By default, once a user selects a row, the data source is instantly notified about it. This may lower the widget performance if the data source is remote and the user is allowed to select all rows at once. In this case, we recommend making the selection deferred.
If this option is set to true, it allows a user to select all rows at once by pressing Ctrl + A or clicking the check box in the selection column's header. The "Select All" check box also allows a user to deselect all rows. The select all functionality allows selecting/deselecting only those rows that meet filtering conditions if a filter is applied.
If this option is set to false, it disables the select all functionality. In this case, the check box clears selection and is hidden if no rows are selected.
Consider making selection deferred if the widget needs to operate a large volume of data and the user is allowed to select all rows at once. Unlike usual (or "instant") selection, in the case of deferred selection, the widget requests data only when you demand this using the API, for example, when the getSelectedRowsData() or getSelectedRowKeys() method is called. This mode has certain specifics that determine the API you need to use. For more information, see the Deferred Selection article.
The following selection modes are available in the widget:
Only one row can be in the selected state at a time.
Several rows can be in the selected state at a time.
SelectionMode enum to specify this option when the widget is used as an ASP.NET MVC 5 Control or a DevExtreme-Based ASP.NET Core Control. This enum accepts the following values:
Specifies the mode in which all the records are selected. Applies only if selection.allowSelectAll is true.
Selects records on currently rendered pages.NOTEThis mode is incompatible with deferred selection.
Selects records on all pages.
SelectAllMode enum to specify this option when the widget is used as an ASP.NET MVC 5 Control or a DevExtreme-Based ASP.NET Core Control. This enum accepts the following values:
Specifies when to display check boxes in rows. Applies only if selection.mode is "multiple".
The selection behavior in multiple mode depends on the check boxes' visibility. Selection is proper multiple only when check boxes are visible. In other cases, the selection behavior resembles the single mode: clicking (or tapping) a row selects it, but cancels the selection of other rows. However, a user still can select multiple rows in this mode using a click and hold, or long tap.
Check boxes can change their visibility state at runtime. The following list describes how they behave in different modes:
Check boxes appear once a user clicks anywhere in the selection column, or if two or more rows are selected programmatically or using keyboard shortcuts. Check boxes disappear once rows selection is canceled.
The selection column with all the check boxes appears and disappears on long tap, and on click and hold.
The selection column with all the check boxes is always visible. A user can select a row by clicking the check box or its grid cell, but not the row itself.
Check boxes are always hidden, which means that selection is always single-like in this mode.
Keyboard shortcuts work identically regardless of the chosen mode.
GridSelectionShowCheckBoxesMode enum to specify this option when the widget is used as an ASP.NET MVC 5 Control or a DevExtreme-Based ASP.NET Core Control. This enum accepts the following values: