A parameter block is created with a parameter block descriptor as an argument. There is exactly one parameter block descriptor for every parameter block. A programmer must create a singleton parameter block descriptor that remains valid throughout the life of the DLL. This can be done by declaring a static instance in the DLL. The ParamBlockDesc2 constructor takes a variable amount of arguments that describe the parameter block. Alternatively you can construct the parameter block descriptor incrementally using methods such ParamBlockDesc2::AddParam() and ParamBlockDesc2::ParamOption().
Of the arguments that need to be listed, the first five arguments are required. After that, some arguments are included only if you supplied some special flags in the 5th argument (flags). The parameter flags are documented in the topic Parameter Block Flags.
Afterwards, for each parameter for which you want a user interface control, you will supply mandatory and optional arguments. At the end of each parameter description section you will supply the special argument tag end. At the end of the entire constructor you must also supply the tag end.
Parameter Block Descriptor 2 Constructor
ParamBlockDesc2
(
// Required specifications
BlockID ID,
TCHAR* int_name,
int local_name,
ClassDesc2* cd,
BYTE flags,
// ONLY IF P_VERSION is specified as a flag
int version_number,
// ONLY IF P_AUTO_CONSTRUCT is specified as a flag
// This is the same reference number that specifies the
// parameter block used in GetReference() and SetReference().
int reference_number,
// ONLY IF P_AUTO_UI is specified above
// Automatic UI parameter map specifications
int dialog_template_ID,
int dialog_title_res_ID,
int flag_mask,
int rollup_flags,
ParamMap2UserDlgProc* proc,
// ONLY IF P_INCLUDE_PARAMS or P_USE_PARAMS is specified as a flag
// Address of source IParamblockDesc to use
ParamBlockDesc2* pSourceDesc,
// OPTIONAL
// FOR EACH variable control create a parameter specification:
// There is one of these parameter specifications for each control.
ParamID id,
TCHAR* internal_name,
ParamType type,
// Optional. Use this argument ONLY IF you use a Tab<> type
[int table_size,
int flags,
int local_name_res_ID,
// FOR EACH parameter specification, specify zero or more parameter tags.
// and optional parameter information
Parameter_Tag
end, //End for each parameter specification
end //End for all the variable arguments
);
Below is a sample parameter block:
static ParamBlockDesc2 widget_param_blk (
//Required arguments ----------------------------
widget_params, _T("params"), 0, &WidgetDesc,
//flags
P_AUTO_CONSTRUCT + P_AUTO_UI,
//Dependent arguments ---------------------------
//required because P_AUTO_CONSTRUCT was flagged
//This declares the reference number of the Parameter Block.
PBLOCK_REF,
//required because P_AUTO_UI was flagged.
//This is the Rollout description
IDD_PANEL, IDS_PARAMS, 0, 0, NULL,
//Parameter Specifications ----------------------
// For each control create a parameter:
widget_size, _T("size"), TYPE_FLOAT, P_ANIMATABLE, IDS_SPIN,
//3 optional tags
p_default, 1.0f,
p_range, 0.0f,1000.0f,
p_ui, TYPE_SPINNER, EDITTYPE_FLOAT, IDC_SIZE_EDIT, IDC_SIZE_SPIN, 0.50f,
end,
widget_left, _T("Left"), TYPE_FLOAT, P_ANIMATABLE, IDS_SPIN,
//3 optional tags
p_default, 0.0f,
p_range, 0.0f,100.0f,
p_ui, TYPE_SPINNER, EDITTYPE_UNIVERSE, IDC_LEFT_EDIT, IDC_LEFT_SPIN, 0.50f,
end,
widget_right, _T("Right"), TYPE_FLOAT, P_ANIMATABLE, IDS_SPIN,
//3 optional tags
p_default, 0.0f,
p_range, 0.0f,100.0f,
p_ui, TYPE_SPINNER, EDITTYPE_UNIVERSE, IDC_RIGHT_EDIT, IDC_RIGHT_SPIN, 0.50f,
end,
end
);