/// <summary>
/// Gets the renderer that can render an assessmentItem.
/// </summary>
/// <param name="assessmentItem">The assessment item to render. This is the <img> element that is in
/// the original LRM content.</param>
/// <remarks>RenderContext must have been set prior to calling this method.</remarks>
internal AssessmentItemRenderer GetRenderer(AssessmentItem assessmentItem)
{
AssessmentItemRenderer renderer = m_renderers[assessmentItem.Type];
renderer.AssessmentItem = assessmentItem;
return renderer;
}
/// <summary>
/// Use an assessmentItem from an LRM page.htm to create an AssessmentItem object.
/// </summary>
/// <param name="assessmentItem">The src attribute value of the img tag that corresponds to the assessment item.</param>
/// <returns>The object representing the parsed value.</returns>
/// <remarks>
/// If more than one of the same name/value pairs exists with the same name, only the first is used.
/// </remarks>
/// <exception cref="FormatException">Thrown if the <paramref name="assessmentItem"/> cannot be parsed.</exception>
public static AssessmentItem Parse(string assessmentItem)
{
AIResources.Culture = LocalizationManager.GetCurrentCulture();
// assessmentItem contains the value of the src attribute, which is of the form:
// "http://localhost:3535/mslamrk,type=1,id=3,cols=10,akey=over,uak=0".
// Split this string by the ',' character.
string[] commaSplit = assessmentItem.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
Dictionary<string, string> parsedValues = new Dictionary<string, string>(10);
foreach (string pair in commaSplit)
{
string[] equalSplit = pair.Split(new char[] { '=' }, 2, StringSplitOptions.None);
if (equalSplit.Length == 2) // gets rid of the "protocol://server/mslamrk" portion, and any non-value markup
{
// convert id to all upper case
string id = equalSplit[0].ToUpperInvariant();
if (!parsedValues.ContainsKey(id))
{
parsedValues.Add(id, equalSplit[1]);
}
}
}
// if (id contains invalid values per LRDG) throw FormatException. id is required.
if (!parsedValues.ContainsKey(AiStrings.Id) || !IsLegalId(parsedValues[AiStrings.Id]))
{
throw new FormatException(String.Format(CultureInfo.InvariantCulture, AIResources.InvalidId, assessmentItem));
}
// if (there is no type value) throw FormatException. see switch statement below.
if (!parsedValues.ContainsKey(AiStrings.Type))
{
throw new FormatException(String.Format(CultureInfo.InvariantCulture, AIResources.InvalidType, assessmentItem));
}
// if other values are not correct (eg, rows is not numeric) then just ignore the invalid values
// and 'be nice' about returning defaults that are appropriate for the type.
AssessmentItem item = new AssessmentItem();
item.m_id = parsedValues[AiStrings.Id]; // id is valid because of above check
switch(parsedValues[AiStrings.Type]) // type is valid because of above check
{
default:
// If the type is not one of the cases, it is an invalid value.
throw new FormatException(String.Format(CultureInfo.InvariantCulture, AIResources.InvalidType, assessmentItem));
case "1":
item.m_type = AssessmentItemType.Text;
item.m_cols = GetCols(parsedValues);
if (parsedValues.ContainsKey(AiStrings.Akey)) // optional argument
{
item.m_akey = LrdgDecodeString(parsedValues[AiStrings.Akey]); // optional argument
// according the LRDG, uak can be "0" or "1", and if it exists then
// akey must exist. Here, if uak exists but akey doesn't, uak is never
// parsed. Also, if uak exists but is anything other than "0" it is
// assumed to be "1" by default.
if (parsedValues.ContainsKey(AiStrings.Uak))
{
if (parsedValues[AiStrings.Uak] == "0") item.m_uak = false;
else item.m_uak = true;
}
}
else
{
item.m_akey = String.Empty;
}
break;
case "2":
item.m_type = AssessmentItemType.TextArea;
item.m_cols = GetCols(parsedValues);
int rows;
if (parsedValues.ContainsKey(AiStrings.Rows)
&& Int32.TryParse(parsedValues[AiStrings.Rows], NumberStyles.Integer, CultureInfo.InvariantCulture, out rows))
{
item.m_rows = rows;
}
else item.m_rows = 5;
break;
case "3":
item.m_type = AssessmentItemType.Radio;
item.m_maxPts = GetMaxPts(parsedValues);
break;
case "4":
item.m_type = AssessmentItemType.Checkbox;
item.m_maxPts = GetMaxPts(parsedValues);
break;
case "5":
item.m_type = AssessmentItemType.ItemScore;
item.m_maxPts = GetMaxPts(parsedValues);
break;
case "7":
item.m_type = AssessmentItemType.Select;
if (parsedValues.ContainsKey(AiStrings.Text))
{
item.m_text = LrdgDecodeString(parsedValues[AiStrings.Text]);
}
else
{
item.m_text = String.Empty;
}
break;
case "8":
item.m_type = AssessmentItemType.Rubric;
item.m_maxPts = GetMaxPts(parsedValues);
break;
case "9":
item.m_type = AssessmentItemType.File;
item.m_cols = GetCols(parsedValues);
break;
}
return item;
}