer
Developer Division Sustained Engineering
Microsoft

[My Articles] [My Blog]

Difference between build and rebuild

steve_rm4-Jan-05 20:34

steve_rm

4-Jan-05 20:34

Hello,

I often wonder what is the difference between build and rebuild. When I am developing a project I sometimes use build and sometimes use rebuild. I seem to get the same results.

What is the purpose of having both when they do the same job?

If there is a difference between the 2, which one should I use and when?

Thanks in advance,

Steve

Re: Difference between build and rebuild

Heath Stewart4-Jan-05 21:36

Heath Stewart

4-Jan-05 21:36

And you should get the same results; but, if you read the Visual Studio .NET Product Documentation[^] - specifically about Building, Debugging, and Testing[^] - you would see that a build performs an incrementable build in a debug build, which only compiles source files that haven't changed into the assembly. In release mode, the build option - like the rebuild option in both configurations - cleans out the intermediate and object files (like the assemblies, which is a target output file) and builds all the sources since their object libraries don't exist.

This is true of just about every build system - including make and nmake - I've ever used or have read about. This allows you to compile your changes more quickly in order to get debugging and spending less time waiting for larger projects to recompile.

The result is the same, more or less. Intermediate linking doesn't produce as efficient libraries as rebuilding, which is why the default configuration for release builds has incremental linking turned off. For C# projects, this is reflected by the "Incremental Build" project under the "Advanced" section of the project options dialog.

This posting is provided "AS IS" with no warranties, and confers no rights.

Software Design Engineer
Developer Division Sustained Engineering
Microsoft

[My Articles] [My Blog]

Asynchronous design question

Yaakov Davis4-Jan-05 20:01

Yaakov Davis

4-Jan-05 20:01

Are multimple threads allowed to access simultaneously the same method of an instance object?

What happend then? they both run a different 'instance' of the method?

Re: Asynchronous design question

jan larsen4-Jan-05 21:14

jan larsen

4-Jan-05 21:14

sb777 wrote:
Are multimple threads allowed to access simultaneously the same method of an instance object?
Yes

sb777 wrote:
What happend then? they both run a different 'instance' of the method?
No, method variables lives on the stack, and each thread maintains its own stack. Example:

public class TestClass
{
   public static int Test(int i)
   {
      int retval = i;
      return retval;
   }
}

Let's assume that two different threads, tA and tB, invokes TestClass.Test:
tA pushes the 'i' integer argument on its stack, let's say the value is 42, and then it invokes
TestClass.Test.

tB pushes the 'i' integer argument on its stack, let's say the value is 9, and then it invokes TestClass.Test.

In both cases TestClass.Test makes room for the variable retval by pushing an integer to the stack of the current thread. It then sets the value of that integer to the value of i. And the value of i is found on the stack of the current thread. When you write 'return retval' you actually tells the compiler to push retval on the stack of the current thread.

So, in the example above, nothing can go wrong in a multithreaded environment. Things are getting ugly if the example looks like this though:

public class TestClass
{
   private static int j;

   public int J
   {
      get:
      {
         return j;
      }
      set:
      {
         j = value;
      }
   }

   public static int Test(int i)
   {
      int retval = i;
      return retval + j;
   }
}

Things are looking good right untill retval is added to j. The problem is that j lives on the heap, so both threads will access the same reference to j. This is where you, the programmer, needs to actually think (ugh!). At some point in you code, you must find the sequence of code that isn't threadsafe, and then you must wrap it in a lock block like this:

lock(aReferenceToAnObjectSharedByBothThreads)
{
   TestClass.J = x;
   int y = TestClass.Test(x + 1);
}

"After all it's just text at the end of the day. - Colin Davies

"For example, when a VB programmer comes to my house, they may say 'does your pool need cleaning, sir ?' " - Christian Graus

Re: Asynchronous design question

Yaakov Davis4-Jan-05 22:47

Yaakov Davis

4-Jan-05 22:47

First, Thanks for your answer.

Now, why did you use static method for your example? Is the same story true for instance methods?

Re: Asynchronous design question

jan larsen4-Jan-05 22:57

jan larsen

4-Jan-05 22:57

You're welcome.

I used static, so I could skip the instantiation part of the code. Instance methods and instance member variables behaves just the same.

"After all it's just text at the end of the day. - Colin Davies

"For example, when a VB programmer comes to my house, they may say 'does your pool need cleaning, sir ?' " - Christian Graus

Re: Asynchronous design question

Yaakov Davis5-Jan-05 2:38

Yaakov Davis

5-Jan-05 2:38

As I understand, there is no need to lock read-only (per method or general) members.

Am I right?

Re: Asynchronous design question

jan larsen5-Jan-05 3:28

jan larsen

5-Jan-05 3:28

You're right. the readonly variables has to be initialized in the constructor, and no threads can change them. Problems in multithreaded environments starts, when a thread assumes something about a variable, that can be changed in between line x and line y by another thread.

"After all it's just text at the end of the day. - Colin Davies

"For example, when a VB programmer comes to my house, they may say 'does your pool need cleaning, sir ?' " - Christian Graus

C# hangs while opening word in web application

NituP4-Jan-05 19:53

NituP

4-Jan-05 19:53

Hi all,

Can any body help me on this ?
C# code hangs while opening word in web application. It hangs the moment it encounters the line "Documents.open" it hangs.........

Please help.

Also can anyone please give me email address of Gold. Member No. 118271 i.e. display name UB ?

Thanks in advance
Nitu Cool | :cool:

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