text: # MemberMapData Class
  
  Namespace: [CsvHelper.Configuration](/api/CsvHelper.Configuration)
  
  The configured data for the member map.
  
  ```cs
  public class MemberMapData 
  ```
  
  Inheritance Object -> MemberMapData
  
  ## Constructors
  &nbsp; | &nbsp;
  - | -
  MemberMapData(MemberInfo) | Initializes a new instance of the ``CsvHelper.Configuration.MemberMapData`` class.
  
  ## Properties
  &nbsp; | &nbsp;
  - | -
  Constant | Gets or sets the constant value used for every record.
  Default | Gets or sets the default value used when a CSV field is empty.
  Ignore | Gets or sets a value indicating whether the field should be ignored.
  Index | Gets or sets the column index.
  IndexEnd | Gets or sets the index end. The Index end is used to specify a range for use with a collection member. Index is used as the start of the range, and IndexEnd is the end of the range.
  IsConstantSet | Gets or sets a value indicating if a constant was explicitly set.
  IsDefaultSet | Gets or sets a value indicating whether this instance is default value set. the default value was explicitly set. True if it was explicitly set, otherwise false.
  IsIndexSet | Gets or sets a value indicating if the index was explicitly set. True if it was explicitly set, otherwise false.
  IsNameSet | Gets or sets a value indicating if the name was explicitly set. True if it was explicity set, otherwise false.
  IsOptional | Gets or sets a value indicating if a field is optional.
  Member | Gets the ``System.Reflection.MemberInfo`` that the data is associated with.
  NameIndex | Gets or sets the index of the name. This is used if there are multiple columns with the same names.
  Names | Gets the list of column names.
  ReadingConvertExpression | Gets or sets the expression used to convert data in the row to the member.
  TypeConverter | Gets or sets the type converter.
  TypeConverterOptions | Gets or sets the type converter options.
  ValidateExpression | Gets or sets the expression use to validate a field.
  WritingConvertExpression | Gets or sets the expression to be used to convert the object to a field.
  