Retrieving values from an Attribute

This section describes how to retrieve the value stored in an FndAttribute object. 

An FndAttribute object can be retrived from a FndDataRow with the string indexer. It takes a String containing the name of the attribute to get as it's argument.

Ifs.Fnd.Data.FndAttribute attr = row["ATTRNAME"];

To determine which kind of data the attribute holds, all record attributes have a data type. To find out the type for an attribute, use the GetAttributeType() method. It returns a FndAttributeType enumeration item.

All attributes contained in a FndDataRow are subclasses of Ifs.Fnd.Data.FndAttribute. The best way of working with attributes is to use type casting.

FndTextAttribute attr = (FndTextAttribute)row["DESCRIPTION"];

The table below shows which type of object the Attribute's GetValue() method returns for each of the data types.

An example

Imagine a record with the following structure (the @ sign is the divisor between the value and the domain):

<PERSON>
  FIRST_NAME:T=Homer
  LAST_NAME:T=Simpson
  AGE:I=38
  SPOUSE:AGG=Marge==>
    <PERSON>
      FIRST_NAME:T=Marge
  CHILDREN:ARRAY=
    <PERSON>
      FIRST_NAME:T=Bart
    <PERSON>
      FIRST_NAME:T=Lisa
    <PERSON>
      FIRST_NAME:T=Maggie 

The syntax for creating and reading the values is shown below:

// First create the meta data
FndDataColumnCollection cols = new FndDataColumnCollection("PERSON");
cols.Add("FIRST_NAME", FndAttributeType.Text);
cols.Add("LAST_NAME", FndAttributeType.Text);
cols.Add("AGE", FndAttributeType.Integer);
FndDataColumn col = cols.Add("SPOUSE", FndAttributeType.Aggregate);
col.ContainedRecordMeta = cols;
col = cols.Add("CHILDREN", FndAttributeType.Array);
col.ContainedRecordMeta = cols;

// Then create the data
FndDataRow row = new FndDataRow(cols);
((FndTextAttribute)row["FIRST_NAME"]).SetValue("Homer");
((FndTextAttribute)row["LAST_NAME"]).SetValue("Simpson");
((FndIntegerAttribute)row["AGE"]).SetValue(38);

FndDataRow spouseRow = new FndDataRow(cols);
((FndTextAttribute)spouseRow["FIRST_NAME"]).SetValue("Marge");
((FndAggregateAttribute)row["SPOUSE"]).SetValue(spouseRow);

FndDataTable childrenTable = ((FndArrayAttribute)row["CHILDREN"]).GetValue();

FndDataRow child = new FndDataRow(cols);
((FndTextAttribute)child["FIRST_NAME"]).SetValue("Bart");
childrenTable.Rows.Add(child);

child = new FndDataRow(cols);
((FndTextAttribute)child["FIRST_NAME"]).SetValue("Lisa");
childrenTable.Rows.Add(child);

child = new FndDataRow(cols);
((FndTextAttribute)child["FIRST_NAME"]).SetValue("Maggie");
childrenTable.Rows.Add(child);

// Trace data
Console.WriteLine("********* TRACE ************\n" + row.ToString() + "\n***************************\n");

// Then read the data
// 1. Get Homer
string name = ((FndTextAttribute)row["FIRST_NAME"]).GetValue();
Console.WriteLine("Name is " + name);

// 2. Get Marge
spouseRow = ((FndAggregateAttribute)row["SPOUSE"]).GetValue();
name = ((FndTextAttribute)spouseRow["FIRST_NAME"]).GetValue(); 
Console.WriteLine("Spouse is " + name);

// 3. Get Children
name = "";
childrenTable = ((FndArrayAttribute)row["CHILDREN"]).GetValue();
for(int i = 0; i < childrenTable.Rows.Count; i++)
{
    if(i > 0)
        name += ", ";
    name += ((FndTextAttribute)childrenTable.Rows[i]["FIRST_NAME"]).GetValue();
}
Console.WriteLine("Children are " + name);

The output from the code above will be:

********* TRACE ************
(
   $PERSON
      (

            (
               $FIRST_NAME:T/*=Homer
               $LAST_NAME:T/*=Simpson
               $AGE:I/*=38
               $SPOUSE:AGGREGATE/*
                  (

                        (
                           $FIRST_NAME:T/*=Marge
                        )
                  )
               $CHILDREN:ARRAY/*
                  (

                        (
                           $FIRST_NAME:T/*=Bart
                        )

                        (
                           $FIRST_NAME:T/*=Lisa
                        )

                        (
                           $FIRST_NAME:T/*=Maggie
                        )
                  )
            )
      )
)

***************************

Name is Homer
Spouse is Marge
Children are Bart, Lisa, Maggie