How to make Data Table required, set field values based on other fields, and calculate total¶
In this article you can find examples of how to use JavaScript to work with Data Table control, and the various things you can do.
In order to access Data Table in JavaScript, you’ll need use fd.control(‘DataTableName’) method, which expects the name of a Data Table you want to work with. All fields and controls have the name property, which you can check in the editor:
Another thing to be aware of is that you shouldn’t simply place JavaScript inside the editor on its own, it must be executed inside fd events like rendered() or beforeSave() in order to actually access the fields or controls that you target.
If you just add these scripts on their own or inside wrong event in JavaScript editor, they will not have access to the specified fields, or will execute at the wrong time. Read more about different events in Manager section.
For more information on working with Data Table control specifically, please, refer to the Data Table section of our JS documentation.
Make Data Table record required¶
Sometimes, you just need to ensure that at least one record is added to the Data Table.
This can be achieved with a simple validator:
//make at least one record required
fd.rendered(function(){
fd.control('DataTable1').validators.push({
name: 'DataTable1 validator',
error: 'Enter at least one record into the table',
validate: function(value) {
//change this number to make more records required
if (value.length < 1) {
return false;
}
return true;
}
});
});
Note
You can adjust the number in the code to make more records required or add other conditions for a more complex validation.
Prepopulating column value for new row¶
To prepopulate column values of a new row in DataTable control, use the code:
fd.rendered(function() {
//select DataTable control to prepopulate
var dt = fd.control('DataTable1');
var isNew = false;
dt.widget.wrapper.find('.k-grid-add').on('click', e => {
isNew = true;
});
dt.widget.bind('edit', function(e) {
if (isNew) {
isNew = false;
//set values for Column1 and Column2
e.model.set('Column1', 'Item 2');
e.model.set('Column2', 'Item 3');
}
});
});
Populating Dropdown column options¶
To populate dropdown column of DataTable control dynamically, use the code:
fd.rendered(function() {
fd.control('DataTable1').$on('edit', function(e) {
console.log(e)
if (e.column.field === "Column1") {
//pass widget + current column value
console.log(e.model);
populateColumn(e.widget, e.model.Column1);
}
})
});
function populateColumn(widget, value) {
widget.setDataSource({
data: ['Category A', 'Category B', 'Category C']
});
//set value if one was select
widget.value(value);
}
Set fields based on other fields¶
Sometimes, you might want to set fields automatically, without direct user input:
For example, the product prices are not something a user should be able to change. Instead, they can be set dynamically, depending on the selected product.
We’ll use a simple JS Object to store product prices, and automatically set unit price on product selection. Here is the code:
//we store prices in JS object
var merch = {};
//use bracket notation to accurately copy dropdown values
merch['Baseball cap'] = 9.99;
merch['T-shirt'] = 19.99;
merch['Key chain'] = 4.99;
fd.rendered(function(){
//set unit price column (2nd column) to be non-editable, as we set it with code
fd.control('DataTable1').columns[1].editable = function(){return false};
fd.control('DataTable1').$on('change', function(value) {
console.log(value); // DataTable's value
if(value){
//these changes are not manual
manualChange = false;
for(var i = 0; i < value.length; i++){
value[i].UnitPrice = merch[value[i].Product];
}
//refresh to update all values
fd.control('DataTable1').widget.refresh()
}
});
});
Calculate total for a row and the whole table¶
Finally, we’re going to calculate total for a row, and for the whole Data Table.
Here is the code:
fd.rendered(function() {
//Disable OrderTotal field
fd.field('OrderTotal').disabled = true;
//Make LineTotal column noneditable
fd.control('DataTable1').columns[3].editable = function(){return false};
fd.control('DataTable1').$on('change', function(value) {
//variable to count Order Total
var orderTotal = 0.0;
//if there are records in the table
var isTableModified = false;
if(value){
//go through each one by one
for (var i = 0; i < value.length; i++){
//if this record has Amount and UnitPrice
if(value[i].Amount && value[i].UnitPrice){
//set LineTotal to their product
var cost = value[i].Amount * value[i].UnitPrice;
if (value[i].LineTotal != cost) {
value[i].LineTotal = cost;
isTableModified = true;
}
}
//add Total to the Order Total
orderTotal += parseFloat(value[i].LineTotal);
console.log(orderTotal);
}
}
//here we refresh the table
if (isTableModified) {
fd.control('DataTable1').widget.refresh();
}
//we set Order Total field to sum of Totals
fd.field('OrderTotal').value = orderTotal;
});
});
If you’re getting an incorrect value in one of your fields, for example, in OrderTotal, make sure that the format is correctly configured and an appropriate number of decimals is selected:
Add a button to duplicate row¶
You can add a button to DataTable rows, which will allow you to duplicate them, like this:
Use the following code:
fd.rendered(function() {
//select DataTable control to add new column to
var dt = fd.control('DataTable1');
var columns = dt.widget.options.columns;
var customRowDataItem = null;
var isCustomAdd = false;
//specify what the column will be like
columns.push({
command: {
text: "Copy row",
iconClass:"k-icon k-i-copy",
click: function(e) {
e.preventDefault();
customRowDataItem = this.dataItem($(e.currentTarget).closest("tr"));
isCustomAdd = true;
this.addRow();
}
}
});
dt.widget.setOptions({
columns: columns
});
dt.widget.bind('edit', function(e) {
if (isCustomAdd && e.model.isNew()) {
isCustomAdd = false;
for (var i = 0; i < columns.length; i++) {
var field = columns[i].field;
if (field) {
e.model.set(field, customRowDataItem[field]);
}
}
e.sender.closeCell(e.container);
}
});
});