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Intro
This example takes an existing workbook that contains some data and creates a PivotTable. The workbook used in this example is available for download: Download BasicExample.xlsx.
Before writing any PivotTable code, make sure to open the workbook with ExcelApplication
and get references to the data worksheet and a worksheet for the PivotTable. See Adding OfficeWriter to your .NET Application.
This example places the PivotTable on a separate sheet. It is recommended that each PivotTable be placed on a separate sheet.
Excel does not allow PivoTables to overlap and will use error messages to prevent users from creating overlapping PivotTables. ExcelWriter does not have the ability to render PivotTables, so it cannot detect if two PivotTables will overlap when they are rendered. To avoid this, we encourage you to keep your PivotTables on separate worksheets.
Writing the code
Step 1. Set up the data source
The data source needs to be a continuous block of cells with a header row with column names. The data source can be defined as an Area
or a NamedRange
.
Here is a snapshot of the data for this tutorial, which can also be found in BasicExample.xlsx:
There are 9 columns and 244 rows in the data set, including the row with the header values.
In this case, the data source for the PivotTable will be a dynamically defined area on the data worksheet. Note that the row of column names is included in the area.
Step 2. Create the PivotTable
To create a PivotTable
, call CreatePivotTable
on the PivotTables
collection. Specify the 0-indexed row and column values for the PivotTable location:
Step 3. Set PivotTable Options
In Excel, there are a number of options that can be set by going to PivotTable Options. These properties are available through PivotTableSettings
.
There are a couple properties that you should always consider when working with PivotTables with ExcelWriter.
Refresh On Open
After creating the PivotTable, always set RefreshOnOpen
to true
.
ExcelWriter does not have the ability to render a PivotTable, so any modifications made to a PivotTable will not take affect until the output file is opened in Excel and the PivotTable is refreshed. If RefreshOnOpen
is true
, Excel will refresh the PivotTable when the workbook opens, which will re-render the PivotTable.
ItemsToRetain
The other important property to set is ItemsToRetain
. When the PivotTable is created, the values that are available through the row label, column label, or page field drop-down filters are based on the values in the data source of the PivotTable at the time the PivotTable was created.
By default, the PivotTable will retain all the original values in those filters, even if those values are no longer in the data source. Set ItemsToRetain
to None
to make sure the original values are cleared out when the PivotTable is refreshed.
Step 4. Add PivotTableFields
There are four types of PivotTableField
: DataFields
, RowLabels
, ColumnLabels
, and PageFields
(also called report filters). PivotTableFields
are created from read-only SourceFields
, which are generated based on the PivotTable
data source.
Source Fields
Get a handle on the SourceFields
to use for building PivotTableFields
later.
PageFields
To add a PageField
, call CreateField
on the PivotTable.PageFields
collection. You will need to specify the SourceField
that will be used to create the PageField
.
RowLabels and ColumnLabels
Similarly to page fields, RowLabels
and ColumnLabels
are created on the PivotTable.RowLabels
and PivotTable.ColumnLabels
collections. As mentioned earlier, only one RowLabel
, ColumnLabel
, or PageField
can be created from a particular SourceField
.
Row labels and column labels display the subtotals for each group of values. The subtotal can be displayed at the top or bottom of the group.
Excel automatically sorts and re-renders a PivotTable any time a change is made. By default, the row label or column label values are sorted alpha-numerically in ascending order.
Since ExcelWriter does not have the ability to render PivotTables or sort the values for a field, the only way to guarantee that the data will be sorted is to set RefreshOnOpen
to true
and set SortOptions.Ordering
on a PivotTablefield
to be Ascending
or Descending
.
This property only affects row and column labels.
When Excel refreshes the PivotTable, it will observe the SortOptions
setting for a particular field.
DataFields
To create a data field, call CreateField
on the DataFields
collection. Unlike row labels, column labels, and page fields, multiple data fields can be created from the same source field.
In Excel, a unique name is given to the data field depending on the type of data in the source field (numerical or mixed), whether or not any other data fields were already created from the same source field, and whether the source field name ends in a number or alphabetical character (e.g. Case1 vs. CaseOne).
ExcelWriter uses a consistent naming convention when creating data fields: all data fields follow the format SOURCEFIELDNAME_#, where # is an incremental number starting at 1. To change the name of a data field, use the DisplayName
property.
The function used to aggregate the data can be specified through the summarize by property. If a column data contains just numbers, the function defaults to SUM. If the column contains mixed data, the function defaults to COUNT. There are other functions available.
A number format can be specified for all PivotTable fields, but it will only take affect on data fields and row labels/column labels/page fields that have numeric data only.
Completed Code
And that concludes how to create a basic PivotTable. Here is the full sample code below:
Additional Resources
- Templates and PivotTables - using PivotTables with ExcelTemplate
- Intro to PivotTables - Terminology from Excel
- Answers post on how to set properties that aren't available
- Using CopySheet with PivotTables