C# Discussion Boards - CodeProject

Re: how to clear screen when i draw to screen?

ping_jacob6-Jan-09 3:04

6-Jan-09 3:04

i can't using fullscreen
because i need to draw to screen when i drag mouse
now i can draw when drag but can't clear that screen

if draw on form, can use invalidate()
if not on form, how can i do?

please give some hints or tips to me

thanks a lot....

Re: how to clear screen when i draw to screen?

Tony Richards6-Jan-09 3:17

Tony Richards

6-Jan-09 3:17

I'm really guessing now, but have you tried using Invalidate? It may force Windows to redraw the desktop (it is, after all, just a different kind of window). If not, I'm afraid I'm stumped, sorry.

My Blog: This Blog

Re: how to clear screen when i draw to screen?

ping_jacob6-Jan-09 7:19

ping_jacob

6-Jan-09 7:19

how to use invalidate?

please advice me...

i read invalidaterect from dllimport user32.dll but don't understand

if have another function or other as same as invalidate.

please advice me.

thanks a lot...

log4net and nhibernate: app.config - conn string pwd in clear?

devvvy5-Jan-09 5:13

devvvy

5-Jan-09 5:13

hello

How not to hardcode conn string username/pwd in plaintext for log4net ADO.NET appender?

<appender name="AdoNetAppender" type="log4net.Appender.AdoNetAppender">
<bufferSize value="0" />
<connectionType value="System.Data.SqlClient.SqlConnection, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />


<connectionString value="data source=LAPPC2;initial catalog=SomeDB;integrated security=false;persist security info=True;User ID=dev;Password=somepwd" />
...
</appender>

See above, username "dev" and password are in plaintext.

Same question for nhibernate - see example below:

<configuration>
<configSections>
<section
name="nhibernate_SomeDB"
type="System.Configuration.NameValueSectionHandler, System,Version=1.0.5000.0,Culture=neutral,PublicKeyToken=b77a5c561934e089" />
<section
name="nhibernate_AuditTrail"
type="System.Configuration.NameValueSectionHandler, System,Version=1.0.5000.0,Culture=neutral,PublicKeyToken=b77a5c561934e089" />
</configSections>

<nhibernate_SomeDB>
<add
key="hibernate.connection.provider"
value="NHibernate.Connection.DriverConnectionProvider" />
<add
key="hibernate.dialect"
value="NHibernate.Dialect.MsSql2000Dialect" />
<add
key="hibernate.connection.driver_class"
value="NHibernate.Driver.SqlClientDriver" />
<add
key="hibernate.connection.connection_string"
value="Server=localhost;initial catalog=SomeDB;User Id=dev;Password=somepwd;Min Pool Size=2" />
</nhibernate_SomeDB>

<nhibernate_AuditTrail>
<add
key="hibernate.connection.provider"
value="NHibernate.Connection.DriverConnectionProvider" />
<add
key="hibernate.dialect"
value="NHibernate.Dialect.MsSql2000Dialect" />
<add
key="hibernate.connection.driver_class"
value="NHibernate.Driver.SqlClientDriver" />
<add
key="hibernate.connection.connection_string"
value="Server=localhost;initial catalog=SomeOtherDB;User Id=dev;Password=somepwd;Min Pool Size=2" />
</nhibernate_AuditTrail>
</configuration>

dev

Re: log4net and nhibernate: app.config - conn string pwd in clear?

#realJSOP5-Jan-09 5:34

#realJSOP

5-Jan-09 5:34

You can put the connection string in your app and set the connection string before attempting to use the database.

Or, you can encrypt it in the app.config file.

Google is your friend.

"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

Re: log4net and nhibernate: app.config - conn string pwd in clear?

devvvy5-Jan-09 14:49

devvvy

5-Jan-09 14:49

John Simmons / outlaw programmer wrote:
You can put the connection string in your app and set the connection string before attempting to use the database.

That's how I do it with ADONET. But what about Hibernate and log4net? I can change connection strings on the fly/programmatically with log4net/nhibernate?

dev

How to declare an use a struct containing an array?

scjsb5-Jan-09 5:13

scjsb

5-Jan-09 5:13

I want to declare a simple array of stuct with the struct containing an array as shown below. But it does not compile. If you can't tell I'm very new to C#.

public struct ChangeRec
{
public datetime LastTimeStamp;
public int last ;
public int mode[10] ; // I want an integer array of values
}

if I change the last line as shown, it will compile, but how do I control the size and access the elements?

public int [] mode ;

This seems too simple to be this hard. Thanks

Re: How to declare an use a struct containing an array?

Christian Graus5-Jan-09 5:17

Christian Graus

5-Jan-09 5:17

You declare an array with int[] and then you set it's size when you create it.

mode = new int[10]; This can go in your contructor.

If your array was of a class then they would all be null and would need to be newd individually, too. As they are int, they will all be fine, but I mention this for future reference.

Christian Graus

Driven to the arms of OSX by Vista.

Re: How to declare an use a struct containing an array?

moon_stick5-Jan-09 5:25

moon_stick

5-Jan-09 5:25

Why does it have to be a struct? Unless this is for Interop I don't see the value in storing a reference type within a value type - why not just declare it as a class?

It definitely isn't definatley

Re: How to declare an use a struct containing an array?

Not Active5-Jan-09 5:53

Not Active

5-Jan-09 5:53

moon_stick wrote:
storing a reference type within a value type

What reference type?

only two letters away from being an asset

Re: How to declare an use a struct containing an array?

moon_stick5-Jan-09 6:25

moon_stick

5-Jan-09 6:25

An array is a reference type, no? Of type System.Array??

It definitely isn't definatley

Re: How to declare an use a struct containing an array?

Not Active5-Jan-09 6:52

Not Active

5-Jan-09 6:52

I guess I looked at the data type and ignored the array

only two letters away from being an asset

Re: How to declare an use a struct containing an array? [modified]

#realJSOP5-Jan-09 5:36

#realJSOP

5-Jan-09 5:36

Personally, I'd make your struct a class, and use a generic list instead of an array.

At that point you could do something like this:

public class ChangeRec
{
    private List<int> m_modes = new List<int>();

    public DateTime LastTimeStamp { get; set; }
    public int LastValue { get; set; }
    public List<int> Modes { get { return m_modes; } }

    public ChangeRec() {}
}

There is now no need to initialize the list beyond what's done in the class.

One other thing... I the variable "Last" refers to the last value added to the list. If that's the case, you can do this (uif you're using the code I posted above):

ChangeRec changeRec = new ChangeRec();

changeRec.Modes.Add(1);
changeRec.Modes.Add(2);
changeRec.Modes.Add(3);
changeRec.Modes.Add(4);

int lastValue = (int)(changeRec.Modes.Last());

modified on Monday, January 5, 2009 11:42 AM

Re: How to declare an use a struct containing an array?

Russell Jones5-Jan-09 5:42

Russell Jones

5-Jan-09 5:42

i think the fixed keyword might help you

unsafe public struct ChangeRec

{
public DateTime LastTimeStamp;
public int last ;
public fixed int mode[10] ; // I want an integer array of values
}
}
The big problem here is that you'll have to allow unsafe code within your project so it's probably not the best plan unless you're planning to use interop.

i'd be tempted to implement the thing as a class and create getMode(int i) and setMode(int i) methods.

Russ

Re: How to declare an use a struct containing an array?

Dragonfly_Lee5-Jan-09 17:39

Dragonfly_Lee

5-Jan-09 17:39

The reason is that C# does not allow us to have instance field initializer in struct.
there is a workaround if you do not want to use the unsafe code, such as:

struct MyStruct
{
public int last;
public int[] mode;
public int[] Mode
{
get
{
if (this.mode == null)
{
this.mode = new int[10];
}

return this.mode;
}
}
}

The code above can be compiled successfully.

Tan Li

I Love KongFu~

Re: How to declare an use a struct containing an array?

Jon Rista6-Jan-09 10:41

Jon Rista

6-Jan-09 10:41

Like everyone else, I would question why this is not a class. That doesn't answer your question, however. If you do indeed need a struct...which indicates you need it to be allocated on the stack, I would do something like the following (this might not be exact...havn't used stackalloc in a long time):

public struct ChangeRec
{
    public ChangeRec(byte modeSize)
    {
        mode = stackalloc int[modeSize];
    }

    public DateTime LastTimeStamp;
    public int Last;
    public int[] mode;
}

Re: How to declare an use a struct containing an array?

scjsb7-Jan-09 1:45

scjsb

7-Jan-09 1:45

Thanks for all your inputs, I've got it working as a class. I still don't know how to make this an array using this structure. What I need is an array of 200 records with each record having the structure as originally shown and guidance on how to actually use it.

can you get rid of data members in a class after inheritance?

bfis1081375-Jan-09 4:38

bfis108137

5-Jan-09 4:38

I want to know if I can inherit a class and then make it so one of the members that is inherited is not visible. My reason is that on top of memory issues, I don't want the empty member because i am going to use a list of members of the inherited class as a datasource of a gridview and if i have the extra member, it will appear on the gridview. I am up for other suggestions on how to deal with this problem.

Re: can you get rid of data members in a class after inheritance?

Christian Graus5-Jan-09 5:14

Christian Graus

5-Jan-09 5:14

bfis108137 wrote:
My reason is that on top of memory issues

You can't fix this, and if the object is empty, the memory usage is negligible anyhow.

bfis108137 wrote:
and if i have the extra member, it will appear on the gridview

Only if you make the gridview auto generate column s

bfis108137 wrote:
I am up for other suggestions on how to deal with this problem.

Create an interface that only exposes the items you want to see, and then bind to a collection of that.

You can't make a property on the base class disappear.

Christian Graus

Driven to the arms of OSX by Vista.

how to use XPath to parse the XML file?

George_George5-Jan-09 3:18

George_George

5-Jan-09 3:18

Hello everyone,

Suppose I have the following XML file, I want to use XPath query based technologies to iterate all attributes for all rules nodes and all attributes for each sub rule nodes (under each rules node).

Could anyone provide some pseudo code please? I know how to query rules and related attribute but do not know how to loop inside embed node rule under each rules node.

<Abc>
    <rules name="USA">
    <rule foo="123" goo="345"/>
    </rules>
    <rules name="CAN">
    <rule foo="321" goo="543"/>
    <rule foo="321" goo="234"/>
    </rules>
</Abc>

thanks in advance,
George

Re: how to use XPath to parse the XML file?

Le centriste5-Jan-09 3:22

Le centriste

5-Jan-09 3:22

Suppose you have the following to query the rules nodes:

XmlNodeList rulesNodes = myDoc.SelectNodes("//rules");

Then, in order to loop the rule nodes:

foreach (XmlNode rulesNode in rulesNodes)
{
   XmlNodeList ruleNodes = rulesNode.SelectNodes("rule");

   foreach (XmlNode ruleNode in ruleNodes)
   {
       ....
   }
}

Hope this helps.

Re: how to use XPath to parse the XML file?

George_George5-Jan-09 3:34

George_George

5-Jan-09 3:34

Thanks Le Centriste,

For this statement -- "myDoc.SelectNodes("//rules");", XMLDocument class does not contain a method called SelectNodes. Any comments?

regards,
George

Re: how to use XPath to parse the XML file?

Le centriste5-Jan-09 3:55

Le centriste

5-Jan-09 3:55