EPPlus can group rows and columns and add buttons to expand or collapse the groups.

Grouping of rows and columns is set by the `OutlineLevel` property. EPPlus 6.1 provides several new methods to group and expand and collapse rows and columns.

| Member | Description |
| --- | --- |
| `OutlineLevel` | A property indicating the level of grouping for the row or column. |
| `Collapsed` | A property indicating the the row/colmns children are collapsed. Setting this property will not hide the children. Use the `CollapseChildren()` or SetVisibleOutlineLevel() methods to collapse and hide columns/rows. |
| `Group()` | Groups rows or columns together. Adds one to `OutlineLevel` property from 1-8 |
| `Ungroup()` | Ungroups rows or columns. Subtracts one from `OutlineLevel` property |
| `CollapseChildren(bool)` | Collapses and hides the children of the row/columns. If the first parameter is true all children will be collapsed and hidden, otherwise only the children on the level below will be collapsed, |
| `ExpandChildren(bool)` | Expands and shows the children of the row/columns.If the first parameter is true all children will be collapsed and hidden, otherwise only the children on the level to the right will be collapsed, |
| `SetVisibleOutlineLevel(int)` | Sets the visible level for a range of rows/columns |
| `SetVisibleOutlineLevel(int,bool)` | Sets the visible level for a range of rows/columns. The second parameter sets if row/column lower than the visible level should be collapsed or left as is. |

The outline can also be set to be on top or bellow a group of rows or to the left or right of a group of columns. This is set by the following methods on the `ExcelWorksheet` |Member|Description| |------|------------| |`OutLineSummaryBelow`|If true the expand/collapse buttons are below the row group, otherwise on-top. |`OutLineSummaryRight`|If true the expand/collapse buttons are to the right of the column group, otherwise to the left.

Sample:

```csharp
  worksheet.OutLineSummaryBelow = false;

  worksheet.Rows[1, 15].Group();
  worksheet.Rows[2, 15].Group();
  worksheet.Rows[4, 15].Group();
  worksheet.Rows[11, 12].Group();
  worksheet.Rows[14, 15].Group();

  worksheet.Cells["A3"].EntireRow.CollapseChildren(true); //Collapses the children rows of row 3. True means sub levels are also collapsed.
```

```vbnet
worksheet.OutLineSummaryBelow = False

worksheet.Rows(1, 15).Group()
worksheet.Rows(2, 15).Group()
worksheet.Rows(4, 15).Group()
worksheet.Rows(11, 12).Group()
worksheet.Rows(14, 15).Group()

worksheet.Cells("A3").EntireRow.CollapseChildren(True) 'Collapses the children rows of row 3. True means sub levels are also collapsed.
```

### See also

- Group/Ungroup is used in our [Sample 3.4 (C\#)](<https://github.com/EPPlusSoftware/EPPlus.Samples.CSharp/tree/master/03-Styling/04-Create a file system report>) and [Sample 3.4 (VB)](<https://github.com/EPPlusSoftware/EPPlus.Samples.VB/blob/master/03-Styling/04-Create a file system report/Readme.md>)