Help with Generic Method

[Guest]

Hi all, below at the bottom are 2 nearly identical overloads for the same
method. As you can see the algorithm is exactly the same. However try as I
may I cannot seem too create a usefull Generic method, i.e. one that compiles.

What I would like to be able to do is something like the following when I
call it.
this.UpdateAnswer<TextBox>(question, answer);

Or better yet.
this.UpdateAnswer<typeof(SomeUiElement.GetType())>(question, answer);

Is this type of thing at all possible with generics or am I headed down the
wrong path?

private void UpdateAnswer(PaginationPageQuestion question, TextBox answer)
{
if (answer != null)
{
question.Answer = !answer.Text.Trim().Equals(string.Empty) ?
answer.Text.Trim() :
null
;
}
}

private void UpdateAnswer(PaginationPageQuestion question, ComboBox
answer)
{
if (answer != null)
{
question.Answer = !answer.Text.Trim().Equals(string.Empty) ?
answer.Text.Trim() :
null
;
}
}

 

[Moty Michaely]

Hi all, below at the bottom are 2 nearly identical overloads for the same
method. As you can see the algorithm is exactly the same. However try as I
may I cannot seem too create a usefull Generic method, i.e. one that compiles.

What I would like to be able to do is something like the following when I
call it.
this.UpdateAnswer<TextBox>(question, answer);

Or better yet.
this.UpdateAnswer<typeof(SomeUiElement.GetType())>(question, answer);

Is this type of thing at all possible with generics or am I headed down the
wrong path?

private void UpdateAnswer(PaginationPageQuestion question, TextBox answer)
{
if (answer != null)
{
question.Answer = !answer.Text.Trim().Equals(string.Empty) ?
answer.Text.Trim() :
null
;
}
}

private void UpdateAnswer(PaginationPageQuestion question, ComboBox
answer)
{
if (answer != null)
{
question.Answer = !answer.Text.Trim().Equals(string.Empty) ?
answer.Text.Trim() :
null
;
}
}

Dear John,

Your answer question must have a text property?

I would suggest using the strategy Pattern to answer the questions.
Sort of a delegate that will handle the return value of the answer.

Something like:
UpdateAnswer(question, answer, predicate);

To use generics you will have to find common properties for the types
that will be used..

Hope this helps.

Moty.

 

[Samuel R. Neff]

No need for generics, just use the common base class as the type for
your second argument:

private void UpdateAnswer(PaginatingPageQuestion question, Control
answer) {
...
}

This is not always possible, but in your particular case both classes
you're concerned with share a common base which declares the property
you want to check (Text).

HTH,

Sam

 

[Moty Michaely]

No need for generics, just use the common base class as the type for
your second argument:

private void UpdateAnswer(PaginatingPageQuestion question, Control
answer) {
...

}

This is not always possible, but in your particular case both classes
you're concerned with share a common base which declares the property
you want to check (Text).

HTH,

Sam

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Yes,
Samuel is right in case of a Control.

If there will be cases in which the *answer* object type doesn't have
the text property (say Age property), it will not work..

Polymorphic calls are preferred in your case.

Moty