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malharone wrote: But there are cases when from you non-generic class, you want to call a generic method and all you want do is to pass the "current type" and not any other type.
Whenever you need to do this, this is the way to write your call:
( CurrentType )InstanceReference.Method( args )
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malharone wrote: WHAT SHOULD GO HERE
The name of a class.
You could use the name of the base class DomainObject.
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Yes, the name of the class would go in the place holder. But it would be the name of the concrete type as opposed to hard-coding base type.
E.g.
If I have Car c = new Car();
and when I perform c.Delete() operation, I'd like to be able to execute _dbStore.DeleteObject<Car>(_id) from the DomainObject.
If I have Boat b = new Boat();
and when I perform b.Delete() operation, I'd like to be able to execute _dbStore.DeleteObject<Boat>(_id) from the DomainObject.
I just dont know how I could dynamically "pass" the runtime class name to the generic method in DBStore.
- Malhar
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<br />
class DBStore<T> where T : class, new()<br />
{<br />
public T CreateObject()<br />
{<br />
return new T();<br />
}<br />
public void DeleteObject<T>(int id)<br />
{<br />
Type t = typeof(T);<br />
}<br />
public DBStore()<br />
{<br />
}<br />
}<br />
abstract class DomainObject<T> where T : class, new()<br />
{<br />
protected int _id;<br />
protected DBStore<T> _dbStore;<br />
public void Delete ()<br />
{<br />
_dbStore.DeleteObject<T>(_id);<br />
}<br />
}<br />
class Boat : DomainObject<Boat><br />
{<br />
public Boat()<br />
{<br />
}<br />
public Boat(int id)<br />
{<br />
this._id = id;<br />
this._dbStore = new DBStore<Boat>();<br />
}<br />
}<br />
class Car : DomainObject<Car><br />
{<br />
public Car()<br />
{<br />
}<br />
public Car(int id)<br />
{<br />
this._id = id;<br />
this._dbStore = new DBStore<Car>();<br />
}<br />
}<br />
<br />
class TestClass<br />
{<br />
public void Run()<br />
{<br />
Boat boat = new Boat(1234);<br />
boat.Delete();<br />
<br />
Car car = new Car(5678);<br />
car.Delete();<br />
}<br />
}<br />
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I think the forum software treated the <s & >s as HTML tags. Do you mean the following instead?
abstract class DomainObject <T> where T : class, new() and
class Boat:DomainObject<Boat> and
class Car:DomainObject<Car>
I have two nags now (nohing major):
a) change method signature from ListViewItem GetItem (DomainObject o) to ListViewItem GetItem (DomainObject <DomainObject> o) in non-generic classes (such as list views)
b) redundancy in class declaration: class Car:DomainObject<Car>
Any opinions?
I think you also meant to genericise the DBStore class, but the lts & gts were converted to HTML. Anyways, in my case, I am planning on keeping the DBStore a non-generic singleton. So, only the methods in it will have generic declaration.
Nonethelss, thanks for your previous suggestion.. I didnt know about the class keyword. i'll look into it!
- Malhar
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If I'm not mistaken, then you're suggesting something like:
public abstract class DomainObject<T>
This will break majority of the app where I'm simply keeping a reference to the base DomainObject as opposed to DomainObject for Car. You could help clarify my misunderstanding .. but:
Assuming I changed the class declaration as above (with generics), what should I change my dependent method signature for the classes that do NOT inherit from generics?
e.g.
01. class ListViewEx
02. {
03.
04. DomainObject _selectedObject;
05.
06. public void AddItem (DomainObject obj)
07. { ... }
08.
09. public DomainObject SelectedObject
10. { get { return _selectedObject; }
11. set { ... } }
12.}
- What should the line #4, 6 & 9 look like after genericising DomainObject?
- And one thing to note is that currently, ListViewEx.AddItem is designed to allow consumer to pass both objects of type Car AND Boat. If I genericize the ListViewEx to class ListViewEx <T> then a. I'll lose the functionality of adding items of multiple types, and b. Win form designer will no longer work.
Thanks,
- Malhar
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I am having to strip some info from some text files to dump into a data table. The problem, well, not a problem, but a nuance, is that the information needed from these text files are at the very end of the file, which average about 400K.
Here is the code I am using:
objRead = new StreamReader(m_strFileName);
while (objRead.Peek() > -1)
{
strRecord = objRead.ReadLine();
if (strRecord.Length > 20)
{
if (strRecord.Substring(44,3) == "NEW")
{
if (strRecord.Substring(87,11) != " ")
{
decDepr[0] = Decimal.Parse(strRecord.Substring(87,11));
}
else{decDepr[0] = 0;}
}
You get the idea...
The question is can I start reading from the end of the file or is there a smarter way to do this? I am having to repeat this process 22 times for 22 different reports, which takes some time.
Thanx in advance!
Jude
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from this code, it seems that whether the data is in the end or start it will take the same time, since you are continuing the loop even after getting the data. so i do not see any difference in time even if you start reading from bottom.
Regards
Shajeel
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Well, if I do start reading from the bottom I will get the information I need then be able to close the stream read and go on to the next file. The data that needs to be read is at the very bottom of the file. I just don't know how to start reading from the end of the file.
Thanx for the reply!
Jude
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Hi,
have a look at FileStream.Seek() or FileStream.Position which will allow you to read
into a byte[] the last N bytes of a file.
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I have some problems with microsoft´s example under void GetObjectData(SerializationInfo info, StreamingContext context) in MSDN VS5. I have executed the code and it´s running, but when I remove formatter.Serialize(fs, a1) and try to Deserialize the binary file, it fails.
Have I misunderstod the example or What is wrong? Can I fix the code I need to serialize a singleton.
Best regards, Gywox
Modified Example:
<br />
using System;<br />
using System.Web;<br />
using System.IO;<br />
using System.Collections;<br />
using System.Runtime.Serialization.Formatters.Binary;<br />
using System.Runtime.Serialization;<br />
using System.Security.Permissions;<br />
<br />
[Serializable]<br />
public sealed class Singleton : ISerializable<br />
{<br />
private static readonly Singleton theOneObject = new Singleton();<br />
private string someString_value;<br />
private Int32 someNumber_value;<br />
<br />
public string SomeString<br />
{<br />
get<br />
{<br />
return someString_value;<br />
}<br />
set<br />
{<br />
someString_value = value;<br />
}<br />
}<br />
<br />
public Int32 SomeNumber<br />
{<br />
get<br />
{<br />
return someNumber_value;<br />
}<br />
set<br />
{<br />
someNumber_value = value;<br />
}<br />
}<br />
<br />
private Singleton()<br />
{<br />
}<br />
<br />
public static Singleton GetSingleton()<br />
{<br />
return theOneObject;<br />
}<br />
<br />
[SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.SerializationFormatter)]<br />
void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)<br />
{<br />
info.SetType(typeof(SingletonSerializationHelper));<br />
}<br />
}<br />
<br />
<br />
[Serializable]<br />
internal sealed class SingletonSerializationHelper : IObjectReference<br />
{<br />
public Object GetRealObject(StreamingContext context)<br />
{<br />
return Singleton.GetSingleton();<br />
}<br />
}<br />
<br />
class App<br />
{<br />
[STAThread]<br />
static void Main()<br />
{<br />
FileStream fs = new FileStream("DataFile.dat", FileMode.OpenOrCreate);<br />
<br />
try<br />
{<br />
BinaryFormatter formatter = new BinaryFormatter();<br />
<br />
Singleton[] a2 = (Singleton[])formatter.Deserialize(fs);<br />
Console.WriteLine("Do both array elements refer to the same object? " + (a2[0] == a2[1]));<br />
Console.WriteLine(a2[0].SomeString + " " + a2[0].SomeNumber);<br />
Console.WriteLine(a2[1].SomeString + " " + a2[1].SomeNumber);<br />
}<br />
catch (SerializationException e)<br />
{<br />
Console.WriteLine("Failed to serialize. Reason: " + e.Message);<br />
throw;<br />
}<br />
finally<br />
{<br />
fs.Close();<br />
}<br />
}<br />
}
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Below is what I use for serialization. It seems to work fine for me?
public void GetObjectData(SerializationInfo info, StreamingContext context){
info.AddValue("id", id);
info.AddValue("applicationId", applicationId);
}
public MyObject(SerializationInfo info, StreamingContext context) {
id = info.GetInt64("id");
applicationId = info.GetInt64("applicationId");
}
File Not Found
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Hi!
Some source code, please.
How do you manage to Serialize/Deserialize a Singleton?
Singleton.Instance = (Singleton)formatter.Deserialize(fs); // Error Singleton is readonly
/Gywox
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Use the System.Xml.Serialization.XmlSerializer class to serialize. As for managing a Singleton that is not a serialization issue but a design issue. But for grins and giggles, in the serialization constructor overwrite your static instance for the singleton.
formatter.Deserialize(fs);
public SomeConstructor(SerializationInfo info, StreamingContext context) {
...
SomeConstructor.me = this;
}
File Not Found
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Hi, I got stuck in a problem and don't know what to do. In my web form. I am trying to display a ModalPopup window(Ajax) when I click on a link button. It gets displayed behind the flash image object which i have in the center of my web form. The modalpopup works completely fine if i remove the flash image object.
I need to make this working is there a way to do. Please help me
Thanks
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I was trying to allow a user to resize one of the panels on my form (by moving arrowicons). However I get these errors.
'System.Windows.Forms.Control.Location' because it is not a variable
'System.Windows.Forms.Control.Size' because it is not a variable
here is what I was trying to do:
AOIpanel.Location.X = leftEdgeArrow.Location.X;
AOIpanel.Location.Y = (centerArrow.Location.Y +(AOIpanel.Size.Height/2));
AOIpanel.Size.Width = (rightEdgeArrow.Location.X - leftEdgeArrow.Location.X);
-- modified at 16:24 Wednesday 21st February, 2007
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Hi,
setting Control.Location.X or Control.Size.Width does not help
(see the remark at Control.Location).
if you want to change the Location or Size you must either use "new Point()" or "new Size()",
or the properties Left, Top, Width, Height.
But it would not generate the errors you mention either (unless the code you are showing is not
actually the code you are compiling). I assume you tried to use Location.X etc. as an
out or ref parameter, which is impossible, out/ref requires a variable, a struct or
a class object, but not a part of them (such as a struct field).
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Hi Guys!
I am having a weird problem with one of our computers here at work, my application uses crystal report viewer with C# application designed in VS2003. All computers print the report just fine but this one computer prints a few rows and columns and then cuts off the rest of the print and if the user goes back and tries to print again the same report then it prints just fine. I am not sure why this is happening, could it be the printer driver.
PLEASE HELP!!!
sasa
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Is it possible to make the mouse pointer follow moving objects on the screen?
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I have an application that save some sort of information in a an xml file. I want to control that application remotely so I want to save that xml file in a web service.
I want to how I can save an xml file via a web service
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Accept an XmlDocument as the parameter to the webservice. Then call the save method.
[WebMethod]
public string SaveXml(XmlDocument document){
string fileName = Guid.NewGuid().ToString();
document.Save(fileName);
return fileName;
}
File Not Found
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Hi
I have created a webservice with a simple function HelloWorld. It works fine in the client application.
How do I change the default url of the webservice that points to the asmx file? I know that I can change in Reference.cs in the client application. But I want to set the default url other than localhost to point to a server where my asmx file is.
I am using VS 2003, C#.
Thanks a lot in advance
Muthu.
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Click the web reference you want to change. Look in the properties window and change the URL Behavior to Dynamic. This will create an entry in your app.config file (or web.config for web projects). This file can be modified before run time to point to the right place.
Also, if you want to save hours of problems down the road change the Web Reference URL to an invalid URL in the properties panel and rely on the generated key.
A sample app.config entry
<add key="SimpleTest.localhost.Service1" value="http://localhost/testsite/Service1.asmx"/>
<pre>
<div class="ForumSig"><hr><font size="-2">File Not Found
</font></div>
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Dear All,
i have a Unmanaged c++ based Library and i want to use it C# application(i.e. it expose some c based function .. ).. could some one give some pointer to use unmanaged library in c#.. so that i don't have to provide some extra dll or lib with c# to my end user....
thanks in advance
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
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