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An interface guarantees that a class will implement some methods. Suppose that you have an interface called IPlugin that contains one method called DoSomethingFunky. The interface is to be used as the basis for all plugins for your application. Now, in your code you don't know what the external classes are going to be and you certainly can't compile against them so you need some method for creating these unknown classes. Well, you can do this by using
IPlugin plugin = null;
plugin.DoSomethingFunky();
Deja View - the feeling that you've seen this post before.
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It is a variable declared with an inteface type instead of a class type and can hold any object that implements the interface.
To give the simplest example, if you have:
public interface IMyInterface{}
public class ClassWhichImplementsMyInterface:IMyInterface{}
You can use the following in your code:
IMyInterface MyVariable = new ClassWhichImplementsMyInterface();
A good example of the usefulness of this in the .net framework is the foreach statement which will accept any object that implements the IEnumerable interface. It uses objects that implement IEnumerable and knows how to handle them based on that interface.
-- modified at 11:11 Monday 21st May, 2007
topcoderjax
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do you knows how it works
in Excel namespace?
the code goes:
Excel.application app = new excel.application();
Excel.application is an Interface!
but I don't need to implement any of the Excel.application interface, I just use it's methods
like a regular class.
p.s. It's shows in msdn also.
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I am using Datagrid to show data.I am also using header template to show column headers.
Now I want to have one row above the header which contains the name of the datagrid and colspan="no of columns" which can be achieved in HTML table. How can i do in Datagrid ?? Any ideas??
Thanx in advance.
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Hello,
Does anybody have SDK of Digital Persona Finger Reader 4000B? or any help material regarding this.
Thank and best regards,
waqasb4all@yahoo.com
|Muhamad Waqas Butt|
waqasb4all@yahoo.com
www.sktech.freewebspace.com
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After reading this post, what do you think the first website would be that anyone is going to go to to find this?
What do you think they'll type into the little search box?
How much do you want to bet that what you seek will be the first item listed in the results?
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Hi,
I'm assigning value to a DataSet ds (from SQL database) in button A Click event and I set this dataset as DataSource for my grid.
Next if I check the value of this DataSet ds in another button click event, I can't get its value. ds is a Class variable, but I still can't get its value.
The DataSet has one table, which I can see in button A Click event, but in another button event click if i Check the values of ds.Tables.Count, its zero. I'm not manipulating the DataSet anywhere. Could anyone tell me why this happens?
Regards,
Blumen
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Your post contains some ambiguity.
blumenhause wrote: ds is a Class variable
What do you mean by class variable?
Do you mean:
* static field
* member instance field
blumenhause wrote: but I still can't get its value.
blumenhause wrote: The DataSet has one table, which I can see in button A Click event, but in another button event click if i Check the values of ds.Tables.Count, its zero.
So, which is it? Either you can see the dataset or you can't.
Is this an ASP.NET application? If so, remember that state is not maintained between postbacks.
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Colin Angus Mackay wrote: Your post contains some ambiguity.
Yes, this is a private Class variable or a field (its declared inside the class outside all Methods)
This is an ASP.NET code-behind file. But there is no post back here. I click Button A and dataset gets filled with data. Now I put a break point in button B click event and inside that button I check if this dataset using Quick Watch in VS 2003. But although inside Button A click event handler the ds showed 1 Table, inside B's click handler its showing zero Tables.
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Is this in ASP.NET pages?
You might have a postback problem...?
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Hi,
This is an ASP.NET code-behind file. But there is no post back here. I click Button A and dataset gets filled with data. Now I put a break point in button B click event and inside that button I check if this dataset using Quick Watch in VS 2003. But although inside Button A click event handler the ds showed 1 Table, inside B's click handler its showing zero Tables.
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I think the page is redeclaring the DS when you click the first button.
Try to add the DS to viewstate.
Then in the 2nd button, use the DS from viewstate.
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ViewState is not returning data as well, I am now populating a DataSet everytime I need to get the data.
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How do i writ a code to extract a file and save it in a folder?
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I actually need a code in c# to extract files from a folder that was extracted from a SWIFT machine
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What is a SWIFT machine ? Is the folder compressed ? As a zip, or something else ?
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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Its just an ordinary folder (very large though) that has a lot of files and i need a code to extract these files and save into different folders for easy accessibility
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Use
System.IO.StreamReader;<br />
System.IO.StreamWriter;
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after using
System.IO.StreamReader;
System.IO.StreamWriter;
then what next.I actually need a procedure,thanks
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Hope this helps:
try<br />
{<br />
string fileContents;<br />
<br />
using (StreamReader sr = new StreamReader(FileName))<br />
{<br />
fileContents = sr.ReadToEnd();<br />
}<br />
return fileContents;<br />
}<br />
catch (Exception exc)<br />
{<br />
return exc.Message;<br />
}
To write contents to a file use StreamWriter instead of StreamReader.
Then use yourStreamWriterObject.Write(ContentWritten); to write the contents to a file.
Hope this is helpful enough to you.
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If you're just moving/copying files from one place to another then File.Copy and File.Move may interest you.
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I am having a samll problem i want to add no of days to a dte variable using c#.net. Say suppose the date variable is haveing a date 25/05/2007. If i add 7 day to it i should get 01/06/2007. Can any one help me in this regard.
thanx in advance
prashanth,
s/w Engineer,
Syfnosys.
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hi,
adding days,months,... is not that hard. the DateTime structure provides the function for that.
just do the following:
DateTime dt = DateTime.Now; //getting present date and time
dt.AddDays(7);// adding 7 days to it
dt.AddDays(-4);// subtracting 4 days
hope this helps
regards
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DateTime dt = new DateTime(2007, 05, 25);<br />
dt = dt.AddDays(7);
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