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Beautify bindable properties documentation

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Some minor formatting changes

Change-Id: I336a442d01cb048397b2a65977cfb96bb7179752
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
This commit is contained in:
Andreas Buhr 2021-03-24 09:53:01 +01:00
parent 3e65d0408b
commit 59b0212215
1 changed files with 14 additions and 13 deletions
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27
src/corelib/doc/src/objectmodel/bindableproperties.qdoc
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@ -127,23 +127,24 @@
Bindable properties must not be used as variables in algorithms. Each value written
would be communicated to dependent properties.
For example, in the following code, other properties dependent on myProperty would be
first informed about the change to 42, then about the change to maxvalue.
For example, in the following code, other properties that depend on
\b myProperty would be first informed about the change to \b 42, then about
the change to \b maxValue.
\badcode
myProperty = somecomputation(); // returning, say, 42
if (myProperty.value() > maxvalue)
myProperty = maxvalue;
if (myProperty.value() > maxValue)
myProperty = maxValue;
\endcode
Instead, perform the computation in a separate variable. Correct usage is shown in the
following example.
\code
int newvalue = somecomputation();
if (newvalue > maxvalue)
newvalue = maxvalue;
myProperty = newvalue; // only write to the property once
int newValue = someComputation();
if (newValue > maxValue)
newValue = maxValue;
myProperty = newValue; // only write to the property once
\endcode
\section2 Writing Bindable Properties in Transitional States
@ -153,15 +154,15 @@
not be written in transient states, when class invariants are not met.
For example, in a class representing a circle which holds two members
"radius" and "area" consistent, a setter might look like this (where radius
\b radius and \b area consistent, a setter might look like this (where radius
is a bindable property):
\badcode
void setRadius(double newvalue)
void setRadius(double newValue)
{
radius = newvalue; // this might trigger change handlers
area = M_PI*radius*radius;
emit radiusChanged();
radius = newValue; // this might trigger change handlers
area = M_PI * radius * radius;
emit radiusChanged();
}
\endcode