Multiple Row and Cell Selection

• Nov 13, 2018
• 9 minutes to read

The Grid Control supports single and multiple row/card selection in the GridView, BandedGridView, AdvBandedGridView, LayoutView, CardView and WinExplorerView. The GridView and BandedGridView additionally provide the multiple cell selection mode. This topic covers information on these modes and related API.

Online Video

DevExpress WinForms: Web Style Row Selection.

Single Row/Card Selection Mode

This is the default selection mode for all Views in which a row/card can only be focused (selected) one at a time.

The table below lists members that can be used to focus (select) records, access the currently focused record and respond to the focus movement.

Member	Description
ColumnView.FocusedRowHandle	Specifies the focused row handle. This property allows you to get the focused (selected) row/card. Assigning a value to this property focuses (selects) the specified row/card at a time.
ColumnView.FocusedRowChanged	Allows you to respond to a focus moving to another row.
ColumnView.SelectedRowsCount	In single row/card selection mode, returns 1.
ColumnView.GetSelectedRows	In single row/card selection mode, returns an array that contains a single element that identifies the focused row handle (ColumnView.FocusedRowHandle).

Multiple Row/Card Selection Mode

In this mode, multiple rows/cards can be selected at one time. By selecting rows, you visually mark them. You can then perform various operations on selected rows (copy to the Clipboard (as text), delete, drag, etc.).

By default, selected rows are painted using the same appearance settings as for the focused row, although it is possible to use different appearance settings to paint selected and focused rows. For the difference between focus and selection, see the Focused Row vs Selected Row subsection below.

To enable multiple row/card selection in all Views, set the ColumnViewOptionsSelection.MultiSelect property (accessible from the View’s ColumnView.OptionsSelection object) to true.

The GridView provides the additional GridOptionsSelection.MultiSelectMode property, with which you can select between two multiple row selection modes: GridMultiSelectMode.RowSelect (default) and GridMultiSelectMode.CheckBoxRowSelect.

In GridMultiSelectMode.RowSelect mode, an end-user can select rows with the keyboard and mouse.

In GridMultiSelectMode.CheckBoxRowSelect mode, the GridView displays an additional ‘Check’ column containing check boxes in each row. An end-user can toggle check boxes to change row selection. Row selection with the keyboard and mouse are also supported.

See the Multiple Row Selection via Built-In Check Column topic to learn more.

Focused Row vs Selected Row

The focused row/card is the row that accepts input from an end-user. There can only be one focused row in a View, regardless of selection mode. Compared to row focusing, row selection is only a visual feature designated for highlighting certain rows.

In multiple row/card selection mode, when an end-user focuses a new row with either the Arrow keyboard keys or using the mouse, then that row is selected (highlighted). When you focus a certain row in code (e.g., with the ColumnView.FocusedRowHandle property), this row is not automatically selected (highlighted). You can select/deselect the focused row in code when required. An end-user can also toggle the selected state for the focused row using the mouse and keyboard, as shown in the End-User Capabilities - Select Grid Rows and Cards topic.

The following images demonstrate the selected and deselected states for a focused row.

Focused Row is selected	The ColumnView.GetSelectedRows method will return three row handles, including the focused row handle.
Focused Row is deselected	The ColumnView.GetSelectedRows method will return two handles that correspond to selected rows. The focused row handle will not be included in the method’s resulting array.

The table below lists members used in working with selection.

Member	Description
ColumnView.SelectRow	Adds a row/card to the current selection.
GridView.SelectRows ColumnView.SelectRange	Adds a range of rows/cards to the selection.
ColumnView.UnselectRow	Removes a row/card from the current selection.
ColumnView.ClearSelection	Unselects any selected rows/cards.
ColumnView.FocusedRowHandle	Specifies the focused row handle. In this mode, the property does not allow you to select rows/cards.
ColumnView.SelectedRowsCount	Returns the number of currently selected rows.
ColumnView.GetSelectedRows	Returns an array of the handles of the selected rows.
ColumnView.SelectionChanged	Allows you to perform actions when the selection is changed.
BaseView.BeginSelection BaseView.EndSelection	This method pair prevents excessive updates when performing multiple successive selection modifications using code. See below.

Each time the selection is changed in multiple selection mode, the ColumnView.SelectionChanged event is generated. You can handle it to perform specific actions. To respond to row focus moving from one row to another (even when multiple selection mode is not used), you can handle the ColumnView.FocusedRowChanged event.

When you make multiple successive calls to the methods that change selection, it is best to wrap such calls in calls to the BaseView.BeginSelection/BaseView.EndSelection methods. This prevents the ColumnView.SelectionChanged event from being fired repeatedly, and thus improves your application’s performance. See the Batch Modifications Overview topic for more information.

Multiple Cell Selection Mode

This selection mode, supported by GridView and BandedGridView, allows an end-user to select contiguous blocks of cells as well as individual cells within different rows. Multiple rows can also be selected in their entirety, for instance, by clicking the Row Indicator Panel.

To enable multiple cell selection mode, set the ColumnViewOptionsSelection.MultiSelect property to true and the GridOptionsSelection.MultiSelectMode property to GridMultiSelectMode.CellSelect.

Similar to the previous selection mode, in this mode, the focused row can be in the selected and deselected state.

The following table lists the methods to select/unselect cells.

Member	Description
GridView.SelectCell	Selects a specific cell.
GridView.SelectCells	Selects a range of cells.
ColumnView.SelectAll	Selects all rows/cards within the View.
GridView.UnselectCell	Removes the specified cell from the current selection.
GridView.UnSelectCells	Removes the specified block of cells from the selection.
GridView.GetSelectedCells	Returns selected cells.
ColumnView.GetSelectedRows	Returns the handles of the rows that contain the selected cells.

Also, see the list of methods for working with the selection provided in the previous section. When applied in multiple cell selection mode, these methods will affect all cells that belong to the specified row(s).

Common Methods to Work with Selection and Rows

Member	Description
BaseView.CopyToClipboard	Copies the focused or selected record(s) to the Clipboard as text.
ColumnView.DeleteRow	Deletes a specific row/card.
ColumnView.DeleteSelectedRows	Deletes the focused or selected rows.
ColumnView.GetRow	Returns an object that represents a specified row.
ColumnView.GetDataRow	Returns a DataRow object that represents a specified row.
ColumnView.GetRowCellValue ColumnView.GetFocusedRowCellValue	Gets the value in a row’s field.
ColumnView.GetRowCellDisplayText ColumnView.GetFocusedRowCellDisplayText	Gets the text representation of a row’s value.
ColumnView.SetRowCellValue ColumnView.SetFocusedRowCellValue	Assigns a value to a row’s cell.

End-User Capabilities

An end-user can select rows/cards and cells with a mouse and keyboard. Please refer to the End-user Capabilities.Selecting Rows topic for more details.

Appearance Settings

By default, selected and focused rows are painted using the same appearance settings. To customize them, use the following properties that are available using a View’s Appearance object (GridView.Appearance, CardView.Appearance, etc.).

Member	Description
GridViewAppearances.FocusedRow	Contains appearance settings used to paint the currently focused row.
GridViewAppearances.SelectedRow	Contains the appearance settings used to paint the selected rows.
GridViewAppearances.HideSelectionRow	Contains the appearance settings used to paint the selected rows when the grid control is not focused.
CardViewAppearances.FocusedCardCaption	Contains the appearance settings used to paint the caption of the focused card.
CardViewAppearances.SelectedCardCaption	Contains the appearance settings used to paint the captions of selected cards.
CardViewAppearances.HideSelectionCardCaption	Contains the appearance settings used to paint the captions of selected cards when the grid control is not focused.

In specific instances, you may need to prevent the focused row from being highlighted in the GridView or its descendant. To do this, set the GridOptionsSelection.EnableAppearanceFocusedRow property to false. The coloring of a focused cell can be disabled using the GridOptionsSelection.EnableAppearanceFocusedCell option.

To prevent selected rows from being highlighted in a specific manner when the grid control is not focused, use the GridOptionsSelection.EnableAppearanceHideSelection property.

Example - Obtain the Selected Rows

This example demonstrates how to obtain selected rows and then change their field values. The handles of selected rows are retrieved by the ColumnView.GetSelectedRows method. Since row handles reflect the order in which rows are displayed within a View, modifying a single row may affect the handles of other rows (e.g., if data is sorted and/or filtered). To prevent possible data corruption, a target row is modified using an underlying record object (in this example, a DataRow object). DataRows that correspond to selected rows are retrieved using the ColumnView.GetDataRow method and are stored in an array prior to data modification.

Bear in mind that when updating multiple rows, Grid View is updated after every row modification. So, to prevent unnecessary updates, you should enclose your code within calls to the BaseView.BeginUpdate and BaseView.EndUpdate methods. Refer to the Batch Modifications Overview document for details.

C#

// Create an empty list.
ArrayList rows = new ArrayList();
// Add the selected rows to the list.
for (int i = 0; i < gridView1.SelectedRowsCount; i++) {
   if (gridView1.GetSelectedRows()[i] >= 0)
      rows.Add(gridView1.GetDataRow(gridView1.GetSelectedRows()[i]));
}
try {
   gridView1.BeginUpdate();
   for (int i = 0; i < rows.Count; i++) {
      DataRow row = rows[i] as DataRow;
      // Change the field value.
      row["Discontinued"] = true;                             
   }
}
finally {
   gridView1.EndUpdate();
}      

VB.NET

' Create an empty list.
Dim Rows As New ArrayList()
' Add the selected rows to the list.
Dim I As Integer
For I = 0 To GridView1.SelectedRowsCount() - 1
   If (GridView1.GetSelectedRows()(I) >= 0) Then 
     Rows.Add(GridView1.GetDataRow(GridView1.GetSelectedRows()(I)))
   End If
Next
Try
   GridView1.BeginUpdate()
   For I = 0 To Rows.Count - 1
      Dim Row As DataRow = CType(Rows(I), DataRow)
      ' Change the field value.
      Row("Discontinued") = True
   Next
Finally
   GridView1.EndUpdate()
End Try

Example - Highlight the Entire Focused Row

This example shows how to paint the focused cell using the same appearance as the entire focused row:

To prevent the focused cell from being highlighted, set the GridOptionsSelection.EnableAppearanceFocusedCell property to false. To prevent the dotted focus rectangle from being painted around the focused cell, use the GridView.FocusRectStyle property.

C#

// Make the grid read-only.
gridView1.OptionsBehavior.Editable = false;
// Prevent the focused cell from being highlighted.
gridView1.OptionsSelection.EnableAppearanceFocusedCell = false;
// Draw a dotted focus rectangle around the entire row.
gridView1.FocusRectStyle = DevExpress.XtraGrid.Views.Grid.DrawFocusRectStyle.RowFocus;

VB.NET

' Make the grid read-only.
gridView1.OptionsBehavior.Editable = False
' Prevent the focused cell from being highlighted.
gridView1.OptionsSelection.EnableAppearanceFocusedCell = False
' Draw a dotted focus rectangle around the entire row.
gridView1.FocusRectStyle = DevExpress.XtraGrid.Views.Grid.DrawFocusRectStyle.RowFocus