/// <summary>
/// Returns the value from a field in a row of the specified table.
/// The row is identified by the primary key field name and value that is passed along.
/// The table is identified by the provided table name.
/// This method can be used to retrieve information from 1:1 related secondary tables
/// in scenarios where child items have related table that extend the child row's schema.
/// In most scenarios, this overload is NOT needed. Use the simpler overloads instead!
/// </summary>
/// <typeparam name="TField">The type of the field.</typeparam>
/// <param name="fieldName">Name of the field that contains the value.</param>
/// <param name="ignoreNulls">Should nulls be returned (true) or should default values be provided for nulls (false)?</param>
/// <param name="tableName">Name of the table that contains the field</param>
/// <param name="searchExpression">Search (filter) expression used to identify the record in the secondary table</param>
/// <returns>Value object</returns>
/// <example>GetFieldValue("CustomerStatus", true, "ExtendedCustomerInformationTable", "cust_id = 'x'");</example>
/// <remarks>May throw ArgumentException and RowNotInTableException.</remarks>
protected virtual TField ReadFieldValue <TField>(string fieldName, bool ignoreNulls, string tableName, string searchExpression)
{
// TODO: We may have to do something with the search expression, which should also support maps
var entity = ParentEntity as BusinessEntity;
if (entity == null)
{
throw new NullReferenceException("Parent entity is not a business entity.");
}
fieldName = ((BusinessEntity)ParentEntity).GetInternalFieldName(fieldName, tableName);
var secondaryTable = CurrentRow.Table.DataSet.Tables[tableName];
// Now that we have the table, we can try to find the desired row
var foundRows = secondaryTable.Select(searchExpression);
// We expect to find exactly one row. If fewer or more rows get returned, we throw an error
if (foundRows.Length != 1)
{
if (foundRows.Length > 1)
{
// The record was not uniquely identified
throw new ArgumentException("Unable to find unique record: " + foundRows.Length.ToString(NumberFormatInfo.InvariantInfo) + " records returned by search expression '@searchExpression'", "searchExpression");
}
throw new RowNotInTableException("Search record not found by expression '@searchExpression'");
}
// We did find the row. We can now make sure it has the field we desire
CheckColumn(fieldName, secondaryTable);
// Finally, we are ready to retrieve the desired field
return(BusinessEntityHelper.GetFieldValue <TField>(entity, foundRows[0].Table.DataSet, tableName, fieldName, foundRows[0], ignoreNulls));
}
/// <summary>
/// Returns the value of the specified field in the database
/// </summary>
/// <typeparam name="TField">The type of the field.</typeparam>
/// <param name="fieldName">Field name</param>
/// <param name="ignoreNulls">Should nulls be ignored and returned as such (true) or should the be turned into default values (false)?</param>
/// <param name="currentRow">Current data row, which contains the value we are interested in</param>
/// <returns>Value object</returns>
protected virtual TField ReadFieldValue <TField>(string fieldName, bool ignoreNulls, DataRow currentRow)
{
if (!(ParentEntity is BusinessEntity entity))
{
throw new NullReferenceException("Parent entity is not a business entity.");
}
return(BusinessEntityHelper.GetFieldValue <TField>(entity, currentRow.Table.DataSet, TableName, fieldName, currentRow, ignoreNulls));
}
/// <summary>
/// Returns the value of the specified field in the database
/// </summary>
/// <param name="fieldName">Field name</param>
/// <param name="ignoreNulls">Should nulls be ignored and returned as such (true) or should the be turned into default values (false)?</param>
/// <returns>Value object</returns>
protected virtual object GetFieldValue(string fieldName, bool ignoreNulls = false)
{
if (!(ParentEntity is BusinessEntity entity))
{
throw new NullReferenceException("Parent entity is not a business entity.");
}
return(BusinessEntityHelper.GetFieldValue <object>(entity, CurrentRow.Table.DataSet, TableName, fieldName, CurrentRow, ignoreNulls));
}
/// <summary>
/// Returns the value of the specified field in the database
/// </summary>
/// <typeparam name="TField">The type of the field.</typeparam>
/// <param name="fieldName">Field name</param>
/// <param name="mode">Accessing a field in the parent (link) or target (child/foreign) table?</param>
/// <param name="ignoreNulls">
/// Should nulls be ignored and returned as such (true) or should the be turned into default
/// values (false)?
/// </param>
/// <returns>Value object</returns>
protected virtual TField ReadFieldValue <TField>(string fieldName, XLinkItemAccessMode mode, bool ignoreNulls = false)
{
if (mode == XLinkItemAccessMode.CurrentTable)
{
return(ReadFieldValue <TField>(fieldName));
}
if (!(ParentEntity is BusinessEntity entity))
{
throw new NullReferenceException("Parent entity is not a business entity.");
}
return(BusinessEntityHelper.GetFieldValue <TField>(entity, CurrentTargetRow.Table.DataSet, CurrentTargetRow.Table.TableName, fieldName, CurrentTargetRow, ignoreNulls));
}
/// <summary>
/// Returns the value of the specified field in the database
/// </summary>
/// <param name="fieldName">Field name</param>
/// <param name="mode">Accessing a field in the parent (link) or target (child/foreign) table?</param>
/// <param name="ignoreNulls">
/// Should nulls be ignored and returned as such (true) or should the be turned into default
/// values (false)?
/// </param>
/// <returns>Value object</returns>
protected virtual object GetFieldValue(string fieldName, XLinkItemAccessMode mode, bool ignoreNulls = false)
{
if (mode == XLinkItemAccessMode.CurrentTable)
{
return(GetFieldValue(fieldName));
}
var entity = ParentEntity as BusinessEntity;
if (entity == null)
{
throw new NullReferenceException("Parent entity is not a business entity.");
}
return(BusinessEntityHelper.GetFieldValue <object>(entity, CurrentTargetRow.Table.DataSet, CurrentTargetRow.Table.TableName, fieldName, CurrentTargetRow, ignoreNulls));
}
