UI Customization

Custom Thumbnails

View Demo

The FileManager widget allows you to provide custom thumbnails for a file system's items in Thumbnails mode.

DevExtreme FileManager - Custom Thumbnails

Handle the customizeThumbnail function to specify which icons the widget should display for files and folders. This function returns different icons based on a file system item's type (file or folder), extension, or other parameters.

You can specify an icon in the following formats:

  • The icon's URL.
  • The icon's name if the icon is from the DevExtreme icon library.
  • The icon's CSS class if the icon is from an external icon library (see External Icon Libraries).
  • The icon in the Base64 format.
jQuery
JavaScript
$(function () {
    $("#file-manager").dxFileManager({
        // ...
        itemView: {
            mode: "thumbnails"
        },
        customizeThumbnail: function (fileManagerItem) {
            if (fileManagerItem.isDirectory)
                return "images/thumbnails/folder.svg";
            var fileExtension = fileManagerItem.getExtension();
            switch (fileExtension) {
                case ".txt":
                    return "images/thumbnails/doc-txt.svg";
                case ".rtf":
                    return "images/thumbnails/doc-rtf.svg";
                case ".xml":
                    return "images/thumbnails/doc-xml.svg";
            }
        }
    });
}); 
Angular
app.component.ts
app.component.html
import { DxFileManagerModule } from 'devextreme-angular';    
// ...
export class AppComponent {
    // ...
    customizeIcon(fileManagerItem) {
        if (fileManagerItem.isDirectory)
            return "images/thumbnails/folder.svg";
        const fileExtension = fileManagerItem.getExtension();
        switch (fileExtension) {
            case ".txt":
                return "images/thumbnails/doc-txt.svg";
            case ".rtf":
                return "images/thumbnails/doc-rtf.svg";
            case ".xml":
                return "images/thumbnails/doc-xml.svg";
        }
    }
}
<dx-file-manager id="fileManager"
    [fileSystemProvider]="fileItems"
    [customizeThumbnail]="customizeIcon" >
    <dxo-item-view
        mode="thumbnails">
    </dxo-item-view>
    <!-- ... -->    
</dx-file-manager>
Vue
App.vue
<template>
    <DxFileManager            
        :customize-thumbnail="customizeIcon">
        <DxItemView mode="thumbnails"/>
        <!-- ... -->
    </DxFileManager>
</template>
<script>
import { DxFileManager, DxItemView } from 'devextreme-vue/file-manager';
export default {  
    methods: {
        customizeIcon(fileManagerItem) {
            if (fileManagerItem.isDirectory)
                return 'images/thumbnails/folder.svg';
            const fileExtension = fileManagerItem.getExtension();
            switch (fileExtension) {
                case '.txt':
                    return 'images/thumbnails/doc-txt.svg';
                case '.rtf':
                    return 'images/thumbnails/doc-rtf.svg';
                case '.xml':
                    return 'images/thumbnails/doc-xml.svg';
            }
        }
    }
};
</script>
React
App.js
import React from 'react';
import FileManager, { ItemView } from 'devextreme-react/file-manager';
class App extends React.Component {
    render() {
        return (
        <FileManager
            customizeThumbnail={this.customizeIcon}>
            <ItemView
                mode="thumbnails"
            />
            {/* ... */}
        </FileManager>
        );
    }
    customizeIcon(fileManagerItem) {
        if (fileManagerItem.isDirectory)
            return 'images/thumbnails/folder.svg';
        const fileExtension = fileManagerItem.getExtension();
        switch (fileExtension) {
            case '.txt':
                return 'images/thumbnails/doc-txt.svg';
            case '.rtf':
                return 'images/thumbnails/doc-rtf.svg';
            case '.xml':
                return 'images/thumbnails/doc-xml.svg';
        }
    }
}