![]() ![]() If you edit a cells value, then the aggregate value at the group level is also updated to reflect the change. Notice the following:Ĭolumn 'Group' is marked as a Row Group and columns A to D are marked as Aggregation columns so that their values are summed into the group level.Ĭolumn 'Total' has a valueGetter which gives a sum of all columns A to D.Ĭolumns A to D are editable. The grid is doing all the refresh by itself with no need for the client application explicitly requesting a refresh. The example below shows change detection impacting the result of groups. So for example, if you are grouping by a column and summing by a value, and one of those values change, then the summed value should also change. Aggregation Change DetectionĪggregation change detection means rerunning aggregations when a value changes. To manually run Value Change Detection to refresh all visible cells call api.refreshCells(). One thing that may entice you to turn it off is if you have some custom Value Getters or Cell Class Rules that areĭoing some time intensive calculations, you may want limit the number of times they are called and have more ![]() Ideally you should not want to turn off change detection, however the option is there if you choose to turn it off. This will stop the change detection process firing when the above events happen. If you do not want change detection to be automatically done, then set the grid property Using the api.applyTransaction(transaction) API method.Using the tDataValue(col,value) Row Node method.double clicking a cell and entering a new value). Editing any value via the grid UI (e.g.The following operations will automatically trigger change detection on all visible cells: const gridOptions = Triggering Value Change Detection For example, the following code snippet provides custom comparison to a 'Name' column where the name is stored in a complex object. If you do need to provide custom comparison of objects, use the colDef.equals(val1,val2) method. If your row data attributes are simple types (string, boolean, number) or immutable objects you don't need to implement your own comparison method. If using mutable objects (data has changed but it's the same object reference), then you will need to override how the value's are compared. This will be a problem for mutable objects as object references will be used for comparison which won't detect internal changes in the object. This will work most of the time for you, especially if your values are simple types (string, number, boolean) or immutable objects. This is of interest if you want to compare values in a different way.īy default the grid will compare values by using triple equals, eg "oldValue = newValue". This section explains how the grid compares values. AG Grid minimises the DOM updates by only updating the DOM where changes are detected. What AG Grid does is similar to the change detection algorithms in frameworks.ĭoing this many checks in JavaScript is not a problem. ![]() You might ask, is checking every cell against its value a performance problem? The answer is no. This means the grid will automatically keep aggregation results (the values in the grouped row) up to date as the data beneath it changes. This allows all cells using valueGetters to be kept up to date where a change to one cell (that was edited) may impact the value of another cell (that references the first cell).Īggregation Change Detection: When a value for any cell changes, the grid will recalculate all aggregations that are impacted by the changed value. If the values differ, the cell is refreshed. after an edit), the grid goes through every cell in the grid and compares the current value to the previous value. Value Change Detection: When a value for any cell changes (e.g. When a value in the grid changes, either via the UI or via the grid API, the grid will check all cells to see which ones need updating and update only those cells, so minimal changes are made to the DOM.Ĭhange detection can be broken down into the following two categories: ![]()
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