Specify a file's GUID

Use the valueChanged event to generate a unique identifier (GUID) for a file before it is uploaded and pass it as a parameter to the upload URL.

See Also: DataGrid - How to use FileUploader as a cell editor.

jQuery
index.js
$(function () {
    $("#{file-uploader}Container").dxFileUploader({
        multiple: false,
        accept: "*",
        value: [],
        uploadMode: "instantly",
        uploadUrl: "https://js.devexpress.com/Demos/NetCore/FileUploader/Upload",
        onValueChanged: function (e) {
            var url = e.component.option("uploadUrl");
            url = updateQueryStringParameter(url, "fileGuid", uuidv4());
            e.component.option("uploadUrl", url);
        }
    })
    .dxFileUploader("instance");
});
function updateQueryStringParameter(uri, key, value) {
    var re = new RegExp("([?&])" + key + "=.*?(&|$)", "i");
    var separator = uri.indexOf("?") !== -1 ? "&" : "?";
    if (uri.match(re)) {
        return uri.replace(re, "$1" + key + "=" + value + "$2");
    } else {
        return uri + separator + key + "=" + value;
    }
}
function uuidv4() {
    return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, function (c) {
        var r = (Math.random() * 16) | 0,
        v = c == "x" ? r : (r & 0x3) | 0x8;
        return v.toString(16);
    });
}
Angular
app.component.html
app.component.ts
<dx-file-uploader
    [(uploadUrl)]="uploadUrl"
    [multiple]="false"
    uploadMode="instantly"
    (onValueChanged)="onValueChanged($event)">
</dx-file-uploader>
import { Component, NgModule } from '@angular/core';
import { BrowserModule } from "@angular/platform-browser";
import { DxFileUploaderModule } from "devextreme-angular";

@Component({
    selector: 'app-root',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.css']
})
export class AppComponent {
    value: any[] = [];
    uploadUrl: string = "https://js.devexpress.com/Demos/NetCore/FileUploader/Upload";
    onValueChanged(e) {
        this.uploadUrl = this.updateQueryStringParameter("fileGuid", this.uuidv4());
    }
    updateQueryStringParameter(key, value) {
        var re = new RegExp("([?&])" + key + "=.*?(&|$)", "i");
        var separator = this.uploadUrl.indexOf("?") !== -1 ? "&" : "?";
        if (this.uploadUrl.match(re)) {
            return this.uploadUrl.replace(re, "$1" + key + "=" + value + "$2");
        } else {
            return this.uploadUrl + separator + key + "=" + value;
        }
    }
    //https://stackoverflow.com/questions/105034/how-to-create-guid-uuid
    uuidv4() {
        return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, function(c) {
        var r = (Math.random() * 16) | 0,
            v = c === "x" ? r : (r & 0x3) | 0x8;
        return v.toString(16);
        });
    }
}

@NgModule({
    imports: [BrowserModule, DxFileUploaderModule],
    declarations: [AppComponent],
    bootstrap: [AppComponent]
})
export class AppModule {}
Vue
App.vue
<template>
  <DxFileUploader
    :accept="accept"
    :multiple="multiple"
    :upload-mode="uploadMode"
    upload-url="https://js.devexpress.com/Demos/NetCore/FileUploader/Upload"
    @value-changed="onValueChanged($event)"
  />
</template>

<script>
import 'devextreme/dist/css/dx.common.css';
import 'devextreme/dist/css/dx.light.css';

import { DxFileUploader } from "devextreme-vue/file-uploader";

export default {
    components: {
        DxFileUploader
    },
    data() {            
        return {
            multiple: false,
            accept: "*",
            uploadMode: "instantly"
        };
    },
    methods: {
        onValueChanged(e) {
            var url = e.component.option("uploadUrl");
            url = this.updateQueryStringParameter(url, "fileGuid", this.uuidv4());
            e.component.option("uploadUrl", url);
        },
        updateQueryStringParameter(uri, key, value) {
            var re = new RegExp("([?&])" + key + "=.*?(&|$)", "i");
            var separator = uri.indexOf("?") !== -1 ? "&" : "?";
            if (uri.match(re)) {
                return uri.replace(re, "$1" + key + "=" + value + "$2");
            } else {
                return uri + separator + key + "=" + value;
            }
        },
        uuidv4() {
            return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, function(
                c
            ) {
                var r = (Math.random() * 16) | 0,
                v = c === "x" ? r : (r & 0x3) | 0x8;
                return v.toString(16);
            });
        }
    }
}
</script>
React
App.js
import React from 'react';

import 'devextreme/dist/css/dx.common.css';
import 'devextreme/dist/css/dx.light.css';

import FileUploader from "devextreme-react/file-uploader";

class App extends React.Component {
    constructor(props) {
        super(props);
        this.state = {
            multiple: false,
            uploadMode: "instantly",
            accept: "*",
            uploadUrl: "https://js.devexpress.com/Demos/NetCore/FileUploader/Upload"
        };

        this.onSelectedFilesChanged = this.onSelectedFilesChanged.bind(this);            
    }

render() {
    return (
        <div>
            <div className="widget-container">
            <FileUploader
                multiple={this.state.multiple}
                accept={this.state.accept}
                uploadMode={this.state.uploadMode}
                uploadUrl={this.state.uploadUrl}
                onValueChanged={this.onSelectedFilesChanged}
            />
            </div>
        </div>
    );
}
onSelectedFilesChanged(e) {
    this.setState({
        uploadUrl: this.updateQueryStringParameter("fileGuid", this.uuidv4())
    });
}
updateQueryStringParameter(key, value) {
    var re = new RegExp("([?&])" + key + "=.*?(&|$)", "i");
    var separator = this.state.uploadUrl.indexOf("?") !== -1 ? "&" : "?";
    if (this.state.uploadUrl.match(re)) {
        return this.state.uploadUrl.replace(re, "$1" + key + "=" + value + "$2");
    } else {
        return this.state.uploadUrl + separator + key + "=" + value;
    }
}    
uuidv4() {
    return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, function(c) {
    var r = (Math.random() * 16) | 0,
        v = c === "x" ? r : (r & 0x3) | 0x8;
    return v.toString(16);
    });
}

export default App;
ASP.NET MVC/Core Controls
@(Html.DevExtreme().FileUploader()
    .ID("file-uploader")
    .Name("myFile")
    .Multiple(false)
    .Accept("*")
    .UploadMode(FileUploadMode.Instantly)
    .UploadUrl(Url.Action("Upload", "FileUploader"))
    .OnValueChanged("fileUploader_valueChanged")
)
<script>
function fileUploader_valueChanged(e) {
    var url = e.component.option("uploadUrl");
    url = updateQueryStringParameter(url, "fileGuid", uuidv4());
    e.component.option("uploadUrl", url);
}
function updateQueryStringParameter(uri, key, value) {
    var re = new RegExp("([?&])" + key + "=.*?(&|$)", "i");
    var separator = uri.indexOf("?") !== -1 ? "&" : "?";
    if (uri.match(re)) {
        return uri.replace(re, "$1" + key + "=" + value + "$2");
    } else {
        return uri + separator + key + "=" + value;
    }
}
function uuidv4() {
    return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, function (c) {
        var r = (Math.random() * 16) | 0,
            v = c === "x" ? r : (r & 0x3) | 0x8;
        return v.toString(16);
    });
}
</script>