I have a class in C++ (VS2010).
This class has public functions, for example "ToString".
Sometimes it happens that I need to call ToString from within the class.
For example:
void::ConvertToLowerCase()
{
wstring ws;
ws = ToString();
ws = lower(ws);
m_wsText= ws
}
I would like to know if I can add an "owner" to the ToString line, for example
ws = self.ToString();
or
ws = me.ToString();
I tried all names that I could imagine, but I did not find any that would work.
Having such an owner name helps me to figure out where the function resides.
In C++ you can do this via this:
ws = this->ToString(); //this is a pointer
but called in that context, this is equivalent to what you already have:
ws = ToString();
this pointer:
ws = this->ToString();
Related
Since a while now I'm implementing services whenever possible with ServiceStack (or WebAPI) instead of WCF.
What I want to do now is sending an interface (-name) to the server and get a class-implementation back. Maybe that's confusing, so I'll give you an example:
My service-client has multiple operations - like "check form":
The logic for checking this form is not implemented. What it has is an interface called IFormChecker with methods like NameIsValid(string firstName, string middleName, string lastName).
Instead of sending the whole form-data to the server for validation, the client will request the implementation of IFormChecker from the server.
I know that's possible with WCF, but I have no idea how to do that with ServiceStack.
If that's possible, what's the way to go? I checked the documentation, but I'm not really wiser.
It seams like there's no "magic trick" or anything.
I have to serialize/deserialize the class "old-fashion way".
If you're interested, here's the solution:
I created a "Root"-Interface, in this example it is IModule.
This IModule contains only 1 property, called Name.
It is a string and only there for convenience:
The IFormChecker from the example would be derived from this interface:
My client knows the value of this Name-property and of course the interface itself.
It will now fire the Name-value to the server, which will return the serialized class.
All I have to do is:
var module = ModuleImplementations.FirstOrDefault(x => x.Name == name);
if(module == null) throw new SomeException();
return module.Serialize();
client-wise I can deserialize it and cast it to the interface. That's it.
Here's my ModuleSerialization-Class:
public static class ModuleSerialization
{
public static string Serialize(this IModule m)
{
using (var ms = new MemoryStream())
{
var bf = new BinaryFormatter();
bf.Serialize(ms, m);
return Convert.ToBase64String(ms.ToArray());
}
}
public static T Deserialize<T>(string serialized) where T : class, IModule
{
var ba = Convert.FromBase64String(serialized);
using (var s = new MemoryStream(ba))
{
var bf = new BinaryFormatter();
return bf.Deserialize(s) as T;
}
}
}
Cheers!
I'm working on an Android app. I created (in a separate .java file) an object like so:
class RRS_Location {
String tagname;
String href;
// Constructor
public RRS_Location(String tagname, String href) {
this.tagname = tagname;
this.href = href;
}
public String getTagname() {
return tagname;
}
public String getHref() {
return href;
}
}
Within an activity, I've declared a List of these items
List<RRS_Location> rrs_list;
I'm getting a NullPointerException when I try to add an RRS_Location object to the list. I'm doing so using this code
rrs_list.add(new RRS_Location(e1, e2));
I've used Toast to echo back to me that I have valid Strings e1 and e2. Any ideas on why I'm getting the exception? TIA!
Are you instantiating rrs_list before making the call to add?
List<RRS_Location> rrs_list = new ArrayList<RRS_Location>();
If not, this is why you are getting a NullPointerException, you are attempting to invoke a method on a null object.
I am new to C# / OOP and am working on converting an existing application into .net 4.0 framework.
My code is as follows:
Class abc
private IList<string[]> GetReportBatchList()
{
List<string[]> rowList = new List<string[]>();
SqlParameter[] prm = { new SqlParameter("#rpt_doc_type_id", SqlDbType.Int, 9) };
prm[0].Value = 101;
try
{
.....
.....
.....
}
return rowList;
}
class xyz
using abc;
Private Function GenerateReport()
Try
{
Dim rptBatchList As ??????
rptBatchList = GetReportBatchList()
While rptBatchList.Read()
......
......
......
}
catch
{
......
}
What type should rptBatchList be declared as?
Since the return value of GetReportBatchList() has IList of string as its type, it makes sense that rptBatchList should be the same type.
Your second example is VB, but you say you are using C#, so...
For C# it would be IList<string[]>.
My VB is a little rusty, but I think it would be IList(Of String()).
Hmmm... is this a question about correct return types, or a question about translating C# into VB.Net?
According to the function definition you have, rptBatchList will be of type IList<string[]> - obviously declared in the correct syntax for VB.Net.
Further to that, because it is a list of string arrays, it doesn't have a Read() function, so maybe you were looking for something that derives from DbDataReader instead (like a SqlDataReader)? If you do intend to stick with the current definition then you can use either a foreach or a for loop to iterate over the list elements, or you can use Linq extensions and use something like this:
rptBatchList.ForEach(z => { z.ForEach(x => doSomethingWithThisResultString(x)); } );
although that can get messy fast - you probably want to just stick with a couple of nested foreach loops.
I have a LINQ dbml class that I am wrapping in a POCO. I have built overloaded constructors that take the DBML class and init. the wrapper objects properties based on the dbml object passed in.
For example
public class MyPerson{
public MyPerson(DBMLPerson p)
{
this.ID = p.ID;
this.Name = p.Name;
}
}
if I then do something like this where I return an IQueryable
{
return from p in datacontext.DBMLPerson
select new MyPerson(p){};
}
When I try to do further queries on that Iquearble I get "System.NotSupportedException: The member 'MyPerson.ID' has no supported translation to SQL.."
However if I do this
{
return from p in datacontext.DBMLPerson
select new MyPerson(){
ID = p.ID;
Name = p.Name;
};
}
I don't get an error at all and everything works perfect. Basically I want to have my class handle the conversion from LINQ object to POCO itself.
Basically I have to use the Object Initializer or I am unable to match on that field.
Ok not sure this will actually help anyone but but myself but my whole problem is the I shouldn't be using IQuerable after a certain point(outside of my repository)
iqueryable-can-kill-your-dog-steal-your-wife-kill-your-will-to-live-etc
I've got a class that's meant to validate input fields to make sure the value is always a decimal. I've tested the regex here: http://livedocs.adobe.com/flex/3/html/help.html?content=validators_7.html, and it looks like it does the right thing, but in my app, I can't seem to get it to match to a number format.
Class Definition:
public class DecimalValidator {
//------------------------------- ATTRIBUTES
public var isDecimalValidator:RegExpValidator;
//------------------------------- CONSTRUCTORS
public function DecimalValidator() {
isDecimalValidator = new RegExpValidator();
isDecimalValidator.expression = "^-?(\d+\.\d*|\.\d+)$";
isDecimalValidator.flags = "g";
isDecimalValidator.required = true;
isDecimalValidator.property = "text";
isDecimalValidator.triggerEvent = FocusEvent.FOCUS_OUT;
isDecimalValidator.noMatchError = "Float Expected";
}
}
Setting the source here:
public function registerDecimalInputValidator(inputBox:TextInput, valArr:Array):void {
// Add Validators
var dValidator:DecimalValidator = new DecimalValidator();
dValidator.isDecimalValidator.source = inputBox;
dValidator.isDecimalValidator.trigger = inputBox;
inputBox.restrict = "[0-9].\\.\\-";
inputBox.maxChars = 10;
valArr.push(dValidator.isDecimalValidator);
}
And Calling it here:
registerDecimalInputValidator(textInput, validatorArr);
Where textInput is an input box created earlier.
Clearly I'm missing something simple yet important, but I'm not entirely sure what! Any help would be much appreciated.
I don't know ActionScript, but as far as I know it's an ECMAScript language, so I expect you need to escape the backslashes if you use a string to define a regex:
isDecimalValidator.expression = "^-?(\\d+\\.\\d*|\\.\\d+)$";
This strikes me as wrong; but I can't quite put my finger on it. For your DecimalValidator instead of composing a RegExpValidator; why not extend it?
public class DecimalValidator extend RegExpValidator{
//------------------------------- CONSTRUCTORS
public function DecimalValidator() {
super()
this.expression = "^-?(\d+\.\d*|\.\d+)$";
this.flags = "g";
this.required = true;
this.property = "text";
this.triggerEvent = FocusEvent.FOCUS_OUT;
this.noMatchError = "Float Expected";
}
}
How when is the registerdecimalInputValidator called? I have a slight worry about the Validator instance is a local variable to a method instead of 'global' property to the function.
protected var dValidator:DecimalValidator = new DecimalValidator();
public function registerDecimalInputValidator(inputBox:TextInput):void {
dValidator.isDecimalValidator.source = inputBox;
dValidator.isDecimalValidator.trigger = inputBox;
}
I'm not sure why you are setting restrictions on the TextInput in the registerDecimalInputValidator method; that should be done when you create the method (in createChildren() or possibly in response to public properties changing, in commitProperties . It is also not obvious to me what the validatorArr does. If you're expecting to access values inside the validatorArrray outside of the method; it would often be a common practice to return that value from the method. Without looking it up; I'm not sure if Arrays are passed by value or reference in Flex.