Cell Styles

Cell customisation is done a the column level via the column definition. You can mix and match any of the following mechanisms:

  • Cell Style: Providing a CSS style for the cells.
  • Cell Class: Providing a CSS class for the cells.
  • Cell Class Rules: Providing rules for applying CSS classes.

Each of these approaches are presented in the following sections.

Cell Style

Used to provide CSS styles directly (not using a class) to the cell. Can be either an object of CSS styles, or a function returning an object of CSS styles.

// return same style for each row var colDef = { name: 'Static Styles', field: 'field1', cellStyle: {color: 'red', 'background-color': 'green'} } // return different styles for each row var colDef = { name: 'Dynamic Styles', field: 'field2', cellStyle: function(params) { if (params.value=='Police') { //mark police cells as red return {color: 'red', backgroundColor: 'green'}; } else { return null; } } }

Cell Class

Provides a class for the cells in this column. Can be a string (a class), array of strings (array of classes), or a function (that returns a string or an array of strings).

// return same class for each row var colDef1 = { name: 'Static Class', field: 'field1', cellClass: 'my-class' } // return same array of classes for each row var colDef2 = { name: 'Static Array of Classes', field: 'field2', cellClass: ['my-class1','my-class2'] } // return class based on function var colDef3 = { name: 'Function Returns String', field: 'field3', cellClass: function(params) { return (params.value==='something'?'my-class-1':'my-class-2'); } } // return array of classes based on function var colDef4 = { name: 'Function Returns Array', field: 'field4', cellClass: function(params) { return ['my-class-1','my-class-2']; } }

Cell Class Rules

You can define rules which can be applied to include certain CSS classes via via colDef.cellClassRules. These rules are provided as a JavaScript map where the keys are the class names and the values are expressions that if evaluated to true, the class gets used. The expression can either be a JavaScript function, or a string which is treated as a shorthand for a function by the grid.

The following snippet is cellClassRules using functions on a year column:

cellClassRules: { // apply green to 2008 'rag-green-outer': function(params) { return params.value === 2008}, // apply amber 2004 'rag-amber-outer': function(params) { return params.value === 2004}, // apply red to 2000 'rag-red-outer': function(params) { return params.value === 2000} }

Cell Style, Cell Class & Cell Class Rules Params

All cellClass cellStyle and cellClassRules functions take a params object that implements the following interface:

interface CellClassParams { // The value to be rendered. value: any, // The row (from the rowData array, where value was taken) been rendered. data: any, // The node associated to this row node: RowNode, // The colDef been rendered colDef: ColDef, // The index of the row about to be rendered rowIndex: number, // If compiling to Angular, is the row's child scope, otherwise null. $scope: any, // A reference to the ag-Grid API. api: GridApi, // If provided in gridOptions, a context object context: any, }

As an alternative, you can also provide shorthands of the functions using an expression. The column Age in the example uses expressions. An expression is evaluated by the grid by executing the string as if it were a Javascript expression. The expression has the following attributes available to it (mapping the the attributes of the equivalent params object):

  • x: maps value
  • ctx: maps context
  • node: maps node
  • data: maps data
  • colDef: maps colDef
  • rowIndex: maps rowIndex
  • api: maps api

In other words, x and ctx map value and context, all other attributes map the parameters of the same name.

The following snippet is cellClassRules using expressions on an age column:

cellClassRules: { 'rag-green': 'x < 20', 'rag-amber': 'x >= 20 && x < 25', 'rag-red': 'x >= 25' }

Refresh of Styles

If you refresh a cell, or a cell is updated due to editing, the cellStyle, cellClass and cellClassRules are all applied again. This has the following effect:

  • cellStyle: All new styles are applied. If a new style is the same as an old style, the new style overwrites the old style. If a new style is not present, the old style is left (the grid will NOT remove styles).
  • cellClass: All new classes are applied. Old classes are not removed so be aware that classes will accumulate. If you want to remove old classes, then use cellClassRules.
  • cellClassRules: Rules that return true will have the class applied the second time. Rules that return false will have the class removed second time.

If you are using cellStyle to highlight changing data, then please take note that grid will not remove styles. For example if you are setting text color to 'red' for a condition, then you should explicitly set it back to default eg 'black' when the condition is not met. Otherwise the highlight will remain once it's first applied.

// unsafe, the red will stay after initially applied cellStyle: params => params.value > 80 ? {color: 'red'} : null // safe, to black will override the red when the condition is not true cellStyle: params => params.value > 80 ? {color: 'red'} : {color: 'black'}

Example Cell Styling

Below shows both cssClassRules snippets above in a full working example. The example demonstrates the following:

  • Age uses cellClassRules with expressions (strings instead of functions). Editing the cell will update the style.
  • Year uses cellClassRules with functions. Editing the cell will update the style.
  • Date and Sport use cellClass, Date sets explicitly, Sport sets using a function. Because a function is used for Sport, it can select class based on data value. Editing Sport will have undetermined results as the class values will accumulate.
  • Gold sets cellStyle implicitly. It is not dependent on the cell value.
  • Silver and Bronze set cellStyle using a function and depends on the value. Editing will update the cellStyle.