Vue Data GridColumn State
Column Definitions contain both stateful and non-stateful attributes. Stateful attributes can have their values changed by the grid (e.g. Column sort can be changed by the user clicking on the column header). Non-stateful attributes do not change from what is set in the Column Definition (e.g. once the Header Name is set as part of a Column Definition, it typically does not change).
The DOM also has stateful vs non-stateful attributes. For example consider a DOM element and setting
element.style.width="100px"
will indefinitely set width to 100 pixels, the browser will not change this value.
However setting element.scrollTop=200
will set the scroll position, but the browser can change the scroll
position further following user interaction, thus scroll position is stateful as the browser can change
the state.
The full list of stateful attributes of Columns are represented by the ColumnStateParams
interface:
Properties available on the ColumnStateParams
interface.
| True if the column is hidden | |
| Width of the column in pixels | |
| Column's flex if flex is set | |
| Sort applied to the column | |
| The order of the sort, if sorting by many columns | |
| The aggregation function applied
| |
| True if pivot active | |
| The order of the pivot, if pivoting by many columns | |
| Set if column is pinned
| |
| True if row group active | |
| The order of the row group, if grouping by many columns |
This section details how such state items can be manipulated without having to update Column Definitions.
There are two API methods provided for getting and setting Column State. columnApi.getColumnState()
gets the current
column state and columnApi.applyColumnState(params)
sets the column state.
// save the column's state
const savedState = this.gridColumnApi.getColumnState();
// restore the column state
this.gridColumnApi.applyColumnState({ state: savedState });
The example below demonstrates saving and restoring column state. Try the following:
- Click 'Save State' to save the Column State.
- Change some column state e.g. resize columns, move columns around, apply column sorting or row grouping etc.
- Click 'Restore State' and the column's state is set back to where it was when you clicked 'Save State'.
- Click 'Reset State' and the state will go back to what was defined in the Column Definitions.
The Column State method interfaces are as follows:
| Gets the state of the columns. Typically used when saving column state.
| |
| Applies the state of the columns from a previous state. Returns false if one or more columns could not be found.
|
It is possible to focus on particular columns and / or particular attributes when getting and / or applying a Column State. This allows fine grained control over the Column State, e.g. setting what Columns are Pinned, without impacting any other state attribute.
When applying a Column State, in cases where some state attributes or columns are missing from the Column State, the following rules apply:
- If a Column State is missing attributes, or attributes are provided as
undefined
, then those missing / undefined attributes are not updated. For example if a Column has a Column State with justpinned
, then Pinned is applied to that Column but other attributes, such as Sort, are left intact. - When state is applied and there are additional Columns in the grid that do not appear in the provided state, then the
params.defaultState
is applied to those additional Columns. - If
params.defaultState
is not provided, then any additional Columns in the grid will not be updated.
Combining these rules together leaves for flexible fine grained state control. Take the following code snippets as examples:
// Sort Athlete column ascending
this.gridColumnApi.applyColumnState({
state: [
{
colId: 'athlete',
sort: 'asc'
}
]
});
// Sort Athlete column ascending and clear sort on all other columns
this.gridColumnApi.applyColumnState({
state: [
{
colId: 'athlete',
sort: 'asc'
}
],
defaultState: {
// important to say 'null' as undefined means 'do nothing'
sort: null
}
});
// Clear sorting on all columns, leave all other attributes untouched
this.gridColumnApi.applyColumnState({
defaultState: {
// important to say 'null' as undefined means 'do nothing'
sort: null
}
});
// Clear sorting, row group, pivot and pinned on all columns, leave all other attributes untouched
this.gridColumnApi.applyColumnState({
defaultState: {
// important to say 'null' as undefined means 'do nothing'
sort: null,
rowGroup: null,
pivot: null,
pinned: null
}
});
// Order columns, but do nothing else
this.gridColumnApi.applyColumnState({
state: [
{ colId: 'athlete' },
{ colId: 'country' },
{ colId: 'age' },
{ colId: 'sport' }
],
applyOrder: true
});
The example below shows some fine grained access to Column State.
Using the techniques above, it is possible to save and restore a subset of the parameters in the state. The example below demonstrates this by selectively saving and restoring a) sort state and b) column visibility and order state.
Note that when saving and restoring Sort state, other state attributes (width, row group, column order etc) are not impacted.
Likewise when saving and restoring visibility and order, only visibility and order will be impacted when re-applying the state.
There are a few items to note on specific state attributes. They are as follows:
For all state attributes, undefined
means "do not apply this attribute" and null
means "clear this attribute".
For example setting sort=null
will clear sort on a column whereas setting
sort=undefined
will leave whatever sort, if any, that is currently present.
The only exception is with regards to Column Width. For width, both undefined
and null
will skip the attribute. This is because width is mandatory - there
is no such thing as a Column with no width.
When Flex is active on a Column, the grid ignores the width
attribute when setting the width.
When getColumnState()
is called, both width
and flex
are returned.
When applyColumnState()
is called, if flex
is present then width
is ignored.
If you want to restore a Column's width to the exact same pixel width as specified in the Column State,
set flex=null
for that Column's state to turn Flex off.
There are two attributes representing both Row Group and Pivot. First using the boolean attributes
rowGroup
and pivot
and then secondly using the index attributes rowGroupIndex
and pivotIndex
.
When getColumnState()
is called, all of rowGroup
, pivot
,
rowGroupIndex
and pivotIndex
are returned. When
applyColumnState()
is called, preference is given to the index variants. For example
if both rowGroup
and rowGroupIndex
are present, rowGroupIndex
is applied.
Column Events will get raised when applying a Column State as these events would
normally get raised. For example columnPinned
event will get raised if applying
the state results in a column getting pinned or unpinned.
The example below demonstrates events getting raised based on Column State changes. The example logs event information to the console, so best open the example in a new tab and observe the dev console.
Column Group State is concerned with the state of Column Groups. There is only one state attribute for Column Groups, which is whether the group is open or closed.
To get the state of Column Groups use the API method columnApi.getColumnGroupState()
. To
set the Column Group state use the API method columnApi.setColumnGroupState(stateItems)
.
The example below demonstrates getting and setting Column Group State. Note the following:
- Clicking 'Save State' will save the opened / closed state of column groups.
- Clicking 'Restore State' will restore the previously saved state.
- Clicking 'Reset State' will reset the column state to match the Column Definitions, i.e. all Column Groups will be closed.