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Component loading

How components are loaded from a DFM file at runtime?

If a component has another component as a property (example: Datasource has a TDataset component as a property), what happens if the pointed to component is deleted?

What is the difference between VCL and RTL? In which case RTL is used?

What is the significance of TPersistent?

Name of the class, which Does not has 'T' as a prefix.

Comments

  • zibadianzibadian Posts: 6,349Member
    : How components are loaded from a DFM file at runtime?
    :
    : If a component has another component as a property (example: Datasource has a TDataset component as a property), what happens if the pointed to component is deleted?
    :
    : What is the difference between VCL and RTL? In which case RTL is used?
    :
    : What is the significance of TPersistent?
    :
    : Name of the class, which Does not has 'T' as a prefix.
    :
    Components are loaded as resources when the form.create() is called.
    Component Properties: every component has a notification list, which is called if it is added or removed. See FreeNotification() method for more info.
    VCL = Visual Component Library. I.e. all TComponent classes and its descendants
    RTL = Runtime Library. I.e. all other routines and objects
    The TPersistent (and its descendants) can be included in the DFM file.
    Only the Exception (and its descendants) are not prefixed with a T, but with an E.
  • Chaitanya_PuneChaitanya_Pune Posts: 87Member
    : : How components are loaded from a DFM file at runtime?
    : :
    : : If a component has another component as a property (example: Datasource has a TDataset component as a property), what happens if the pointed to component is deleted?
    : :
    : : What is the difference between VCL and RTL? In which case RTL is used?
    : :
    : : What is the significance of TPersistent?
    : :
    : : Name of the class, which Does not has 'T' as a prefix.
    : :
    : Components are loaded as resources when the form.create() is called.
    : Component Properties: every component has a notification list, which is called if it is added or removed. See FreeNotification() method for more info.
    : VCL = Visual Component Library. I.e. all TComponent classes and its descendants
    : RTL = Runtime Library. I.e. all other routines and objects
    : The TPersistent (and its descendants) can be included in the DFM file.
    : Only the Exception (and its descendants) are not prefixed with a T, but with an E.
    :
    ------------------------------------------------------------------------
    Thanks.
    Can you clear following doubt?
    If a component has another component as a property (example: Datasource has a TDataset component as a property), what happens if the pointed to component is deleted?
  • zibadianzibadian Posts: 6,349Member
    : : : How components are loaded from a DFM file at runtime?
    : : :
    : : : If a component has another component as a property (example: Datasource has a TDataset component as a property), what happens if the pointed to component is deleted?
    : : :
    : : : What is the difference between VCL and RTL? In which case RTL is used?
    : : :
    : : : What is the significance of TPersistent?
    : : :
    : : : Name of the class, which Does not has 'T' as a prefix.
    : : :
    : : Components are loaded as resources when the form.create() is called.
    : : Component Properties: every component has a notification list, which is called if it is added or removed. See FreeNotification() method for more info.
    : : VCL = Visual Component Library. I.e. all TComponent classes and its descendants
    : : RTL = Runtime Library. I.e. all other routines and objects
    : : The TPersistent (and its descendants) can be included in the DFM file.
    : : Only the Exception (and its descendants) are not prefixed with a T, but with an E.
    : :
    : ------------------------------------------------------------------------
    : Thanks.
    : Can you clear following doubt?
    : If a component has another component as a property (example: Datasource has a TDataset component as a property), what happens if the pointed to component is deleted?
    :
    The deleted component signals the refering component that it is being deleted. The refering component can then gracefully remove the property link, just before the deleted component is really destroyed.
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