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Using PrintPreview as a Default ViewMode in the Web Report Designer


Product Version
Product Progress® Telerik® Reporting
Report Viewer Blazor


Currently, the report viewer's options of the Web Report designer are not exposed. For that reason, you need to use a custom logic to set the default viewMode.


In some of the upcoming releases, we will expose the viewer's options and you will be able to set them out of the box. For now, you need to use some custom code to set the default viewMode. Please, check the workaround below.

Suggested Workarounds

If you are using the pure HTML Web Report Designer (not the Blazor wrapper), you can use the follwoing piece of code after the initialization of the designer"

    // Second callback for mutationObserver will fire once WebReportDesigner is finished loading
    // This callback listenes for a click on the Preview button and triggers Print-preview mode while initialization of the ReportViewer
    const secondCallBack = function (mutationsList, observer) {
        $(".top-menu-area__button.-preview").on("click", () => requestAnimationFrame(() =>
            $("#webReportDesigner_preview").data("telerik_ReportViewer").bind(telerikReportViewer.Events.RENDERING_BEGIN, () => {
    // First callback waits for the loader HTML element to appear in the DOM, then creates a new MutationObserver for the loader
    const firstCallback = function (mutationsList, observer) {
        new MutationObserver(secondCallBack).observe(document.getElementsByClassName('twd-loader')[0], { attributes: true });
    // Inital setup of the first MutationObserver
    const targetNode = document.getElementById('webReportDesigner');
    new MutationObserver(firstCallback).observe(targetNode, { childList: true });
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