/// <summary>
/// Gets the table schema from table mapping.
/// </summary>
/// <param name="tableMapping">The table mapping.</param>
/// <returns>DataTable.</returns>
private static DataTable GetTableSchemaFromTableMapping(ITableMapping tableMapping)
{
tableMapping.Validate();
string tableName;
if (!string.IsNullOrWhiteSpace(tableMapping.Schema))
{
tableName = $"{tableMapping.Schema}.{tableMapping.TableName}";
}
else
{
tableName = tableMapping.TableName;
}
var dataTable = new DataTable
{
TableName = tableName
};
foreach (var columnMapping in tableMapping.ColumnMappings)
{
dataTable.Columns.Add(columnMapping.AsDataColumn());
}
return(dataTable);
}
/// <summary>
/// Populates the specified data table.
/// </summary>
/// <param name="dataTable">The data table.</param>
/// <param name="objects">The objects.</param>
/// <param name="tableMapping">The table mapping.</param>
/// <param name="enforceConstraints">If set to <c>true</c>, it enforces constraints.</param>
private static void Populate(this DataTable dataTable, IEnumerable <object[]> objects, ITableMapping tableMapping, bool enforceConstraints = false)
{
if (!enforceConstraints)
{
dataTable.Constraints.Clear();
}
var internalObjects = objects.Where(item => item != null && item.Length > 0);
foreach (var objectArray in internalObjects)
{
var dataRow = dataTable.NewRow();
var columnMappings = tableMapping.ColumnMappings;
for (var idx = 0; idx < columnMappings.Count; idx++)
{
var columnMapping = columnMappings[idx];
var columnName = columnMapping.Name;
var value = objectArray[idx];
if (value != null)
{
if (columnMapping.Type.IsEnum)
{
dataRow[columnName] = value.GetHashCode();
}
else
{
value = Convert.ChangeType(value, columnMapping.Type);
dataRow[columnName] = value;
}
}
else
{
if (!columnMapping.AllowNull)
{
if (columnMapping.Type == typeof(string))
{
dataRow[columnName] = string.Empty;
}
else
{
dataRow[columnName] = columnMapping.DefaultValue;
}
}
else
{
dataRow[columnName] = DBNull.Value;
}
}
}
dataTable.Rows.Add(dataRow);
}
}
/// <summary>
/// Converts the objects to a strongly typed data table.
/// </summary>
/// <param name="objects">The objects.</param>
/// <param name="tableMapping">The table mapping.</param>
/// <returns>DataTable.</returns>
/// <exception cref="ArgumentNullException">
/// objects
/// or
/// tableMapping
/// </exception>
/// <exception cref="ArgumentException">
/// Objects have different lengths.
/// or
/// Columns
/// </exception>
public static DataTable AsStronglyTypedDataTable(this IEnumerable <object[]> objects, ITableMapping tableMapping)
{
if (objects == null)
{
throw new ArgumentNullException(nameof(objects));
}
if (tableMapping == null)
{
throw new ArgumentNullException(nameof(tableMapping));
}
if (objects.Any(x => (x?.Length).GetValueOrDefault() != tableMapping.ColumnMappings.Count))
{
throw new ArgumentException("Objects have different lengths.");
}
var dataTable = GetTableSchemaFromTableMapping(tableMapping);
if (dataTable.Columns == null || dataTable.Columns.Count <= 0)
{
throw new ArgumentException(nameof(dataTable.Columns));
}
dataTable.Populate(objects, tableMapping);
dataTable.AcceptChanges();
return(dataTable);
}
