WebDocumentViewerClientSideEventsBuilder.BeforeRender(String) Method
Specifies the JavaScript function that handles the client-side BeforeRender event.
Namespace: DevExpress.AspNetCore.Reporting.WebDocumentViewer
Assembly:
DevExpress.AspNetCore.Reporting.v20.2.dll
NuGet Package:
DevExpress.AspNetCore.Reporting
Declaration
public WebDocumentViewerClientSideEventsBuilder BeforeRender(
string callback
)
Public Function BeforeRender(
callback As String
) As WebDocumentViewerClientSideEventsBuilder
Parameters
Name |
Type |
Description |
callback |
String |
The name of a JavaScript function or entire JavaScript function code that runs when the BeforeRender event occurs.
|
Returns
Handle the BeforeRender event to customize the Web Document Viewer’s View Model before it is bound to an HTML element and/or Knockout binding is activated.
The handler function receives two parameters. The first parameter is the object that exposes the IPreviewModel interface (or the JSReportViewer object). The second is the Document Viewer model that allows you to adjust the control’s settings.
The following code snippet sets the zoom level to 25%, enables multi-page mode, and indicates the moment when the first page is loaded:
<div id="loader"> <div id="loaderText" > </div> </div>
<script type="text/javascript" id="script" >
function onBeforeRender(s, e) {
e.reportPreview.zoom(0.25);
e.reportPreview.showMultipagePreview(true);
$("#loaderText").text("Waiting for the first page..");
$("#loader").dialog({ title: "Document Viewer", hide: { delay: 1000 } });
//Get a property that contains the document's page information.
var pages = e.reportPreview.pages;
//Subscribe to property change.
var pagesSubscription = pages.subscribe(function (newValue) {
if (newValue.length > 0) {
$("#loader").dialog("close");
//Stop tracking changes.
pagesSubscription.dispose();
}
});}
</script>
@{
var viewerRender = Html.DevExpress().WebDocumentViewer("DocumentViewer")
.Height("1000px")
.ClientSideEvents(configure => configure.BeforeRender("onBeforeRender"))
.Bind("TestReport");
@viewerRender.RenderHtml()
}
report-viewer.html
<div>
<dx-report-viewer [reportUrl]="reportUrl" height="800px">
<dxrv-request-options [invokeAction]="invokeAction" [host]="hostUrl">
</dxrv-request-options>
<dxrv-callbacks (BeforeRender)="onBeforeRender($event)">
</dxrv-callbacks>
</dx-report-viewer>
</div>
report-viewer.ts
import { Component, Inject, ViewEncapsulation, ViewChild } from '@angular/core';
import { DxReportViewerComponent } from 'devexpress-reporting-angular';
@Component({
selector: 'report-viewer',
encapsulation: ViewEncapsulation.None,
//...
})
export class ReportViewerComponent {
@ViewChild(DxReportViewerComponent, { static: false }) viewer: DxReportViewerComponent;
reportUrl: string = "TestReport";
invokeAction: string = '/DXXRDV';
onBeforeRender(event) {
event.args.reportPreview.zoom(0.25);
event.args.reportPreview.showMultipagePreview(true);
alert("Page load starts...");
//Get a property that contains the document's page information.
var pages = event.args.reportPreview.pages;
//Subscribe to property change.
var pagesSubscription = pages.subscribe(function (newValue) {
if (newValue.length > 0) {
alert("First page is loaded.");
//Stop tracking changes.
pagesSubscription.dispose();
}
});
}
constructor(@Inject('BASE_URL') public hostUrl: string) { }
}
import React from 'react';
import ko from 'knockout';
import 'devexpress-reporting/dx-webdocumentviewer';
import './App.css';
class ReportViewer extends React.Component {
constructor(props) {
super(props);
this.reportUrl = ko.observable("TestReport");
this.previewModel = ko.observable();
this.requestOptions = {
// Specify the backend ASP.NET Core application URL.
host: "https://localhost:44370",
invokeAction: "/DXXRDV"
};
this.callbacks = {
BeforeRender: function(s, e){
e.reportPreview.zoom(0.25);
e.reportPreview.showMultipagePreview(true);
alert ("Page load starts...");
//Get a property that contains the document's page information.
var pages = e.reportPreview.pages;
//Subscribe to property change.
var pagesSubscription = pages.subscribe(function (newValue) {
if (newValue.length > 0) {
alert ("First page is loaded.");
//Stop tracking changes.
pagesSubscription.dispose();
}
});}
}
};
};
render() {
return (
<div>
<div ref="viewer" data-bind="dxReportViewer: $data" style={{ width: "100%", height: "900px" }}></div>
</div>
);
}
componentDidMount() {
ko.applyBindings({
reportUrl: this.reportUrl,
viewerModel: this.previewModel,
requestOptions: this.requestOptions,
callbacks: this.callbacks
}, this.refs.viewer);
}
componentWillUnmount() {
ko.cleanNode(this.refs.viewer);
}
};
function App() {
return (<div style={{ width: "100%", height: "1000px" }}>
<ReportViewer />
</div>);
}
export default App;
<template>
<div>
<div ref="viewer" style="position: absolute; left: 0; right: 0" data-bind="dxReportViewer: $data">
</div>
</div>
</template>
<script>
import ko from "knockout";
import 'devexpress-reporting/dx-webdocumentviewer';
export default {
name: "WebDocumentViewer",
data() {
return {
previewModel: ko.observable(),
}
},
mounted() {
var reportUrl = ko.observable("TestReport");
var requestOptions = {
// Specify the backend application URL.
host: "https://localhost:44370/",
// Use this line if you use an ASP.NET MVC backend
//invokeAction: "/WebDocumentViewer/Invoke",
// Use this line if you use an ASP.NET Core backend
invokeAction: "DXXRDV"
};
var callbacks = {
BeforeRender: function(s, e){
e.reportPreview.zoom(0.25);
e.reportPreview.showMultipagePreview(true);
alert ("Page load starts...");
//Get a property that contains the document's page information.
var pages = e.reportPreview.pages;
//Subscribe to property change.
var pagesSubscription = pages.subscribe(function (newValue) {
if (newValue.length > 0) {
alert ("First page is loaded.");
//Stop tracking changes.
pagesSubscription.dispose();
}
});}
};
ko.applyBindings({
reportUrl: reportUrl,
viewerModel: this.previewModel,
requestOptions: requestOptions,
callbacks: callbacks
}, this.$refs.viewer);
},
beforeDestroy() {
ko.cleanNode(this.$refs.viewer);
}
};
</script>
See Also