5.6 Data Functions

Functions that are declared as data functions in the dialog description must be declared in C as follows:

DM_Boolean DML_default DML_CALLBACK <function name> (DM_DataArgs *args);

if the function is defined as

{ export | reexport } function datafunc <function name> ();

in the dialog script

or as

DM_Boolean DML_c DML_CALLBACK <function name> (DM_DataArgs *args);

if the function is defined as

{ export | reexport } function c datafunc <function name> ();

in the dialog script.

The parameter of this function is predefined by the ISA Dialog Manager and cannot be changed. It represents a Data Model (Model component) that provides the presentation objects (View component) with data values or stores and manages them.

This function is called when a synchronization between View and Model components is required. This may either happen automatically, according to the control options in the .dataoptions[]attribute of the involved components. The call can also be triggered by explicit invocation of the :collect(), :propagate(), :apply() and :represent() methods. For each Model attribute there is a separate call.

Example

Dialog File 

dialog D
function datafunc FuncData();
function void     Reverse(integer Idx);

window Wi
{
  .title "Datafunc demo";
  .width 200;  .height 300;

  edittext Et
  {
    .datamodel FuncData;
    .dataget .text;
    .dataset .text;
    .xauto 0;
    .xright 80;
  }

  pushbutton PbAdd
  {
    .text "Add";
    .xauto -1;
    .width 80;

    on select
    {
      this.window:apply();
    }
  }

  listbox Lb
  {
    .xauto 0;  .yauto 0;
    .ytop 30;  .ybottom 30;
    .datamodel FuncData;
    .dataget .content;

    on select
    {
      PbReverse.sensitive := true;
    }
  }

  pushbutton PbReverse
  {
    .xauto 0;  .yauto -1;
    .text "Reverse element";
    .sensitive false;

    on select
    {
      Reverse(Lb.activeitem);
    }
  }

  on close { exit(); }
}

C File 

#ifdef VMS
#  define EXITOK    1
#  define EXITERROR 0
#else
#  define EXITOK    0
#  define EXITERROR 1
#endif

#include <IDMuser.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "datafuncfm.h"

#define DIALOGFILE "~:datafunc.dlg"

static DM_ID     data_id = (DM_ID)0;
static DM_Value  data_vec;
static DM_String data_str;

void DML_default DM_CALLBACK FuncData __1((DM_DataArgs *, args))
{
  if (!data_id)
    data_id = args->object;
  switch (args->task)
  {
  case MT_get:
    switch(args->attribute)
    {
    case AT_text:
      args->retval.type = DT_string;
      args->retval.value.string = data_str;
      break;
    case AT_content:
      if (args->index.type == DT_void)
      {
        args->retval = data_vec;
      }
      else if (args->index.type == DT_integer)
      {
        DM_ValueGet(&data_vec, &args->index, &args->retval, 0);
      }
      break;
    default:
      break;
    }
    break;
  case MT_set:
    switch(args->attribute)
    {
    case AT_text:
      if (args->data.type == DT_string)
      {
        if (DM_ValueChange(&data_vec, NULL, &args->data, DMF_AppendValue))
          DM_DataChanged(data_id, AT_content, NULL, DMF_Verbose);
      }
      break;
    default:
      break;
    }
    break;
  default:
    break;
  }
}

void DML_default DM_ENTRY Reverse __1((DM_Integer, Idx))
{
  DM_Value  index, data;
  char     *cp,    ch;
  size_t    len,   i;

  DM_ValueInit(&data, DT_void, NULL, 0);
  index.type = DT_integer;
  index.value.integer = Idx;
  if (DM_ValueGet(&data_vec, &index, &data, 0) && data.type == DT_string)
  {
    if (DM_StringChange(&data_str, data.value.string, 0))
      DM_DataChanged(data_id, AT_text, NULL, DMF_Verbose);

    /* reverse the string */
    cp = data.value.string;
    if (cp)
    {
      len = strlen(cp);
      if (len>2)
      {
        len--;
        for (i=0; len>0 && i<len/2; i++)
        {
          ch = cp[i];
          cp[i] = cp[len-i];
          cp[len-i] = ch;
        }
      }
    }
    if (DM_ValueChange(&data_vec, &index, &data, 0) && data_id)
      DM_DataChanged(data_id, AT_content, &index, DMF_Verbose);
  }
}

int DML_c AppMain __2((int, argc), (char **,argv))
{
  DM_ID dialogID;
  DM_Value data;

  /* initialize the Dialog Manager */
  if (!DM_Initialize (&argc, argv, 0))
  {
    DM_TraceMessage("Could not initialize.", 0);
    return (1);
  }

  /* load the dialog file */
  switch(argc)
  {
  case 1:
    dialogID = DM_LoadDialog (DIALOGFILE,0);
    break;
  case 2:
    dialogID = DM_LoadDialog (argv[1],0);
    break;
  default:
    DM_TraceMessage("Too many arguments.", 0);
    return(EXITERROR);
    break;
  }
  if (!dialogID)
  {
    DM_TraceMessage("Could not load dialog.", 0);
    return(EXITERROR);
  }

  data.type = DT_type;
  data.value.type = DT_string;
  DM_ValueInit(&data_vec, DT_vector, &data, DMF_StaticValue);

  data.type = DT_string;
  data.value.string = "^ Enter a string";
  DM_ValueChange(&data_vec, NULL, &data, DMF_AppendValue);
  data.value.string = "and press 'Add'";
  DM_ValueChange(&data_vec, NULL, &data, DMF_AppendValue);

  DM_StringInit(&data_str, DMF_StaticValue);
  DM_StringChange(&data_str, "Change me!", 0);

  /* install table of application functions */
  if (!BindFunctions_D (dialogID, dialogID, 0))
    DM_TraceMessage ("There are some functions missing.", 0);

  /* start the dialog and enter event loop */
  if (DM_StartDialog (dialogID, 0))
    DM_EventLoop (0);
  else
    return (EXITERROR);

  return (EXITOK);
}

See also

Function DM_DataChanged