Update README

README.md

@@ -3,17 +3,19 @@
 [![](https://img.shields.io/badge/Open_in_DevExpress_Support_Center-FF7200?style=flat-square&logo=DevExpress&logoColor=white)](https://supportcenter.devexpress.com/ticket/details/T1202789)
 [![](https://img.shields.io/badge/📖_How_to_use_DevExpress_Examples-e9f6fc?style=flat-square)](https://docs.devexpress.com/GeneralInformation/403183)
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-# DevExtreme Examples Template
+# DataGrid for DevExtreme - How to Validate Unchanged Cells
 
-This is the repository template for creating new examples. 
+This example demonstrates how to validate unchanged cells in the DataGrid component on button click. To implement this functionality, define the `validateVisibleRows` function:
 
-Use **_Product_ for DevExtreme - _Task_** template for a title. 
+1. To trigger DataGrid [changes](https://js.devexpress.com/Documentation/ApiReference/UI_Components/dxDataGrid/Configuration/editing/changes/), map an array of all [visible rows](https://js.devexpress.com/Documentation/ApiReference/UI_Components/dxDataGrid/Methods/#getVisibleRows) into change objects and assign it to the changes property.
 
-Describe the solved task in this section.
+2. [Repaint](https://js.devexpress.com/Documentation/ApiReference/UI_Components/dxDataGrid/Methods/#repaint) DataGrid.
 
-Put a screenshot/gif that illustrates the result here.
+3. Use **private** `getController` method to validate unchanged cells.
 
-Then, add implementation details (steps, code snippets, and other technical information in a free form), or add a link to an existing document with implementation details. 
+![DataGrid with validated unchanged cells](/data-grid-validate-unchanged-cells.png)
+
+If you want to validate unchanged cells after DataGrid is loaded, you can call the `validateVisibleRows` function in the [onContentReady](https://js.devexpress.com/Documentation/ApiReference/UI_Components/dxDataGrid/Configuration/#onContentReady) event handler.
 
 ## Files to Review
 
@@ -31,12 +33,6 @@ Then, add implementation details (steps, code snippets, and other technical info
 
 ## Documentation
 
-- link
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-## More Examples
-
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+- [editing.changes](https://js.devexpress.com/Documentation/ApiReference/UI_Components/dxDataGrid/Configuration/editing/changes/)
+- [getVisibleRows()](https://js.devexpress.com/Documentation/ApiReference/UI_Components/dxDataGrid/Methods/#getVisibleRows)
+- [onContentReady](https://js.devexpress.com/Documentation/ApiReference/UI_Components/dxDataGrid/Configuration/#onContentReady)