Re: Reflection and array´s... - C# Discussion Boards

Re: Xml Serialization and Interfaces...

2-Aug-04 4:13

mgaerber wrote:
is there a way I can let the serializer ignore the inheritance?

You can ignore certian elements with attributes, but I suspect you havent done much reading on this, I suggest you do, unless u wanna write your own de/serializer. And no u can never instantiate an interface or an abstract class, so unless u wanna break .NET that will never succeed!

^{top secret xacc-ide 0.0.1}

mgaerber12-Aug-04 23:10

mgaerber

12-Aug-04 23:10

Alright,

the problem was in a class from which I inherited,
[XmlIgnore] did the trick...

Thanks for your hints!

Reflection and array´s...

Norman-Timo2-Aug-04 0:43

Norman-Timo

2-Aug-04 0:43

And here I´m again...

I have problems to get a specified Array Length from an assembly file.

First here is a extract from the assembly file (source):

public class SEGMENT_FLATNESS
{
public int ID { get{ return 221; } }

// date as 8-digit integer in format yyyymmdd
public int DATE;
// time as 6-digit integer in format hhmmss
public int TIME;
// test
public float[] FLATNESS;

public SEGMENT_FLATNESS ()
{
FLATNESS = new float[35];
}

}

To get the array length I tried following:
first I have ceated an instance from the upper class, then I got the related Field and tried to get the Property 'Length' from it.

The second way was to invoke the Method GetLength from the array, but both didn´t work.

Here my last try:

using System;

using System.Reflection;

namespace DummyTest
{
///

/// Summary description for Class1.
///

class Class1
{
///

/// The main entry point for the application.
///

[STAThread]
static void Main(string[] args)
{
Assembly testAss = System.Reflection.Assembly.LoadFrom("KorrektesFile");

Type testType = testAss.GetType("SEGMENT_FLATNESS");

object testInvoke = Activator.CreateInstance(testType);

FieldInfo testInfo = testType.GetField("FLATNESS");

Type fieldType = testInfo.FieldType; // weiß nicht ob das nötig ist

PropertyInfo p = fieldType.GetProperty("Length");

MethodInfo[] testMethodInfo = p.GetAccessors(false); //liefert nur die public get Methode für die Länge!!!

testMethodInfo[0].Invoke(testInvoke, null); // **************

string tmpString = testInfo.Name; //dummyZeile wg. debug (kein vorzeitiges Ende)
}
}
}

What did I wrong? And how can I get the array length?

Please help me...
Norman-Timo

leppie2-Aug-04 1:01

2-Aug-04 1:01

Norman-Timo wrote:
testMethodInfo[0].Invoke(testInvoke, null);

if u want a value, u should assign it!

^{top secret xacc-ide 0.0.1}

leppie2-Aug-04 1:08

2-Aug-04 1:08

Norman-Timo wrote:
FieldInfo testInfo = testType.GetField("FLATNESS");

Type fieldType = testInfo.FieldType; // weiß nicht ob das nötig ist

PropertyInfo p = fieldType.GetProperty("Length");

MethodInfo[] testMethodInfo = p.GetAccessors(false); //liefert nur die public get Methode für die Länge!!!

testMethodInfo[0].Invoke(testInvoke, null); // **************

try this rather:

FieldInfo testInfo = testType.GetField("FLATNESS");

Type fieldType = testInfo.FieldType;

PropertyInfo p = fieldType.GetProperty("Length");

int length = (int)p.Invoke(testInvoke, new object[0]);

^{top secret xacc-ide 0.0.1}

Norman-Timo2-Aug-04 1:30

Norman-Timo

2-Aug-04 1:30

Thanx for the very fast help, but there are compiler errors in your hint.

p.Invoke... (-> 'System.Reflection.PropertyInfo' does not contain a definition for 'Invoke')

Are there framework differences? I use framework 1.1!

But I tried somithing similar and I only got Exceptions like that:

"An unhandled exception of type 'System.Reflection.TargetException' occurred in mscorlib.dll

Additional information: Object does not match target type.
"

the Exception is trown with following lines:
FieldInfo testInfo = testType.GetField("FLATNESS");
Type fieldType = testInfo.FieldType;
PropertyInfo p = fieldType.GetProperty("Length");

int iii = (int) p.GetValue(testInvoke, null); // -> ********** Exception!

Please help me (I can´t [under]stand this thing!)

Norman-Timo

leppie2-Aug-04 4:14

2-Aug-04 4:14

Sorry that was meant to be GetValue! Smile | :)

dont pass null pass new object[0]

^{top secret xacc-ide 0.0.1}

How to decide Page Break insertion criteria in RTF doc?

Norman-Timo2-Aug-04 20:00

Norman-Timo

2-Aug-04 20:00

I´m very sorry, but this is not working too! I really don´t understand the second parameter?
What sense does it make? I always found this method with second parameter is null!

Hey, but I found the solution at another forum:

int arrLength = (int) p.GetValue(testInfo.GetValue(testInvoke), null);

This is the soltion. My problem was the wrong object for the first parameter!

So now I can go on with my work. Wink | ;-)

Anyway thanx a lot for your help @leppie!
Norman-Timo

sachinkalse2-Aug-04 0:05

sachinkalse

2-Aug-04 0:05

I am trying to develope a small RTF writer to generate project report at runtime, with a limited RTF writing capability. RTF is one page document only, untill we intentionally put page breaks in it and Project report consists of number of pages. Thus, on what criteria it should be decided to insert page break? How to keep track of page's empty area before inserting anything?
OR
The next issue to overcome is to determine how to page-break text that is too long for one page.

Is there some way to identify exactly how many characters I can print before I run out of room in the current rectangle that defines the output, and do to a new page.
RTF specification 1.6 to 1.8 doesn't give any example regarding this issue.
Please guide.

serialize an object for use by drag & drop

misterbear1-Aug-04 23:15

misterbear

1-Aug-04 23:15

Hello, I posted a similar question a couple of days ago, got some advice but don't seem to be able
to make this one work anyway. Here is the problem: I have a custom class derived from treenode that I want to be able to perform drag'n'drop on to another instance of the same application. I want to serialize the treenode so I implement the ISerializable interface and add a constructor taking a SerializationInfo and a StreamingContext parameter

The class essentially looks like this:

<br />
[Serializable()]<br />
public class InheritedTreeNode : TreeNode, ISerializable<br />
{<br />
   bool bool_property1, bool_property2, bool_property3;<br />
   string string_property4;<br />
   public InheritedTreeNode() : base() {}<br />
   ...<br />
}<br />

here's what the serialization code in the InheritedTreeNode does:

<br />
public void GetObjectData(SerializationInfo info, StreamingContext context)<br />
{<br />
  // Serialize all properties of this item<br />
  info.AddValue("bool_property1", typeof(bool));<br />
  info.AddValue("bool_property2", typeof(bool));<br />
  info.AddValue("bool_property3", typeof(bool));<br />
  info.AddValue("string_property4", typeof(string));<br />
<br />
  // serialize all it's children<br />
  ArrayList al = new ArrayList();<br />
  foreach(InheritedTreeNode itn in this.Nodes)<br />
    al.Add(mc2);<br />
  info.AddValue("Nodes", typeof(ArrayList));<br />
}<br />

...and here is how it is Deserialized:

<br />
public InheritedTreeNode(SerializationInfo info, StreamingContext context) : base()<br />
{<br />
  this.bool_property1 = info.GetBoolean("bool_property1");<br />
  this.bool_property2 = info.GetBoolean("bool_property2");<br />
  this.bool_property3 = info.GetBoolean("bool_property3");<br />
  this.string_property4 = info.GetString("string_property4");<br />
<br />
  // copy all child nodes<br />
  ArrayList al = (ArrayList)info.GetValue( "Nodes", typeof(ArrayList) );<br />
  foreach(MyTreeNode2 mc2 in al)<br />
  Nodes.Add(mc2);<br />
}<br />

now for drag'n'drop i do this:

<br />
BinaryFormatter bf = new BinaryFormatter();<br />
MemoryStream ms = new MemoryStream();<br />
bf.serialize(ms, instance_of_a_tree_node);<br />
<br />
DataObject dObj = new DataObject("InheritedTreeNode", ms)<br />
theTreeView.DoDragDrop( dObj, DragDropEffects.All );<br />

and when dropping in the other tree view the code looks like:

<br />
<br />
IFormatter formatter = new BinaryFormatter();<br />
MemoryStream ms = (MemoryStream)e.Data.GetData( "InheritedTreeNode" );<br />
ms.Position = 0;<br />
InheritedTreeNode data = (InheritedTreeNode)formatter.Deserialize(ms);<br />
<br />

this will throw an exception in the deserialization constructor at the first info.getBoolean() call
saying that it is an invalid cast...

Is the problem that i put the memorystream object on the clipboard, because it's a reference? In that case, how do I put copy of the bytes contained in it onto the clipboard in global memory so that other instance can retrieve it?

the byte[] of the memory stream

global Variables??

JayJ1-Aug-04 22:37

JayJ

1-Aug-04 22:37

Hi all. I know this may seem like a stupid question but hey I'm new @ this.
Please tell me how to add a global variable. I come from vb and it was easy to do it there but I've tried everything in c#, please help.

Thanx
:P

El'Cachubrey1-Aug-04 23:13

El'Cachubrey

1-Aug-04 23:13

use static variable for this goal

sreejith ss nair1-Aug-04 23:18

sreejith ss nair

1-Aug-04 23:18

hi,
you can use app.config file for accessing globel level variables in C#.

steps.
add an xml file to your solution. And give the value to your globel variable.
eg

<configuration>
<appSettings>
<add key="sourcename" value="DummyDb" />
<add key="DtFormat" value="MM-dd-yyyy" />
</appSettings>>
<

ILoveCS1-Aug-04 23:22

ILoveCS

1-Aug-04 23:22

Hello,JayJ.
First of all,have you studied the cpp language?
Add a global variable there are many methods.
for instance:
1. Add a field into the mainclass which contains the main method.
Such as "public int G_variable = 0 ;".You can even add some modify words as static,readonly.Remember readonly field must be initiated in the constrcution method.
2.C# is completely oo,so everything is class.So more formal way to add a global variable is to write a public class and make the global variable be a field of the class.I suggest you use this way.
Enjoy it!Welcome to world of C#!
Smile | :)

Never understand
ridical version!

Colin Angus Mackay1-Aug-04 23:55

Colin Angus Mackay

1-Aug-04 23:55

ILoveCS wrote:
C# is completely oo

I would disagree with that statement. There are many things that are Object Oriented that C# does not have, such as multiple inheritance.

"If a man empties his purse into his head, no man can take it away from him, for an investment in knowledge pays the best interest." -- Joseph E. O'Donnell

Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!

misterbear2-Aug-04 0:17

misterbear

2-Aug-04 0:17

But does that make C# not OO?
By pointing at something C# HAS that is NOT OO would maybe better falsify the statement.

Agree? Disagree?

Colin Angus Mackay2-Aug-04 0:34

Colin Angus Mackay

2-Aug-04 0:34

misterbear wrote:
But does that make C# not OO?

The original statement said "completely OO". Implying that the set of features in C# includes at exactly all the features in OO.

RESOLVED

JayJ2-Aug-04 5:09

JayJ

2-Aug-04 5:09

Thanx guys, appreciate it :P

ILoveCS2-Aug-04 15:36

ILoveCS

2-Aug-04 15:36

I'm afraid i can not agress with you.
I don't think mutiple inheritance is the property of standard oo.
It is just implemented in cpp.
Java and C# don't support multiple inhertance.A class can implement many interface but not inhert many fathers.
In your opinion,what the "completely or standard" oo is?
Nice to discuss with you.
Smile | :)

Never understand
ridical version!