TConfigStorage.WriteProperty procedure

Declaration

procedure WriteProperty(Path: string; Instance: TPersistent; 
                       PropInfo: Pointer; DefInstance: TPersistent=Nil; 
                       OnlyProperty: string='')

Arguments

Description

WriteProperty is based on the actions performed by the TWriter class in the FPC RTL. Is uses the RTTI property information passed in the PropInfo argument to access each of the properties in Instance. No actions are performed for a given property if it does not provide both a getter and a setter routine for the property value.

APath contains the fully-qualified path where value(s) are stored in the configuration storage.

Instance is the RTTI-enabled persistent object with the value(s) retrieved and written in the method.

PropInfo in a pointer to type information for the persistent object in Instance (and DefInstance). It is used to access each property, and to convert and store each value in the storage mechanism by calling the SetValue method.

OnlyProperty contains an optional name for a single property name stored in the method. When omitted (or set to an empty string), all of the properties in the type information are stored starting at the specified path using the Name for the property type as an identifier.

DefInstance is a persistent object which contains values to be treated as the default values for the corresponding properties in Instance. When a property has the same value in both Instance and DefInstance, it is deleted from the configuration storage. DefInstance can be Nil - but default property values cannot be determined when omitted.

WriteProperty handles values for the following type kinds in property type information:

• tkInteger (including string identifiers for the value)
• tkChar
• tkEnumeration
• tkSet (as comma-delimited identifiers in the set)
• tkWChar
• tkFloat
• tkSString
• tkLString
• tkAString
• tkBool

The following type kinds are not explicitly handled in the current LCL version:

• tkWString
• tkInt64
• tkQWord