Update Readme.md

Author: ritazakhodyaeva

Readme.md

@@ -5,7 +5,9 @@
 
 # How to Add Custom Field Values (Rows/Columns) that are not Present in a Data Source
 
+Pivot Grid does not display field values in row and column areas if these values are not represented in the underlying data source. This example demonstrates how to create a data source wrapper that contains all required values on its level, and there is no need to modify original data source. In the example, the `CustomDates` collection is filled with DateTime values based on the actual Start/End DateTime range and the specified interval (for example, `Month`). This collection is passed to the `DateDataSourceWrapper` class instance along with the original data source collection (`Table.DefaultView`). `CustomDates` collection is merged with the original data table and you do not need to modify the data source. When Pivot Grid requests data with the common [IList](https://msdn.microsoft.com/en-us/library/system.collections.ilist(v=vs.110).aspx) and [ITypedList](https://msdn.microsoft.com/en-us/library/system.componentmodel.itypedlist(v=vs.110).aspx) interfaces methods, the `DateDataSourceWrapper` object returns data from the original collection or generates `EmptyObjectPropertyDescriptor` objects to return rows with null "Date" field values.
 
+The following image illustrates Pivot Grid that displays the custom `March` field value from the `CustomDates` collection along with field values from the data source:
 
 ![Pivot Grid - Custom Field Values](./images/custom-field-values.png)