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Check out this[^] and this[^] (search for __FILE__ in this link).
Take care,
Tom
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Check out my blog at http://tjoe.wordpress.com
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Hi guys,
This may be a dumb but it has given me a lot of problems.
Here is my situation:
I have widnows form with a tabcontrol, on that tab control i have two tabs (groups and emails).
On the groups tab I have a datagridview that fills itself from a database displaying the current groups. ( Customers,Retailers,Suppliers and Employees). That works well.
On the Emails Tab i have datagridview that its suppose to fill when i click a group from the tab (group datagridview) displaying the emails asociated with the selected group.
How can i acomplish this?
The database is set up correctly. So theres no need to look in there.
But here is my table structure
groupstable
ID
name
recipients
emailstable
ID
groupiID
email
description
Primary keys asign to ID columns on both tables. ID on grouptable related to groupID on emailstable.
Thanks guys,
Juan R. Castillo
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Why don't you use the tabcontrol selectedindex change event to see if that tab page has focus and then bind your datagrid?
Hope that helps.
Ben
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Try this.
Set the SelectionMode property of the datagridview to FullRowSelect and then try handling the SelectionChanged event. On that event set the visible tab to be the second and bind the second datagridview to the database considering the selection from the first datagridview.
Hope it helps.
Do your best to be the best
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Thats what i have been trying to do... It doesn't work.
DO you have any example code you can show me?
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I have a class Categroy that derives from it's base RESTResource .
public class Category : RESTResource
{
}
public class RESTResource
{
public < derived type > Get()
{
}
}
The above example should evaluate to ... public Category Get() ... at runtime.
Depending on the Type of the derviced class from RESTResource , how Can I set the return type of RESTResource.Get() ?
/\ |_ E X E GG
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I'm not sure if you can write generic properties. If not, all you can do is return the base type, and users would have to cast it. I don't think you can override a property and change it's return type.
Christian Graus - Microsoft MVP - C++
"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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I guess ruby got my hopes up...
/\ |_ E X E GG
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It really shouldn't matter that you can't change the return type. Assuming that you could, you would still need to declare a variable to hold it using the dervied type. This implies that you know the type like:
RESTResource r = ;
Category c = r.Get();
Since you need to know the return type anyway, you can simply set the return type of Get to RESTResource then cast it like so:
RESTResource r = ;
Category c = r.Get() as Category;
if (null != c)
Now, you may be referring to virtual functions, which work like this:
public class RESTResource {
public virtual RESTResource Get() {
return new RESTResource();
}
}
public class Category : RESTResource {
public override RESTResource Get() {
return new Category();
}
}
RESTResource r = new RESTResource();
RESTResource r2 = r.Get();
Category c = new Category();
Category c2 = c.Get() as Category;
Take care,
Tom
-----------------------------------------------
Check out my blog at http://tjoe.wordpress.com
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Thanks. I think I'm going to head in a different direction with this...
Now, is this the right use of generics?
Category has a static string endpoint_url. I would like to get that from T1 in the Create method.
Create<Category>();
.
.
.
public Response Create<T1>()
{
string url=
}
public class Category
{
public static string endpoint_url = "/categories";
public int id;
public string name;
public int content_provider_id;
}
-- modified at 1:50 Tuesday 2nd October, 2007
/\ |_ E X E GG
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Your code isn't complete, so I can't really tell what you are doing (or want to do). Can you provide a little more info or more complete example?
Take care,
Tom
-----------------------------------------------
Check out my blog at http://tjoe.wordpress.com
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I have this class structure:
public class Test
{
public Response Create<T1>()
{
string url=
}
}
public class Category
{
public static string endpoint_url = "/categories";
public int id;
public string name;
public int content_provider_id;
}
My Category class has a static string endpoint_url. I want to get that string from inside of create using the Type T1 and save it to url.
My expected results are to have url set to "/categories"
/\ |_ E X E GG
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You can either create an abstract base class or an interface (from which Category and others would derive). If Category and any possible other classes have common functionality, then you should go with an abstract base class, because you can put that common functionality in there. If you go with an interface, then your classes (e.g. Category) really won't share code.
You won't be able to get the static endpoint_url without creating an instance of Category. Both methods above require an instance of Category. Assuming you are willing to create an instance of Category, the code would be like this:
public Response Create<T>() where T : MyBaseClass {
T myClass = new T();
String url = myClass.GetURL();
}
public abstract class MyBaseClass {
public abstract String GetURL();
}
public class Category : MyBaseClass {
public static string endpoint_url = "/categories";
public override String GetURL() {
return Category.endpoint_url;
}
}
Response r = t.Create<Category>();
Take care,
Tom
-----------------------------------------------
Check out my blog at http://tjoe.wordpress.com
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TJoe wrote: If Category and any possible other classes have common functionality, then you should go with an abstract base class
Yeah, I have a few other classes... I was just using Category as an example.
I'll try out what you've worked out first thing tomorrow.
Thanks,
Alex
/\ |_ E X E GG
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I get a compile error on this line:
T myClass = new T();
Error 1 Cannot create an instance of the variable type 'T' because it does not have the new() constraint
/\ |_ E X E GG
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This means that the constraint for the generic is missing the new() keyword. For example:
public T Create() where T : ISomething, new()
{
T item = new T();
return item;
} The new constraint can only be used with a zero-arg constructor.
Deja View - the feeling that you've seen this post before.
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"Because not all objects are guaranteed to have public default constructors, the compiler does not allow you to call the default constructor on the type parameter. To override this compiler restriction, you add the text new() after all other constraints are specified. This text is a constructor constraint, and it forces the type parameter decorated with the constructor constraint to have a default constructor." (http://www.codeproject.com/books/EssentialCS20.asp[^])
Fix is easy, public Response Create<T>() where T : MyBaseClass, New()
[ My Blog] "Visual studio desperately needs some performance improvements. It is sometimes almost as slow as eclipse." - Rüdiger Klaehn "Real men use mspaint for writing code and notepad for designing graphics." - Anna-Jayne Metcalfe
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Sorry, forgot about the new() keyword. Pete's response describes how to use it.
Take care,
Tom
-----------------------------------------------
Check out my blog at http://tjoe.wordpress.com
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Did you perhaps for get to escape a < in your code?
Take care,
Tom
-----------------------------------------------
Check out my blog at http://tjoe.wordpress.com
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just fixed it.
/\ |_ E X E GG
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This will do it.
public class Category : RESTResource<Category>
{
}
public class RESTResource<T> where T : RESTResource, new()
{
public <T> Get()
{
T item = new T();
return item;
}
}
Deja View - the feeling that you've seen this post before.
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No problem. I hope it helped.
Deja View - the feeling that you've seen this post before.
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I'm developing a windows application in C# with crystal reports. In one of my reports I deisplay passenger list comes by cruises. I group it by cruise no. I want to display group footer with total no of passengers by their nationality and grand total, something like this,
Malaysia 10
Singapore 15
Thailand 10
Total 35
and I need to do the same thing at the report footer as well with totals of groups. Can anybody tell me how to do it.
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